Wikipedia talk:WikiProject Mathematics/Archive/2013

Jan 2013

Binary numeral system/Binary number system

In this edit, User:Apteva moved Binary numeral system to Binary number system. The edit summary mentions what I surmise may be Google hits. I think if an error is widespread, a Wikipedia article might help correct it. Students often write

${\frac {-b\pm {\sqrt {b^{2}-4}}\ ac}{2a}}$

when they ought to write

${\frac {-b\pm {\sqrt {b^{2}-4ac}}}{2a}}.$

If we found that error to be as widespread on the web (and I suspect it's out there in lots of places) as it is in turned-in homework assignments, would we follow the erroneous usage here?

(We had an article titled Number system that carried a hatnote saying that it is not about numeral systems. On March 17, 2012, User:Mlm42 redirected that to Number, and the redirect remains intact. We put a lot of work into finding links to number system that ought to link to numeral system, and there don't seem to be any of those now.) Michael Hardy (talk) 19:13, 19 December 2012 (UTC)

I strongly agree that "numeral" is correct. Is the right approach to find textbooks, articles, etc. that use "numeral", and then to redirect the "number" article to the "numeral" article? Mgnbar (talk) 19:55, 19 December 2012 (UTC)

Binary numbering system is used far more commonly in books than binary numeral system.[1] There is only one article. The discussion is on what it should be called. Binary number system is the most common term used.[2] Correct to one particular post-doc or mathematics professor is not important. What is important is what is most commonly used. Apteva (talk) 20:04, 19 December 2012 (UTC)

From the dictionary: wikt:numeral; noun 1. a word, letter, symbol, or figure, etc., expressing a number; number: the Roman numerals. Apteva (talk) 20:09, 19 December 2012 (UTC)

The policy on common names says that the title should agree with the most common use in reliable sources. I find that a Google Scholar search on "binary number system" turns up 4150 results as opposed to 391 for "binary numeral system". Of course, search results depend a lot on the choice of search string. Michael Hardy, what is your source for saying that "binary numeral system" is correct and "binary number system" isn't? RockMagnetist (talk) 20:10, 19 December 2012 (UTC)

Relatedly, what is the point of including "system" in the title? Why isn't it just binary number (or binary numeral, both currently redirects)?— Preceding unsigned comment added by David Eppstein (talk • contribs) 20:13, 19 December 2012‎ (UTC)

I can answer the question as to the source - it is 20 years of studying mathematics and having a PhD in Mathematics. A number is only a number. A numbering system is the mathematics used for calculation using that particular base. Apteva (talk) 20:16, 19 December 2012 (UTC)

Yes, you have explained the difference between a numeral and a numeral system, but you haven't answered my question. I didn't ask "what is a numeral system", I asked why the title should be about the more complex object (the system) rather than about the simpler objects (the numerals). —David Eppstein (talk) 22:21, 19 December 2012 (UTC)

Are you answering my question on sources for yourself or Michael Hardy? Personal qualifications are not relevant to Wikipedia policy. RockMagnetist (talk) 20:24, 19 December 2012 (UTC)

Subject experts are often needed and are always welcome. Apteva (talk) 20:28, 19 December 2012 (UTC)

Absolutely - but citations are still needed (and subject experts should be good at finding them). RockMagnetist (talk) 20:30, 19 December 2012 (UTC)

So I would choose the title "base 2" though,[3] except that it is not "encyclopedic". Apteva (talk) 20:39, 19 December 2012 (UTC)

You should choose something comparable like binary number compared to base 2 number compared to base two number as in [4] where you see binary number is a clear winner. Base 2 does not identify the topic well. Dmcq (talk) 03:05, 20 December 2012 (UTC)

See Talk:Binary numeral system#Requested move. Apteva (talk) 20:28, 19 December 2012 (UTC)

"Number system" is a misnomer, as shown by the dictionary definitions quoted by Apteva: a word, letter, symbol, or figure, etc., expressing a number. Michael Hardy (talk) 04:44, 20 December 2012 (UTC)

Lots of things are misnomers. So many that we even have a list of mathematical misnomers. But if they're in wide enough use, that's what we should call them anyway. —David Eppstein (talk) 05:11, 20 December 2012 (UTC)

That depends on how firmly entrenched it is. "Fundamental theorem of algebra" may be beyond hope, but in certain matters we can correct popular misunderstandings. For example, mathematical illiterates think "exponential growth" is synonymous with something like "surprisingly fast growth". Our article with that title sets the record straight. Michael Hardy (talk) 18:50, 21 December 2012 (UTC)

The article Number makes a clear distinction between "number" and "numeral". Moreover we have Numeral system. On the other hand, formally speaking, a "binary number" or "binary fraction" is a rational number with a power of two as a denominator. Thus, the correct title of the article would be "binary numeral system" (or "binary numeration" if one want to avoid "system"). Personally, I prefer "binary numeral system", but, if we want to name after the most common use, and if we decide the most common use after the number of Google hits, "binary number system" seems the best choice. D.Lazard (talk) 09:38, 20 December 2012 (UTC)

I think trying to use numeral in places where it is very uncommon in normal usage is just wrong in Wikipedia - we should use common language.. Decimal numeral for instance hardly ever occurs compared to decimal number, and it has been that way for the last two centuries at least according to [5] in Google ngrams. Numerals normally refers to the numbers as written using the symbols of different writing systems like Babylonian or Roman or the digits in our current system, not how they are put together. Dmcq (talk) 11:50, 20 December 2012 (UTC)

Actually "Number system" is not a misnomer. Michael Hardy has committed the fallacy of affirming a disjunct. In the OED, one of the definitions of number is "Something which graphically or symbolically represents a numerical quantity, as a word, figure, or group of these; a numeral; (also) a ticket or label bearing such signs." Thus, although "Number system" is less precise, it is a synonym for "Numeral system". RockMagnetist (talk) 01:16, 21 December 2012 (UTC)

What the word "number" means may vary with the context. In some contexts a "number" is a _song_. That doesn't mean it wouldn't be a misnomer if used that way in most math articles. Michael Hardy (talk) 18:47, 21 December 2012 (UTC)

The requested move has now been closed and the article moved to binary number. Probably it would be a good idea to edit the article (and especially its lead section) to discuss common usage vs correct usage here, and also to say what a single binary number is as well as what the whole system is. I suppose one advantage of the new title (not included in the discussion) is that it doesn't use the phrase "number system" so we can still use the more precise "numeral system" terminology for that while also using "binary numbers" to refer to numbers represented using this system. (Relatedly, a binary numeral is just a bit, not a multi-bit number, right? So why does it redirect here and not to bit?) —David Eppstein (talk) 04:42, 3 January 2013 (UTC)

"Bit" means "binary digit". A numeral is not necessarily just one digit, it can be multiple digits. So "binary numeral" is not limited to one bit. JRSpriggs (talk) 06:34, 3 January 2013 (UTC)

As an interested layman, I would expect the term "numeral" to refer to a typographic arrangement comprising one or more symbols, while a "number" is a mathematical idea which may be represented by the numeral. In practice, the numeral for a given number is also commonly referred to as the "number". For example in the decimal numbering system, I might write "6" where an ancient Roman would have written "VI". In binary I would write "110". Here are three different numerals representing the same number, and all commonly referred to (in their respective spoken languages) as "the number six". I'd suggest that provided we understand that the term "number..." is often used as shorthand for "the number represented by the numeral...", there should be no problem. For example WP:COMMONSENSE tells us that "No. 10 Acacia Avenue" is using the number/numeral as the name of a property. I'd also agree that we are well rid of the term "system" in the title. I don't know if that helps. — Cheers, Steelpillow (Talk) 17:17, 3 January 2013 (UTC)

Well, but the binary system is most frequently used in contexts which have very little to do with systems of writing — in computers. Are those numbers or numerals? —David Eppstein (talk) 17:27, 3 January 2013 (UTC)

I would suggest that since most patterns of information within an electrical circuit are not typographic arrangements then they cannot be numerals. But equally, they are only representations of the mathematical idea of the number, not the idea itself (I certainly find it hard to believe they might be sets of sets, for example). It would seem that, whatever the precise mathematical definition of a number, linguistically we use the term to cover a multitude of sins, without full regard to consistency. — Cheers, Steelpillow (Talk) 17:51, 3 January 2013 (UTC)

To Eppstein: Do you really mean that the common use of the binary system in computers is not a system of writing the numbers in the memory? What is the significant difference between writing on a paper sheet and writing in the memory of a computer? On the other hand one of the side advantages of computers is that the common use of several numeral systems (decimal, binary, floating point, ...) may help to clarify the important distinction between the abstract notion of a number and its representation as a numeral that has been perfectly summarized by Steelpillow. D.Lazard (talk) 18:20, 3 January 2013 (UTC)

It is a representation that is intended for calculation rather than for visual communication. In that sense it is more similar to a configuration of an abacus than to a sequence of written digits. —David Eppstein (talk) 01:53, 4 January 2013 (UTC)

QUOTE from David Eppstein: "Relatedly, a binary numeral is just a bit, not a multi-bit number, right?" END OF QUOTE.

No, a binary numeral can have more than one binary digit, just as a decimal numeral can have more than one decimal digit. Michael Hardy (talk) 19:02, 5 January 2013 (UTC)

Well, I have to admit, I still find the way you're making this distinction between numbers and numerals to be confusing. If it were "a number is an abstract mathematical object and a numeral is a written representation of a number" then fine, that would make sense to me, but then binary numbers would be numbers to me and not numerals. Because, binary numbers are abstract mathematical objects (sequences of bits) that are not primarily used as a system of writing, and that have an arithmetic that obeys the Peano axioms and other properties that one would expect integers to have. It is as if you defined a vector in a way that required it to only be an object in a coordinate-free vector space, but insisted on calling it a "vectroid" whenever it was given coordinates in a space with a basis. I don't see that as being a useful distinction. —David Eppstein (talk) 19:30, 5 January 2013 (UTC)

Multiplication algorithm

I would appreciate it if someone could give a third opinion on this addition.—Emil J. 16:28, 3 January 2013 (UTC)

Even if it were notable, and I don't believe it is, that article would be the wrong place. Something like the Mental calculation article would be more suitable. Dmcq (talk) 18:07, 3 January 2013 (UTC)

Perimeter: review wished

Hello,
I'm trying to translate French good article fr:Périmètre into English (see Perimeter, work in progress). As English is not my native tongue, a review may be useful, to correct my mistakes.

All the sources in fr:Périmètre are in French, so I didn't insert them in the English article, thinking we could find other ones in English. Did I do well? If you prefer, I can easily copy and paste French sources in Perimeter. --El Caro (talk) 16:52, 5 January 2013 (UTC)

Mathematician biography nominated for deletion

• Paul Jefferys (AfD discussion)

It won't get automatically listed by the 'bot. Uncle G (talk) 10:46, 6 January 2013 (UTC)

Trace inequalities

Trace inequalities is a new article and could probably benefit from more eyeballs. In particular: Which other articles should link to it? (I've added a few links including one from the list of inequalities, but I haven't attempted to figure out which others there should be.) Michael Hardy (talk) 18:24, 7 January 2013 (UTC)

Merging ring theory into ring (mathematics)

Hi all,

I would like to propose the merger above. ring theory has not developed well for years and most of stuff there is already in the "ring" article. There are some duplications like "history" section. I can see an argument for separate articles for "object" and "theory". But the current setup isn't this sort, and unless there are editors who want to write ring theory, there is little point having it. I'm also interested in hearing any open-ended suggestions (as to what we do about them.) -- Taku (talk) 21:28, 7 January 2013 (UTC)

As a general principle I would expect an article on Ring (mathematics) to concentrate on telling the reader about rings as mathematical objects: their structure, properties, morphisms, associated objects; whereas Ring Theory should describe the theory, in terms of historical development, applications, relationships to other theories, key results, comparisons with other theories. Deltahedron (talk) 22:28, 7 January 2013 (UTC)

My take is that this doesn't make sense. It wouldn't make sense to merge group (mathematics) and group theory or even number and number theory, (or music and music theory, for that matter).

The articles have very different purposes. The theory article should address questions like "How are rings studied and what has been discovered?" while the ring (object) article should answer questions like "what is a ring and what features and flavors do they have?".

One thing we can agree upon is cleaning up duplication between the two articles. Still though, I bet an almagam of the articles would produce a monster-sized article that is less useful than the separate articles. Rschwieb (talk) 14:28, 8 January 2013 (UTC)

I think a merger is the right thing to do, the current ring (mathematics) article is a bit long but I don't think ring theory is a reasonable subtopic article. I'd prefer to see the two merged and then have some discussion about splitting off a couple of major bits as subtopics. Dmcq (talk) 14:38, 8 January 2013 (UTC)

Agree with the first two comments -- probably some chunks of Ring (mathematics) should be moved over to ring theory (like, e.g., the sections on commutative and noncommutative algebra). --JBL (talk) 14:53, 8 January 2013 (UTC)

@Dmcq Seemingly, this logic would apply to all of these pairs, most of which are comparably sized with ring/ring theory: graph theory / graph (mathematics),knot (mathematics) / knot theory , group (mathematics) / group theory, category (mathematics) / category theory, field theory (mathematics) / field (mathematics) and several more I have not listed. If you do not agree that all these pairs should be merged, I am very interested in knowing why rings are different. Rschwieb (talk) 18:11, 8 January 2013 (UTC)

I can't say I'm keen on those. The split seems to be basic intro versus more advanced and I don't think that is a good way of going round the business. There are a number of articles like Introduction to special relativity and Introduction to quantum mechanics and they suffer from the same sorts of problems of not having a clear idea of the split and not knowing the level of knowledge needed at each stage in the articles and not being clear about how much should be included. They try to sidestep an editing problem by forking and instead created two worse problems. I think Wikipedia:Make technical articles understandable has a better approach in general. It says one can start up 'Introdyuction to ...' articles but does not recommend it in general. Dmcq (talk) 00:29, 9 January 2013 (UTC)

I think in most cases it makes sense to have separate "object" and "theory" articles. The split should not be based on more-or-less advanced, though, I agree with that. The "object" article should ordinarily be shorter than the "theory" article, but probably more "technical", not in the sense of "advanced", but in the sense that it's largely about the definition of the object and its basic properties. The "theory" article will be more narrative, and discuss what it is that interests foo theorists about foos.

On the other hand, the "object" article is the natural place to talk about applications of foos to things other than foo theory. For example, a lot of stuff that's done with groups is not group theory, and perhaps makes more sense at group (mathematics) than at group theory. --Trovatore (talk) 00:36, 9 January 2013 (UTC)

I still think there should be a hierarchy and in that case the theory should be under the object article. However if you look at the group theory article its says at the top 'This article covers advanced notions. For basic topics, see Group (mathematics).' and if you read the introduction it does not make clear that it is a subtopic or a split in the sense you say. Dmcq (talk) 00:44, 9 January 2013 (UTC)

I wouldn't argue that a ring is different. In fact, the same argument I made above applies to field theory. It hasn't developed much; "history" sections are duplicate. Why not merger it into field (mathematics)? The caregory theory is "much" more than category: think of functors, natural transformations. In contrast, the ring theory is all about rings. -- Taku (talk) 22:52, 8 January 2013 (UTC)

I am all with you on eliminating the duplication between these two articles (and any of the other pairs I mentioned, for that matter). But I still have no idea why doing that with a wholesale merger is warranted. You just delete duplicate places or abbreviate them with links to the body of the material.

Let's put the reasons for and against a wholesale merger on the table:

Against: The articles (with duplication removed) have plenty of content, and merging them would make an overlarge article. (I would also go so far as to say that putting them in the same article is shoehorning two distinct topics into one topic.)

Against: It would be inconsistent with the precedent set by a large number of pairs of articles that I mentioned above. If ring and ring theory should be merged, then so should all of those.

I haven't really seen that there is a strong reason for at all. If your reason is to remove duplicaton and overlap, then sure, by all means, that is a good thing to do... but not by a wholesale merger. The costs of the merger obviously outweigh the benefit of removed duplication.

If it helps make you feel the article theory is more useful, I would be interested in improving the ring theory article in the future, when I get some time. Rschwieb (talk) 14:55, 9 January 2013 (UTC)

You noted in the talk page for Ring (mathematics) that it might be worthwhile spelling out the purpose of the separate articles. I think this is the crux of the problem. It really needs to be spelt out or you get the current mess. I agree there is material for more than one article but we haven't done what should always be done at the start of the 'theory' articles which is say clearly what the topic of the article is. I think there would still be a need to move some stuff around in accordance with the topics. Dmcq (talk) 17:44, 9 January 2013 (UTC)

OK: that sounds like a good place to start. I'll be on the talkpage sometime soon to help with eliminating duplication and discussing content sorting. See everyone there! Rschwieb (talk) 18:10, 9 January 2013 (UTC)

Abelian algebra

User:r.e.b. has created an article in which in the first sentence we find the phrase "extensions of a commutative algebra". It's obviously a bad idea to write "extensions of a commutative algebra", since the linked article is about the study of commutative rings. But a hatnote at the top of that article says "For algebras that are commutative, see Abelian algebra." Currently Abelian algebra redirects to Algebra#Abstract_algebra. Is there a better target for that redirect? Or should a better target be created? Michael Hardy (talk) 16:50, 9 January 2013 (UTC)

I suggest to redirect it to commutative ring and to add a short mention of this additional structure to the lead of the latter article. Probably, with a corresponding section. Incnis Mrsi (talk) 16:59, 9 January 2013 (UTC)

List of things named after Johannes Kepler

List of things named after Johannes Kepler is a new article. It should get divided into appropriate sections. Michael Hardy (talk) 03:55, 1 January 2013 (UTC)

Done, by someone. Michael Hardy (talk) 17:53, 11 January 2013 (UTC)

Archimedean–Galileo spiral

Archimedean–Galileo spiral is a recent article whose deletion is proposed. Are there reasons to keep it, or other reasons to delete it than the one cited? Michael Hardy (talk) 18:57, 10 January 2013 (UTC)

As far as I can see, this is OR whose only source is [6], as reported in A202407, and as such the prod is appropriate. (Furthermore, the name appears to be only invented for Wikipedia, and I find it ungrammatical: if anything, it should be either Archimedean–Galilean spiral or Archimedes–Galileo spiral.)—Emil J. 19:58, 10 January 2013 (UTC)

I certainly agree about the grammar. Michael Hardy (talk) 17:57, 11 January 2013 (UTC)

Tsit-Yuen Lam

We currently have three links to Tsit-Yuen Lam, but the number of articles that mention him in references and otherwise is much largers, maybe dozens. Should we have an article about him? (If so, those references should have authorlinks.) Michael Hardy (talk) 17:55, 11 January 2013 (UTC)

Relevant articles exist in the German and French editions. Liege mooch (talk) 12:39, 12 January 2013 (UTC)

He very likely passes WP:PROF criteria #1 (many very highly cited publications, as counted e.g. in Google scholar), #2 (Steele Prize), and #3 (Fellow of AMS). Only one criterion would be sufficient. So I agree, an article is justified. It would probably be a better idea to stub out something for him first, rather than putting in all those authorlinks as redlinks, though. —David Eppstein (talk) 17:07, 12 January 2013 (UTC)

Is there any chance I can convince you two write "criterion #1"? Michael Hardy (talk) 00:28, 13 January 2013 (UTC)

Now it exists; here's a to-do list

I've created the article. Tsit-Yuen Lam now redirects to Tsit Yuen Lam. I translated the German article, which I think is pretty much identical to the French article (except that I moved one short paragraph to an earlier place in the article and made it part of a larger paragraph).

So the following should be done:

• Further expansion;
• Checking for accuracy by people who know things about him;
• Going to the many Wikipedia articles that mention his name and adding links to the new article.
• Probably other things as well.

Michael Hardy (talk) 02:29, 13 January 2013 (UTC)

Maybe there's aren't so many articles that mention him. I've linked from some of them to the new article. Here's a question: should one title the article Tsit-Yuen Lam or Tsit Yuen Lam? The latter is what he uses on his university web page. His publications seem to get cited using the hyphenated version, or else T. Y. Lam. Michael Hardy (talk) 02:43, 13 January 2013 (UTC)

Fundamental recurrence formulas

I suggest that Fundamental recurrence formulas should be merged either to Generalized continued fraction or to Convergent (continued fraction). There seem to be several articles covering the material already, and this one is unsourced and with a debatable name. I raised this at Talk:Fundamental_recurrence_formulas#Suggest_merger but no-one seems to be watching the article. Deltahedron (talk) 07:37, 14 January 2013 (UTC)

Seems fine to me. In fact I wonder why there is Convergent (continued fraction) either. People seem to stick in every term as if Wikipedia was a dictionary rather than an encyclopaedia. We've got redirects for that sort of thing. Dmcq (talk) 10:02, 14 January 2013 (UTC)

I would support both merging Fundamental recurrence formulas into Generalized continued fraction and Convergent (continued fraction) into Continued fraction. The first merge would benefit Generalized continued fraction as well: it includes the recurrence formula in the lead but does not discuss it in the body. RockMagnetist (talk) 17:14, 14 January 2013 (UTC)

Deltahedron, I think your experience is the reason that WP:MERGEPROP recommends discussing merges at the destination article's talk page. There are probably many more eyes watching Generalized continued fraction. RockMagnetist (talk) 17:23, 14 January 2013 (UTC)

While we're at it, Convergence problem seems too general a name for the criteria for convergence of continued fractions. RockMagnetist (talk) 17:32, 14 January 2013 (UTC)

Wikilinks in publication titles

See this edit. My feeling is that a wikilink only belongs on the title of a publication if it is a link to an article about that specific publication, because otherwise it looks too much like a link to the publication itself, and that wikilinks for topics discussed by a publication should instead be included in prose describing the publication. But I'd welcome further discussion or additional opinions. —David Eppstein (talk) 00:39, 15 January 2013 (UTC)

I think in this case, with the exception of Serre's Conjecture, the links aren't misleading because only part of the title is linked. But I agree - it's a poor substitute for discussing the work of this scientist in the body of the article. RockMagnetist (talk) 01:36, 15 January 2013 (UTC)

I agree with David. These edits seem to originate from an overzealous wikilink-er. These are titles and should be treated as wholes. If a subject that is relevent to the article appears in a title and is not already linked to in the article, then an appropriate place to put the link would be in the ==See also== section. If the subject is not relevent to the article (or to the understanding of the article) then it shouldn't be linked to in the first place (IMHO). Bill Cherowitzo (talk) 17:41, 15 January 2013 (UTC)

MathJax problem

I turned on MathJax rendering, and in general it looks good, but I noticed a problem in the articles Euclidean algorithm and continued fraction - the lines in the fractions are too long and overlap with other parts of the expression:

$a_{0}+{\cfrac {1}{a_{1}+{\cfrac {1}{a_{2}+{\cfrac {1}{\ddots +{\cfrac {1}{a_{n}}}}}}}}},$

${\frac {1}{2.25}}={\frac {4}{9}}=[0;2,4].$

If someone would notify the right parties, and tell me how to in the future, thanks in advance! - Virginia-American (talk) 19:14, 15 January 2013 (UTC)

Looks ok to me (in Chrome under OS X). Occasionally on other sites (but not here) I've had to reload a page to get mathjax to render properly without overlapping the surrounding text. —David Eppstein (talk) 19:18, 15 January 2013 (UTC)

I do not see the problem in any of three rendering modes. BTW, these "lines in the fractions" are called vincula. Incnis Mrsi (talk) 19:24, 15 January 2013 (UTC)

On a Mac, I see this problem frequently when I use Chrome, but not Safari or Firefox. RockMagnetist (talk) 20:36, 15 January 2013 (UTC)

I'm using Chrome Version 23.0.1271.97 m, under Windows 7 service pack 1 - Virginia-American (talk) 21:54, 15 January 2013 (UTC)

I'm using Chrome and I see the comma under the top line rather than after it which is a bit peculiar. Under Firefox it seems okay. Dmcq (talk) 00:44, 16 January 2013 (UTC)

Looks good to me. On stackexchange it sometimes comes out wrong when first saved, but looks OK after reloading. Michael Hardy (talk) 06:43, 16 January 2013 (UTC)

Now it's OK. - Virginia-American (talk) 12:31, 16 January 2013 (UTC)

I'm using Chrome 24.0.1312.52 m and it has a comma under the top line rather than at the end. I have the default experimental MathJax set in my preferences rather than using 'importScript('User:Nageh/mathJax.js')' in my common.js file, perhaps that's the difference. Dmcq (talk) 13:29, 16 January 2013 (UTC)

The difference, your said? It is easy to check that Virginia-American does not use any personal script. Incnis Mrsi (talk) 14:06, 16 January 2013 (UTC)

It seems that is a problem that is specific to Chrome: all users reporting it have this problem with Chrome and nobody report it on another browser. Myself, I use standard MathJax (set on the "preferences" page) with Firefox under Window 7, and above formulas look fine. D.Lazard (talk) 14:43, 16 January 2013 (UTC)

Affine function

Hello,
Affine function is a redirect to Affine transformation. Affine functions deserve their own article, don't they? Do you agree? --El Caro (talk) 14:47, 18 January 2013 (UTC)

What’s the difference between an affine function and an affine transformation? I thought they were synonyms.—Emil J. 15:20, 18 January 2013 (UTC)

In other words: the $\mathbb {R} \rightarrow \mathbb {R}$ functions defined by f(x) = ax+b deserve their own article on WP, in my opinion. What should be the title of this article? --El Caro (talk) 15:31, 18 January 2013 (UTC)

This family of functions are included as a simple case, being affine transformations on a one-dimensional space. Unfortunately the article places excessive emphasis on a geometric interpretation at the expense of a more general definition, particularly in the lead. I see no reason to have a separate article, though it may make sense to give this specific example under the Examples of affine transformations section. — Quondum 17:38, 18 January 2013 (UTC)

Possible plagiarism

Pointed out by anon at Talk:Riemannian manifold. No one responded there so, I figured I'd bring it to the attention of folks here. Mct mht (talk) 07:51, 19 January 2013 (UTC)

Proved or proven

Is "proved" or "proven" the preferred usage for mathematics articles? It seems that "proved" is more common in specifically mathematical contexts, but another editor has suggested this is a British/American difference. Is there an established convention? Deltahedron (talk) 19:15, 6 January 2013 (UTC)

There is no solid convention in mathematics, and both terms are commonly used. I would just treat them as synonyms and leave the original use unless it sounds particularly bad. — Carl (CBM · talk) 19:22, 6 January 2013 (UTC)

Thank you, but my question was specifically about whether there was a convention here on Wikipedia. Deltahedron (talk) 19:40, 6 January 2013 (UTC)

Not that I am aware of. — Carl (CBM · talk) 19:52, 6 January 2013 (UTC)

I think I tend to use "proven" only as an attributive adjective, and maybe not always then. As a past participle, I use "proved". Maybe this will go where "gotten" has gone in England, i.e. it's no longer used by respectable writers, and the ignorant masses there seem to think it's an Americanism. Michael Hardy (talk) 18:26, 7 January 2013 (UTC)

I find myself accused on my talk page of describing the English as ignorant masses. I did nothing of the sort. In every country there are ignorant masses; England is no exception. Michael Hardy (talk) 00:19, 9 January 2013 (UTC)

I wrote you appear to describe the English as "ignorant masses". This has nothing to do with mathematics and I am surprised to see the discussion continued here. Deltahedron (talk) 07:28, 9 January 2013 (UTC)

You complained to Michael that his comment here could be misconstrued as being offensive, hence Michael added here a clarification of his comment. This sounds like the most natural course of action to me.—Emil J. 13:00, 9 January 2013 (UTC)

I've encountered a couple instances where, when a point of correctness was concerned, two sides both pointed to each other and said "I think that's what they prefer." The one I remember the best is the use of "an historic," to which both Americans and English seem to say that it's the other side's preference. The other day I hit a webpage concerning the use of "matrixes" where the same finger-pointing happened between physicists (or it might have been chemists) and mathematicians. Rschwieb (talk) 14:35, 8 January 2013 (UTC)

If it’s still relevant, I would say “[name] proved [theorem]”, “[theorem] was proved”, “[theorem] has been proven”, etc. Standard English usage (I think). But if an article consistently uses one in the other’s context, go with that. —Frungi (talk) 06:38, 9 January 2013 (UTC)

I second that the verb forms are prove, proved, and proved, and that proven is an adjective. 192.35.44.24 (talk) 19:27, 22 January 2013 (UTC)

Participles are adjectives, so that's not really such a clear distinction. I would avoid making any firm rulings on this. For things that sound outright wrong, like "a proved fact", go ahead and change it, but for things that are reasonable, even if it's not the way you (generic you) would personally say it, just leave them alone. It might be partly an ENGVAR issue but it's clearly not a clear enough one to base the decision on whether the article as a whole is in American English or British English, so mostly just leave it alone.

As for Frungi's distinction, it does somehow sound better that way, but it's weird because there is no grammatical distinction. In both cases prove{d|n} is being used as a passive, so really it should be the same form in both cases — the verb form of to be is irrelevant to the verb form of prove. --Trovatore (talk) 21:13, 22 January 2013 (UTC)

König's theorem: two versions and implicit use of induced subgraph?

Hello,

I very much enjoyed the article König's theorem (graph theory) but I have some comments/questions:

It also mentions König's Line Coloring Theorem, which looks very different. I don't know if one of these theorems follows from the other, but now there is no comment on this in the article.(Perhaps the other deserves a separate article?)

I also thought the treatise of perfectness of graphs was interesting. The definition of perfect graphs relies on induced subgraphs, however, here only the full line graph (and its complement) of a bipartite graph are considered. Shouldn't it be explained why this does cover everything?

Many thanks, Evilbu (talk) 16:32, 21 January 2013 (UTC)

Willard Gibbs

Hi. I've been working for a while on the bio. of Josiah Willard Gibbs. First, I'd like to mention that I think the article should of rated as of High (rather than Mid) importance in math. As a mathematician we owe him the concept of the cross product, the formulation of vector calculus in terms of div, grad, curl, and all that, and many of the ideas of what later became convex analysis. And Gibbs is one of the people most responsible for rescuing the work of Hermann Grassmann from obscurity. His work on statistical mechanics also had a very deep and long-lasting impact on mathematical physics.

Second, I'd like to attract other editors who might wish to work on improving the article. Last Nov. I nominated it for FA. It got significant support, but some of the FA review regulars kept asking for independent copyediting and in the end the discussion just stalled and was archived. Gibbs's work as a theoretical scientist is extremely interesting and important, and I think his wikibio deserves more attention. - Eb.hoop (talk) 23:46, 17 January 2013 (UTC)

I agree high importance does seem appropriate for him. Dmcq (talk) 16:28, 24 January 2013 (UTC)

Need help at set theory

User:Multipundit is insisting on spamming the set theory article with an enormously disproportionate quantity of material on multisets and fuzzy sets, two topics that are extremely minor areas of concern to set theorists. Please take a look. I have not attempted to engage him because I don't think it would go well. --Trovatore (talk) 04:43, 18 January 2013 (UTC)

The article Named set could probably also do with some attention. Deltahedron (talk) 07:38, 18 January 2013 (UTC)

A few days later, this article now reads as a personal essay on the work on Burgin, making grand claims which do not appear to be supported by references to any independent assessments in mainstream scientific literature. Deltahedron (talk) 07:32, 24 January 2013 (UTC)

I just read the named set article and it strikes me as verbose and lacking in substance and I don't see why the whole lot of it can't just be treated as just one functor in category theory. The words 'vacuous waffle' come to mind. Dmcq (talk) 16:21, 24 January 2013 (UTC)

The editing history of User:Multipundit shows the account has some connection to Burgin, at least as an advocate of Burgin's work. Taking that for granted, I don't think the current edits are completely bad. I would support trimming down the named set article somewhat, but I think it is generally OK, and the detailed references are useful. The lede is particularly bad. For the main article set theory, the due weight of named sets is extremely small. — Carl (CBM · talk) 16:33, 24 January 2013 (UTC)

Hyperbolic Fibonacci and Lucas functions, aka a new maths article that's too "essay-like" for creation at the moment

Hullo mathematical peoples. A new editor has written Wikipedia talk:Articles for creation/Hyperbolic Fibonacci and Lucas functions, which looks very well referenced (I've pointed him to how to do inline citations properly). However, it's been rejected as "more like an essay than an encyclopedia article", even though I don't see distinctive signs of WP:OR in it. This is a rejection reason that's notoriously difficult to get past - can anyone help in assessing the suitability of the article in its current form, or in improving it to the point where it's acceptable?

(If you think, at any point, that in fact it's not too essay-like, but don't want to bother with the mechanics of the WP:AFC creation process, just let me know or say so here and I'll accept/create it, as I'm otherwise happy with it.) --Demiurge1000 (talk) 21:24, 18 January 2013 (UTC)

Keep this article. I question the whole process of article rejection because someone (who are they and what gives them this authority) decides that an article can be rejected on such grounds. It's terribly offputting for new authors. Has the deletionist regime got such a firm grip on this site that they can even get stuff deleted before it's even had a chance to get off the ground? --Matt Westwood 06:21, 19 January 2013 (UTC)

Comment. The article does read like an essay, and an essay based on the work of a small number of people. There is a disturbing similarity to this paper by two of that small group. The mathematics is not nearly as novel as is claimed and there is far more to the history of these functions. The wider question about Article Creation is interesting, but there is no requirement to go through that process. Anyone can simply write an article directly if they want. If they want other editors to comment first, they can ask, as happened here. Deltahedron (talk) 07:49, 19 January 2013 (UTC)

I find the idea of a link between the Fibonacci/Lucas numbers and the sinh/cosh functions to be interesting. Can we not keep it? JRSpriggs (talk) 08:56, 19 January 2013 (UTC)

I agree that it is interesting, and have thought so ever since first coming across it years before the work reported on in this article. It was certainly known to Édouard Lucas, and goes back to Lagrange and Legendre: see page 71 of Williams (1998). Any article on this subject should give a proper history of these ideas. Deltahedron (talk) 09:13, 19 January 2013 (UTC)

Deltahedron, I wanted to firstly thank you for thanking the time to review my article. I would like to first address your concern that there is a "disturbing similarity" to a paper by Alexey Stakhov and Boris Rozin. Their work is fundamental to the modern day developments of this subject therefore it played a major part in the creation of this article but it is definitely not the only source of information. The other concern is that this article is written in an essay style. This is my first article on wikipedia and I am still only a beginner at this, so still learning how to write in a more encyclopedic manner. I would be really grateful for any constructive suggestions on what to improve in the article, or if experienced editors could optimise what is already there. You also mention that this topic goes back to Édouard Lucas, Lagrange and Legendre, it would be great if you could possibly add some information regarding that as I am not that well informed about their works on this subject. All in all, I am glad you find this topic interesting and hope with the help of experienced editors like your good self and others we will be able to refine this article to a proper wiki standard. Matt Westwood & JRSpriggs thank you for the support. WIKIWIZDOM (talk) 22:38, 20 January 2013 (UTC)

Thanks to all for the feedback. I've accepted the article and created it at Hyperbolic Fibonacci and Lucas functions; I've also added templates indicating the current problems with it, and linked to Deltahedron's comments from its talk page. --Demiurge1000 (talk) 20:20, 19 January 2013 (UTC)

Demiurge1000 thank you very much for your help. WIKIWIZDOM (talk) 22:38, 20 January 2013 (UTC)

This article is about functions of the form $a\cosh(x\log b)$ and $a\sinh(x\log b)$. The integer sequences that appear in the article (λ-sequences) are special cases of Lucas sequences. Does this deserve a separate article? I have commented this in more details on the talk page D.Lazard (talk) 17:03, 22 January 2013 (UTC)

I have proposed the deletion of this article with the following concern:

The subject of this article on mathematics is not notable. The mathematical content of the article consists in results that are trivial consequences of known theories, typically that of linear recurrences. When these known theories are cited in the article, this results always of my edits. Instead of referring to knowns theories, the article cites only non-notable publications that, for most of them, are not reliably published. The part of the article devoted to phylotaxis is a blatent WP:fringe theory and I suspect that it is also pseudo science. See the talk page for more details.

D.Lazard (talk) 17:46, 24 January 2013 (UTC)

The prod tag being removed I have nominated this article for deletion, with the same concern D.Lazard (talk) 23:42, 24 January 2013 (UTC)

Moebius plane and Möbius plane

user:Ag2gaeh has created a new article titled Moebius plane when there was alrady an article titled Möbius plane. Both spellings are correct and in one sense equivalent (whereas Mobius is by some reasonable standards a third, and incorrect, spelling). The initial edit summary when the article was created suggests that the creator knew of the other article but simply preferred spelling it without the umlaut. The proper way to handle that situation is with the "move" button. I've put "merge" tags on the two articles. (I haven't yet looked to see what links to them.) Michael Hardy (talk) 18:35, 19 January 2013 (UTC)

I've gone ahead and changed Moebius plane into a redirect. Anyone who wants to merge content from the previous version into Möbius plane is welcome as far as I am concerned. --JBL (talk) 20:23, 19 January 2013 (UTC)

I undid that because it was not done properly. I recommend giving the author of Moebius plane time to respond and then (if there is still consensus) following the procedure in Help:Merge. RockMagnetist (talk) 20:44, 19 January 2013 (UTC)

That the articles need to be merged is obvious (well, unless by some chance there are two notions called "Möbius plane", which I doubt, but I haven't looked at the articles). So I think an RM is just unnecessary proceduralism here. Certainly, the major contributors might have views on how the merge should be done, and a courtesy notice on that point would not be out of line. --Trovatore (talk) 21:00, 19 January 2013 (UTC)

What is the point of pretending that the consensus will be anything other than for the author of the new stuff to edit the existing article? Moebius plane should be and will be a redirect sooner or later and anyone who wants to see earlier versions can go to the history; all you've done is to perpetuate a ridiculous situation. Also, please see Bill Cherowitzo's comments at Talk:Moebius plane: the material you've restored is almost certainly copyrighted. --JBL (talk) 21:07, 19 January 2013 (UTC)

(To clarify, JBL is responding to RockMagnetist here, not to me. --Trovatore (talk) 21:17, 19 January 2013 (UTC)

I agree that the consensus is almost certainly going to be for a merge, but what is the rush? Michael Hardy put the merge tags on, so you might as well give people a chance to respond. Having said that, I probably wouldn't have reversed the merge if it had been done properly. Just at a glance, Moebius plane has more material and more references than Möbius plane, and anything that would improve the latter should be moved over. RockMagnetist (talk) 22:39, 19 January 2013 (UTC)

Correction: anything that would improve the latter and isn't a copyright violation should be moved over. —David Eppstein (talk) 22:58, 19 January 2013 (UTC)

I wouldn't call a copyright violation an improvement. Is there copyright violation in Moebius plane? RockMagnetist (talk) 23:28, 19 January 2013 (UTC)

Never mind, I see it. I'll remove the material. RockMagnetist (talk) 23:38, 19 January 2013 (UTC)

Is the person who added the copyrighted material the owner of the copyright? That seems probable under the circumstances. If so, what is the proper notice he should give that it's being done with permission? Michael Hardy (talk) 20:06, 24 January 2013 (UTC)

Try Wikipedia:Donating copyrighted materials especially at #Granting us permission to copy material already online. Deltahedron (talk) 20:43, 24 January 2013 (UTC)

Since a redirect was created, I've merged the edit histories of the two articles. The article is now almost as user:Ag2gaeh left if. I suspect we need to consider whether some of the earlier material should be merged into the now-existing version. Michael Hardy (talk) 04:29, 20 January 2013 (UTC)

Wave maps equation

The new article titled Wave maps equation has a bunch of obvious problems. Among them:

• What should the link to connectivity link to rather than to that disambiguation page?
• Is a summation convention followed here, where the repetition of $\alpha$ means one is to sum over all values of the index $\alpha$?
• Some context is needed. Is this something from physics?? I don't know.
• The article is an orphan: no others link to it.

Michael Hardy (talk) 17:38, 23 January 2013 (UTC)

The ZMATH review of the article cited states in part

This is the simplest geometric nonlinear wave equation. [They] arise in the analysis of more difficult hyperbolic Yang-Mills equations either as special cases or as equations for certain families of gauge transformations. They arise as well in general relativity for spacetimes with two Killing vector fields.

Zbl 1065.35199 Deltahedron (talk) 17:49, 23 January 2013 (UTC)

Maths related DRN

Hello WP Maths,

I volunteer over at Dispute Resolution Noticeboard and currently we have an active dispute revolving around the Golden Ratio. It's quite a technical dispute so if some of you with a bit more mathematics knowledge than I would be able to swing by and offer any opinions we'd be greateful. Dispute here: Wikipedia:Dispute resolution noticeboard#Golden Ratio. Thanks, Cabe6403 ^{(Talk•Sign)} 08:49, 25 January 2013 (UTC)

deletion of Hyperbolic Fibonacci and Lucas functions?

Hyperbolic Fibonacci and Lucas functions is listed in Articles for Deletion. Express opinions on this page. Don't just say Keep or Delete; give your arguments. Michael Hardy (talk) 18:37, 26 January 2013 (UTC)

Destruction of {{math}} and similar templates

The activity of the self-styled "latex to html" user, especially that he exposes spaces to line-wrapping, is known for a long time. What is not well-known is that he destroys not <math> only, but also {{math}}, {{mvar}} and {{open-open}} [7]. As I can extrapolate his attitude, he will raze all what is not "standard HTML typesetting" in his views: {{frac}}, {{sfrac}}, {{sqrt}}. I know that distrust to templates is entrenched in minds of some Wikipedians, but the bare wiki code has some disadvantages:

• It is unexpressive because math symbols (such as variables) would have the same appearance as the usual italic text.
• In the wiki code, it does not provide easily noticeable marker and bounds of a math expression.
• It is susceptible to silly replacement patterns of AWB and user scripts, such as [8][9].
• The hard-coded stuff like (0,1) or √2 cannot be improved across multiple articles by few changes, unlike {{open-open}} and {{sqrt}}.

On the other hand, templates which use the "texhtml" class can be customized to use good fonts, for example fonts uploaded with MathJax (although is it some work yet to be performed). Incnis Mrsi (talk) 08:45, 13 January 2013 (UTC)

I think {{math}} should go away. It looks very ugly to mix serif and sans-serif in the same line. If the formula really can't be understood in sans-serif, then display it and use LaTeX. --Trovatore (talk) 08:52, 13 January 2013 (UTC)

This view is unconstructive here, as it in no way addresses the issue raised (and we have no evidence that it even reflects a majority view; my own preferences are contrary to these). At best, it is an argument to modify the template definition (e.g. to match/use MathJax fonts), not remove its use. Though I have not reviewed the edits of the mentioned user, I agree with the concern expressed by Incnis. A single user on a mission can destroy a lot of useful formatting detail over time in this way. — Quondum 10:04, 13 January 2013 (UTC)

Any wiki which is not actively working towards replacing all of its html math with the MathJax version of $\LaTeX$ is in danger of falling behind the technological curve. It's like the difference between programming in machine-code and/or assembler and using a high-level language: $\LaTeX$ renditions in MathJax (rapidly becoming the de facto presentational tool) can be universally ported to any other platform hosting it. That's just to start with. --Matt Westwood 10:25, 13 January 2013 (UTC)

For these guys lazy enough to make some efforts towards correct appearance of "texhtml" it, certainly, looks very ugly. See user:Incnis Mrsi/standard.css and then, look at MediaWiki talk:Common.css/Archive 14 #Definitions for class="texhtml". Unfortunately, I have not a sysop in any Wikimedia project to try something like integration of MathJax's fonts with class="texhtml". Incnis Mrsi (talk) 12:32, 13 January 2013 (UTC)

For displayed formulas, <math> with $\LaTeX$ is the gold standard. Unfortunately, inline formulas with <math> don't match nicely with the surrounding text. Currently I have the impression that the {{math}} template gives the best optical compromise (in particular concerning variable names and non-breakable spaces), together with supporting templates like {{open-open}} and {{sqrt}}. Of course, there is a serious demand to improve the current situation to make it more appealing to put mathematics into Wikipedia. Maybe other fonts for the <math> environment are a solution, but I leave this to the experts (is someone working on this?). For the time being, converting {{math}} to just bare italic text for variables is certainly a step in the wrong direction when the unavoidable <math> environment for displayed formulas is present. Schmock (talk) 11:26, 13 January 2013 (UTC)

The assumption here is that mathematics formulae need to match "nicely" with the surrounding text. My contention is to ask: why should it? As long as it's not glaringly jarring. In MathJax, mathematical symbols rendered thereby are obviously mathematical entities, and are rendered in a font and with a presentation that makes them obviously stand out from the surrounding text, but so that they fit in aesthetically neatly with that text. Contrast that with the MediaWiki presentation which does not do that so well, which is what many people are put off by.

When the mathematical symbols are in the same font (albeit italicised) as the surrounding text, it makes it very much more difficult to follow any mathematical argument being made. Also, if all mathematics were presented using MathJax and an attempt were made to make this completely consistent, then a colossal amount of tedious markup code (sub and sup, specific markings to make stuff italic, all that undesirable overhead) can be completely disposed of. --Matt Westwood 11:50, 13 January 2013 (UTC)

(Edit conflict with Westwoodmatt, that illustrates his first sentence) I agree with the majority that {{math}} and the relative templates is the best choice for inline formulas. To Trovatore: I strongly disagree with you: using the same font for text and inline math is confusing: it results in the fact that a variable looks not the same inline and in displayed formulas. Thus, if an article contains a, a or a (inline), a and a or a (displayed), the reader should understand that there are two variables (one scalar and one vector) and not one nor four (nor six). Moreover the distinction between "a" (article) and "a" (variable) may be unclear, especially for people which is not accustomed with mathematics typographical conventions, or inside emphasized text. D.Lazard (talk) 12:28, 13 January 2013 (UTC)

In published mathematics the norm is for the math to be in the same font family (although italic) as the usual text. For example, the default in TeX is Computer Modern text and Computer Modern math. Variables in math have exactly the same appearance as italic text, because they are taken from the same font files - the "math fonts" have symbols only, not text. There is some professionally published math that has a different font for math, but this is a small fraction of the overall literature. So arguments that say there will be confusion from having the same font are not compelling to me.

Personally, I am willing to accept the {{math}} template. The {{mvar}} template (and the use of var in general) never had any significant support, and is based on some misunderstandings about the HTML var tag. In the end, the goal is to convert everything to MathJax. Someone should poke the developers to see what the status of that is. — Carl (CBM · talk) 13:03, 13 January 2013 (UTC)

If you use MathJax for inline math then you're accepting the use of a special font for inline math which is different from what Trovatore wants and what the person being complained about is doing in changing math to html. Personally I prefer having the maths bits be obvious and I believe that the default MathJax fonts should be used by default, but we should also be trying to get MathJax to support other fonts so logged in users can make the maths look like the surrounding text. Some people have a real thing about finding different fonts jarring and we should try and cater for them. Maybe that nuisance that is changing the articles is one of those. Dmcq (talk) 14:03, 13 January 2013 (UTC)

Perhaps the best solution is (dare I say it) to make the default Wikipedia skin use a serif font, like any normal reference work. It will never happen, of course, but we can dream... anyway, I'm inclined to agree with Matt Westwood that for the long-term health of the project it's best to encourage the use of LaTeX markup. It does look awful, but then again so do all of our math typesetting options. Zueignung (talk) 17:38, 13 January 2013 (UTC)

@Dmcq: I can accept a different font for MathJax only because MathJax has so many other advantages. But I don't accept the argument that the math font is supposed to be different, or that it is better for it so be different, because professional publishing (e.g. journals and textbooks) almost always use the same font for math and text. If there was a way for MathJax to use a font that matched the body text, that would be even better. (For those who don't know, the main font issue is that TeX needs more detailed font alignment info, so it is a general problem to make fonts work with math in TeX, and MathJax must have inherited this issue, so it uses its own fonts which have the necessary typesetting info.) — Carl (CBM · talk) 17:43, 13 January 2013 (UTC)

One of the problems that I have always had with professional publications is precisely the fact that the same font is used for mathematical symbols as for the text surrounding. It makes it far easier to follow the mathematics if the fonts are different enough for it to be clear what's mathematics and what's text. And the exciting thing about the net is that it is not necessary to be bound by the conventions of the past, which are restricting - it costs no more to present the mathematical stuff in a completely different font from the text, and IMO this is as it should be. I don't see that "this is what has traditionally been used in books, so this is what we must continue to traditionally do" should be the slavish rule of mathematics on wiki sites. --Matt Westwood 19:02, 13 January 2013 (UTC)

It's an exciting thing about the net that we have the freedom to present stuff that looks ugly? That's nothing special about the net; professional publications on paper could do this font-switching if they wanted to. They don't, because it's ugly. If the default for Wikipedia text in general were a serif font, we'd never be having this discussion; everyone (or almost) would agree that we shouldn't switch inline.

So you, "personally", think what I propose "looks ugly"? Why should your complete lack of sense of style affect what is clearly and obviously an improvement over the way they did it in the mediaeval times? --Matt Westwood 20:07, 13 January 2013 (UTC)

It is true that sans is not ideal for mathematics, and it's true that serif is not ideal for web display, at least at current resolutions. That's the source of the conflict. I don't agree with resolving the conflict by presenting a mishmash that looks like a ransom note with letters cut out of magazines. --Trovatore (talk) 19:14, 13 January 2013 (UTC)

You'd obviously know all about that, as it's obviously your field of expertise. --Matt Westwood 20:07, 13 January 2013 (UTC)

I think you're getting upset, which is a pity; let's remember we're just talking about typography. I know I do it too. On the substance, let's imagine as a thought experiment that the default font family were serif. Would you really want to switch to sans inline for mathematics? --Trovatore (talk) 20:27, 13 January 2013 (UTC)

The example you cite is exactly what I don't want. If you'd said it the other way round: imagine as a thought experiment that the default font family were sans serif. Would you really want to switch to a serif font for mathematics?" The answer to that is: Yes, I seriously do. I'm not a fan of sans serif of any description, I think there's absolutely no excuse for its pointless existence. What's the point of a font where you can't tell the difference between I, l and 1? See what I mean?

Having the mathematics in a font where every character is uniquely identifiable is utterly essential in all mathematics. You can not guarantee that in one of those egregious sans serif fonts. --Matt Westwood 20:35, 13 January 2013 (UTC)

I would not oppose a global switch to serif. From the point of view of our project, it would be an improvement. But we'll never be able to convince the rest of Wikipedia; the general consensus is that sans is better for the Web. Maybe when pixel sizes shrink by a factor of two (in linear dimension) that might change.

In any case, we seem to have established that your preference has at least two sources, and while one may still be that you would like to distinguish mathematics from English, one of comparable importance is that you just generally prefer serif? --Trovatore (talk) 20:44, 13 January 2013 (UTC)

More accurately: a) Mathematics must be in serif in order to be completely unambiguous, b) it does not matter whether the text and the mathematics are in different fonts - the juxtaposition is not "ugly", it's just that it may take the eye a little getting used to. Putting that together: if you must insist on your text being sans serif, then you really ought to compromise and make your mathematics in a different (i.e. "serif") font. --Matt Westwood 21:38, 13 January 2013 (UTC)

On the first point, the de facto standard for slide presentations in mathematics is the LaTeX beamer class, which uses sans by default, so it can't really be "must". On the second point I'm going to flatly contradict you — yes, it is ugly. --Trovatore (talk) 21:58, 13 January 2013 (UTC)

Okay, you've pwned me. --Matt Westwood 22:06, 13 January 2013 (UTC)

It's not a competition, I hope. We're both trying to improve the presentation of mathematics articles. --Trovatore (talk) 22:27, 13 January 2013 (UTC)

@MattWestwood: the problem with simply asserting "this is how it should be" it that it isn't very convincing. As Trovatore said, since journals and books are electronically produced these days, they could also switch. Knuth spent a long time researching typography for TeX, and he could have used different fonts if he had wanted to (he designed all the Computer Modern fonts from scratch specifically for TeX, after all). It's not clear why Wikipedia would be the right place for experimental typography. If we could achieve typesetting here as good as TeX, that would be ideal. I think MathJax will move us in that direction, but there is a long way to go. Also, MathJax will mean all math needs to be in <math> tags; all HTML and template formatting is temporary until/unless MathJax is enabled. — Carl (CBM · talk) 19:26, 13 January 2013 (UTC)

Here is the compromise I would propose (which I think is also the current best practice): articles that primarily use <math> and HTML should remain that way, and articles that primarily use <math> and {{math}} should remain that way. Editors who start new articles can pick the style they want.

We should discourage the IP editor from wholesale changes between styles (although that editor also seems to do other useful things, like changing <math> to something else for single-letter formulas). — Carl (CBM · talk) 19:32, 13 January 2013 (UTC)

I don't actually think "changing <math> to something else for single-letter formulas" is useful, for those of us who view articles using mathjax. It makes the variables look different from the way they do in longer formulas. —David Eppstein (talk) 19:38, 13 January 2013 (UTC)

This is why I consider wikipedia is last-eon technology. Life moves on. Get with the beat, luddites. Cross the Atlantic to a more progressive continent. --Matt Westwood 20:07, 13 January 2013 (UTC)

Although I take it in good humor, comments like that are not very distinguishable from trolling... — Carl (CBM · talk) 20:37, 13 January 2013 (UTC)

@David Eppstein: yes, it is certainly worse for people who use MathJax, but I am personally more worried about the default appearance, because few people have MathJax enabled compared to the number who just read articles without logging in. For the latter group, an HTML letter such as x (in any font) will usually be better than $x$. If we ever get MathJax enabled by default, I will help convert these to use it. — Carl (CBM · talk) 20:37, 13 January 2013 (UTC)

I certainly much prefer to have the symbols look as far as possible the same wherever they are. They are symbols not words. The symbol x just looks like a different symbol from x to me, and a definitely looks different from a. I guess it isn't so important that they are distinguishable from normal text as usually you have a few variables in so the italics show it is a bit of math so it is fairly easy to spot. The MathJax site uses Georgia font as far as I can see which is a serif font so the body text is closer to the MathJax equations - Perhaps people could do that on Wikipedia who were annoyed by the change from non-serif to serif. I'm sure it must be fairly easy to change the body text to Georgia though of course the MathJax font is closer to Times so just saying serif might be okay. Dmcq (talk) 02:22, 14 January 2013 (UTC)

Taking a step back for a moment, shouldn't we separate this into two discussions? Namely: (a) whether the the IP should be discouraged from making wholesale style changes to whole articles (ref Incnis and Carl), (b) the age-old discussion around math fonts, which I predict will not reach consensus soon. — Quondum 07:18, 14 January 2013 (UTC)

Yes, this debate erupts periodically and never results in agreement. This case seems analogous to citation styles and spelling differences, where there can also be strong conflicting opinions. The recommendation in WP:CITEVAR to seek consensus and "if there is disagreement about which style is best, defer to the style used by the first major contributor," seems appropriate here. RockMagnetist (talk) 01:42, 15 January 2013 (UTC)

Of course we like the math to be laid out properly. Trouble is the typeset stuff on Wikipedia looks like it's been photocopied out of a text book. RF 09:08, 18 January 2013 (UTC) — Preceding unsigned comment added by 109.153.136.200 (talk)

You're probably looking at it with the default appearance preferences f 'default to PNG' which is like that. In the future those will be rendered using MathJax which can be got by logging in and setting the preference to 'MathJax (experimental; best for most browsers)'. There is an argument between those who think variables inline should match surrounding text and not math separate equations and those like me who like the symbols to look the same everywhere they are used. In print the problem doesn't arise so much because they use a serif font normally, but I think it is an overhead distinguishing between the various symbols in Help:Math#Alphabets and typefaces but not on the basis of serifs so I have to count a and a the same. I think people who want the fonts the same for running text and symbols should change their default font to Times or Garamond, which is quite easy I believe if you have a username and log in. Dmcq (talk) 15:17, 18 January 2013 (UTC)

I just tried changing my css. I edited the custom css from preferences appearance which for me was my vector.css file and put in

div#bodyContent { font-family: Georgia, serif !important; }

span.texhtml { font-size: 1em !important; }

And now my text has serifs and looks more like the math. One could easily put in other serif fonts like Times New Roman instead. There's some misalignment problems but they're not bad and I'm sure some expert could help if they worry. Dmcq (talk) 16:29, 18 January 2013 (UTC)

I tried your custom css and found it prettier but harder to read. RockMagnetist (talk) 16:51, 18 January 2013 (UTC)

I like it with Times New Roman, though. RockMagnetist (talk) 17:47, 18 January 2013 (UTC)

You might like Cambria then if you're using Windows just make the list 'Cambria, Time New Roman, serif'. Dmcq (talk) 19:08, 18 January 2013 (UTC)

I like it! Very clean. RockMagnetist (talk) 19:26, 18 January 2013 (UTC)

The response from an IP address is a timely reminder that the great majority of people visiting Wikipedia do not log in and do not set any preferences. Shouldn't their needs be our priority? When you're editing a page, it would be a good idea to view it in an incognito window so you can see how it will look to most people. RockMagnetist (talk) 16:56, 18 January 2013 (UTC)

WP:«math»

Please, contribute to classification and comparison of all types of math typesetting in Wikipedia which are known to me. Thanks for the discussion which helped to write it. Incnis Mrsi (talk) 15:31, 20 January 2013 (UTC)

Using <blockquote> to delineate theorems

The same editor seems also be going around and delineating theorems using the html <blockquote> construct everywhere, under the guise of a "formatting improvement". I don't think this is a standard practice. I've reverted a few such changes (e.g., [10]) where there was a substantial change to the intended way in which the theorems were to be displayed. That seems to be most in keeping with the standard philosophy of not making unilateral changes to article formatting. Sławomir Biały (talk) 12:50, 27 January 2013 (UTC)

TAFI

Hello, Please note that Remainder, which is within this project's scope, has been selected to become a Today's Article for Improvement. The article is currently in the TAFI Holding Area, where comments are welcome about ideas to improve it. After the article is moved from the holding area to the TAFI schedule, it will appear on Wikipedia's Main Page in the "Today's Article for Improvement" section for one week. Everyone is invited to participate in the discussion and encouraged to collaborate to improve the article. Thank you, TheOriginalSoni (talk) 07:36, 27 January 2013 (UTC) (From the TAFI team)

The remainder article is currently not rated by the project. Sławomir Biały (talk) 12:53, 27 January 2013 (UTC)

Cocycle and cochain (algebraic topology)

In 2005, Cocycle was a regular dab page, but during this 7 years it was tampered by two users. Meanwhile, I found Cochain (algebraic topology) (edit | talk | history | links | watch | logs) to be an ancient redirect to cohomology and almost without inbound links, which IMHO does not make much sense. A volunteer to fix these irregularities? Incnis Mrsi (talk) 19:24, 20 January 2013 (UTC)

I think these should just be redirected to singular cohomology. Oh, wait, the article doesn't exist :D -- Taku (talk) 01:10, 30 January 2013 (UTC)

n-simplex

There are a series of articles about simplexes (5-simplex 6-simplex etc.) which contain a sentence of the form "More simply, the vertices of the 9-simplex can be positioned in 10-space as permutations of (0,0,0,0,0,0,0,0,1). This construction is based on facets of the 10-orthoplex." The form is not completely regular, but some (all?) of these are wrong. The 10-simplex, for example, has 11 vertices, but there are only 10 listed, the 9-simplex is right (ten vertices in 10-space) except that there are only 9 coordinates are listed. I think it's intended that the (regular) n-simplex be constructed in (n+1)-space, like in the 8-simplex article. 173.227.48.5 (talk) 23:41, 28 January 2013 (UTC)

Feb 2013

Triangular rule

I fear this is a hoax. Comments would be welcome. Deltahedron (talk) 07:40, 1 February 2013 (UTC)

After [11] it looks more as a poorly sourced stub rather than a hoax. My first impulse was also to wipe them out, all of them. But the observation of 1/2 b_i h_i under <math> suggested just an extreme incompetence in exposition of the idea, initially valid. IMHO such primitive numerical integration method may exist; but the article is not written yet. Incnis Mrsi (talk) 10:18, 1 February 2013 (UTC)

I've noted on the talk page I can't find the term in the index of the book on Amazon which even if it is something else badly put it is not notable. Dmcq (talk) 13:38, 1 February 2013 (UTC)

Now at Wikipedia:Articles for deletion/Triangular rule. Deltahedron (talk) 20:10, 1 February 2013 (UTC)

"Unregistered" appearance of <math> and latex to html

There are two distinct problems, but the latter is a consequence of the former.

Since the trimming of texvc a year ago, the default look of <math> (even for simplest cases) became, as another IP recently said, “like it's been photocopied out of a text book”. Could anybody propose an idea to make <math> in Wikipedia more accessible?

The main problem with Special:Contributions/99.241.86.114 is that he tries to make better look of Wikipedia for unregistered users, a thing which we neglect. But he apparently does not understand that he frequently makes articles worse for us. Sometimes complaints appear at his user_talk, the most recent being user talk: 99.241.86.114 #Methods of contour integration, but it's the time to develop a permanent solution. I propose: let us make a typography quality scale such that its quality in any mathematics-related article could be assessed. Then, let IPs "improve" articles which are anyway poorly formatted, but they should be barred from "improvements" in articles with a good typography. Incnis Mrsi (talk) 07:30, 2 February 2013 (UTC)

Today he replaces the standard notation for Sⁿ with a boldface perversion. How long will we await this shadow person in front of the negotiation table? Incnis Mrsi (talk) 17:03, 3 February 2013 (UTC)

Earlier they replaced some of the \oplus and \otimes symbols at gyrovector space with a unicode character, but not all of them and not the \ominus symbols. This has nothing to do with looking better for unregistered users. It is just latex to html for the sake of it. And it's not even anything to do with html - it's just pasted unicode characters. Admittedly the article does use these symbols inline in the middle of standard text so the symbols do look large. 78.144.197.99 (talk) 18:06, 3 February 2013 (UTC)

Well, most of the edits are actually fine with me. But sometimes the editor includes drastic changes to notation or formatting, such as replacing $S^{n}$ with $\mathbf {S} ^{n}$ as you noticed, or awkwardly stuffing theorems into blockquotes. Unfortunately, the edit summaries are not sufficiently detailed to decide whether an edit is potentially controversial or not, and individual edits sometimes account for fairly substantial changes without much indication of the nature of those changes. Sławomir Biały (talk) 18:11, 3 February 2013 (UTC)

For example, I just noticed that this sequence of edits introduced the notation of a bold face H to denote the upper half plane, apparently without actually saying what the notation is supposed to mean, and also opted to spell "half plane" in the germanized manner "halfplane". This is just below the threshold of me caring enough to do something about though... Sławomir Biały (talk) 18:29, 3 February 2013 (UTC)

Tropical geometry

Some other eyes would be helpful at Tropical geometry. Deltahedron (talk) 18:50, 3 February 2013 (UTC)

typography of (typographical) ellipses

In this edit, WP:ELLIPSES was cited as justification. Whoever wrote that manual page section never contemplated the use of ellipses in mathematical notation. In TeX is it commonplace to write

$a+b+c+\cdots \,$

$a+\cdots +z\,$

Notice that

$a+\ldots +z\,$

looks different from

$a+...+z\,$

and the latter is not standard in TeX. Donald Knuth obviously thought more deeply and insightfully about typography than did whoever wrote that Wikiepdia manual page.

I think the manual page should note that it is not intended to apply to mathematical notation, whose conventions may be different. That may seem obvious, but apparently it wasn't obvious to whoever did the linked edit. Michael Hardy (talk) 17:42, 2 February 2013 (UTC)

I would like to be clearer too on mathematical notation there. I moved the pages because it was impossible to type ellipses. I believe that the manual is correct when it writes that ellipses "is harder to input and edit" but I don't have strong opinion on the matter as soon as we have redirects to cover both writing styles. -- Magioladitis (talk) 17:55, 2 February 2013 (UTC)

You are apparently preoccupied with typography, but there is also a semantic aspect. Although a dedicated character U+22EF ⋯ MIDLINE HORIZONTAL ELLIPSIS exists, the former article's title ended with interpuncts and spaces, which have enough typographic appeal, but are rather nonsensical. Now someone replaced a finely-looking nonsense with a roughly-looking semantically substantial character. The former was bad and the result is not good, too. Incnis Mrsi (talk) 18:02, 2 February 2013 (UTC)

I regard ellipses as a symbols under WP:TITLE#Special characters, and as such, should be avoided in article titles. If there must be an ellipses in the title (hard to imagine), there must be a redirect containing three unspaced dots. So IAFAIC, any title with an ellipses should be moved to a title with dots. — Edokter (talk) — 18:28, 2 February 2013 (UTC)

"IFAIC"? --JBL (talk) 18:47, 2 February 2013 (UTC)

Corrected. — Edokter (talk) — 09:48, 3 February 2013 (UTC)

Instrument for Assessing Identity Confusion [12] Deltahedron (talk) 09:51, 3 February 2013 (UTC)

Ellipses are punctuation, and punctuation is not forbidden in article titles. I've moved the series articles in Template:Series (mathematics) to titles with the ⋯ character, and I've created or updated redirects from titles with three unspaced periods. (The lone exception is 1 − 2 + 3 − 4 + · · ·, which I lack the ability to move.) Ozob (talk) 16:32, 5 February 2013 (UTC)

I noticed that 3.14... does not have a page. Should the redirect be created? Tkuvho (talk) 16:41, 5 February 2013 (UTC)

Yes. Obviously to τ/2. Sławomir Biały (talk) 22:05, 5 February 2013 (UTC)

I'd like to add my supporting opinion to Ozob. We should use the correct symbol in the article title, unless there is some way (and clearcut reason) for avoiding symbols altogether. The usual arguments about people with screen readers clearly don't jibe if we are going to use an incorrect symbol as a substitute (like using three periods instead of a centered ellipsis). So what if the screen reader knows how to pronounce it? it's not the correct symbol. Sławomir Biały (talk) 22:05, 5 February 2013 (UTC)

Linear or affine?

I have noticed some folks (not very systematically) going around elementary mathematics articles and changing instances of "linear function" to "affine function": [13] and [14]. While this is perhaps technically correct terminology in higher mathematics, is this usage really very common in grade school mathematics? Also, I don't think it is helpful in an article like function (mathematics) to link to the article affine transformation in the caption of a simple affine function of one real variable (i.e., a grade-school "linear function"). Do we have a better place to link to such a notion? Sławomir Biały (talk) 01:10, 5 February 2013 (UTC)

I had just been considering this exact same problem and wondering what should be done about it. In the artricle here on linear function I'd normally call the first use of linear function an additive function and I'd call the vector one a linear transformation. I've never said affine function for affine transformation and what they are calling an affine function I'd normally call a linear relation. Over and above all that though is the main problem that the articles this is being applied to are supposed to be accessible to schoolchildren and I really think 'affine' is a blocker word in that context. Dmcq (talk) 01:48, 5 February 2013 (UTC)

The word "linear function" actually means that its graph is a line, and does not refer to the meaning from linear algebra. Because of confusion, Wikipedia currently has articles on degree-2, -3, -4, and -5 polynomials, but lacks an article (or even a section) on ax + b functions. The {{Polynomials}} navbox links to linear equation instead. IMHO a separate article must be created (possibly, by splitting of linear equation) – it is an important class of functions far beyond its rôle as endomorphisms and the automorphism group (for a ≠ 0) of the affine line. Incnis Mrsi (talk) 08:02, 5 February 2013 (UTC)

For one thing, it's what one tries to construct when one does linear regression. See for instance Linear predictor function, which has a link to the wrong kind of linear function in its lead. —David Eppstein (talk) 08:20, 5 February 2013 (UTC)

Sorry, David, you're wrong. You're making the usual clumsy mistake of thinking that the reason why linear regression is called linear is that one is fitting a line. But if you fit a parabola by least squares, that's still linear regression. And the reason for calling it that makes sense. Nonlinear regression is something else. The article on linear predictor functions has the right link. You're neglecting the fact that a column whose every entry is the number 1 may be one of the predictors, so you're taking a linear combination of that and the others. See this question and its answers. Michael Hardy (talk) 15:40, 5 February 2013 (UTC)

Ok, fine, I should have said simple linear regression. My point was not about what the "linear" in linear regression means, but rather that these functions are important in this role. —David Eppstein (talk) 16:49, 5 February 2013 (UTC)

"Affine function" smacks of the "New math" approach, and (I should hardly add) that is not the direction where we want to take Wikipedia. This is also more popular in French textbooks (Berge's Geometry, unless I am mistaken, makes a big deal out of "affine spaces" in general). I am reminded of David Mumford's story about his daughter's textbook's definition of the plane, in a French school in late 1960's, as a "torseur", a concept then very popular among mathematicians at IHES. Arcfrk (talk) 22:52, 5 February 2013 (UTC)

Maybe we can follow the approach of the German wikipedia, which distinguishes explicitly between the "highschool use" (ax + b ) of term and its meaning otherwise (linearity of operations) and has separate articles for it. We could change linear function into a disambiguation page linking to the appropriate articles, though the article for the "highschool" variant still needs to be written. --Kmhkmh (talk) 09:54, 5 February 2013 (UTC)

I agree. [15]. --El Caro (talk) 11:59, 5 February 2013 (UTC)

This seems very simple: calling an affine function linear is wrong. Isn't it? Like a grammar mistake, just because many people make the same mistake, that doesn't make it right. We have to use the "correct definition", regardless of the sophistication of mathematics. -- Taku (talk) 01:54, 6 February 2013 (UTC)

No it is actually not that simple since is about common naming conventions and a name as such is neither right nor wrong it is just name. You may argue whether particular name a misnomer and not very helpful, but that's a separate question. Moreover WP should describe mathematical terms and names as they are used and resists pushing its own naming conventions. As that name is common in "highschool" math literature (and probably some other areas) WP should explain it (and of course point out that it is not a linear function in terms operations or the usual usage of the term linear). Moreover we can combine that with (highschool oriented) article on the ax + b function, which we currently seem to lack anyhow.--Kmhkmh (talk) 02:29, 6 February 2013 (UTC)

It's not as if the definitions of linear and affine were handed down on stone tablets. Probably 99.9% of people have never heard of an affine function—a figure that even includes most scientifically literate individuals—but I'd wager a fair number have heard of a linear function (and think it means a function whose graph is a line). And anyway, regardless of terminology, it's a useless perversity to link to the article affine transformation in a context that means a linear function of a single real variable. Sławomir Biały (talk) 03:41, 6 February 2013 (UTC)

Yes, the link to affine transformation would be very unhelpful, especially when a reader is not mathematically minded. -- Taku (talk) 12:47, 6 February 2013 (UTC)

It's completely and utterly common to call any degree 1 (or constant) polynomial "linear", in the context of elementary algebra and calculus, at least in the United States. In particular, this terminology is used in both Spivak's Calculus and Stewart's Calculus (the former is a well-regarded rigorous calculus textbook; the latter is probably the most used calculus textbook in the U.S.). This is not the same meaning as in linear algebra, and it is very hard to claim that both Spivak and Stewart are "incorrect". It is completely uncommon to call these functions "affine". We should not use a word that nobody else uses in these contexts. Nobody calls them "cosets", either, even if that's what they are. — Carl (CBM · talk) 02:39, 6 February 2013 (UTC)

I suppose I stand corrected. (I didn't go to high school in US. On the other hand, Stewart is the textbook we're using to teach calculus, so maybe I should have known better.) Ok, how about degree 1 polynomial or polynomial of degree at most 1, because it's what it is? To use "linear function" to refer to such a polynomial in the context beyond elementary calculus would be very confusing. -- Taku (talk) 12:47, 6 February 2013 (UTC)

As a name for the future article that's ok with me. However linear function needs to become disambiguation and link to this article and the name linear function needs to be mentioned in that article as well because it is the under which highschool students or college freshmen are likely to look for it. The article itself then can establish the context under which the name is used, so that there's no confusion. You can quickly sample various highschool textbooks via a Google Books search, in case you want to check it out yourself (a few samples: [16], [17], [18], [19], [20], [21]). This usage of the term is actually not a particular English thing either at least in German highschool literature it is more or less a standard term for the polynomial of degree one and and occasionally used in that fashion in university level calculus books and in some engineering books as well. It even used in such classics as Bronstein (the European analogon to Abramowitz and Stegun).--Kmhkmh (talk) 13:34, 6 February 2013 (UTC)

Several remarks:

• It is clear that "linear" has two related but different meaning in mathematics, namely "of degree one" and "commuting with addition". The meaning of this adjective depends on the object that is qualified and on the context. As far as I know, the ambiguity occurs only with "linear function" and sometimes "linear polynomial". In the latter case, "linear" has usually the first meaning and affine is rarely (but sometimes) used. For the second meaning (homogeneous polynomial of degree one), the standard is to use "linear form".
• Strangely linear form, which is a standard terminology is a redirect to linear functional, an unusual terminology for the same notion; this leads to a strange hatnote explaining that a linear functional may be a functional, but not necessarily.
• Even more strange: linear polynomial is a dab page that asserts that a linear polynomial may be several things, but not a polynomial!
• The use of "linear function" for "polynomial function of degree one" appears in wp in piecewise linear function (piecewise affine function does not exists).
• Several editors have considered the usage in other languages. In French, although "function" (fonction) and "map" (application) are formally almost synonymous (a map is defined everywhere, a function not necessarily), "function" is used, in practice, only for real and complex valued functions, and is never user for linear maps between vector spaces. Thus "linear function" means "polynomial function of degree one" and "linear map" means "additive map" even for a map which is a real valued function. My feeling is that these informal conventions are also used in English by most professional mathematicians.

Thus, I suggest

1. To rewrite linear polynomial, may be as a redirect to the future "linear function" (done as a redirect to Polynomial#linear polynomial)
2. To move linear functional to linear form (done)
3. To merge the present state of linear function into linear map, and to explain there that "linear function" is sometimes a synonymous, but has frequently another meaning, may be with a hatnote {{distinguish}}.
4. To write the article "linear function" devoted to polynomial functions of degree one, with explanation and hatnote to distinguish with "linear map"
5. Do not make a dab page "linear function that will be more confusing"
6. Update linear and linear (disambiguation) (the latter being rather confusing)

D.Lazard (talk) 16:00, 6 February 2013 (UTC)

I agree with you that the better solution is to make linear function be the one that allows an additive constant term, and to have a hatnote pointing to the other one (which could reasonably be called linear map). Doing it with a disambiguation page is both more confusing and unnecessary (we don't generally need dabs with only two links). As I already commented earlier (in a remark that was quickly sidetracked into the sort of pedantry that has led us into this mess) we should also consider how linear predictor function fits into this picture. It's a bit of a confusing example because it starts out as a function with a constant term but then later on in the article (by introducing an auxiliary variable) turns it into a linear map. —David Eppstein (talk) 18:43, 6 February 2013 (UTC)

Linear functional is a fairly common synonym for linear form, by the way, but I think one that tends to be used more in analysis rather than algebra. Sławomir Biały (talk) 21:48, 6 February 2013 (UTC)

At some point a long time ago, someone replaced "linear" with "affine" in the article Logical connective. I let it go, because I don't know what the kids are calling it these days. However, if there is a distinction, please help make sure the appropriate term is being used. My understanding of the concept as it relates to logical connectives is that when the truth-value of both statements always makes a difference or never makes a difference to the resulting truth value (as for instance they do when connected by "and" or "if and only if") then the connective is linear. When both statements do not always but also do not never make a difference (as they do not for "or" or "if...then") then the connective is not linear. This usage of the terminology is consistent with what Post used in his writing on functional completeness. Greg Bard (talk) 16:06, 6 February 2013 (UTC)

Just remove that affinity section. The only things that satisfy that are the logical equivalence relations or their negatives and a quick google search gives nothing so it can't be exactly a common term there. The link is definitely wrong. Dmcq (talk) 18:38, 6 February 2013 (UTC)

No, don't remove it. We have Post using the term "linear" so if no one knows any better, we will use "linear" if necessary. Greg Bard (talk) 00:54, 7 February 2013 (UTC)

There is a bit of a problem with that too in that there is linear logic, and really how often do people use the term? In fact where did Post use it? Dmcq (talk) 12:30, 7 February 2013 (UTC)

There are lots of papers and books on the theory of clones and coclones (not only on) the two-element set. I fail to see the relevance of linear logic to this issue, but unlike Girard’s naming conventions, the terminology here makes perfect sense: an n-variate Boolean function is affine/linear in the sense mentioned by Greg Bard if and only if it is an affine mapping from the n-dimensional affine space over $\mathbb {F} _{2}$ to the 1-dimensional space. Which also shows that the naming issue of linear vs. affine for this concept is exactly the same one as being discussed in this thread, and if any consensus comes out of this discussion, it applies to it as well. The only actual problem with the Logical connective article is that despite the name and the lead paragraph, it only deals with classical logic and its two-valued semantics.—Emil J. 13:51, 7 February 2013 (UTC)

I had considered that but being pedantic an output of always false is also a linear output whereas in that article they have every input affecting the output - which if one expressed it using the equivalence relation with ⊕ one would have to say was affine as one might have all false going to true. Having a term for something with just the two possibilities seems overkill as I can't find references for the words in the context of logical connectives. Dmcq (talk) 16:20, 7 February 2013 (UTC)

I think you are misreading it. The condition is that every variable either always affects the output (i.e., for every assignment, switching the truth value of this particular variable changes the value of the function) or never affects the output. The constant false function is the case where no variable affects the output. Also, you seem to be under the false impression that connectives or truth functions have to be binary, there are in fact infinitely many possible affine connectives. One reason why affine/linear connectives are important is that they form a maximal clone, and as such appear in Post’s characterization of functional completeness. Let me stress again that this classical result is about connectives of arbitrary arity.—Emil J. 16:54, 7 February 2013 (UTC)

Sorry yes I misread. That does make more sense and I've found some references to affine even if I couldn't find any for linear or affinity in this context. The link to affine transformation still seems rather strained to me, and I think having some non boolean logic relation satisfying that in a useful way seems unlikely. Dmcq (talk) 18:16, 7 February 2013 (UTC)

Well I think I'll just leave the bit about 'affinity' in Logical_connective#Properties and its link to affine transformation alone. It may sound strange to me but I'm no expert. Dmcq (talk) 18:36, 7 February 2013 (UTC)

Comment added to my preceding post: I have not found in WP any definition of "linear function of several variables". All the implicit definitions that I have found are equivalent to that of linear form. None of the given definitions for univariate functions extend immediately to the multivariate case. For the definition as linear form, if $f(x,y,z)$ is a linear function of three variables, then $f(x,y,1)$ is not linear. This is a further witness that one has to consider different definitions of "linear" in algebra and in calculus. The future article "linear function" should also consider the multivariate case. D.Lazard (talk) 17:32, 6 February 2013 (UTC)

Policy on cross-reference pages

It has been proposed at this page to make the concept of cross-reference pages (formerly "multiple-cross-reference pages") into a Wikipedia guidelines. Opinions should be posted there.

The first several such pages were math pages and the concept first appeared on this present WikiProject talk page. See Category:Cross-reference pages. Michael Hardy (talk) 04:29, 8 February 2013 (UTC)

See Category:Cross-reference pages for the few current examples. Michael Hardy (talk) 04:31, 8 February 2013 (UTC)

Ordered set under the scope of WikiProject Mathematics?

Just came across Ordered set, it needs a lot of work and seems to me to be under the scope of WP Mathematics. I added a reference, but that is as far as I can go with this page with my limited mathematics understanding. Currently the page is not listed as being under any WP. Cheers, Keetanii (talk) 03:04, 7 February 2013 (UTC)

I think it needs, not so much work, as deletion. Wikipedia is not a dictionary and we don't have to document every possible phrase that might come up in mathematics. There is nothing to say that is not already covered at either partial order or total order. A disambig page that points to those two might be OK, but what's the point? Alternatively, just redirect to partial order, the more general of the two. --Trovatore (talk) 04:44, 7 February 2013 (UTC)

Could rederict to order theory alternatively. AHusain (talk) 05:06, 7 February 2013 (UTC)

Well to some degree an encyclopedia is a dictionary on steroids, meaning technical terms should be covered. Whether they havetheir own entry or potentially just a redirect and coverage in a larger article is separate matter. But one should be able to look up the term in WP.--Kmhkmh (talk) 19:12, 7 February 2013 (UTC)

I've changed it to a cross-reference page, so far having only two items. Any time you see it proposed that a title could redirect to any of two or more articles, and all of them seem just about equally reasonable redirect targets, one should consider making it a cross-reference page listing all of them. Michael Hardy (talk) 04:05, 8 February 2013 (UTC)

Interesting idea. I'll have to let it percolate for a while before I can be sure whether I like it, but it does seem to be a niche not currently filled. --Trovatore (talk) 10:25, 9 February 2013 (UTC)

A ten-year old error in an article?

In 2003 I created the article titled Kolmogorov's zero–one law. It says

Suppose

$X_{1},X_{2},X_{3},\dots \,$

is an infinite sequence of independent random variables (not necessarily identically distributed). Then, a tail event is an event whose occurrence or failure is determined by the values of these random variables but which is probabilistically independent of each finite subset of these random variables.

I think that's stood there since 2003.

I wonder if I should have said something else instead, as follows. One would not assume independence of the random variables in the sequence, and one would say that a tail event is an event whose occurrence or non-occurrence is determined by the values of the random variables in the sequence but whose occurrence or non-occurrence is unchanged by changing the values of finitely many of the random variables in the sequence. I think that says the same thing if they're independent, but not if they're not. For example, suppose p is a random variable taking values in (0,1) and each random variable in our infinite sequence of Xs is 1 with probability p and 0 with probability 1 − p, and are conditionally independent given p. Then the Xs themselves are not independent because if one of them is 1, that makes it more probable that p is large and thus more probable that the next X is 1. Then the event that

$\lim _{n\to \infty }{\frac {X_{1}+\cdots +X_{n}}{n}}>1/2$

would be a tail event by the second definition but not by the first. (The probability that that limit is more than 1/2 is actually just the probability that p is more than 1/2. This tail event would not violate the zero–one law because the hypothesis of independence does not hold.)

The definition given in that article is good enough for that article because independence is assumed. But should I have given the latter defintion?

Tail event currently redirects to Kolmogorov's zero–one law. Michael Hardy (talk) 00:38, 9 February 2013 (UTC)

"... a tail event is an event whose occurrence or non-occurrence is determined by the values of the random variables in the sequence but whose occurrence or non-occurrence is unchanged by changing the values of a finite subset of the random variables in the sequence."

You left out the underlined phrase. JRSpriggs (talk) 10:34, 9 February 2013 (UTC)

Fixed. Thanks. Michael Hardy (talk) 18:10, 9 February 2013 (UTC)

Gaussian elimination vs. Gauss–Jordan elimination

I've proposed to merge Gauss–Jordan elimination into Gaussian elimination. While it is true that most textbooks treat these as distinct concepts, I think having two articles is unnecessary. Gauss–Jordan elimination could be a subsection of Gaussian elimination. Does this seem like a good idea?

For me, the ideal article arrangement would be to join both articles into one titled Row reduction. I think it would be much easier to explain the concepts under this less ambiguous title. Because "Gaussian elimination" may or may not stop after it's in row echelon form (before the matrix is reduced), depending on the textbook. Thoughts? Mark M (talk) 09:13, 9 February 2013 (UTC)

Yes, a good plan which makes sense. Stating any differences in what authors refer to as "Gaussian elimination" or "Gaussian–Jordan elimination" shouldn't be a problem in a sentence or two. Row reduction is the main operation, and yet it's just a redirect. M∧Ŝc²ħεИ_τlk 09:47, 9 February 2013 (UTC)

I would suggest to merge also these two articles with Row echelon form. In fact, row echelon forms are defined independently of any algorithm and Gaussian and Gauss-Jordan eliminations are the most natural algorithms to compute them. Without such a merge, I do not see how to explain that "the result of Gauss-Jordan elimination is independent of the way of doing Gauss-Jordan elimination". By the way, properly speaking, Gauss-Jordan elimination is not Gaussian elimination followed by a further reduction; this "further reduction" is mixed with Gaussian reduction. It is only the unicity of the result that allows to call Gauss-Jordan elimination these two different algorithms. D.Lazard (talk) 10:19, 9 February 2013 (UTC)

List of well-known mathematical operations

I tried to compile a list of mathematical notations which a reader of an article about physics is presumed to know: see WP:MOSPHYS #Mathematics (it’s a draft yet). IMHO the extent of the “well-known notation and semantics” should be first standardized outside articles on fundamental mathematical – certainly, the article ring (mathematics) may not deal with the “multiplication” operation as with a known concept, even if any reader is familiar with the notation.

Does anybody see flaws, omissions, or have other insights? BTW parts of this material may be later reused by (or moved into) WP:MOSMATH. Incnis Mrsi (talk) 10:47, 4 February 2013 (UTC)

It seems like the cross product and wedge product would also be there, if the dot product and bra-ket notation are... I'm not entirely sure of the purpose of that section, though. Is it to show the preferred format of each operation? Or, as the final note suggests, notations which can be assumed to be known? I can understand the former purpose, but the latter purpose would be problematic to figure out. I would be really amazed if tensor contraction is really better known than the cross product... Rschwieb (talk) 21:58, 4 February 2013 (UTC)

Surely this depends on context? E.g. (to pick two fairly recently created mathematics articles) I'd expect a different level of background knowledge for a reader of Good filtration than for a reader of 888 (number). Otherwise it wouldn't be possible to write articles about highly technical subjects without immediately getting bogged down in definitions. —David Eppstein (talk) 22:33, 4 February 2013 (UTC)

Not necessarily definitions. I said that anything outside the standard list shall be declared, with links. Incnis Mrsi (talk) 07:37, 5 February 2013 (UTC)

Yes. For example, $|D|$ would mean the complete linear system of a divisor in algebraic geometry (not absolute value). This sort of program strikes me as feasible as trying to stabilize conventions across math articles. -- Taku (talk) 01:57, 5 February 2013 (UTC)

I do not see anything wrong with 21st-century physicists who know contraction better than the notation from the age of James Clerk Maxwell. To "show the preferred format" is a secondary aim. First of all, the list should, by exclusion, prescribe to declare certain notations in articles. Incnis Mrsi (talk) 07:37, 5 February 2013 (UTC)

I'm not sure what "prescribe to declare" means, but if it means that you are prescribing what notation should be used in articles, then I think i agree with Taku that this is infeasible. It is also overstepping the bounds of being encyclopedic. On the other hand, if the purpose is to list the different things the same notation can be used for, then that would be useful for a reader trying to track down a bit of notation. Rschwieb (talk) 14:34, 5 February 2013 (UTC)

Do you actually read what I said? The primary aim is to form a list of notation which are presumed to be known for a reader which has interest in math formulae. Other notation, of course, may be used, but it must be declared(explained). For example, in Majorana equation:

“

$-i{\partial \!\!\!{\big /}}\psi +m\psi _{c}=0\qquad \qquad (1)$

written in Feynman slash notation. Here ψ_c is the charge conjugate of ψ, which can be defined in the Majorana basis as

$\psi _{c}:=i\psi ^{*}.\$

”

It declares the use of $\partial \!\!\!{\big /}$ and _c symbols, but i, *, and := are assumed to be known notations. Incnis Mrsi (talk) 09:54, 6 February 2013 (UTC)

To maintain our civil environment here I will interpret "Did you actually read what I said" as "Given my history of problems communicating in English I would appreciate elaboration on your last comment." In words you say the purpose is to make a table of notation which is "safe to assume is understood". In action a table was made which includes comparatively obscure notations (You cannot claim that bra-ket and tensor contraction are on a par with "+" and "sin(x)". The tensor contraction does not even render in my browser.) and has so far it has omitted something as simple as the cross product. Given the apparent clash of words and action, I had to get clarification on what the task was.

At any rate, I think I can stop asking for clarification and go frame my comments for the original post. Flaws: highly subjective, needs a good way to explain multiple meanings of single notations. Omission: cross product, (probably) wedge product. Rschwieb (talk) 15:30, 7 February 2013 (UTC)

Regarding the the list entries themselves, the tensor contraction code has problems, as it does not parse (Failed to parse (lexing error):...). In the braket entry, the phi and angle brackets seem to be in boldface, whereas the other symbols are not. Perhaps this is browser dependent. In your notation example above, I have never seen ":=" used in a physics textbook; this sort of notation is more popular with computer scientists.

Regarding presumption of knowledge of mathematical notations, I don't think we can establish a single threshold, for two reasons. First, what notation needs to be explained is dependent on the expected audience for the article. The article on quantum mechanics may be viewed by people wanting to learn about it--they probably won't know the braket notation. A high school student wanting to learn about Newton's laws of motion may not know calculus. This is not to say that all notation must be explained in all articles, but which notation gets explained is dependent both on the subject material and the expected audience. Second, mathematical notation is, to use a CS concept, highly overloaded. |A| may mean set cardinality, determinant, complex magnitude, vector norm (yes, I've seen this done), the complete linear system of a divisor, ..., and occasionally absolute value. Thus even familiar notations may need to be explained depending on context. --Mark viking (talk) 18:00, 14 February 2013 (UTC)

calculate

Can somebody calculate the midway point between 500 and 2,200,000,000 please? Please show the calculation as well. Thanks Pass a Method talk 19:50, 9 February 2013 (UTC)

You're more likely to get help with your homework at Wikipedia:Reference desk/Mathematics. Deltahedron (talk) 20:17, 9 February 2013 (UTC) Tr

Ask yourself: What does it mean to say that m is the midpoint between a and b? How can I express that as a mathematical equation? If I solve the equation for m, what do I get? JRSpriggs (talk) 06:54, 11 February 2013 (UTC)

Disambiguation help needed with Matrix algebra

Matrix algebra has a large number of incoming links for which expert assistance is required. Please help if you can. Cheers! bd2412 T 03:00, 13 February 2013 (UTC)

It's a little annoying to members of the project when disambiguators make changes like this, which point to the wrong article. I'm not accusing anyone of everything, except to say that people probably shouldn't be involved in mathematics disambiguation if they don't know the difference between a tempered distribution and a tempered representation—or, by extension, between a matrix algebra (as a count noun) and matrix algebra. Sławomir Biały (talk) 03:47, 13 February 2013 (UTC)

It's a little annoying to members of the disambiguation project when these pages are allowed to build up such large numbers of incoming links that they crowd the list of the most linked-to disambiguation pages. Now, I note that Adjoint representation has recently been made a disambiguation page (and a WP:TWODABS page at that), and nothing has been done about it. Disambiguators disambiguate, and presented with a list of incoming links like this, will likely try to fix them all by making the best guess from the context of the terms. I have made posts here several times requesting the sort of expert assistance that you suggest we need. Frankly, I think it would be fantastic for everyone involved if this project could just take over the maintenance of all of its disambiguation pages. Cheers! bd2412 T 05:22, 13 February 2013 (UTC)

What means “a WP:TWODABS page”? This wording is apparently chosen to suggest that certain guideline discourages disambiguations pages with only two entries, which is a lie (if I do not see here something which BD2412 did not say at all). Incnis Mrsi (talk) 07:33, 13 February 2013 (UTC)

That is incorrect. The guidelines do indeed discourage the making of disambiguation pages with only two entries if one of the topics is primary (i.e. substantially more likely to be the target sought), because such a page is not needed as a navigational device. It is important to remember that the purpose of disambiguation pages in the first place is merely to assist readers in finding the topic they are trying to find. If the reader is just as likely to be assisted by a redirect to one of two possible articles, which has a hatnote pointing to the other, then there is no basis for making a disambiguation page in the first place. The existence of such a page will only complicate the efforts of the reader to find what they are looking for. Consider: if a term has only two meanings, at least fifty percent of the time the reader must be looking for one of those meanings. If that title is a disambiguation page, then the reader must figure out which meaning to go on to. In other words, they would type or click the name and get taken to a page from which they need to make another click to get where they really want to go. Where there are only two possible meanings, having the more likely of those meanings at the undisambiguated title means that at least half the time, the reader landing on that page does not need to click any further, because they have found exactly what they are looking for. For the reader who is looking for the sole other meaning, it is right there in the hatnote, so they are not inconvenienced any more than they would be if they had gone to a disambiguation page. The basic question, of course, is which of the two pages is the primary topic that should be at that title, but that is often much easier to determine then people imagine, particularly if only one page contains an exact match to the title. In short, avoiding a disambiguation page in a WP:TWODABS situation inconveniences no one, while saving at least half the people who come to the page from having to read, decide, and click again. bd2412 T 12:57, 13 February 2013 (UTC)

The guideline states:

As discussed above, if an ambiguous term has no primary topic, then that term needs to lead to a disambiguation page. In other words, where no topic is primary, the disambiguation page is placed at the base name.

What is not clear? The term has no primary topic ⇒ it must lead to a dab page. Hence, by modus tollens, “something other than disambiguation is possible” ⇒ “the term must have a primary topic”. I do not see here even a hint from BD2412 that some title of (matrix algebra, adjoint representation) has some definite primary topic. BD2412’s eloquences above (starting from “It is important to remember that the purpose…”) represent a well-known tendency, deeply entrenched in minds of many Wikipedians which deal with popular culture topics, but having less support among Wikipedian scientists. It does not represent an official guideline by no means. Users which create and maintain a quality content do not forget that dab pages make Wikipedia better, in the long-term perspective. An attempt to save readers’ clicks by eliminating the dab page at a really ambiguous title will inevitably be paid by erroneous internal links. Incnis Mrsi (talk) 16:41, 13 February 2013 (UTC)

Dab pages only make the encyclopedia better when they are used appropriately. Please consider the (official) guideline WP:CONCEPTDAB, which applies to adjoint representation. Mark M (talk) 17:06, 13 February 2013 (UTC)

I known what is CONCEPTDAB and even largely participated in creation of one. If you will opt for a CONCEPTDAB for adjoint representation, then look to Adjoint, please. Apparently, there is already a botched attempt to create such CONCEPTDAB. Incnis Mrsi (talk) 18:40, 13 February 2013 (UTC)

It's really not much work to make the article a concept dab.. in fact adjoint representation of a Lie group basically already is. Anyway, please discuss this further on the RM I've linked to below. Regarding adjoint.. I hadn't noticed it before, but I think that one should be a dab. While there is technically a very broad concept, my feeling is that it should primarily be for disambiguating (which it currently does anyway). The broad concept is more likely to confuse than clarify. Mark M (talk) 19:41, 13 February 2013 (UTC)

Is this edit of R'n'B a single mistake, or a pattern of incomwpetence? For example, I would not say anything bad about a user which makes one erroneous link change for five hundreds accurate dab link eliminations. Incnis Mrsi (talk) 07:33, 13 February 2013 (UTC)

I don't know if it's part of a pattern of incompetence, but the tempered representation wasn't the only worrying thing about that edit. The editor was unsure that Cauchy's theorem should point to Cauchy's integral theorem, which strongly suggests that he lacks a basic literacy in mathematics. We've also heard from Wikiproject disambiguation before, about incoming links to disambiguation pages where (in my opinion) none of the disambiguations would have been correct. I just don't see that disambiguation should trump all other considerations. Obviously, it's something that we should do, but not at the expense of having a link point to the wrong article. Sławomir Biały (talk) 13:52, 13 February 2013 (UTC)

First, R'n'B is one of our best disambiguators, an editor for whom a charge of "incompetence" treads close to being a personal attack. Second, this is a general purpose encyclopedia, for which "basic literacy in mathematics" means no more than knowing what a square root is and knowing the difference between a numerator and a denominator. Part of the problem with efforts to disambiguate math concepts is that the articles themselves border on the unreadable, sinking immediately into inaccessible technical jargon. Ideally, it should be possible for the average reader to figure out which disambig term is the right solution by reading a line or two of the articles linked on that page. If it isn't, then the problem lies in the writing. As an intellectual property attorney, I know that I need take great care to avoid dropping into legalese, and to remember that I am writing for a general audience, even if other attorneys may read what I have written and find it simplistic. As for instances wherein none of the disambiguations are correct, what good does it do the reader who wants to find out what Cauchy's theorem means in an article if even the disambiguation page says nothing about the particular theorem being referenced? In that case, the best solution is to turn the link into a red link for the name of the article that should exist, but is missing. bd2412 T 17:29, 13 February 2013 (UTC)

Do you believe that Cauchy's integral formula "sink[s] immediately into inaccessible technical jargon", whereas the article tempered representation is immediately evident to someone who "know[s] what a square root is"? If so, that is a fascinating point of view. In Wikipedia, there are articles aimed at many levels of technical understanding. Obviously, someone with a grade-school knowledge of mathematics should not be editing an article about advanced mathematics. Period. I'm utterly baffled by your suggestion that the opposite should be the case. Do we live in backwards world? Sławomir Biały (talk) 02:09, 14 February 2013 (UTC)

Whether or not people with "grade-school knowledge of mathematics" should be editing these article, this is a wiki, which means that there is no controlling the level of education of those who edit. There is no button by which editing can be limited to those with an understanding of mathematics that even most Wikipedia administrators do not possess. What I am proposing, therefore, is that for ambiguous topics like the various theorems listed on Cauchy's theorem, the topics should be written clearly enough that an average person coming upon a link to the disambiguation page will be able to figure out how to fix the link. Such a level of clarity happens to coincide with the fact that the articles themselves may be read by that average person, and should be written with sufficient clarity for that reader to understand the topic. bd2412 T 02:18, 14 February 2013 (UTC)

[edit conflict] In other words, you think we shouldn't have articles on topics that are sufficiently advanced that grade-school mathematics students can't be expected to understand what the topic is, at least in the cases where the topic might one day be referred to by an ambiguous title? That seems very limiting to me. For instance, I doubt anyone without at least the equivalent of an undergraduate mathematics education could ever be expected to properly distinguish the topics in Zeta function, but should that mean we can't have an article on the Riemann zeta function and the Riemann hypothesis? —David Eppstein (talk) 02:35, 14 February 2013 (UTC)

I have seen some very complex topics described with sufficient clarity that the average reader can indeed at least understand the topic well enough to fix an errant link. It takes some talent, and hard work, but it is doable. As for Zeta function, that does not seem to be an ambiguous topic at all, since all of the links are partial title matches which, if the lede is to be trusted, are merely types of the thing described by the lede. In other words, this is a list of zeta functions, not a list of terms unrelated but for the fact that they share the exact same name (as with Mercury, the planet, and Mercury, the automobile, or Phoenix, the city, and Phoenix, the mythological bird. bd2412 T 03:07, 14 February 2013 (UTC)

On the contrary, there have been cases where zeta function is used, intending some specific zeta function, and needing disambiguation to a more specific article (for instance, in a context where something else in the article says "nonzero characteristic" and to disambiguate it properly you need to infer from that that probably Local zeta-function is the right one). The more you assert that these examples don't exist, the more it seems that your own ignorance is what's on display. They do exist, and telling us that we need to make a royal road for ignorant disambiguators won't make them go away. —David Eppstein (talk) 03:22, 14 February 2013 (UTC)

In that case, here is a list of all disambiguation pages with incoming links. Please go through it, find those pages that are mathdabs, and fix those incoming links so that they point to the appropriate article. You might notice that this thread began with me coming here to ask for exactly this sort of expert assistance. Do this, and you'll never need to deal with us ignorant disambiguators. bd2412 T 03:52, 14 February 2013 (UTC)

You seem to think that everything on Wikipedia should be basically understandable by anyone able to read basic English, and that such persons should therefore be editing every article. Fourth graders should edit articles on the Langlands program, why not? Fortunately, that is not the perspective of most editors, who must maintain constant vigil against the barbarians always ready to destroy what we have made. Wikipedia is an encyclopedia, not a primary school. Sławomir Biały (talk) 02:33, 14 February 2013 (UTC)

I do think that everything on Wikipedia should at least have an introduction or summation that is basically understandable by anyone able to read basic English. Whether I think people with that level of skill should be editing articles is irrelevant. They are able to, and they do so. Of course, you wouldn't need to defend articles against the ministrations of disambiguators if your project would fix those disambiguation links so that they point to the right page. bd2412 T 03:14, 14 February 2013 (UTC)

I'm sorry, but in mathematics there are some topics that just cannot be explained to someone with only a basic knowledge. At least, there are topics that no one in the history of the subject has managed to be able to do so. That's just a fact. Now I'm sure you've seen topics that you felt were quite abstract, yet presented in a very clear way. But mathematics is the science of abstraction: everything we do is abstract. You might find this notion personally objectionable, but that isn't really up for debate. It's actually quite rare that mathematicians can find a good way to explain what it is that they do. When they are successful, they write a book about it, win awards, and make a lot of money. The basic standard of mathematics exposition for advanced topics are the "What is..." column of the AMS Notices and the "Princeton Companion to Mathematics". However, these generally assume mathematical literacy at a postgraduate level. If you know of any other sources of mathematical exposition, we would love to hear them. But, yeah, we all know how biology articles are easy to read because every word means something, but mathematics articles are impossible to read because every linked word is just another abstraction. Sławomir Biały (talk) 03:58, 14 February 2013 (UTC)

None of this will be of any concern if this project will undertake to fix links currently pointing to disambiguation pages so that they instead point to the article meant by the context of the link. bd2412 T 04:09, 14 February 2013 (UTC)

This conversation is getting a bit sidetracked, but I'd like to thank the disambiguators for their hard work. It seems to me they are doing their best to make sense of articles that are in pretty sad states to begin with; so thank you. If there is this much resistance from every wikiproject, it's a wonder they get anything done at all! Mark M (talk) 07:25, 14 February 2013 (UTC)

I think we can all agree that it would be better if mathematicians resolved more disambiguations. The problem is: Most people have better things to do than clicking on all links in an article they are working on to see if there are disambiguation pages among the links. And working on the disambiguation project's list is certainly not everybody's idea of fun, especially when there is no guarantee that it contains mathematical articles.

Two things immediately come to mind that we could do:

• The disambiguation project could inform the maths project when a maths dab page moves to a prominent position. Then editors who have a clear idea what they are doing can work on the problem.
• Members of the mathematics project should consider installing User:Anomie/linkclassifier. I have had it for a while, and I wouldn't want to do without it any more. Links to pages that are at AfD or have a CSD tag or prod appear in reddish colours. Redirects appear in green. And, importantly in this context, links to disambiguation pages have a yellow background. Editors using this script will recognise each link that requires disambiguation immediately when reading or working on an article. Hans Adler 05:38, 13 February 2013 (UTC)

IMO, matrix algebra should restored to a redirect to Matrix ring (its state of the beginning of 2005), and a hatnote {{Redirect}} should be added in the target.  Done D.Lazard (talk) 05:58, 13 February 2013 (UTC)

Substantiation? A confusion between the matrix algebra M_n(F ) and a matrix algebra (certain its subalgebra or, in other words, a faithful representation of some associative algebra in Fⁿ) does exist, isn’t it? Incnis Mrsi (talk) 10:57, 13 February 2013 (UTC)

Surely, such a confusion may exist. It must be resolved in matrix ring or in an article about matrix algebras, whichever name it should have. The dab page was not related with that confusion, but with the confusion between the subarea of mathematics and the algebraic structure(s). By the way, I have linked the hatnote in matrix ring to matrix (mathematics); another good choice would be linear algebra. I will add it to the hatnote. D.Lazard (talk) 11:23, 13 February 2013 (UTC)

Thanks very much for that pointer to linkclassifier. That's very useful for someone who just wants to check for problems in pages they have some interest in, I think it should be in the standard toolbox for anyone who is interested in properly cleaning up articles. Dmcq (talk) 09:05, 13 February 2013 (UTC)

Agreed; thanks for the link! -- Avi (talk) 17:11, 14 February 2013 (UTC)

I agree with the above comments, that neither Matrix algebra nor Adjoint representation should be disambiguation pages, per WP:TWODABS. I think Adjoint representation of a Lie group should be moved to Adjoint representation, and Matrix ring moved to Matrix algebra. I suppose we will need to start Requested Moves to accomplish such moves? Mark M (talk) 09:31, 13 February 2013 (UTC)

If you like to move “Adjoint representation of a Lie group” back to the short ambiguous title, but are unable to substantiate, then your RM will unlikely have high chances to succeed. Incnis Mrsi (talk) 10:57, 13 February 2013 (UTC)

Incnis, I cited the guideline WP:TWODABS, which clearly supports the case for a move. In fact, the concepts are so closely related, WP:CONCEPTDAB probably applies as well. Just because it's a technically ambiguous term doesn't mean we need to force the reader through a disambiguation page. Mark M (talk) 12:19, 13 February 2013 (UTC)

See above. Any possibility of de-disambiguating Adjoint representation implies that the term has a WP:Primary topic, not only “the topic that they are most likely searching for”. Arguments for the former? Incnis Mrsi (talk) 16:41, 13 February 2013 (UTC)

Incnis, I think you are getting hung up on small differences. The adjoint representation of a Lie group and of a Lie algebra are so closely related that textbooks sometimes cover them both in the same chapter. Consider Representation (mathematics). It's not a disambiguation page, even though there are several meanings. Similarly Adjoint representation should not be a disambiguation page. Mark M (talk) 16:55, 13 February 2013 (UTC)

I agree with Mark. It is not the case that a term with more than one meaning must automatically point to a disambiguation page. If it was, then Apple and Blackberry and Avatar would be all be disambiguation pages, which they are not. Those pages relate to the primary meaning of the term, and each has a hatnote providing several other possibilities. The question in terms of deciding whether to have a disambiguation page at all, and whether to have it at the base page name or at a "Foo (disambiguation)" name, must always, always be: what will most efficiently bring readers to the topic that they are most likely searching for. For a title with only two topics, the most efficient path will virtually always be to have the more prominent title at that page (or redirecting to that page), and to have a hatnote indicating the second-best option. bd2412 T 13:15, 13 February 2013 (UTC)

I would have thought that Matrix algebra should point to something like matrix multiplication -- ie how to do algebra with matrices, as the most entry-level and probably most commonly searched-for meaning of the term for the general reader. Of course a matrix algebra is a different thing, as is the notion of matrix algebras in general, but I suspect they may not be the most commonly sought (or even the most commonly linked) meanings of the term. Jheald (talk) 13:23, 13 February 2013 (UTC)

Hmm.. while I see your point, I'm not really convinced. The term "Matrix algebra" is definitely used in the sense of the article Matrix ring. Perhaps some people readers might use the term "Matrix algebra" to mean "algebra with matrices".. but matrix multiplication is linked from the first sentence of Matrix ring anyway, plus there is a hatnote further explaining the situation. So while you might be right, without convincing evidence that this is causing a problem, I don't see a reason to move. Also, the two concepts you are contrasting are in fact very closely related, of course. Mark M (talk) 14:14, 13 February 2013 (UTC)

I agree with Mark. I had a quick look on the links to matrix algebra. Most of them are well redirected to matrix ring. The other fall in two categories: in some mathematician biographies, "matrix algebra" could better be rewritten as "matrix algebra". In any case, for such non technical articles, such links seem rarely followed. The other category of links is related to software libraries; as, from a computing point of view, "matrix algebra" is not really different of "linear algebra", these links would be advantageously replaced by linear algebra. Thus, this a clear application of what BD2412 wrote above: "particularly if only one page contains an exact match to the title"; the only page containing an explicit definition of matrix algebra (in boldface) is matrix ring. D.Lazard (talk) 14:42, 13 February 2013 (UTC)

Looking at the discussion, I'm wondering about the "disambiguation" in the matrix ring article itself:

"Matrix algebra" redirects here. For the subarea of mathematics, see Matrix (mathematics) and Linear algebra.

If find that line rather odd and irritating. What exactly is the "subarea of mathematics"? And are we to believe that matrix ring itself is not mathematics (as the formulation may suggest to a (naive) reader)? As far as the general problem is concerned I agree with Sławomir Biały, the style guide should not trump content. If for some reason no really appropriate article as a link target exists (yet), the the link target should remain the disambiguation page (for now). Enforcing a different not really appropriate link target just to comply the style guide is a no-go from my perspective.--Kmhkmh (talk) 15:17, 13 February 2013 (UTC)

I have rephrased the hatnote as follows:

This page is about a type of algebraic object. For algebraic operations on matrices see also Matrix (mathematics) and Linear algebra.

I had to do it by hand because we have the unusual situation that the alternative use is covered by the present article as well, just not at a level of abstraction appropriate for a typical reader looking for "matrix algebra" as a subfield of algebra. So I used "see also". Hans Adler 23:16, 14 February 2013 (UTC)

I do not agree: the new hatnote does not mean anything for readers that do not come to this article through the redirect "matrix algebra". Thus "redirect here" must be restored. I suggest: "Matrix algebra redirects here. For the algebraic theory of matrices see ..." I have not the time now, but unless somebody finds a better wording, I'll do this change later and transfer this discussion on the right talk page. D.Lazard (talk) 07:19, 15 February 2013 (UTC)

I have changed the hatnote of Matrix ring as announced. I have also copied into talk:matrix ring those of the above posts that concern this article. It you continue this part of the discussion, please do it there. D.Lazard (talk) 14:29, 15 February 2013 (UTC)

I had simply forgotten the first sentence and I think it would have been enough to add it. Still, your version is shorter and it works for me. Thanks. Hans Adler 18:15, 15 February 2013 (UTC)

Requested move

Since this discussion is getting a little disorganized, I started a requested move here, to move Adjoint representation of a Lie group -> Adjoint representation. So please comment there. Thanks, Mark M (talk) 17:19, 13 February 2013 (UTC)

Finitely generated

FWIW I just disambiguated a bunch of links in Finitely generated (disambiguation). Doing so involved creating a new stub, finitely generated object — please improve it. And I'd like to thank Hans Adler for suggesting User:Anomie/linkclassifier — I installed it because of this discussion, and find it very helpful not just for spotting ambiguous links but also unnecessary redirects. —David Eppstein (talk) 19:06, 14 February 2013 (UTC)

Requested move part 2

There is also a requested move for Adjoint endomorphism → Adjoint representation see Talk:Adjoint endomorphism#Requested move. Its been open a while now but there is not really enough discussion to establish a consensus and close it.--Salix (talk): 20:44, 16 February 2013 (UTC)

Why is it physics?

New article Reflection Principle (Wiener Process) "is within the scope of WikiProject Physics" and "needs attention from an expert in Physics"; why? Boris Tsirelson (talk) 17:03, 14 February 2013 (UTC)

For the first, any WikiProject may lay "claim" to any article it wants to, so I don't see that it matters. (Though perhaps this is just someone's confusion about "Brownian motion".) For the second, probably you should ask User:Freebirds who is the one who tagged it. --JBL (talk) 18:45, 14 February 2013 (UTC)

I tagged it as requiring an expert in math, and gave it a math category. It needs some words, not just the symbols, though. — Arthur Rubin (talk) 19:39, 14 February 2013 (UTC)

Yes. Also it could be added to the mini-disambig (or how to call it?) in the beginning of "Reflection principle". Boris Tsirelson (talk) 20:07, 14 February 2013 (UTC)

It's usually called a hatnote, but that one looks crowded enough that it should probably be turned into a proper disambig. —David Eppstein (talk) 20:47, 14 February 2013 (UTC)

In response to the original question: Physicists might know something about Wiener processes too. (But of course they can't be trusted...) I do think that a better solution for the encyclopedia would be to fix the article, rather than quibbling about which project was notified and adding templates and then arguing about whether those templates were applied in the correct bureaucratic fashion. But of course, it's always easier to talk about work than it is to do work, and it generally pays better too. Sławomir Biały (talk) 23:04, 14 February 2013 (UTC)

You are right: I am lazy :-) Boris Tsirelson (talk) 07:37, 15 February 2013 (UTC)

I speak for myself as well... Sławomir Biały (talk) 23:52, 15 February 2013 (UTC)

Arthur, don't forget to add a reason for your expert tag. RockMagnetist (talk) 22:25, 14 February 2013 (UTC)

I dove in and edited the article a bit. I tried to make the lead a bit more intuitive, added an illustration, added words to explain a little the notation and equations, added wiki links and a couple of references verifying new assertions. I am not an expert, and worryingly for Sławomir, I am a physicist, so feel free correct anything I mucked up. --Mark viking (talk) 23:07, 15 February 2013 (UTC)

Negation (algebra)

I accidentally discovered this "article" which strays into the topic of additive inverse, if not to say that it is a WP:POV fork. There are few inbound links and I could undertake my own corrective actions. But I am not familiar with the terminology enough to decide either “negation (algebra)” may (and should) redirect to “additive inverse”, or some more elaborate solution is preferred. For example, negation in a boolean algebra (structure) is namely a negation, not the additive inverse. Incnis Mrsi (talk) 08:40, 9 February 2013 (UTC)

Negation is the operation that takes an element to its additive inverse.. so I agree, I think there should be only one article (with "negation" defined in the "additive inverse" article). I'm usually in favour of merging articles, given the chance. :-) Mark M (talk) 09:18, 9 February 2013 (UTC)

That's a very elementary article, but that seems appropriate for the topic. Merging the two while preserving most of the content seems the best solution, though integrating the elementary treatment with a modern mathematical one could be tricky. Hans Adler 09:30, 9 February 2013 (UTC)

There is also negative number. Merging Negation (algebra) into it may be more appropriate with the levels of the articles. In any case, this would explain the etymology (making negative) and the reason to have these two meanings in mathematics. Independently of any merging, I suggest to rename Negation (algebra) as Negation (number), because, I do not believe that "negation" is used for other additive inverses than numbers, boolean rings and boolean algebras. D.Lazard (talk) 09:57, 9 February 2013 (UTC)

IMHO there is no need to create yet another clumsy title. I could solve all content problems myself without deliberations, moving each chuck of text to an appropriate destination. I am interested, mainly, in opinions of native speakers what we should do with the title “negation (algebra)”: redirect it to “additive inverse”, redirect to negation (disambiguation), or make a stand-alone dab page? What is the primary topic of “negation (algebra)”? Incnis Mrsi (talk) 10:54, 9 February 2013 (UTC)

Just saw this. I notice you didn't list "delete it" as an option. I think that should at least be considered. Not every search term has to have a target. --Trovatore (talk) 08:06, 18 February 2013 (UTC)

See also this discussion from a few years ago. And the word "negation" is used with respect to things that aren't necessarily "numbers".. for example the more abstract setting of rings and algebras (you could negate the complex number i, but you wouldn't call -i a negative number). This would be an argument against redirecting to negative number. The term "Negation (algebra)" isn't going to be a popular search term anyway, so I think there would be no harm in merging it into the article about the abstract concept of additive inverse. Mark M (talk) 11:34, 9 February 2013 (UTC)

It was informative to reveal some obscure discussion in 2010 as the origin of the problem, but you apparently do not read what I write. I say in the third time: there is no problem to decide to where the content should be transferred (you may describe it with “to merge” verb of else). There is a problem about the title. Is the alternative meaning from boolean algebras and similar structures notable enough? If it is, then a disambiguation page, a disambiguation redirect, or a {{redirect}} hatnote (as the last resort) are appropriate. If it is not, then it has just to be redirected to “additive inverse”, it is obvious and shall not be repeated several times. Incnis Mrsi (talk) 12:48, 9 February 2013 (UTC)

You appear to be concerned about the title "additive inverse", and that most people don't care about this more abstract and encompassing concept.. and I agree. My point is that there is already a disambiguation page at Negation (disambiguation). In the event of a merge, this disambiguation page should obviously be modified. Most people are probably looking for content found in either the article Negative numbers, or even Plus and minus signs, so those should be linked from Negation (disambiguation). But I don't think there should be an article called Negation (algebra).. so the incoming links to that article should be sent elsewhere, and the content merged into additive inverse. There is nothing currently in the Negation (algebra) article that isn't easily available in other better written articles. So I don't follow your question about notability.. nobody's going to search for "Negation (algebra)", they will search for "Negation". So we just have to make sure they are directed to the right place from Negation. Right? In other words, it doesn't matter what the primary topic of "Negation (algebra)" is, because people aren't likely to search for it. Mark M (talk) 13:19, 9 February 2013 (UTC)

Proof of logical inferences

Would there be any objection to removing all those so-called "proofs" except possibly those by detailed truth table. One of the "proofs" is here, as noted in the section above. Reasons for deletion include WP:OR (not helped by WP:CALC), and the fact that a "proof" of a rule of inference has to be in some formal system, and that system is not named, and is arbitrary. I suspect most of the above-referenced user's edits are mathematically wrong. — Arthur Rubin (talk) 08:01, 18 February 2013 (UTC)

The varying formal systems are more curious to me. There was a "proof" of modus ponens via the disjunctive syllogism, and then a "proof" of disjunctive syllogism via modus ponens. I am not worried about these being original, but without some text in the articles to give their motivation it is not clear why they are there at all. The main place where one has to "prove" inference rules is in verifying that some class of structures preserves them, e.g. to show that all the classical inference rules are valid in an arbitrary Boolean algebra. But then, as you say, there is a clear set of background axioms - the axioms of the algebra - that are used in the proof. Unless there is a clear reason we can articulate for including the "proofs" in the articles, I am fine with removing them. — Carl (CBM · talk) 13:17, 18 February 2013 (UTC)

"summation theory" redirected

I found a reference to summation theory in an article and linked to it. It was a red link. I redirected it to divergent series. Are there opinions of the appropriateness of that? Michael Hardy (talk) 17:16, 18 February 2013 (UTC)

It seems very reasonable to me, in the sense that the divergent series article is basically a definition followed by a detailed exposition of summability methods. In fact Summability and Summability methods already redirect there. There is a Category:Summability methods category which has no main article. If such a main article ever gets created, that would be the best target; until then, your redirect seems like the best solution. --Mark viking (talk) 19:12, 18 February 2013 (UTC)

It seems that that "main article" already exists and it's called divergent series. It the main article ought to be called summability methods or the like, then that should be done with the "move" button, not by creating a new article. But I wondered if there might also be some _other_ topic also called "summation theory", to which the article that used that term was referring. Michael Hardy (talk) 15:38, 19 February 2013 (UTC)

Looking at what links to the summation theory redirect page, only this page and Gunnar Kangro link there. In the Gunnar Kangro article summation theory is used in the lead, but summation methods is used in the research section; my understanding is that these two terms were meant to be synonyms. Summation (disambiguation) could refer to math sums, neuroscience, or law; there could conceivably be theories of the other two. --Mark viking (talk) 17:51, 19 February 2013 (UTC)

Linearly ordering the mathematics articles

A desirable property of mathematics articles would be that the the links in the head of articles describing a topic point to simpler topics. That won't of course always be the case, for instance one would also say where something is used. However I was wondering if there was a tool to automatically give a 'depth' order to the articles so most of the references at the tops of articles pointed to 'earlier' articles whether that might help with finding and fixing usability and circularity problems.

The sort of thing I was thinking of which mightn't take too large an effort would go something like this: first collect the links in each article and the order they first appear in them so the ones at the start can be given more importance. Then one would try to optimise a total order of the articles to minimise the cost of links pointing the wrong way. This would then enable one to do things like list articles with the links in the top quarter of their text which point to deeper articles. I guess there might also be room for other useful analysis if the ratings of the articles were also associated with them.

Perhaps something like this could make the business of determining the level the lead and start of articles should be aiming at a bit more objective and make it easier to fix some of the recurring problems people have with following the links and just getting to more difficult topics. Dmcq (talk) 10:49, 19 February 2013 (UTC)

I don't think they should necessarily point to simpler topics. They should (usually) point to more general topics (but only about one step more general; for example, you wouldn't like directly to mathematics from the lead of Stone–Čech compactification, but rather "one step more general" to general topology). The more general ones also tend to have simpler leads, but that's just a correlation. --Trovatore (talk) 11:05, 19 February 2013 (UTC)

That's interesting - so links that point a long distance downwards could also be problematic. Dmcq (talk) 12:05, 19 February 2013 (UTC)

I suppose they could, but I haven't noticed it being as much of a problem. I mean, sure, it would be really weird to link Stone–Čech compactification from the lead section of mathematics, but who would be tempted to do that? Whereas links to over-general articles is something I see regularly (not just in mathematics articles). --Trovatore (talk) 03:00, 20 February 2013 (UTC)

Oh, maybe more to the point: There are two issues that need to be distinguished — what gets linked, and what gets mentioned. You probably wouldn't link the SCC from the lead of mathematics because you probably wouldn't mention it there. But if for some reason you did mention it, you should absolutely link it.

On the other hand, it's quite possible the SCC article will mention the word "mathematics" — but that mention should not be linked, because someone reading about something as detailed as the SCC is not particularly likely to suddenly want to see the top-level article on mathematics. Is my distinction clear? My reasoning? --Trovatore (talk) 03:11, 20 February 2013 (UTC)

I guess you meant a partial ordering, though. Linearly ordering mathematics is a mistake that only school curricula are allowed to make :) Rschwieb (talk) 14:55, 19 February 2013 (UTC)

I was only linearly ordering for the purpose of making the business easier to deal with, though that does prompt the idea of if one assigned real numbers rather than integers one could group a wide branching part all close together, that sounds like an interesting problem of what rationale one would use for that. Dmcq (talk) 17:03, 19 February 2013 (UTC)

A directed graph of topics already exists in the form of the categories for an article. Looking at the categories of an article often leads to more general topics and their associated main articles, which can have simpler expositions. I use categories any time I want to get my bearings and "back up a step". It also seems a convention to place a little context in the lead sentence of an article, e.g., "In the mathematical discipline of general topology, Stone–Čech compactification...". But I don't think we should necessarily reproduce all the categories of an article in the lead. --Mark viking (talk) 18:05, 19 February 2013 (UTC)

I want something quite a bit finer than that, something that would for instance out of the articles about logarithms, exponentiation, the exponential function and various related topics indicate those terms in the lead of them which might need to be checked because they led to something more specialised or which wasn't normally introduced till later, or even things which are too simple at that level and one shouldn't be bothering with the article if one doesn't know them. Also to do this automatically on a large body of articles so problem articles can be spotted and prioritized. Unfortunately in the interest of rigor many articles, especially the less visited ones, use terms in the lead which one wouldn't normally come across until one were already quite familiar with the topic. Dmcq (talk) 18:19, 19 February 2013 (UTC)

Anyway if someone has a student who wants a data mining project this sounds like a simple one with possibilities for extension. Personally I've already got enough on my plate with two rather more complex ones of my own (not Wikipedia I'm afraid). Dmcq (talk) 19:35, 20 February 2013 (UTC)

Linking the orphaned Stanley symmetric function

The article Stanley symmetric function has been an orphan for pretty much all of its year and a half of life. I've finally linked it from symmetric polynomial, but if anyone else has ideas about what articles could link it (or for any improvements to the article itself), that would be helpful. Thanks. --JBL (talk) 03:50, 20 February 2013 (UTC)

Quasisymmetric_function also has the Stanley paper as a reference. It could be useful to link to Stanley symmetric function in the Applications section of that article. --Mark viking (talk) 03:59, 20 February 2013 (UTC)

Great, thanks! --JBL (talk) 18:40, 20 February 2013 (UTC)

Calculus and mathematical analysis

The first line of mathematical analysis is (with the link removed)

Mathematical analysis is a branch of pure mathematics that includes the theories of differentiation, integration, measure, limits, infinite series, and analytic functions

The first line of calculus is

Calculus (...) is a branch of mathematics focused on limits, functions, derivatives, integrals, and infinite series.

In other words we have two branches of mathematics that have essentially the same object of study. The relationship between these "branches" is not clearly explained an any of the articles. A merge of these two articles seems not a good solution and will certainly not get a consensus. Thus the articles have to be edited to clarify the situation. For the first lines, I suggest to replace "pure mathematics" by "mathematics" per WP:NPOV and to begin Calculus by

Calculus is the part of mathematical analysis that is usually taught in elementary courses of mathematics.

But my knowledge of the subtleties of English language and American educational system is not enough to be WP:BOLD and do this edit myself. Moreover, this change of the first line would imply to edit calculus in depth and this is outside my competences. D.Lazard (talk) 13:17, 20 February 2013 (UTC)

Good point. Analysis is part of applied math also! As far as the calculus page is concerned, the second paragraph of the lede states that "This subject is a major part of modern mathematics education. A course in calculus is a gateway to other, more advanced courses in mathematics devoted to the study of functions and limits, broadly called mathematical analysis." This seems clear enough. Tkuvho (talk) 13:22, 20 February 2013 (UTC)

I had a look on Mathematics Subject Classification. "Calculus" and "analysis" each appear in the titles of several two digits entries, but always with qualifiers. In section 97-Mathematics education, there is a section "analysis" (97Ixx) but no section calculus". Therefore, it is dubious to call them "branches of mathematics". Using "parts of mathematics" would be more accurate and more neutral point of view. D.Lazard (talk) 18:12, 20 February 2013 (UTC)

I see, I understand your concern now. Calculus is certainly not a branch of mathematics if by "mathematics" one means "modern research mathematics", which is basically the viewpoint of MSC. It is less clear to me that wiki pages should follow the MSC perspective. "Mathematics" in the lay sense of the term certainly includes calculus. Tkuvho (talk) 18:25, 20 February 2013 (UTC)

There is no question that calculus is mathematics. The question is, is it a "branch" of mathematics? It seems to me that it's part of the same branch as analysis, but it's not a subbranch of analysis, because that would imply that at some point it had branched away and started investigating its own concerns. The "living" part of the branch is what we now call analysis; calculus is the unchanging wood further towards the trunk. --Trovatore (talk) 20:36, 20 February 2013 (UTC)

I don't think this is a good idea. I would not say that calculus is a branch of mathematical analysis. For one, calculus was historically prior to mathematical analysis. It might be better to say that mathematical analysis started as an attempt to extend the methods of calculus, and to put those methods on a solid logical foundation. Anyway, regardless of which is a branch of which, I don't see that it helps readers to point that out in the first sentence. Someone who doesn't already know what "calculus" means is not going to know what "mathematical analysis" means. Sławomir Biały (talk) 13:38, 20 February 2013 (UTC)

In Category:Mathematical analysis, it is stated that

Analysis is a branch of mathematics that deals with real numbers and complex numbers and their functions. It has its beginnings in the rigorous formulation of calculus and it studies concepts such as continuity, integration and differentiability in general settings.

which seems to nicely summarize the relation between the two fields an d might serve as an alternative first sentence for the analysis article. For calculus, the first sentence is correct, but needlessly abstract. Anyone who wants to know what calculus is will not know what limits, derivative and integrals are. I'd rewrite the first paragraph as

Calculus is a branch of mathematics focused on the study of rates of change and accumulation of quantities, as represented by functions of variables such as time or space. Calculus is the study of change, in the same way that geometry is the study of shape and algebra is the study of operations and their application to solving equations. It has two major branches, differential calculus (rates of change), and integral calculus (accumulation), that are related by the fundamental theorem of calculus. Both branches make use of the fundamental notions of the limit and infinite series. Calculus has widespread uses in science, economics, and engineering and can solve many problems that algebra alone cannot. The word "calculus" comes from Latin (calculus) and means a small stone used for counting.

--Mark viking (talk) 17:27, 20 February 2013 (UTC)

Mark, I was thinking the same thing; your wording for the calculus intro is better than the one I had thought of, so I added it to the article (hope you don't mind). Mark M (talk) 17:55, 20 February 2013 (UTC)

The study of "area" should be mentioned at least with the same level of priority as "rate of change". I agree that the mention of limits is less essential in the lede, as they are a technical tool rather than a quintessential subject of calculus. Tkuvho (talk) 18:03, 20 February 2013 (UTC)

Thanks for reviewing my rewrite and including it in the Calculus article. I agree with Tkuvho that area (and slope, too) are good, concrete concepts that should be in the first paragraph. I have added the second sentence

Informally, the rate of change of a function f(x) at a point corresponds to the slope of the curve at that point and the accumulation of a function in an interval from a to b corresponds to the area between the curve and the x-axis in that interval.

The paragraph doesn't flow quite as well as before, but is perhaps more accessible. As always, please feel free to improve the prose. Thanks, --Mark viking (talk) 20:26, 20 February 2013 (UTC)

I've taken this bit out; I think "accumulation" is a better term than "area", just as "rates of change" is better than "slope". Perhaps further down in the introduction, but I think the second sentence is too early to have so many jargon words (point, slope, curve, interval, area, x-axis..). Mark M (talk) 20:53, 20 February 2013 (UTC)

I think this is a very nice intro. One thing it leaves out is convergence of sequences and series; this is both historically important to the development of calculus and a standard part of a complete high school or college calculus curriculum; is there a way to fit it in? --JBL (talk) 18:44, 20 February 2013 (UTC)

Agreed, convergence and sequences should be in there, too. I changed one of the sentences to read,

Both branches make use of the fundamental notions of convergence of infinite sequences and infinite series to a well-defined limit.

--Mark viking (talk)

I still have some issues with the word "branch" as applied to calculus. I don't think it's a branch. Maybe "collection of techniques"? --Trovatore (talk) 20:37, 20 February 2013 (UTC)

I'm not wedded to "branch". Perhaps we could say "Calculus is traditionally divided into differential calculus (rates of change), and integral calculus (accumulation),..." and in the next sentence, " Both approaches make use of..." ? --Mark viking (talk) 20:48, 20 February 2013 (UTC)

I've removed the word "branch" from the opening sentence:

Calculus is a collection of mathematical techniques in the study of rates of change and accumulation of quantities.

I like the structure of the current opening paragraph; though maybe the clarity of the first sentence could be improved / simplified.. "study of rates of change" seems clumsy. Mark M (talk) 09:25, 21 February 2013 (UTC)

I'm quite happy with the current version of the lead, as edited most recently by David Eppstein. (I was also quite happy with Mark viking's original proposed version, but the current one is less wordy.) This is a substantial improvement over what was originally there. Sławomir Biały (talk) 22:11, 21 February 2013 (UTC)

Seismic inverse Q filtering

Would an expert please take a look at this new article. It is sourced to one book, which makes me think that the subject may not meet the notability requirements. Thanks.--ukexpat (talk) 20:26, 21 February 2013 (UTC)

Note: I am not an expert. The article looks somewhat promotional, but seems to have some good information, too. Inverse Q filtering has been around for some time; here is a 1987 article that might be the first to call it that, and there were isolated results earlier than that, as mentioned here. So I think "inverse Q filtering" is notable. But all articles I found (admittedly a quick search on GScholar) on "Seismic inverse Q filtering" involved Y. Wang, the author of the book, which raises the question of the existence of independent sources for this specialization. If the article was renamed to inverse Q filtering and some independent refs added, I think it could pass notability standards. --Mark viking (talk) 20:51, 21 February 2013 (UTC)

RFC on Tau

Someone has opened a new formal discussion on whether Tau, the alternative circle constant, is notable enough for its own article. The link is

User_talk:Tazerdadog/Tau_(Proposed_mathematical_constant)#RFC:Article_Notability

--JohnBlackburne^words_deeds 15:39, 22 February 2013 (UTC)

Algebra

I have edited algebra to clarify the function of this article (WP:DABCONCEPT article and article about a mathematics area). I have also transformed algebra (disambiguation) into a redirect, moved History of elementary algebra to history of algebra, and adapted the first lines of Elementary algebra and abstract algebra. The main parts of my edits are:

• A complete rewriting of the lead to make it clearly a WP:DABCONCEPT
• Inserting a new section "Algebra as branch of mathematics" to explain what is algebra and how the answer to this question has evolved.
• Splitting the history section into "prehistory" and "history".

As these edits are very far to be minor and this article is a vital one, some reviews of my edits would be helpful.

Moreover this article needs some more work implying some decisions that may be controversial.

• The section history is a stub that should be expanded. My competence in history of mathematics is not enough to do it myself.
• There are sections dedicated on two among the sub-areas (elementary algebra and abstract algebra), and almost nothing a bout the remainder of algebra, outside links without explanation in the new lead and in the section Topics containing the word "algebra".

My opinion is that

• The lists in section Topics containing the word "algebra" should be moved at the end and transformed in a kind of section "See also". In particular, the list of the sub-areas should be completed by the sub-areas whose names do not contain the word "algebra".
• The sections "Elementary algebra" and "Abstract algebra" contain material that duplicate unnecessarily part of the content of the corresponding article and that have to be replaced by a description of what are these areas and how they interact with other sub-areas of algebra. For example, describing what is a polynomial is not useful here, but it is important to mention that polynomials are considered in elementary algebra, and that the theory of polynomials is much wider and has numerous aspects that are far to be elementary (Gröbner basis and Resultant, for example)
• The other main sub-areas of algebra (see the lists in the lead and in section "topic") need to appear at the same level as "Elementary algebra" and "Abstract algebra" (WP:NPOV) in sections describing their subject and their interrelations.

This is a wide program that I am unable to do alone. But I think that the vital importance of the article deserve it.

I'll copy this post in talk:algebra.

D.Lazard (talk) 16:23, 24 February 2013 (UTC)

I agree with the need for algebra to be more than a mere disambiguation page. One broader issue is the level of detail that the page should go into. For instance, we have overlapping lists of abstract algebraic systems in algebra, Outline of algebra, abstract algebra, algebraic structure, and the tree in Category:Algebra. It's a bit of a mess. People searching for the term 'algebra' could have experience levels ranging from the typical 10 year old to Nicholas Bourbaki.

My opinion is that the most elementary aspects of algebra should be first in the article, to direct the most inexperienced users to the appropriate articles without the distraction and intimidation of up-front indecipherable jargon. That would suggest putting the "Elementary algebra" section right after the lead or perhaps after the "Algebra as a branch of mathematics" section, if we can make that section less imposing.

For the more advanced subjects, we could make things less confusing by cutting down on the number of redundant articles noted above. My opinion is that it would be best to have a single list of abstract algebraic systems in either the algebra article of the some other article pointed to by the algebra article. I don't think it is a problem for duplication of concepts like polynomials in the elementary and advanced, sections, however. Such objects are treated differently in the two different domains.

For history, it would probably be best to keep this as a minimum in the algebra article, just enought to provide a context for the more specialized articles like History of algebra and Timeline of algebra. Should there be a list of prominent algebraists in the article?--Mark viking (talk) 21:51, 24 February 2013 (UTC)

Michael Sean Mahoney

Michael Sean Mahoney wrote a biography of Fermat that's quite popular by Scholar standards: 170 cites. On the other hand, his other work does not seem to be that influential. Should we have a biopage for him? Tkuvho (talk) 14:35, 13 February 2013 (UTC)

Not unless there are secondary reliable sources writing about him, including any peculiarities of his biography of Fermat. JRSpriggs (talk) 15:20, 13 February 2013 (UTC)

Note that in this case not only his notability as mathematician needs to be considered but that as a (popular science) writer as well. --Kmhkmh (talk) 16:04, 13 February 2013 (UTC)

He was actually a historian, not a mathematician (nor a popular science writer). Actually there were many responses to his book, including one by Andre Weil. Weil didn't like the first edition. Mahoney seems to have taken into account some of Weils' criticisms in the second edition. Tkuvho (talk) 15:52, 18 February 2013 (UTC)

To say that Weil didn't like the 1973 book is a vast understatement. I came across Weil's review in the 1980s and was stunned by Weil's thorough thrashing of Mahoney's competence as a scholar. Perhaps Mahoney's disastrous book motivated Weil to tell the early history of number theory properly, as he did in his masterful Number Theory: An Approach Through History from Hammurapi to Legendre. — Myasuda (talk) 02:13, 21 February 2013 (UTC)

The review may have made a number of good points, but Weil's claim that as every mathematician knows, there has never been a "deutscher Mathematiker-Verein" seems overdone (apparently it should have been Vereinigung rather than Verein). Even in 1973, German was hardly a language that every mathematician needed (though certainly it was a useful one). --Trovatore (talk) 03:24, 21 February 2013 (UTC)

That particular comment of Weil's was one of the least consequential ones that I can recall from that review. Why did you bring up that particular one? — Myasuda (talk) 03:32, 21 February 2013 (UTC)

Because it was the one that most annoyed me. --Trovatore (talk) 03:35, 21 February 2013 (UTC)

Weil held Mahoney to a very high standard, perhaps appropriately so. Note that there were other reviews that were much calmer. Regardless of Weil's reaction, Mahoney's book has been influential in terms of scholar cites: 170 last time I checked (this went up to 173 in the last few days). There is little doubt that it is an influential book, even though it may have been flawed. Mahoney did a number of other notable things; was a Sloan fellow; etc. If somebody wishes to chip in at Michael S. Mahoney that would be fine. Tkuvho (talk) 21:37, 21 February 2013 (UTC)

I disagree with your comment that Weil was holding Mahoney to a very high standard. Based on Weil's very detailed and erudite review, one can easily see that Mahoney's book failed to meet a rather low standard of scholarship. Did you actually read more than the first page of Weil's review? — Myasuda (talk) 04:18, 22 February 2013 (UTC)

Hi User:Myasuda and thanks for your interest in this new page. I would like to comment that I also think Mahoney's book has its shortcomings, and obviously I have the highest esteem for Weil. Do you think this disqualifies Mahoney from having a bio page in wiki? The problem of historians of mathematics not being sufficiently familiar with the actual mathematics of their historical period is not an uncommon one. I did read Weil's review from beginning to end (and perhaps more than once). As I mentioned, there were other reviews that were far less critical. Tkuvho (talk) 09:33, 22 February 2013 (UTC)

Well, based solely off of Weil's analysis of Mahoney's Fermat book from 1973, I would not endorse Mahoney's bio page. I am not, however, familiar with Mahoney's other body of work. Koblitz's comments on page 92 of his autobiography Random Curves don't say much in Mahoney's favor (e.g., he speaks of Mahoney's "rather thin list of accomplishments"), other than he was popular with students. But Koblitz was also speaking about Mahoney regarding the time period leading up to his full tenure and not after that. Did any of Mahoney's other works on the history of mathematics receive a review in the Bulletin of the AMS (or the Notices)? I would find this informative. — Myasuda (talk) 14:22, 22 February 2013 (UTC)

I am not aware of reviews in Bulletin and Notices. This does not necessarily mean there were none. On the other hand, there were numerous other reviews. Some of them can be found on M. S. Mahoney. I don't think either Weil, Bulletin, or Notices should have the final word on whether a notable historian should have a bio page. Tkuvho (talk) 16:45, 25 February 2013 (UTC)

Form/structure/application of Template:Tensors

Not a burning issue, but input/feedback may be helpful at Template talk:Tensors if time/inclination allows. Thanks, M∧Ŝc²ħεИ_τlk 09:34, 25 February 2013 (UTC)

Update: I created a navbox version there, since some editors think that's the better form. M∧Ŝc²ħεИ_τlk 09:18, 26 February 2013 (UTC)

I'm going to change {{tensor}} to the navbox version - due to consensus and no objections for that. M∧Ŝc²ħεИ_τlk 21:14, 26 February 2013 (UTC)

mathematics: natural science?

This discussion is copied from Talk:History of science. I thought it might be of interest to WPM participants. Tkuvho (talk) 12:46, 26 February 2013 (UTC)

Sorry to barge in from the cold but there does not seem to be an entry for "mathematics" under the various sciences listed in the "natural science" section of History of science. Was this discussed in the past? Tkuvho (talk) 17:39, 25 February 2013 (UTC)

The explanation is simple: Mathematics is not listed as a science because it does not qualify as a science. The scientific method requires that hypothesis and predictions be tested to confirm correctness. This is not possible with mathematics as it is a form of logic (e.g. there is no means to independently test and verify that 1+1=2). Mathematics is instead one of the primary "languages" used by science. --Allen3 ^talk 19:01, 25 February 2013 (UTC)

Mathematics has always been considered marginal in definitions of the history of science. Here are two recent ones:

• Science comprises, first, the orderly and systematic comprehension, description and/or explanation of natural phenomena and, secondly, the [mathematical and logical] tools necessary for the undertaking. Marshal Clagett, Greek Science in Antiquity, (1955)

• Science is a systematic explanation of perceived or imaginary phenomena, or else is based on such an explanation. Mathematics finds a place in science only as one of the symbolical languages in which scientific explanations may be expressed. David Pingree, "Hellenophilia versus the History of Science," (1992)

--SteveMcCluskey (talk) 19:37, 25 February 2013 (UTC)

I believe Allen3 and SteveMcCluskey are using "science" as a shorthand for natural science. Agreed that mathematics is not a natural science, but let's not forget that there are other branches of science besides the natural sciences. Mathematics is in fact a formal science. Gandalf61 (talk) 13:21, 26 February 2013 (UTC)

It will be possible to find literature that says math is a science, and also possible to find literature that says it is not a science - both in very reliable sources. This is because there are so many different notions of what 'science' is, and also different notions of what 'mathematics' is. One nice explanation that I have seen is at [22]. — Carl (CBM · talk) 15:49, 26 February 2013 (UTC)

Thank you for this link, I enjoy it. Boris Tsirelson (talk) 13:47, 27 February 2013 (UTC)

There is some plausibility to the view that mathematics is a formal science, but ultimately it is too restrictive. Furthermore, such a view originates around the end of the 19th century. Up until that point everybody viewed mathematics as integral part of what was known as "natural philosophy". Whatever one's particular views may be on this, it seems an omission not to include mathematics in a summary of the natural sciences in the context of the history of science. If a few editors subscribe to this view, we could develop a paragraph for inclusion at history of science in the list of natural sciences. This does not contradict a possible interpretation of math as a formal science, but merely seeks to reflect the full spectrum of possibilities. Tkuvho (talk) 15:57, 26 February 2013 (UTC)

I'm not at all sure that is correct. For instance Newton's Principia was the mathematical principles of natural philosophy, it didn't treat maths as part of the subject matter of natural philosophy but something outside it. I think even in Aristotle's time it had divided into what we would consider pure and applied maths where he had maths mixed with the sciences but others would have classed it more in line with something like music. Dmcq (talk) 00:52, 27 February 2013 (UTC)

It is an interesting philosophical question. But for the WP articles on natural science or history of natural science, the perhaps more relevant question is: Are there reliable sources, historical or otherwise, that assert that mathematics is a part of natural science? If so, then these could be used to add mathematics as another natural science to these articles. --Mark viking (talk) 01:11, 27 February 2013 (UTC)

Of course there are; see Naturalism in the Philosophy of Mathematics for example. — Carl (CBM · talk) 14:04, 27 February 2013 (UTC)

I hardly see that as supporting including mathematics in the history of science. To me having the whole question of whether there is any link proposed in such an abstract way indicates the exact opposite if anything is the practical fact . Dmcq (talk) 14:54, 27 February 2013 (UTC)

It is not a simple matter. It is very common for universities to classify the mathematics department under their "natural sciences" college. However, in truth mathematics and logic are not "under" natural or other sciences, they are "above" them. This is to say that math and logic are metatheory to the theories whose subject matter is physics, chemistry, biology, geology, etcetera. Philosophy and logic are also metatheory to the various theories of the arts. Every art and science, within the context of scholarly academia obey the laws of logic, and this includes mathematics. Greg Bard (talk) 01:21, 27 February 2013 (UTC)

It seems to me that the real question that we should focus on is not whether mathematics is a natural science, but what role the history of mathematics has in the history of science. This seems to be a glaring omission from the history of science article, which fails to mention prominently the history of mathematics. It scarcely needs to be emphasized that, until relatively recently, the history of mathematics and science were one and the same. I don't personally think that mathematics is a science, but failing to mention the role of mathematics in the history of science seems, well, a bit whiggish. Sławomir Biały (talk)

Mathematics is a science in the fullest sense. Indeed, elementary mathematics (such as arithmetic or geometry) is the most easily and thoroughly tested and confirmed of all sciences. Count out two marbles in one hand and three marbles in the other hand; then combine them (addition) on the table top; the result is five marbles as one can determine by counting. Thus 2+3=5 is empirically confirmed. JRSpriggs (talk) 07:26, 27 February 2013 (UTC)

That's not science, that just shows that maths has been used to model the real world. As said before it is a metatheory as far as science is concerned, just like the scientific method. Until recently only a few people contributed to both maths and science, Archimedes would I'd have thought of as being the earliest and 'The Method' which used the crossover idea of levers to do integration got lost. You don't really get anyone like that again till Newton but after that mathematical physics has contributed to both science and mathematics and maths and statistics have increasingly being used in all the sciences. How many people though have contributed both at the suck it up in a pipette tube level to chemistry or dissecting a frog level to biology and also to advancing maths? Dmcq (talk) 08:24, 27 February 2013 (UTC)

I think as has been said before one needs sources on the history of science that link maths in. And for weight it should appear in a reasonable proportion of histories. I don't think one can put more than a very basic amount in really from what I've seen. I think it is interesting how the belief that the world follows rules and the rules can be codified in mathematics arose so early with things like the belief the planets must move in circles, but that is not what the histories go on about. Dmcq (talk) 08:46, 27 February 2013 (UTC)

Note that we are discussing the article history of science, not "history of natural science". This article contains sections for "natural science" and other sciences such as social sciences. The subdivision is somewhat artificial and math seems to have been lost in the shuffle. I agree with the sentiment expressed by User:JRSpriggs and User:Sławomir Biały that we are dealing with a glaring omission as far as the article history of science is concerned. Tkuvho (talk) 13:58, 27 February 2013 (UTC)

The real question is what do histories of science say with any weight on the subject? Dmcq (talk) 14:57, 27 February 2013 (UTC)

History of science currently lists psychology as a science but not mathematics. This is hardly defensible. Tkuvho (talk) 16:27, 27 February 2013 (UTC)

Perhaps at this point substantive discussion should move back to Talk:History of science? --JBL (talk) 16:51, 27 February 2013 (UTC)

Requiring a ring to have unity by definition

Hi all,

I have started a poll on whether or not "Wikipedia" requires a ring to be unital at Talk:ring (mathematics). The feelings among algebra editors are that this is the way, but we can also use perspectives from other-type of editors. (I'm assuming this doesn't concern a generic Wikipedia editor.) -- Taku (talk) 19:08, 27 February 2013 (UTC)

Mar 2013

More disambig help requested.

Not sure if Orbital angular momentum (21 links) is a math issue, but Secure Hash Algorithm (21 links) seems to be and has been tagged as WP:DABCONCEPT, and we also have Algebraic semantics (20 links) and Curvature tensor (20 links). Please help if you can. Cheers! bd2412 T 12:15, 28 February 2013 (UTC)

I agree Secure Hash Algorithm is a WP:DABCONCEPT. What if the procedure to proceed? Is it sufficient to remove the {{disambig}} and {{conceptdab}} tags and to add a stub tag? D.Lazard (talk) 12:53, 28 February 2013 (UTC)

While this is sufficient, it would be better to add a sentence or two, with sources, indicating how the listed links are examples of a general concept. bd2412 T 03:56, 1 March 2013 (UTC)

Orbital angular momentum is a physics concept, a topic in quantum mechanics. Secure Hash Algorithm is a topic in computer science, but of interest to mathematicians as well. The last two are math concepts. I disambiguated links for a number of articles for Orbital angular momentum, but not all of them. It's a drag to be manually chasing down all the link locations and going through the edit cycle for each one. Are there any automated tools to help with this? --Mark viking (talk) 14:16, 28 February 2013 (UTC)

There are a few really excellent tools for disambiguation. The primary tool is a program available at Wikipedia:AutoWikiBrowser. bd2412 T 03:56, 1 March 2013 (UTC)

Thanks for the tip. I've finished with Orbital angular momentum in article space. --Mark viking (talk) 04:40, 1 March 2013 (UTC)

I’ve done algebraic semantics.—Emil J. 14:23, 28 February 2013 (UTC)

Thanks! bd2412 T 03:56, 1 March 2013 (UTC)

By the way, almost all of the incoming links to Degree (total 55 links) are through the Degree (mathematics) redirect, and judging by the listings on the disambig, these will also need expert attention. Cheers! bd2412 T 03:56, 1 March 2013 (UTC)

Review request

Hi, I created a new article Dershowitz-Manna_ordering and it was suggested to me to ask here for some reviews (it's my first new article). I would appreciate any hints or comments as how to improve it (e.g. it is an orphan, but I refrained adding any links before getting some feedback). Dtldarek (talk) 19:48, 1 March 2013 (UTC)

I only took a quick glance, but here are some quick comments:

• It would be nice to include the statement of who Dershowitz and Manna are.
• Some more information (even just a sentence or two) about the context or importance of this order would be helpful; right now, I am skeptical that this article would be of much use to someone who didn't already know its contents.
• There's a lot of notation used that isn't necessary; most notably, the use of the quantifiers $\forall ,\exists$ instead of writing out a sentence makes the reader work harder for no obvious benefit.

--JBL (talk) 20:07, 1 March 2013 (UTC)

I'm a fairly new editor myself. Welcome! The article looks like a good start to me. Some suggestions for improvement:

• Break the main section into

1. A lead section, where you introduce the ordering, give an informal notion of what it is about for the non-specialist, and why it is significant in term rewriting systems of computer science in general
2. A definition section where you precisely define the ordering. I second JBL's suggestion to replace non-necessary notation with English prose. It also helps to define your notation. For instance, let readers know that $S$ is a set and that $M(y)$ is a cardinality function (I think) representing the multiplicity of element $y$ in $M$.

• How does this ordering compare to other multiset orderings? It may be useful to establish a "See also" section pointing to other orderings with articles on Wikipedia.
• It is useful to a give web pointer to references where you can. For instance, here is a pdf of the Jouannaud paper.

--Mark viking (talk) 20:56, 1 March 2013 (UTC)

I suggest moving this discussion to the article's talk page. RockMagnetist (talk) 21:16, 1 March 2013 (UTC)

Good suggestion, I'll copy the comments so far over there. --JBL (talk) 23:02, 1 March 2013 (UTC)

Math Jax problem

I switched over to Math Jax. On my browser (Windows IE 9, version 9.0.8112.16412, update 9.0.13) the formula

$n=4,\;\;z=-1,\;\;z^{2}=z^{4}=1,\;\;2\not \equiv 4{\pmod {4}}.$

< math >n = 4, \;\; z = -1, \;\; z^2 = z^4 = 1, \;\; 2 \not\equiv 4 \pmod{4}.< /math >

does not render correctly (the \not\equiv should be ≡ with a line through it, but is a space on my browser)

Is there some other place where this should be reported?

Thanks - Virginia-American (talk) 16:10, 3 March 2013 (UTC)

Should work: $\not \equiv$ (Windows 7, IE 8). Maybe just your browser... you might see help:displaying a formula and the talk page. Sorry, M∧Ŝc²ħεИ_τlk 16:39, 3 March 2013 (UTC)

Works for me (OS X, Chrome) so it does seem likely to be a browser or installation issue. —David Eppstein (talk) 17:13, 3 March 2013 (UTC)

It looks OK in my Firefox 19 browser. JRSpriggs (talk) 07:51, 4 March 2013 (UTC)

Also OK on my Firefox 19 under Linux. Boris Tsirelson (talk) 11:33, 4 March 2013 (UTC)

I'd guess it is a font problem of some kind. Dmcq (talk) 12:53, 4 March 2013 (UTC)

I have precisely the same version of IE on Windows 7 and it works for me. Rschwieb (talk) 14:00, 4 March 2013 (UTC)

Did you install the STIX fonts? (see here). RockMagnetist (talk) 18:04, 4 March 2013 (UTC)

Graph theory ~ too technical tag

Hi,

I have added a too technical tag to graph theory for the following reason:

talk:graph_theory#Too_technical__.2803.2F03.2F2013.29

Perhaps we could try and reach a consensus on a course of action?

Bg9989 (talk) 12:43, 4 March 2013 (UTC)

Graph automorphisms table missing an implication

The table at Graph_automorphism#Graph_families_defined_by_their_automorphisms (and at Template:Graph families defined by their automorphisms) doesn't indicate that all distance-regular graphs are regular graphs. They are, aren't they? There isn't some subtlety to the definition that I'm missing? Is there a stronger implication from distance-regularity? -- Creidieki 18:50, 4 March 2013 (UTC)

Please review Matrix_multiplication#Multiplication_of_n-dimensional_matrix

A large new section materialized at the end of the matrix multiplication article: Matrix_multiplication#Multiplication_of_n-dimensional_matrix. It is apparently some operation which is not even power-associative. I don't immediately recognize the mathematical content, and the English is a bit broken. It is also unsourced. Still, it could be a candidate for inclusion in that article. If anyone has a chance to take a look, please drop an opinion on the talkpage. I'm mainly trying to figure out if it is something real or some sort of niche topic. Thanks! Rschwieb (talk) 14:14, 6 March 2013 (UTC)

I agree, and apologies to Rschwieb for edit conflicts. M∧Ŝc²ħεИ_τlk 14:29, 6 March 2013 (UTC)

Templates braket, vec and intmath

Not a desperate issue... Anyway I recently created these templates for use with {{math}}, so faults are my responsibility. Are they discouraged by WP:MOSMATH? Probably... I need to know for compatibility with the up-and-coming WP:MOSPHYS. Please note I inserted them into this table. Thanks in advance for feedback. M∧Ŝc²ħεИ_τlk 17:25, 7 March 2013 (UTC)

Wikipedia is just awful for mathematics

You can learn a lot from reading most Wikipedia articles, unless the article you're reading is about mathematics. Mathematics articles on Wikipedia are written entirely in domain specific jargon and protected by an impenetrable wall of circular learning dependencies.

Is it that mathematics is such a hard problem, or that our mathematician editors are far too concerned with being technically correct and not enough with educating? — Preceding unsigned comment added by 2.29.74.212 (talk) 03:00, 18 February 2013 (UTC)

Gee, who would have ever guessed that anyone would think that?! This project has been told this many many times. Their response is the boilerplate language visible on this page above. Basically the idea is that they don't care, and would prefer if the people levying this kind of criticism would just accept that the culture is the way it is, and that they won't change to satisfy anyone but themselves. Greg Bard (talk) 03:06, 18 February 2013 (UTC)

What do you propose? Let us not only tolerate illiteracy and destructured thinking like a formal proof of modus ponens, but even promulgate such oversimplified and appealing lies? To my opinion, there should be even more “walls of circular learning dependencies”. Each article should state which theories it uses, or, at least, on which facts (theorems) it depends. With present chaotic structuring it is sometimes impossible to understand which concept depends on which assumptions. Incnis Mrsi (talk) 07:05, 18 February 2013 (UTC)

Math is hard. Barbie took a lot of criticism for saying it, but she was right. There is no royal road.

As for being correct versus educating, all articles, not just mathematics ones, need to be first and foremost correct. "Educating" per se is not their purpose at all — Wikipedia is a reference work, not a textbook. It's an excellent resource for self-education, but you have to do the work yourself. --Trovatore (talk) 04:01, 18 February 2013 (UTC)

There is no excuse. It's a wiki. It is always possible to make the concepts available to someone who wants to reason it out for themselves. I have seen cultural and systemic behavior which frustrates those ends. Greg Bard (talk) 04:20, 18 February 2013 (UTC)

The problem is not with the corpus of mathematics articles. Collectively, they are the best free resource for mathematics that exists on the planet, by far. The problem is that people expect to be able to understand them without doing work, and it can't be done. --Trovatore (talk) 04:31, 18 February 2013 (UTC)

To misquote George Bernard Shaw, "The reasonable man adapts himself to the Wikipedia; the unreasonable one persists in trying to adapt the Wikipedia to himself. Therefore, all progress depends on the unreasonable man." Tom Ruen (talk) 05:07, 18 February 2013 (UTC)

Mathematics is hard, but using more jargon than necessary and needless upfront generality can make it harder than necessary. The first thing we should ask when someone complains is for some example articles. Many math articles will always be incomprehensible to the general reader, but many, even in advanced topics, admit a basic explanation that give non-specialists some idea of the topic. There is always room for improvement. For example, I just edited the traveling salesman problem to state the problem in simple terms before the flood of jargon. There is always room for improvement without sacrificing accuracy and completeness.--agr (talk) 05:25, 18 February 2013 (UTC)

No doubt. There are lots of articles that can be improved along these lines, and specific examples are welcome, preferably with specific reports about what part is confusing. --Trovatore (talk) 05:30, 18 February 2013 (UTC)

To misquote Larry Niven and his Neutron Star, find yourself a middle ground or the tide will rip you apart. I spend much more time on the wiki for my place of employment these days than Wikipedia... I think I agree with you, if what you are saying is that there is a constant struggle between what we already know and what we have to repeat in order to get that message across. Wikipedia is a moving target. --Trakon (talk) 05:24, 11 March 2013 (UTC)

"domain specific jargon and an impenetrable wall of circular learning dependencies"... I remember that my late father complained me, in quite similar words, about mathematics, more than 40 years ago, when neither Wikipedia nor Internet were not imagined. This is not a property of Wikipedia but a property of mathematics. Boris Tsirelson (talk) 06:50, 18 February 2013 (UTC)

Some mathematics articles are bad, some are very good. Wikipedia is still a work in progress. Sławomir Biały (talk) 12:43, 18 February 2013 (UTC)

Really I think the biggest problem with mathematics articles on Wikipedia is that there are simply not very many editors who are good at writing mathematics articles and are willing to spend additional volunteer hours to make our articles better. I have edited maybe one or two hundred mathematics articles (out of tens of thousands). But of these, I would say that on fewer than ten articles was I really willing to devote the many hours it takes to produce prose that is understandable to a general audience and is, at the same time, thorough in its coverage and depth, and encyclopedic. The fact is, this is very difficult to do. It's much harder than writing pedagogical material aimed at a particular audience. It requires, among other things, that the author have a nearly complete understanding of the topic, a sense of how everything fits into the subject of mathematics and the sciences as a whole, as well as good skill at communicating in English.

Also, editing mathematics articles is something of a thankless job. Instead of being praised for the work that we do, here we are repeatedly collectively heckled because of the generally poor quality of mathematics articles for the purposes of learning a subject. We also have to then defend the articles we devoted all this time to against misguided attempts to rewrite them. There are roughly two kinds of rewrite attempts: the formalists, who think that every mathematics article should start with formal definitions and theorem statements, and the bad pedagogues, who think that because an article mentions topics that they do not understand means that they must rewrite the article—ironically without actually understanding the topic themselves!

And, let me add, that of course mathematics is different from other areas. Whereas with a few months of study, I imagine someone with a basic science background can edit articles on climate change or evolution, it literally takes years of study for someone to even understand the statements of some of the top problems in mathematics (such as the Langlands conjectures, the Hodge conjecture, and the Birch and Swinnerton-Dyer conjecture). Of course, someone with only a few months of background in a subject will almost certainly lack perspective, and I believe this is a problem of articles in more accessible areas of science such as climate science which suffer from too many editors, in mathematics lack of perspective is particularly glaring. Even experts can lack perspective, as often experts only know what they do, and not how it relates to other topics. Thus their way of thinking about something is clearly the right way.

There is only one good solution to this problem. We need more expert mathematicians editing Wikipedia, since these are the only people who are really able to help with articles on advanced mathematics. Sławomir Biały (talk) 13:55, 19 February 2013 (UTC)

I think you've hit the nail on the head here.. in fact, I found your rant motivational. :-) Mark M (talk) 16:38, 19 February 2013 (UTC)

I'll admit I'm one who is definitley responsible as a "bad pedagogue" in the above description... M∧Ŝc²ħεИ_τlk 17:13, 19 February 2013 (UTC)

Broadest possible audience

There is a norm in Wikipedia that the introductory material in an article should be accessible to the broadest possible audience. I think I've followed that in the many mathematics articles I've written. And I think it's generally been followed in Wikipedia mathematics articles.

There are cases where it has not been followed. Especially in new articles. Those often need a lot of work, not only because of that. Michael Hardy (talk) 17:12, 18 February 2013 (UTC)

Relevant to this discussion, there is an open CfD discussion at Wikipedia:Categories for discussion/Log/2013 January 24#Category:Elementary mathematics which proposes to "upmerge" certain elementary mathematics categories. I think that one step towards making math articles as user friendly as they reasonably can be made is to identify levels of difficulty within the field (for example, algebra is obviously going to be more complex than multiplication), and aim to insure that articles covering less difficult topics are indeed less complex. The hard stuff may be hard, but it should be possible to figure out the hard articles by starting with basic articles and methodically working up from them. bd2412 T 21:00, 18 February 2013 (UTC)

I must admit I'm not altogether keen on that. I believe every article should aim to have the first third of it at least fairly easily understandable to someone who is about six months away from starting on it but wants to know something about it. I'd be happy for elementary school children learn the basics of calculus. As to going from basics to more complex the thing I would like is for a way of placing articles into a partially ordered list of depends on and dependencies. This would make instances of circularities and undue dependencies more obvious. We're always going to have circular dependencies because we're describing things as they are rather than writing a textbook but I certainly think something like this would help. Dmcq (talk) 22:06, 18 February 2013 (UTC)

I've been looking at a bunch of math articles at the college and lower level and I think there is a common problem with them. Their introductions tend to be a sea of jargon and blue links to other articles. If we were trying to scare off lay readers, we'd have a hard time doing better. Here is one example: Group (mathematics). This article is supposed to be the elementary explanation (it's advertised as such at Group theory). As of this writing Group (mathematics) begins:

"In mathematics, a group is an algebraic structure consisting of a set together with an operation that combines any two of its elements to form a third element. To qualify as a group, the set and the operation must satisfy four conditions called the group axioms, namely closure, associativity, identity and invertibility."

Only much later in the article do we get a full definition, and that is surrounded by a bunch of well meaning explanatory material that I find excessive and which fails to mention the cyclic groups, perhaps the easiest example to understand. Instead we get a ponderous explanation of the symmetry group of a square. Oh, and it's a Featured article. And I am afraid this is not an isolated instance. --agr (talk) 17:28, 19 February 2013 (UTC)

The observation about a sea of jargon and blue links in the intro is true, but it is not clear that this is avoidable. Dancing around the real concepts by avoiding terminology will probably result in a more tortured, harder to understand intro, but I could be wrong. Supply what you think is a good alternative wording for the group article.

It's a shame that cyclic examples might be missing from the juncture you mentioned. They should definitely appear!

Explaining the symmetry group of a square is a good idea, but that is pretty ponderous... this would be better material on the symmetry group page, which could be referenced in the group example. Rschwieb (talk) 17:47, 19 February 2013 (UTC)

The first sentence pulled by agr is an illustration of what happens when "formalists" edit articles. The first sentence went from "In mathematics, a group is a set of elements together with an operation that combines any two of its elements to form a third element", which I think more harmoniously segues into the rest of the somewhat leisurely discussion of what a group is, to its present form which has a bit more unnecessary jargon. Also, from the third sentence on, the rest of the first paragraph now seems like excessive throat-clearing and needs to be streamlined or cut.

I differ in my assessment, however, since I think the selection of examples in the "Definition" section is exactly appropriate: an abelian group and a non-abelian group that illustrates the notion of symmetry group (which is in some sense why there are groups). Cyclic groups of course are treated as examples in their own right later in the article. Although cyclic groups are algebraically simpler objects to understand, I don't think that makes them intrinsically simpler things to understand than, say, a group of permutations on a set or a symmetry group of a geometrical figure.

--Sławomir Biały (talk) 18:15, 19 February 2013 (UTC)

I don't mind the first section of Group (mathematics) too much. And, contrary to possible impressions, the article does discuss a cyclic group first - the integers are the first example given. — Carl (CBM · talk) 18:35, 19 February 2013 (UTC)

I should have said finite cyclic groups. These are the simplest examples of a group that is not an ordinary number system like the integers, and they are easy to understand. Remember this is supposed to be the introductory article. Symmetry groups are harder to understand because the elements are the rotations, not the positions. The elements of the finite cyclic groups are the numbers themselves and the operation is modular addition, which is also simple. The analog clock face is a familiar example. agr (talk) 21:52, 19 February 2013 (UTC)

I think the symmetry group conveys essential information that finite cyclic groups do not: namely that a group is something "active" rather than something passive. I actually think this is helpful especially to readers hoping to get a sense for a group without getting distracted by technical details. Although obviously first year students taking a first course in abstract algebra would also benefit by rote checking that the axioms are satisfied, as an encyclopedia I think it's important to do something more substantial than that if we are to illustrate the importance of the group concept from the beginning. Sławomir Biały (talk) 22:08, 19 February 2013 (UTC)

I'm not saying it should not be mentioned, but it should not be the first non-trivial example.--agr (talk) 22:29, 19 February 2013 (UTC)

I think finite cyclic groups are somewhat too trivial to be the first non-trivial example, but not trivial enough to be the first example. Our articles are not intended to be thorough introductions to a subject, and I think there is some benefit in using a non-commutative group for one of the two "highlghted" examples. — Carl (CBM · talk) 20:19, 20 February 2013 (UTC)

Groups are a perfect example of a math subject that laypeople are capable of understanding with no prerequisites and group (mathematics) is supposed to be the basic introduction to the topic. It would somehow be beneath us to make this article to easy to read? "... too trivial to be the first non-trivial example, but not trivial enough to be the first example..." We can't have 3 examples, increasing in sophistication? I don't follow your logic here at all. --agr (talk) 16:25, 21 February 2013 (UTC)

I note that two more examples were added to the definition section of the group (mathematics) article. Opinions? Like I hopefully expressed above, I thought the original two examples were a good selection to give in the definition section. I could be pursuaded that cyclic groups might be worth covering in that section, but four detailed examples seems way over the top. We are supposed to be an encyclopedia, after all, not a textbook. Sławomir Biały (talk) 17:51, 4 March 2013 (UTC)

I've removed the example of the even integers. This group is isomorphic to the integers, so doesn't illustrate anything new, and as an example I think it was confusing than clarifying of the original definition, as it brought in notions such as homomorphisms, which hadn't been defined at that point of the article. I left the cyclic group and Klein four group, pending further discussion. Sławomir Biały (talk) 19:08, 4 March 2013 (UTC)

I would suggest moving the discussion of these edits to Talk:Group (mathematics), since they concern that article.--agr (talk) 04:01, 5 March 2013 (UTC)

The discussion has continued there. Sławomir Biały (talk) 22:47, 5 March 2013 (UTC)

Broadest possible may in fact be very narrow. As pointed out above, many math topics are simply inaccessible to people without the requisite knowledge. It would be great if you could write a meaningful "lead" sentence that someone whose last math education was high school algebra 20 years ago could find useful, but that's not always possible and when it is possible, it's not always beneficial. Perhaps the best thing to do is ask yourself "1) what is the least amount of education someone would have to have to understand the bulk of the article, and 2) what is the least amount of education someone would have to have to understand a 1-paragraph, written-as-lay-as-possible summary of what the topic is about?" Frequently #2 would be "2 or 3 semesters of college-level math in a sequence that leads to this topic" or at the very least, several weeks or months studying key ideas pulled from a 2- or 3-semester college-level math sequence. Frequently for #1 it's the same or more. For a few articles, it probably requires the equivalent of a 1- or 2-semester graduate-level sequence, having done a Masters Thesis in a closely-related topic, or having followed research in a closely-related topic for several months or years. The bottom line: Do what you can to make articles as accessible as practical, but don't sweat it if the problem of "how to we write high-level math articles so they can be understood by someone who doesn't even remember high school math" turns out to be intractable. davidwr/(talk)/(contribs)/(e-mail) 19:59, 10 March 2013 (UTC)

Opening sentence

To quote the Manual of Style WP:BEGIN: "The first sentence should tell the nonspecialist reader what (or who) the subject is." I don't see any reason why we can't strive to achieve the same in mathematics articles. Nonspecialist being the key word. The difficulty, of course, is that it's not easy to explain a topic in one or two sentences to a nonspecialist reader, due to the (seemingly) necessary use of jargon. But difficult is not the same as impossible; striving to minimize the amount of jargon in the lead (especially early in the lead), together with mentioning simple examples in the lead, both seem like achievable goals. Mark M (talk) 19:38, 19 February 2013 (UTC)

Not really in reply, but an additional thought along these lines. WP:LEAD demands that the lead should define the topic for the widest likely audience, and should summarize the main points of the article. I have always felt that there is a tension between this and making the lead of the article understandable to a layperson, since I think part of the task of the lead is not just to summarize the more understandable parts of a topic, but also the more sophisticated aspects of it to some (usually lesser) extent. It can be difficult to strike the right balance, and there is not clear consensus about what this entails (not even within this Wikiproject). Sławomir Biały (talk) 19:46, 19 February 2013 (UTC)

To the extent that there is any conflict here, it has an easy and natural resolution. A specialist will have no trouble recognizing and getting past an introductory paragraph or two that takes a limited, initial view of the subject, to find a broader treatment within the the article, while most non-specialists will be put off by a blast of jargon and miss any introductory material later in the article. If need be, the intro can end with a "More generally,..." paragraph with the jargon and the links. --agr (talk) 19:54, 20 February 2013 (UTC)

I agree with this, to the extent that it is usually desirable to put the more easily understood things earlier in the lead. But I find it personally helpful to avoid canned phrases like "More generally..." since they don't often lead to clear writing. Sławomir Biały (talk) 21:13, 20 February 2013 (UTC)

Without concrete examples of particular first sentences, it is hard to say anything concrete. Not all "jargon" (i.e. vocabulary) is bad, and not all of our articles are intended for readers who have no background whatsoever. But some jargon is avoidable, and doing so can make the article more accessible. I find it better to write "one level down": assume that the reader is just taking the course before the one where the topic at hand would be covered. I think that the idea that we could write generalized flag variety in a way that would be meaningful to 6th graders is farfetched. At some point it is up to the reader to use the helpful blue links to chase down the prerequisites for the topic. — Carl (CBM · talk) 20:15, 20 February 2013 (UTC)

I quoted Group (mathematics) above. It's since been improved a little. A someone else pointed out, Wikipedia is a work in progress by volunteers. Writing a level N article for a level N-1 audience is better than writing for a level N or, worse a level N+1 audience (which happens), but I do not think we should be content with that. It's a judgement call how far down an opening sentence can reach, but even in an article as technical as generalized flag variety perhaps some context for mathematicians working in different fields could be given.--agr (talk) 16:36, 21 February 2013 (UTC)

Template {{no footnotes}}

Some editors tag systematically math article with {{no footnotes}} and similar templates. In many cases, like in Algebraic variety, this is true, but it suggests wrongly to the reader that some part of the content is controversial. This is the reason for which I have moved the tag at the bottom of the article, considering that the tag should not removed (it is true and it puts the article in a relevant category), and that it is not useful for the general reader. I have been reverted.

My question is thus the following. Is there a recommendation of this project for the place of the tags like {{no footnotes}}, when there are not a warning about a possibly controversial content? At the top, or like for stub templates, at the bottom? D.Lazard (talk) 03:14, 6 March 2013 (UTC)

Imho this is sometimes simply overtagging not every math article needs footnotes. If you have relatively short math article with no content issues, based on very few sources (say textbook section or journal articles). It is good enough to simply list them at the end. If I see such articles tagged I simply remove the tag.--Kmhkmh (talk) 04:09, 6 March 2013 (UTC)

Algebraic variety doesn't fall in this class, though. RockMagnetist (talk) 04:23, 6 March 2013 (UTC)

Well, i somewhat agree. Imho Algebraic variety is in a grey area, it is probably already a bit too long with and given the references are not really specific enoug (no pages or chapters) to locate the content quickly.--Kmhkmh (talk) 04:59, 6 March 2013 (UTC)

IMO, the footnotes serve two purposes: provide a source to potentially verify controversial content and to guide the reader to the sources for more details. As a reader, I find it pretty irritating to read large swaths of unreferenced paragraphs and sections and have no idea where this content came from. Articles are necessarily summaries of the topics, and particularly for advanced math topics, it would be nice to know where to go for proofs and more examples. For non-controversial content, one would not need many citations to point the reader to the source or sources, but they should be there.

In that context, it would be nice to have a tag along the lines of "This article needs citations to show readers where to go for further information." --Mark viking (talk) 04:40, 6 March 2013 (UTC)

Well the article sort of tells you where to go for further information though, any of the 4 books listed under references, they lack specifity though.--Kmhkmh (talk) 04:59, 6 March 2013 (UTC)

The bottom line, though, is that there is no special property of math articles that justifies a separate policy on footnotes. RockMagnetist (talk) 05:51, 6 March 2013 (UTC)

T:No, not in particular I treat other articles the same way. However in my subjective experience that scenario is more common in math articles, maybe because they are more likely to be be uncontroversial (in comparison to some other areas)--Kmhkmh (talk) 06:14, 6 March 2013 (UTC)

Well we had a very similar discussion several years back and came up with Wikipedia:Scientific citation guidelines, so in reply to RockMagnetist there is a special guideline on footnotes for scientific articles.--Salix (talk): 06:52, 6 March 2013 (UTC)

Thanks for pointing that out - I don't recall seeing those guidelines before. To me, their approach to uncontroversial knowledge seems misguided. If a single expert were writing the article, a few general citations at the beginning might suffice. But if multiple editors contribute, this method provides cover for all sorts of sins. Somewhere I read the suggestion that a reference or two, added at the end of a paragraph, could be taken as support for the whole paragraph. That method seems better to me. RockMagnetist (talk) 16:47, 6 March 2013 (UTC)

In Algebraic variety, the first section is full of definitions and probably is uncontroversial. But Discussion and generalizations is full of judgements and sweeping generalizations and is crying out for citations. RockMagnetist (talk) 16:54, 6 March 2013 (UTC)

Wikipedia conventions are that tags like "No footnotes" should be at the top of the article or section to which they apply. Why? Because that's where editors expect to see them, and they will likely be moved there if they are elsewhere. For articles which footnotes are clearly not needed, perhaps a different template can be added to the top of a "References" section stating something like:

This mathematical article discusses general, widely-known mathematical concepts for which references are not needed. If you add a reference here, remove this template. If you believe references are needed for this article and do not have references to add now, [[ARTICLE_TALK_PAGE|discuss]] it and if there is no objection within 7 days, remove this tag and add {{unreferenced|date=MONTH YEAR}} or a similar template to the top of this article.

davidwr/(talk)/(contribs)/(e-mail) 19:46, 10 March 2013 (UTC)

Examples of convolution

I saw the wiki page, but I couldn't find any examples using actual numbers evaluating the formula. Could you give some examples of convolution, please? Mathijs Krijzer (talk) 22:45, 9 March 2013 (UTC)

Just FYI: this user seems to be spamming widely with this question. --JBL (talk) 22:58, 9 March 2013 (UTC)

No, I try to be very targeted and small scale! ;) Mathijs Krijzer (talk) 23:31, 9 March 2013 (UTC)

Mathijs, leaving messages at 18 user pages is excessive; see contributions, range:

14:07, 2013 March 9 User talk:Zueignung

…

14:22, 2013 March 9 User talk:PAR

(Also at 3 project pages and the article talk page.)

Further, there is no need to place a large article extract with your question (example diff) – if the editor in question has any expertise, the brief question as edited above (“The wiki page has no concrete examples – concrete examples please?”) is sufficient.

I assume you just want to improve Wikipedia, or personally want some help, but leaving this many messages makes a lot of work for people – at the least everyone needs to read through your request and the page in question, and then look around to see if anyone else is working on it.

Instead, if you have a question or request for improvement, please ask it first on the one project page that seems best. In this case the Wikipedia:Reference desk/Mathematics or perhaps this page (Wikipedia talk:WikiProject Mathematics) would be relevant. If you don’t get an answer in a day or two, it is appropriate to slowly ask at more places.

Also, in your reply to Joel, who is clearly upset at your messages, denying it – saying “no, I’m not spamming” – does not help the discussion. If you instead say “I’m sorry if I’ve caused any problem – I tried focusing my question to 18 people who seemed active on the page.” you’ll at least come across as thoughtful and considerate.

So in future, I would suggest:

• Place questions and requests at a single project page, such as this.
• Apologize when you offend someone, even unintentionally.

Good luck with future editing!

—Nils von Barth (nbarth) (talk) 03:30, 10 March 2013 (UTC)

I’m sorry if I’ve caused any problem – I tried focusing my question to 18 people who seemed active on the page. --Mathijs Krijzer (talk) 11:25, 10 March 2013 (UTC)

I don't have a problem with the message on my talk page. I'm not sure I see any urgency about numerical examples in this instance. Michael Hardy (talk) 13:17, 10 March 2013 (UTC)

Image at The Quadrature of the Parabola article

I was browsing through The Quadrature of the Parabola and came across this image:

Now, am I missing something, or is that incorrect? It seems like the dotted line (and "height" arrow) should be perpendicular to the base. --JaGa^talk 04:45, 10 March 2013 (UTC)

That's a different formula. The area of a triangle is 1/2 (side) (segment from opposite vertex to side, perpendicular to the side), the formula you're thinking of. But it's also 1/2 (projection onto x axis) (segment from opposite vertex to side, parallel to y axis), as the picture shows. The second formula can be related to the first by an affine transformation. —David Eppstein (talk) 05:35, 10 March 2013 (UTC)

The h is indeed perpendicular to the w, as should be evident from the pictures. Notice that if you take the vertical dotted line to be the "base", then you have two triangles – one to the left of the dotted line and one to the right – and the sum of their two heights is w, so (1/2)hw is the sum of their two areas. So the formula is correct. Michael Hardy (talk) 13:19, 10 March 2013 (UTC)

The statement is certainly true, but it is also liable to be extremely confusing to anyone who e.g. stopped taking math after calculus. It would be nice if it could be reworded so as to not cause this problem. In particular, the use of the word "height" for the segment in question is surely misleading. Is there a better phrasing/wording? -JBL (talk) 15:22, 10 March 2013 (UTC)

Yeah, it would be nice if the section mentioned this "x/y axis projection" area formula - I've never heard of it, and it would have made for an interesting discovery. Instead, I was just confused by the diagram. --JaGa^talk 17:17, 10 March 2013 (UTC)

List of orderings?

The new article Dershowitz–Manna ordering is currently an orphan, i.e. no other articles link to it. I looked at List of order theory topics and Glossary of order theory, and it didn't seem to fit in either in their present forms. Then I looked for Lexicographic order in both lists, and it isn't there. How many other special types of orders are not in any such lists? Should another list be created for more concrete things like these? Michael Hardy (talk) 13:38, 10 March 2013 (UTC)

Creating a new list for concrete ordering schemes is a good idea. The other two lists you mentioned seem to be about ordering theory in general. Lexicographic and Dershowitz-Manna orderings are more used in computer science than mathematics, but I could not find a relevant CS list, either. Collocation deals with types of ordering relations, but seems more specialized to alphabetic ordering relations. --Mark viking (talk) 17:41, 10 March 2013 (UTC)

Monomial order does not appear in Glossary of order theory. It appears in List of order theory topics, but the specific monomial orders listed in eponymous article do not. D.Lazard (talk) 19:33, 10 March 2013 (UTC)

See below — we could also use a list for classes of orderings (total order, partial order, weak orders, preorder, cyclic orders and well-quasi-ordering, etc. as well, to which ordered set could redirect. This would be different from Dershowitz–Manna though because that's an individual ordering rather than a class of orderings. I have started such a list at List of types of ordered set.—David Eppstein (talk) 19:36, 10 March 2013 (UTC)

Cross reference to list

Apparently {{cross-reference}} is now deprecated, and users have been going around converting it to {{dab}}, which is generally a mistake (cross-reference pages are the deliberate target of links from other pages; dabs cannot be). I think this affects this project more than others, as the cross-reference format was invented for math pages by Michael Hardy. A solution I have used for the former Erdős conjecture is to convert it to a list format: List of conjectures by Paul Erdős. Perhaps others like this should be converted in the same way. Pages formerly listed as cross-references and needing attention include

• Continuity (mathematics)
• Dedekind completeness (already gutted and turned into a redirect to one specific type of Dedekind completeness)
• Ordered set (already gutted and turned into a redirect to one specific type of ordered set)
• Real-valued function (still in place with the cross-ref template removed)

—David Eppstein (talk) 16:07, 10 March 2013 (UTC)

User:Wikid77 and "breaking up complex formulas"

Tracked in Phabricator
Task T47973

After his goal of speeding up citation templates at the expense of accuracy and formating, he's now doing it to < math> templates. See his edits to Gamma function.

This is as neutral as I can get. He made it both mathematically and visually wrong, and impossible to edit. — Arthur Rubin (talk) 17:20, 10 March 2013 (UTC)

So far, as far as I can tell, he's only edited Gamma function and Ring (mathematics). — Arthur Rubin (talk) 17:26, 10 March 2013 (UTC)

Wow, that is an unmaintainable mess of math tags! The Gamma function page should not load so slowly; maybe this is a MathJax problem on his end. In any case, this decimation of math formulas should be reverted, to preserve the mathematical and typographical structure of the formulas and to preserve editors' sanity. --Mark viking (talk) 17:52, 10 March 2013 (UTC)

• Optimization of math-tag text can be taught in essays, and problems have been exaggerated, just as fears of fast cite templates were hyped to exaggerate small differences; instead, many claims of "broken templates" were actually caused by invalid parameters in older articles. -Wikid77 14:35, 11 March 2013 (UTC)

Most (but not all) of Wikid77's edits to Ring can be undone; I'm on a mobile device so didn't do it myself, but it seems to me that they should all be reverted ASAP. --JBL (talk) 18:25, 10 March 2013 (UTC)

The problem seems to due to problems with the time taken to render the page. There is a hard limit of about 60 secs to render a page after the "save page" button has been pressed. If that time is passed you get an error page displaying and the edit will not be processed. There is a section on the talk page Talk:Ring (mathematics)#Technical difficult with editing ring (mathematics) when an editor repeatedly had problems getting an edit saved. Part of the problem is the number of math tag which seem to be taking a long time to process. A similar problem was seen at Wikipedia:Reference desk/Mathematics#Posting here is really slow today. What I find curious is that we have not had similar problems before, why have we suddenly started getting these getting problems.

Given a real problem with timesouts when rending the page uneditible something needs to be done. We can hope the problem goes away, we can try and find out from developers when these problems have started, or we can change the article so it does render within the allowable time. Personally I think the article is overlong which too many section on generalisations and special cases. These could be split of into other articles. Using {{math}} for simple equations is one way of getting the page to render in time. Splitting up <math> tags does not seem a good solution.

PS on the topic of citation templates Wikid77 is doing good work with help of the community on converting citations to Lua at Module talk:Citation/CS1. These should be almost identical to the current templates and will cure a similar timeout problem on pages with lots of citations.--Salix (talk): 20:52, 10 March 2013 (UTC)

I don't know if his actions with Lua citation templates are constructive; I know there is consensus that his creation of "cite-quick" templates was a significant change, and should never have been implemented as a replacement for the "standard" citation templates, as it changed formating and lost data. — Arthur Rubin (talk) 21:37, 10 March 2013 (UTC)

There was no final consensus in long discussions, but some editors even suggested to use {cite_quick} for entire articles, which can work in thousands of articles, because support for all major parameters was added later. It was similar to seeing a new house under construction, then claiming, "This house can never withstand rain," because some windows needed window panes. Total exaggeration. -Wikid77 14:35, 11 March 2013 (UTC)

I remember that, but I think his new work on citations is much improved. There are very few changes of formatting, and the changes that are there are clear improvements. (I tried it on Riemann hypothesis as a test case.) There is a minor hangup getting this installed (Lua is broken for pdf downloads) but when these citation changes do roll out I think it will be a good thing. —David Eppstein (talk) 23:52, 10 March 2013 (UTC)

The Lua-based cites run nearly the same speed as the fast markup-based cites, but support all prior parameters plus variant spellings, such as "authorlink" or "author1-link". -Wikid77 14:35, 11 March 2013 (UTC)

I've filed a bugzilla ticket, bugzilla:45973, in relation to the issues that have apprently recently appeared with the math caching system. Dragons flight (talk) 02:48, 11 March 2013 (UTC)

• See below: "#Teaching math-tag optimization". -Wikid77 14:35, 11 March 2013 (UTC)

It looks like there is a fix to the bug on cache problems with maths which should be rolled out in the next version. So hopefully rendering speed problems will go away.--Salix (talk): 23:10, 12 March 2013 (UTC)

Teaching math-tag optimization

I think the optimization of math-tag text can be taught, so more editors will be aware of the techniques to run 105x faster. Also, other editors have suggested there might be some ways to write multiple math-tag groups in a clearer format. For example, to set $x$ to a rare value "67.5431" rapidly, then just separate that value as {math} font, to format over 100 times faster:

• Old format:  <math>x = 67.5431</math>
• New format: <math>x =</math> {{math|67.5431}}   ←runs 105x faster

To calculate the optimized speed, just divide by 105, so the old format, running $\approx$ 0.6 second, will quicken to 0.6/105 or $\approx$ 0.00571 second to rapidly format with a separated value as {math|67.5431}. The basic principle is that optimized math tags can reformat about 105x times faster than complex math tags, so that is how I had changed article "Ring (mathematics)" to reformat within 19 seconds, rather than the original 54 seconds of the complex math tags. I can sympathize with fears of becoming "math-tag calculus" but the main technique is akin to "substitution by parts" to solve the slow speed by rapid handling of each part of an equation.

The problem, as slow math-tag processing (lack of quick symbol cache images), has persisted for weeks, and there is no guarantee of a quick fix because some complex equations, and most separate symbols, are in fact, using quick symbol cache images, but not every formula, even though some very complex, multi-line equations use rapid cache images. Hence, use more math tags everywhere, rather than italic letters, so write more: "where $f(x)$" not "where f(x)" because the math-tag version of short $f(x)$ is lightning fast. Also, many of the most-complex equations can be left in the original math-tag format, where optimization is not needed everywhere. Instead, just optimize some shorter equations, such as $x=$ 67.5431, until the total reformat time drops below about 20 seconds for the entire article page. These simple rules of "math-tag calculus" can be explained in an essay. We want more people writing the Gamma function as "$\Gamma (z)$" not "Γ(z)" when the optimized math tags can reformat so quickly, using the same font as in the longer equations. -Wikid77 (talk) 14:35, 11 March 2013 (UTC)

To repeat my comment from your user page: please never again edit a Wikipedia math article in the way you have done to Ring and Gamma function. Bug-fixing for certain users is not, in fact, more important than general usability, which you destroyed. --JBL (talk) 14:47, 11 March 2013 (UTC)

I see little benefit in having our editors learn a particularly arcane method of tag optimization which renders certain equations difficult to read or edit. It seems that if the current variant runs too slowly, that is a technical problem to be solved by the developers, and editors can continue editing in the style to which we are accustomed, and have been trained to use by years of reading and writing in TeX. Ray^Talk 15:22, 11 March 2013 (UTC)

If this conversion could be automated (which I doubt, because big fences (such as parenthesis) [reasonable], big integrals [perhaps unreasonable], and spacing could not be preserved in the "optimized" version), and the original formula were left in comments, then it would only be a minor inconvenience for editing. If an editor needed to edit the formula, he could kill the "optimized" version and uncomment the reasonable version. — Arthur Rubin (talk) 15:37, 11 March 2013 (UTC)

For reference:

<math>x = 67.5431</math>

$x=67.5431$

<math>x =</math> {{math|67.5431}}

$x=$ 67.5431

<math>x =</math> <big>{{math|67.5431}}</big>

$x=$ 67.5431

Please do not convert this to a table, because < big> doesn't expand the table row height. — Arthur Rubin (talk) 15:44, 11 March 2013 (UTC)

I sympathize with wanting to make things load faster but you have to keep your priorities right. In the third pillar of WP:5P it says 'Wikipedia is free content that anyone can edit, use, modify, and distribute.' The only complex things that should be put in are things which are really needed for the purpose of producing an encyclopaedia. Anything else and we detract from the 'anyone can edit'. I would really like people to ensure articles are split a bit sooner as there is a tendency to produce monolithic blocks and that is I believe what we should mainly be trying to do to get things to load faster, after all it is supposed to be mainly web based with links rather than being a book, plus there's room for improvement of course ensuring pages can be cached better. Mathjax has been chosen as the main target for anything more than very simple maths and it will be improved and the hardware for displaying pages will be improved too. Putting in funny tricks is just destructive of Wikipedia's aims. It might help a few people in the short term to load a page faster but tricks like that are very destructive in the long term. Dmcq (talk) 15:54, 11 March 2013 (UTC)

This sort of change should not be done. If an article does not already use the {{math}} template, but instead uses the <math> tag consistently, editors should not change the way the math is formatted. This has been discussed at length on this talk page. Moreover, using both {{math}} and <math> is the "worst of both worlds" - if we were going to use {{math}} we would use it for the entire formula, not just for half of the formula. The ultimate goal, as Dmcg says, is to use MathJax for everything, as which point these tricks are only going to make things worse. — Carl (CBM · talk) 15:56, 11 March 2013 (UTC)

This is typographically completely insane. Breaking formulas like this results in a mumbo-jumbo of bits using different fonts and sizes, it destroys proper spacing (such as around relation symbols), let alone the fact that the resulting markup is unreadable and unmaintainable. It also appears from bugzilla:45973 that the bug which prompted all this discussion has already been fixed, so a proper remedy should come in a reasonable time-frame.—Emil J. 16:06, 11 March 2013 (UTC)

I agree with the others above, especially Dmcq--we must maintain the ability to easily read and edit math formulas. The recent slow rendering was a regression and a fix is already in the works. But even if this were a permanent problem, the speed optimization strategy you are proposing is the wrong kind of optimization--forcing editors to maintain template spaghetti code and forcing users to puzzle out math equations with ransom-note typography. A proper optimization, from a software engineering perspective, should be done behind the scenes and be transparent to the users. TeX can process many pages of complex math equations per second on a modern machine and caching eliminates even that delay. It's very likely this is fixable in mediawiki, rather than forcing a language change. Start optimizing mediawiki first and save breaking the user interface as a last, desperate resort. --Mark viking (talk) 16:39, 11 March 2013 (UTC)

Since this came up I thought I'd point to an example of a case where splitting the formula inside the math tag is exactly the right thing to do: [23]. (Yes, they could be coded as html but math makes them more consistent with the other formulae in the article.) —David Eppstein (talk) 07:20, 12 March 2013 (UTC)

That may not even count as splitting a formula, since they are naturally two formulae to begin with. RockMagnetist (talk) 16:26, 12 March 2013 (UTC)

Efficient performance is an important issue, but individual local fixes for it are imho not a good idea. Such needs things need to be fixed by improving that global rendering process (mediawiki software) rather than amending/changing the existing syntax. Other than that imho an easy to use universal way of handling math formulas is important, in particular for occasional editors. The more complicated we make that process by additonal tags and style requirements, the incovenient it becomes of editors in will in doubt drive them away. For that reason I personally already dislike the existing additional accepted templates and I don't mind to live to with a slightly less than optimal display if it allows for universal way for handling formulas. --Kmhkmh (talk) 08:17, 12 March 2013 (UTC)

Agreed that mixing {{math}} and <math> is not effective... very unsightly/awkward practically and visually and it's so much easier to just use one or the other. M∧Ŝc²ħεИ_τlk 20:44, 12 March 2013 (UTC)

Believe my experience, mixed {{math}} and MathJax looks fine when the former uses MathJax fonts. I have them installed locally and hence need only tweaks in the personal CSS. To make it an easily accessible option for registered users, Wikipedia needs class="texhtml" to use the same client-downloadable fonts as MathJax uses – it would allow to conserve a great amount of client-side CPU time and other resources. I could request a sysop at testwiki: and experiment with it there, but, without an actual interest of Wikipedia users, it would be worthless. Unfortunately, many attempts to discuss {{math}} within the range of WP:MATH degenerated to a pointless flame where a loud minority shouts that {{math}} and so will die (or must die), and no solution becomes possible. Incnis Mrsi (talk) 21:36, 16 March 2013 (UTC)

Hi all,

It looks like the problem went away. Of course, the problem didn't go away by itself; it has been fixed according to [24]. My thanks to all who tried to help. Time to go back to math. -- Taku (talk) 23:55, 12 March 2013 (UTC)

Renaming discussion regarding the article on Element (category theory)

The proposed renaming being discussed at Talk:Element (category theory)#Requested move may be of interest to members of this WikiProject. Favonian (talk) 21:11, 16 March 2013 (UTC)

Transformation

Please see WT:PHYSICS, where a discussion on creating an article on "transformation" is occurring. -- 65.92.180.137 (talk) 21:41, 16 March 2013 (UTC)

Confusing wording in section "Confidence Interval"

This section refers to "chi-square deviate with lower tail area p and degrees of freedom n". From googling and wikipediaing, "deviate" isn't a well defined term. Also an authoritative notation for 2-parameter chi-squared distribution is difficult to find online, and I was under the impression that p is the area to the right of a threshold. Here, p is referred to as the lower tail area. Is this in fact the case? Craniator (talk) 23:16, 17 March 2013 (UTC)

Which article do you mean? In "Confidence interval" I do not see such words. Boris Tsirelson (talk) 06:46, 18 March 2013 (UTC)

Poisson distribution#Confidence interval, it seems. —David Eppstein (talk) 06:56, 18 March 2013 (UTC)

Accordingly, I move the above comment to the talk page there. Boris Tsirelson (talk) 16:34, 18 March 2013 (UTC)

Gen'ichirō Sunouchi

Does anyone know enough about the mathematician Gen'ichirō Sunouchi to add some evidence of notability to his biography? — Carl (CBM · talk) 13:19, 19 March 2013 (UTC)

He has a solid publication record sufficient to place him beyond any AfD. I added some of the most popular titles. Tkuvho (talk) 14:46, 19 March 2013 (UTC)

A collection of papers by some of the heavyweights in the field was dedicated to his 60th birthday (Tohoku Math J. 1972). Perhaps this is evidence of notability. Tkuvho (talk) 14:52, 19 March 2013 (UTC)

This is usually considered suggestive but not definitive for notability. In any case it should be added to the article.

Fermat 1607 birth?

Recent changes at Pierre de Fermat place Fermat's birth as "probably in 1607". There is recent scholarship claiming that the traditional date of 1601 is incorrect, and the correct date is 1607, but I am not sure to what extent this has been generally accepted. Tkuvho (talk) 14:30, 4 February 2013 (UTC)

The new user's recent edit concludes with the words "That's all nonsense. It's equal." (see adequality). Tkuvho (talk) 13:36, 5 February 2013 (UTC)

The source regarding the date of birth seems legit, but apparently not undisputed or generally accepted yet. The German and the French wikipedia therefore simply state the first decade of the 17th century as (approximate) date of birth. The French one also has a footnote explaining the situation in more detail. The MacTutor also doesn't side for a particular date ([25]). I found one recent number theory book that has adopted the new date but also other recent ones still carrying the old date. All in all it seems reasonable for the time being not to pick one date but give both or simply the decade.

The other unsourced other edit and its language don't instill confidence though. I#d remove that in doubt.--Kmhkmh (talk) 14:12, 5 February 2013 (UTC)

An initial publication for the 1607 date appears to be Barner, Klaus (2001). “How old did Fermat become?,” NTM: International Journal for History and Ethics of Natural Sciences, Technology and Medicine (New series) 8(4), 209-228. Cited by Friedrich Katscher [26]. Texts that have accepted this argument include Mollin, Fundamental Number Theory with Application (2008) [27] (also cites [28]); Lemmermeyer, Reciprocity Laws (2000) [29]; Dauben & Scriba (2002) Writing the History of Mathematics [30]. Deltahedron (talk) 07:26, 6 February 2013 (UTC)

An experienced editor just deleted (appropriately) some material that the new editor (Barner himself) added to the adequality page. I am concerned though that the new editor might misinterpet this. Can someone place an explanatory note at his userpage explaining notation such as POV, as well as the idea that a wiki article is not seeking the ultimate truth but rather documenting what reliable sources said about the topic? His edits go in the direction of enforcing a single interpretation (which happens to be his own) and show an insufficient awareness of wiki rules. Tkuvho (talk) 09:02, 8 February 2013 (UTC)

Some further comments by the new editor at Talk:Adequality are a bit disappointing, since he describes the work of both Enrico Giusti and Fermat historian Michael Sean Mahoney as "absurd". On the other hand, this is a rare historian of mathematics that actually volunteered to work on a wiki article. If someone has an effective way of explaining wiki policy this may be helpful in the long run. Tkuvho (talk) 14:13, 13 February 2013 (UTC)

The size of adequality more than quadrupled in the past few minutes. An extra pair of eyes would be helpful. Tkuvho (talk) 17:31, 26 February 2013 (UTC)

The new section Adequality#Analysis of "adequality" meaning in Fermat's work smells like a copyright violation to me. JRSpriggs (talk) 06:58, 27 February 2013 (UTC)

Yet another controversial edit here. Tkuvho (talk) 15:07, 11 March 2013 (UTC)

There is a further deletion of sourced material here. I would appreciate input from other editors. Tkuvho (talk) 09:50, 22 March 2013 (UTC)

WP 1.0

The titles in tables for the individual subject area ratings (Wikipedia:WikiProject Mathematics/Wikipedia 1.0/Table) link to historical pages (e.g., Wikipedia:WikiProject Mathematics/Wikipedia 1.0/Algebra) Where would be a better place to send the link in the titles? Regards, Illia Connell (talk) 21:59, 18 March 2013 (UTC)

I think that just removing the links would work, there is no natural place to link the tables to. — Carl (CBM · talk) 12:50, 19 March 2013 (UTC)

Is this something I can just go ahead and do, or will the bot overwrite the change next time it updates the table? Illia Connell (talk) 21:08, 20 March 2013 (UTC)

an "arguments" page for pi?

There is a lot of activity at Talk:Pi not really related to improving the page; see for example an anti-pi song post here. At 0.999... we have a special "arguments" page where entries not relating to improving the page can be moved. Should this be created for pi, as well? Tkuvho (talk) 15:43, 20 March 2013 (UTC)

That anti-pi song post actually was relevant to something that had been talked about to improve the page. Sorry I didn't get around to elaborating on it. Some people had suggested, during the discussions about tau and pi, that it would be good to add a section explaining how there was nothing special mathematically about pi specifically as opposed to some other variant on the number, like 2pi, or pi/2. If you listened to the song, it addressed other misconceptions people have about pi. Like that pi is very unique in not having a finite decimal representation. The song doesn't bash pi. It expresses some of the same things I've heard editors here express. That's why I said it was pretty good and thought I'd share it. A section on "Popular Misconceptions About Pi" might make a great addition to the article. --Joseph Lindenberg (talk) 08:01, 21 March 2013 (UTC)

I guess it would be okay to have such a subpage. Another option is to to just collapse the section like this:

{{Collapse top|title=This section is not related to improving the pi article}}

.... discussion not related to improving article

{{Collapse bottom}}

--Noleander (talk) 15:58, 20 March 2013 (UTC)

Collapsing is recommended in WP:TPO. There is probably a policy against having a page for off-topic posts. RockMagnetist (talk) 20:33, 20 March 2013 (UTC)

Pythagorean triple

There's a big pile of edits going on at Pythagorean triple (after a big pile of similar tldr at the talk page) by C. W. Vugs that could probably use attention by other mathematics editors. I'm not sure whether or not it's original research but it's written in a telegraphic notation-heavy style that I'm not convinced is appropriate for the article. —David Eppstein (talk) 18:56, 24 March 2013 (UTC)

Reversion was definitely the way to go -- I didn't see anything in those edits that looked like an improvement to the article. --JBL (talk) 21:50, 24 March 2013 (UTC)

The Pythagorean triple#Proof of Euclid's formula does not seem to deal correctly with the possibility that a and b are both odd (and c is even). No proof is given that this cannot be true for a Pythagorean triple, as far as I can see. JRSpriggs (talk) 21:57, 24 March 2013 (UTC)

Variational method

The usage of "Variational method" is up for discussion, see talk:Variational method -- 65.92.180.137 (talk) 01:06, 25 March 2013 (UTC)

Eyes needed at FLT

Eyes needed at Fermat's Last Theorem where IP contributor 37.190.220.127 (talk · contribs) is repeatedly adding and re-adding crackpot material. Maybe a case can be made for semi-protection of the article ? Gandalf61 (talk) 10:48, 25 March 2013 (UTC)

I semiprotected it for three days. —David Eppstein (talk) 14:56, 25 March 2013 (UTC)

Excellent - thank you. Gandalf61 (talk) 15:34, 25 March 2013 (UTC)

Wilf–Zeilberger pair

I can't make sense of the example in the article on Wilf–Zeilberger pairs. Even if I suspend disbelief for a moment and accept that the two given functions are a pair, I don't see how that pair would verify the given identity. AxelBoldt (talk) 01:30, 26 March 2013 (UTC)

I agree, I cannot see it either. The example looks incomplete as well and the equation for the proof certificate is different than that of the Tefera article. I added the Tefera definition of the proof certificate to the preceding section, but the example needs work. MathWorld has a nice example using the binomial theorem, but I wouldn't know how to use it without committing plagiarism. --Mark viking (talk) 03:54, 26 March 2013 (UTC)

math template cat hierarchy

Category:Mathematics source templates and Category:Mathematics referencing resources are sub-cats of each other. Could someone from this project figure out the correct hierarchy? Thanks, Illia Connell (talk) 04:15, 26 March 2013 (UTC)

They appear to be equivalent, and should probably be merged. I'm not crazy about either name - "source templates" is a little unclear while a "resource" is a vague alternative to "template". I suggest Category:Mathematics referencing templates. RockMagnetist (talk) 14:51, 27 March 2013 (UTC)

On second thought, I notice that Category:Mathematics source templates is one of many similarly named cats in Category:Specific-source templates. RockMagnetist (talk) 16:53, 27 March 2013 (UTC)

The best "simple" fix I see is to remove the "resources" category from the "templates" category and leave the "templates" category in the "resources" category. — Carl (CBM · talk) 15:04, 27 March 2013 (UTC)

That would leave several files in both the parent cat and subcat. RockMagnetist (talk) 16:54, 27 March 2013 (UTC)

I've now listed this at Wikipedia:Categories for discussion/Log/2013 March 29 as a proposed merge of source templates into referencing resources.--Salix (talk): 09:08, 29 March 2013 (UTC)

LaTeX style & web software

Somewhere on the web there is software intended to provide to people who don't know how to code math notation in TeX the TeX code for things that they create by pointing-and-clicking. The TeX code that they get involves things like this:

\left( {{{x}_{0}}}^{{2}} \right)

where one could just write this:

(x_0^2)

This shows up a lot on math.stackexchange.com, but this morning I found some of it in a Wikipedia article. This kind of thing is a disservice to (1) people editing Wikipedia articles in which this appears, and (2) anyone getting impressions of how to write this sort of code from what they find in Wikipedia articles that they edit. Could one create a bot that would identify suspected instances of this sort of thing and compile a list of them to be looked at? Michael Hardy (talk) 14:35, 27 March 2013 (UTC)

New tessellation article

I created a new article, Catoptric tessellation. I am not very familiar with the rating process for mathematical articles though. Any help in rating and improving the article is welcome. -- Toshio Yamaguchi 14:17, 30 March 2013 (UTC)

Also, that article could really use some images. I already asked at the illustration workshop, but I understand that this might be a difficult request for people unfamiliar with the topic. -- Toshio Yamaguchi 14:38, 30 March 2013 (UTC)

Nice start - I added the {{maths rating}} banner to the talk page, anyone is welcome to change the settings. I could produce images, feel free to detail on that article's/mine/your talk page, but they would be pseudo-3d only, like this --->

and I'm short of time right now (exams in a month)... will try and draw some as and when. M∧Ŝc²ħεИ_τlk 18:17, 30 March 2013 (UTC)

Apr 2013

Dubious addition at determinant?

See this unsourced edit, claiming the Sarrus rule extends to n × n matrices, and changes made to the 4 × 4 determinant. Is it true? Thanks, M∧Ŝc²ħεИ_τlk 07:13, 1 April 2013 (UTC)

Something is not quite right with that material. Deltahedron (talk) 08:40, 1 April 2013 (UTC)

by: Doctor Engr. Ramjie Jovero,PhD Atty. Christian B. Concillo,MD-Drug Lord

Automatic numbering of equations

Is there a way to label equations and refer to them by their labels, while consecutive numbers are assigned to the equations and their corresponding references. I mean something similar as in LaTeX? I haven't seen such a feature used on Wikipedia, but some mathematical articles like binomial coefficient could benefit from it. At least for referring to equations given earlier in the article, such a feature should be possible, as the use of footnote and references shows. Any help, hints or example pages? Schmock (talk) 12:04, 1 April 2013 (UTC)

There are the templates {{EquationNote}} and {{EquationRef}} that can be used in tandem to produce numbered equations. However, they do not automatically handle the numbering. I don't know how technically feasible it is to number the equations automatically, although this seems to be within the scope of functionality provided by mw:Extension:Cite/Cite.php. Sławomir Biały (talk) 12:34, 1 April 2013 (UTC)

binomial coefficient is a great example of how cumbersome the current system is. They now have an equation 3.5 and lots of letters after the numbers. Also, there are several equations with numbers but nothing linked to them; probably it would be best to remove those numbers. My impression is that the article could use some rewriting to make it more like an encyclopedia article and less like a textbook. RockMagnetist (talk) 16:13, 1 April 2013 (UTC)

On EoM automatic numbering works, thanks to MathJax, see here. I noted that MathJax was implemented also on Wikipedia. Or not? Boris Tsirelson (talk) 10:37, 2 April 2013 (UTC)

Slovin's Formula

I recently declined this draft article about Slovin's Formula, which is used in statistics. It was supposedly invented in 1843. I've never heard of it. If it is a notable formula and it can be backed up by reliable sources, perhaps an article should be written about it. Has anyone heard of this formula, either under this name or another name? The listed formula is

n= N/1+Ne^2 where 
n= sample size, 
N= population size, 
e= margin of error

According to late Ramjie Jovero it is widely use as formula in surveying the population of aliens, but according to late General Christian Concillo, it used for measuring the size of girls butt and boobs.

Anyone heard of such a formula? If it already has an article under a different name, it might be a good idea to add a section about how this is sometimes mis-labeled as "Slovin's Formula" and provide a redirect. davidwr/(talk)/(contribs)/(e-mail) 14:00, 30 March 2013 (UTC)

Looks like a case of WP:NFT to me. I think the decline was correct. —David Eppstein (talk) 07:21, 1 April 2013 (UTC)

Well the formula itself seems clearly notable as you get quite a number of hits under Google books ([31]). Slovin publication of the formula is however dated 1960 not 1843, but it might have known to others earlier.--Kmhkmh (talk) 09:05, 1 April 2013 (UTC)

Fortunately David Eppstein's pessimistic take is mistaken. There are lots of mentions of this same formula by this same name in Google Books and Google Scholar. The article's contradictory assertions about when it originated and who did it cannot be allowed to stand, and the article obviously needs work in some other respects as well. Michael Hardy (talk) 16:29, 1 April 2013 (UTC)

I'm happy to have been shown to be mistaken here. —David Eppstein (talk) 17:35, 1 April 2013 (UTC)

How is "margin of error" defined? Is n the minimum sample size necessary to keep the "error" (how defined?) less than the margin of error? How is Slovin's formula justified? It seems quite strange to me. JRSpriggs (talk) 13:55, 2 April 2013 (UTC)

It's a formula, not a theorem (though there probably is some precise mathematical statement attached to it); the purpose is to give a rule of thumb for choosing the size of a sample for an experiment in order to get representative results. Searching for Slovin's formula here should be helpful. --JBL (talk) 14:53, 2 April 2013 (UTC)

Some context setting is needed in the form of a statement of the sort of problem to which the formula is to be applied. Michael Hardy (talk) 20:33, 2 April 2013 (UTC)

I spent a while looking through the google books and scholar hits; none of them have a genuine citation (i.e., there is never more information than "Slovin (1960)"). Most of them are probably traceable to the various "Handbooks for researchers in [field]" books that one can dig up on Google Books. The formula appears to be a rule for choosing a sample size for performing a survey or other similar experiment in order to get an acceptable margin of error; it's unclear to me what the assumptions of the formula are, but the clearest claim seems to be that it assumes nothing (i.e., it's some kind of worst-case estimate) -- e.g., see www.ehow.com/way_5475547_slovins-formula-sampling-techniques.html. At least one reference also included related rules named after Mildred Parten and Milagros D. Ibe, but as with Slovin's formula I find no evidence of these formulas that doesn't seem to trace back to the same handbooks. There is no author in MathSciNet with the name "Slovin", and the only published article I could find for a person named "Slovin" in 1960 is an unrelated patent. No reference bothered with any statement about why the formula applies. Without a genuine reference and some actual argument for the validity of the formula, I don't think there's enough here to write an article on; at least, an article that isn't just another duplicate of the same paragraph that appears in a dozen of these google books hits. --JBL (talk) 04:07, 3 April 2013 (UTC)

Definitely some context-setting is needed. I do wonder why the authors and readers of those books tolerate the absence of a precise statement of the problems to which this is to be applied. As for references, one place I haven't yet looked it the Current Index to Statistics database. Michael Hardy (talk) 16:05, 3 April 2013 (UTC)

Some background search might be warranted but given the nature of textbook containing the formula (none of them are math books), I would necessarily expect Slovin to be mathematician or to have published in a math journal, i. e. one needs to research publication databases for the (natural) sciences and social sciences in general.--Kmhkmh (talk) 20:51, 3 April 2013 (UTC)

Proof of André's theorem

I've created this userspace draft: User:Michael Hardy/proof of André's theorem. The idea is that it could be incorporated somewhere into the article titled alternating permutation. I thought I'd cite something from the writings of Richard P. Stanley, but details remain to be ascertained.

Comments, criticisms, or suggestions? Michael Hardy (talk) 04:33, 2 April 2013 (UTC)

Hi Michael,

I thought the exposition around the sentence "This needs to be done for each possible value of k to get a complete list, hence we sum from k = 0 to k = n" could be a little clearer; the point here is that every permutation that is either alternating or reverse alternating can be gotten in exactly one way by choosing some k, then choosing a subset etc. etc. Also, the use of the symbol f(x) is slightly ambiguous; when it's introduced, it is not clear whether it is defined to be the power series for the E_n or whether it is defined to be sec(x) + tan(x). Also also, a minor typo: in "i goes from 1 to ∞" the 1 should be 0. I might have a few final comments, but it would be helpful to know what level audience you're aiming for. --JBL (talk) 04:20, 3 April 2013 (UTC)

I think one thing about the target audience should be clear from the way it's written: I included some things to make it comprehensible to intelligent students and not only to experienced mathematicians. The reader should know what exponential generating functions are before reading this article, and should have some facility with bijective arguments, and should be able to do things like solving the differential equation by separating variables and proving the half-angle identity at the end----it's reasonable to consider those things prerequisite material. But I expanded on how to rearrange the series more than I would for an audience consisting only of mathematicians, and in a few of the other operations on series I was explicit rather than leaving some details to be deduced by the reader. In other words, the audience should know reasonable prerequisite material but maybe nothing more. Michael Hardy (talk) 08:27, 3 April 2013 (UTC)

Whether I should cite something Richard Stanley wrote or something by someone else also remains unclear at this point. Michael Hardy (talk) 08:33, 3 April 2013 (UTC)

Nice work. I just wrote de:Alternierende Permutation; feel free to use any material (images, tables) from there for your article. Best wishes, --Quartl (talk) 16:47, 3 April 2013 (UTC)

Stanley's survey http://www-math.mit.edu/~rstan/papers/altperm.pdf gives three proofs, including the one presented. He doesn't give a citation. --JBL (talk) 20:05, 3 April 2013 (UTC)

I'll include that, but something already refereed would also be good. Michael Hardy (talk) 13:06, 4 April 2013 (UTC)

The first proof is also in Stanley's book [32]. It's basically the same as André's [33]. Best wishes, --Quartl (talk) 14:40, 4 April 2013 (UTC)

Thank you. I'll certainly cite that. Michael Hardy (talk) 04:38, 6 April 2013 (UTC)

Stack, Descent are not well-founded

Stack (descent theory) is not rigorously defined at all. Descent (category theory) has a treatment of vector bundles. Some time ago I found a reference on stacks and tried to remedy this, but ultimately I couldn't understand it well enough to make an exact description from it. Its absence is really a big barrier to getting any coherent information about moduli spaces from Wikipedia, so I'm requesting expert attention on Stack. ᛭ LokiClock (talk) 11:56, 5 April 2013 (UTC)

Well, waiting for "experts" is a kind of like, ah, Waiting for "Superman". It's better to think about more constructive steps. For example, something anyone can do is add more reliable references. The natural step following that is to quote the definitions/examples. -- Taku (talk) 10:57, 6 April 2013 (UTC)

I have added one (Pedicchio & Tholen (2004)) and tidied up a bit. Deltahedron (talk) 08:41, 7 April 2013 (UTC)

André's theorem, part 2

("Part 2" above refers to this present discussion, not to the theorem.)

I've added this section, stating and proving André's theorem. Doubtless it could benefit from others' contributions. Michael Hardy (talk) 18:04, 7 April 2013 (UTC)

Malfunctioning template?

I have linked 438 EOM-articles to Wikipedia's mathematics articles as external links since August 2012 (EOM stands for 'Encyclopedia of Mathematics' and its online version). As a tool to make these external links I have principally used Wikipedia's 'springer' template. However, it has recently come to my knowledge that 1) a malfunction has emerged to this template and 2) a discrepancy is associated with it, namely:

1) Its property to show the headword as a hyperlink has become sporadic; in some articles the link works, in some others it won't. (Eg., in the entry

"Inequality", Encyclopedia of Mathematics, EMS Press, 2001 [1994]

the word "Inequality" is the headword that I am referring to.)

2) {{Springer}} redirects to {{SpringerEOM}} in the Template documentation, although the template codes 'springer' and 'SpringerEOM' follow a completely different syntax. The syntax of the former is:

{{springer|title=headword|id=p/string}}

As to the problem 1: Has someone changed recently the code for the 'springer' template, thus producing its sporadic malfunctioning? And as to the problem 2: Template documentation for the 'springer' template should be updated according to its syntax. Since I am still a novice, I kindly ask advise from someone more mature Wikipedian. And many thanks for your attention and help! — Policron (talk) 23:40, 8 April 2013 (UTC)

Do you have an example of a broken instance of this template? Sławomir Biały (talk) 01:27, 9 April 2013 (UTC)

'Monoid', for example, didn't open up properly in my machine a few days ago. — Policron (talk) 18:53, 9 April 2013 (UTC)

It seems to work now Monoid. There has been quite a bit of work redoing the citation templates to use the new Lua feature and SpringerEOM depends on those. (See Module talk:Citation/CS1‎‎) Maybe it was a temporary problem caused by these other templates.--Salix (talk): 20:14, 9 April 2013 (UTC)

{{Springer}} is a template redirect to {{SpringerEOM}} so the syntax is exactly the same. The software automatically uses the same code to parse the parameters. What makes you think the syntax is different? PrimeHunter (talk) 01:55, 9 April 2013 (UTC)

The template for 'springer' is as stated above; for 'SpringerEOM' it is

{{SpringerEOM|id=headword&oldid=string|title=headword|first=name|last=name}}

(Please refer to {{SpringerEOM}}.) So the syntax is different, to my eyes at least. — Policron (talk) 18:53, 9 April 2013 (UTC)

What makes you say that {{Springer}} uses the syntax you say it does? The template source and documentation disagrees with that, PrimeHunter is right. Judging from the history, the template has not been significantly changed recently.—Emil J. 19:57, 9 April 2013 (UTC)

{{SpringerEOM|id=headword&oldid=string|title=headword|first=name|last=name}} and {{Springer|id=headword&oldid=string|title=headword|first=name|last=name}} give exactly the same result:

• name, name (2001) [1994], "headword", Encyclopedia of Mathematics, EMS Press
• name, name (2001) [1994], "headword", Encyclopedia of Mathematics, EMS Press

You can always swap {{Springer}} and {{SpringerEOM}}. That's how template redirects work. "Springer" simply becomes an alternative name for "SpringerEOM". Maybe you have seen the names used in different ways and falsely assumed they had to be used in that particular way. PrimeHunter (talk) 20:09, 9 April 2013 (UTC)

I think that's what Policron means. Looking at the first few articles that explicitly use {{springer}} the source says

Algorithm: springer|title=Algorithm|id=p/a011780

Axiom of choice: springer|title=Axiom of choice|id=p/a014270

Absolute value: springer|title=Absolute value|id=p/a010370

Asymptote: springer|id=A/a013610|title=Asymptote|first=L.P.|last=Kuptsov

Antinomy: springer|title=Antinomy|id=p/a012710

I have no idea why it should suddenly have stopped working. Deltahedron (talk) 20:16, 9 April 2013 (UTC)

The explanation given by Salix seems to be, I think, the most probable cause to the anomalies we have recently been talking about. After an extensive sample trial, all the external links that I have added work properly now. I thank you all for your interest, advises and patience! — Policron (talk) 21:04, 9 April 2013 (UTC)

Incorrect formulae at Lists of integrals#Absolute value functions?

It has been pointed out to me by a new User:Syed Wamiq Ahmed Hashmi that the integrals of absolute values of trigonometric functions are wrong. Does anyone have a source? I've looked in a couple of formulae books with integral tables but of all things they don't have the functions listed in that WP section. I'll keep looking around also, just thought to notify the project. Thanks, M∧Ŝc²ħεИ_τlk 15:03, 9 April 2013 (UTC)

Prime pages unreachable

I just noticed that the Prime Pages is no longer online. I have no idea whether this is temporary, but I think many mathematical articles, especially about prime numbers link to it, so all citations and external links pointing there are broken now. -- Toshio Yamaguchi 12:11, 6 April 2013 (UTC)

The urls in question may be on the wayback machine. ᛭ LokiClock (talk) 00:08, 7 April 2013 (UTC)

Indeed it does. While I suspect that the outage is temporary, I suggest that the maintainer of the website be gently questioned by email about the status of the site. He may not even be aware of the outage: The site is still listed prominently on the author's homepage. If this outage is intended, then his homepage needs to be updated. I suggest that a local administrator is appropriate for this task. I nominate either User:Michael Hardy or User:David Eppstein as a good representative of the project. Sławomir Biały (talk) 00:56, 7 April 2013 (UTC)

It's temporary. Friday evening Chris Caldwell wrote the web server is being moved.[34] It worked at first but something must have happened. I assume he is monitoring the situation already. If we ever do want to contact him then I have emailed with him many times. PrimeHunter (talk) 01:27, 7 April 2013 (UTC)

It is online now. -- WillNess (talk) 10:25, 12 April 2013 (UTC)

What is a Pinor in mathematics?

In Glossary of tensor theory#Spinors there's a link to pinor, which redirects to Piñor. Just thought to point it out - maybe replace the redirect with an article? There is no pinor (mathematics) by the way. Thanks, M∧Ŝc²ħεИ_τlk 10:48, 11 April 2013 (UTC)

I am not sure where this should be added. An additional difficulty is that the meaning of "spinor" is a bit ambiguous: sometimes it refers to what is more properly a "spinor field", i.e. a section of a bundle, and sometimes to an element of the Spin group itself. At any rate, if spinor is taken to be an element of the Spin group, then a pinor could be defined as an element of the Pin group. Here Spin(n) is the simply-connected double cover of the orthogonal SO(n) (at least if $n\geq 3$), and Pin(n) is a similar cover of O(n). Hope this post doesn't start a war between mathematicians and physicists. Tkuvho (talk) 11:28, 11 April 2013 (UTC)

Not element of spin group, but element of a (minimal?) representation of the spin group. Spinors (and pinors) are elements of a vector space.--LutzL (talk) 14:16, 11 April 2013 (UTC)

I knew it. The war trumpets. To fire a salvo for the math side, I wish to clarify that, while Spin(n) can be defined as a double cover of SO(n), it can also be embedded in the Clifford algebra, and therefore viewed as a vector. But on purely mathematical grounds, this is not strictly necessary. Running for cover. Tkuvho (talk) 14:19, 11 April 2013 (UTC)

Yeah, of course every matrix and linear operator is also a vector in the corresponding space. And the Clifford algebra is a (non-minimal) representation. But the sphere in the Clifford algebra, where the Pin and Spin groups live, is not a vector space itself. You can't scale an element of the Spin group, but you can scale a spinor. Anyway, besides these academic points, can pinor not redirect to a corresponding section in the spinor article? Is there a Twistor article? Apparently, yes.--LutzL (talk) 16:39, 11 April 2013 (UTC)

Do all textbooks require a spinor to be necessarily scalable? I agree that this would be natural from physical considerations, of course. A redirect sounds reasonable. Tkuvho (talk) 16:55, 11 April 2013 (UTC)

It should not redirect to spinor, it won't get covered and those who don't know it won't be able to make the inference. It should redirect to Pin(n) if anything. ᛭ LokiClock (talk) 01:59, 12 April 2013 (UTC)

That seems sensible - I'll do just that. Feel free to change it. Thanks to all, M∧Ŝc²ħεИ_τlk 07:29, 12 April 2013 (UTC)

On second thought it should be a DAB page with the links Pin(n) and Piñor? Typing "Piñor" every time just to get to that article would be a pain... M∧Ŝc²ħεИ_τlk 07:34, 12 April 2013 (UTC)

If there are only two alternatives, it is better to use a hat note. JRSpriggs (talk) 07:36, 12 April 2013 (UTC)

...or that. Thanks, good idea, will do that now. M∧Ŝc²ħεИ_τlk 08:22, 12 April 2013 (UTC)

Euclid (Toddhunter)

I note that :- Wikisource:Index:The_Elements_of_Euclid_for_the_Use_of_Schools_and_Colleges_-_1872.djvu is nearing completion in terms of text translation.

It would be appreciated if some WP:MATH people would assist carefully in reviewing it. ShakespeareFan00 (talk) 22:36, 13 April 2013 (UTC)

April disambiguation pages.

Please help fix incoming links to April's most-linked mathematics-related disambiguation pages, Geometric shape, Extra dimensions, Parametric, Positive definiteness, Planar, and Delta function. Some of these may also be questionably ambiguous. Cheers! bd2412 T 03:17, 14 April 2013 (UTC)

The lack of a proper article at Geometric shape has bugged me for a long time. We have a list of geometric shapes and an article shape which discusses a rather technical statistical usage, but nothing about simple geometric figures.--Salix (talk): 16:37, 14 April 2013 (UTC)

I made this a stub. Again, a clear non-disambiguation disambiguation page. Please feel free to add. It's currently just a dicdef. Sławomir Biały (talk) 20:26, 14 April 2013 (UTC)

Isn't a geometric shape just a shape? ᛭ LokiClock (talk) 23:01, 14 April 2013 (UTC)

Another possibility here would be to redirect geometric shape to list of geometric shapes. —David Eppstein (talk) 23:15, 14 April 2013 (UTC)

I think that is an excellent suggestion, particularly since the only other close hit, Geometric Shapes, is already on that page. I will see to it. bd2412 T 00:29, 15 April 2013 (UTC)

On the contrary, if ever there were a clear candidate for a dab entry in this business, it would be shape. Most of the content now at shape would be more appropriate at geometric shape. (And no, the article Geometric Shapes is actually about a Unicode character set, more or less irrelevant as an article to this discussion.) Sławomir Biały (talk) 00:35, 15 April 2013 (UTC)

This discussion is not about the word "shape", which could well be ambiguous to terms like Body shape, and even Physical fitness (which is also referred to as being "in shape"). It is, rather, about the phrase "Geometric shape", although it now seems to me that we can just move Shape to Geometric shape for both purposes. bd2412 T 00:51, 15 April 2013 (UTC)

No, it's certainly not about the word "shape. But the article shape is clearly relevant, especially considering that it's a proper article whereas geometric shape is only a dab. My very point is that, if anything, the situation should be reversed: shape should be a dab, with geometric shape containing most of the contents thereof. Do we disagree? I am confused. Sławomir Biały (talk) 01:05, 15 April 2013 (UTC)

I think we are in agreement, actually. I suggested moving shape to geometric shape, since the current content at shape is all about the geometric variety. The question remains whether shape would then redirect to geometric shape, or whether the shape (disambiguation) would be moved to shape. I don't know that anything on the disambiguation page which would outstrip the geometric meaning, so I think that the latter move would require a requested move discussion. bd2412 T 01:34, 15 April 2013 (UTC)

Delta function

Kronecker delta is called delta function by anyone in last 80 years, really? Incnis Mrsi (talk) 18:48, 14 April 2013 (UTC)

Try Google for "Kronecker delta function". It appears to be standard usage in MATLAB. Deltahedron (talk) 19:12, 14 April 2013 (UTC)

I think probably the issue is not whether the phrase "Kronecker delta function" has been used recently, but rather whether the exact phrase "delta function" has actually been used to refer to the Kronecker delta. It's hopefully clear that the Dirac delta function is by far the more common use of "delta function" (with no additional qualifications) so I think a disambiguation page (as opposed to a hatnote) is not terribly helpful here. Sławomir Biały (talk) 20:03, 14 April 2013 (UTC)

Since there are only two articles for "delta function", and the Dirac one is arguably primary, I converted it to a redirect with a hatnote rather than having a separate dab. —David Eppstein (talk) 20:34, 14 April 2013 (UTC)

I forgot to note here that I disambiguated all the delta function links in article space except the redirects. Thanks for finishing it off. Most of the ambiguous links were in fact referring to Dirac delta functions. --Mark viking (talk) 21:03, 14 April 2013 (UTC)

And now Delta function is back to being a dab, or will be after the history rearrangement is complete. Are the modular discriminant and Ramanujan delta functions considered the same thing? They're almost the same but the discriminant has a factor of (2π)¹² that doesn't seem to be present when talking about the corresponding cusp form. This is far from my area, though, so maybe I'm just confused. —David Eppstein (talk) 06:53, 16 April 2013 (UTC)

Could someone please explain what is going on with all the page moves here -- two lots today? Deltahedron (talk) 17:28, 16 April 2013 (UTC)

There appears to be some disagreement over whether delta function should go to Dirac delta function or to delta function (disambiguation). But if it goes to the disambiguation page, it should be the main title of the page rather than redirecting to it. The page moves are trying to keep the edit history synchronized with the titles. —David Eppstein (talk) 17:38, 16 April 2013 (UTC)

I'm concerned that all these moves, counter-moves, deletions, undeletions and so forth, are taking place before any kind of consensus has been achieved. Deltahedron (talk) 18:14, 16 April 2013 (UTC)

And now it's been moved again — Steel1943 seems to be doubting that Dirac should be primary. See Wikipedia:Requested moves/Technical requests. —David Eppstein (talk) 23:24, 16 April 2013 (UTC)

Yes, yes. Let's just drop it for now. Anyone can comment on the appropriate discussion pages about the ultimate outcome. An RfC might be appropriate, with this project notified along with all affected discussion pages, although at present it seems likely that this can be handled amicably without appealing to a wider consensus. Sławomir Biały (talk) 00:24, 17 April 2013 (UTC)

This should be resolved just like any other primary topic discussion. Generally, a primary topic is determined by page views and extrinsic evidence of the proportion of real-world uses (on Google and the like) wherein the term is used to refer to proposed primary topic as opposed to other topics. bd2412 T 00:29, 17 April 2013 (UTC)

If the problem is considered to be settled by Googliomancy, then David Eppstein's solution is obviously the correct one. I challenge anyone to a Google competition on this point. Sławomir Biały (talk) 00:36, 17 April 2013 (UTC)

I agree completely. A quick Google search yields 320,000 results for Dirac AND "Delta function", compared to 78,800 results for Kronecker AND "Delta function"; Google Books results yield 109,000 results for Dirac AND "Delta function", compared to 20,100 results for Kronecker AND "Delta function". In terms of Wikipedia primacy, last month Dirac delta function got 26741 hits, compared to Kronecker delta getting 6870 hits, and (just for the heck of it) Modular discriminant getting 115 hits. bd2412 T 00:43, 17 April 2013 (UTC)

To me, Mark viking's anecdotal evidence that most of the ambiguous links that he fixed were to the Dirac delta is more convincing, since what we want to know is not how popular the different deltas are but rather how often each is the intended meaning for the unqualified phrase "delta function". But the distinction doesn't matter much, since all the evidence points the same way. —David Eppstein (talk) 01:00, 17 April 2013 (UTC)

Positive definiteness

Positive definiteness should me a multiple cross index page rather than a dab. I know that concept is supposedly deprecated, but you should seriously wonder why it is that every few months it comes to the top of your blacklist. I have gone ahead and changed it to a multiple-cross-reference page. Presumably the onus is now on those who oppose this idea to write an article instead, since it was clearly not a dab page. Perhaps User:BD2412 would obligingly write such an article? Sławomir Biały (talk) 20:20, 14 April 2013 (UTC)

I would not presume the expertise to begin such an enterprise (which is, of course, why I have come here to seek the help of experts in the field). Cheers! bd2412 T 00:33, 15 April 2013 (UTC)

Very well, and good luck with that. Unfortunately, no one to my knowledge has so far been willing to write an article on "positive definiteness" in general, despite half a decade of prodding. Although most of us know what positive-definiteness means (precisely in some cases, roughly in others), there is apparently no adequate secondary source that links the various cases. So therefore under our WP:PILLARS, no proper article can be written. Yet equally clearly, this should not be a dab page: the uses of the term are each a hair's breadth from each other. I honestly don't know what this means procedurally, but my suggestion is either: (1) leave it as an unsanctioned {{Multiple-cross-reference page}}, or (2) nominate the page for deletion via the standard process. If neither of these options is tasteful to you, then I should remind you that there is no deadline. Eventually the ultimate expert on positive definiteness in mathematics may come along and write an article that adheres to our WP:PILLARS. Until that time, if you notify this Wikiproject (as you have several times in the past about this very issue) you'll have to be satisfied with the responses offered by the idiotic schlubs that occupy it. Sławomir Biały (talk) 01:27, 15 April 2013 (UTC)

Of course, if there is no real meaning to "positive definiteness", it raises the question, why do so many articles link to it? As a disambiguator, I only bring here the disambiguation pages that regularly come up as having the most incoming links requiring repair, in the course of dealing with recurring errors. If the concept is ambiguous, the incoming links need to be fixed. If it is unambiguous, then the appropriate page should be there. If some other solution is appropriate, I will be glad to see it implemented. We are all working together here to correct mistakes such as ambiguous links. bd2412 T 02:05, 15 April 2013 (UTC)

They link to it because they are more interested in the general concept than in specific variations of it. But the rules prevent us from having things that look like disambiguation pages but are allowed to have links. Perhaps that indicates a problem with the rules. Perhaps calling it list of positive definite topics would help; after all, the dsiambiguation rules enthusiasts haven't yet succeeded in ruling that lists are too similar to disambiguation pages to be allowed to exist. —David Eppstein (talk) 02:23, 15 April 2013 (UTC)

An article on a list of positive definite topics sounds like a good idea. There exist surveys of what positive definiteness means in different mathematical contexts that could be used to provide the intro needed for such an article, for example, Positive definite functions and generalizations, an historical survey and Positive Definite Kernels: Past, Present and Future. --Mark viking (talk) 02:38, 15 April 2013 (UTC)

I know of no effort on the part of disambiguators to rule that lists are too similar to disambiguation pages to be allowed to exist. In fact, quite the opposite, we have converted many pages into lists that were incorrectly tagged as disambiguation pages, but did not contain ambiguous topics. We have also set up {{SIA}} pages for lists of things that share a common name, but for which examples are unlikely to individually notable (for example, Iasus) or for which references are likely to be for the entire class of members rather than any individual member (like NO2). bd2412 T 02:49, 15 April 2013 (UTC)

The context is Wikipedia talk:Policies and guidelines/Archive 13#Accepting "WP:Multiple-cross-reference page" as a guideline. —David Eppstein (talk) 02:58, 15 April 2013 (UTC)

I agree with Einstein's proposition: "Everything should be as simple as it can be, but not simpler". I would say that to the greatest extent possible, we should have articles if an article can be written on a topic, no matter how abstract or nebulous the topic; or, if there is not enough material to justify an article, then a section in whatever article encompasses the topic. However, I am all for innovative solutions, so long as we do not end up having disambiguation pages for topics that are not truly ambiguous to one another. In that vein of thought, what should be done with Extra dimensions, which has been tagged as WP:DABCONCEPT? bd2412 T 13:02, 15 April 2013 (UTC)

IMO, Extra dimensions must be merged as a new section in Dimension (mathematics and physics). For Positive definiteness, I suggest to add at the beginning ot the article the sentence: "Positive definiteness is a property of any mathematical object to which a bilinear form or a sesquilinear form may be naturally associated, which is positive definite. See, in particular:". As such, the article would become a WP:DABCONCEPT stub. The remaining problem is that I do not know any tag warning the editors to not add the tag {{dab}} to a WP:DABCONCEPT article. D.Lazard (talk) 14:22, 15 April 2013 (UTC)

A hidden note would probably suffice. bd2412 T 15:30, 15 April 2013 (UTC)

Defining "positive definite" only in terms of bilinear or quadratic forms fails to capture the definition relating to dynamical systems (currently at Positive-definite function) or that of Positive-definite function on a group. Deltahedron (talk) 17:21, 15 April 2013 (UTC)

I do not agree: I do not well understand the definition given in Positive-definite function on a group, but a bilinear function appears clearly in it (bracket notation). On the other hand, a Positive-definite function is a function whose gradient is zero and the Hessian matrix of second derivatives is definite positive. The fact that some articles are incomplete does not implies that the definition I have given is wrong. D.Lazard (talk) 18:01, 15 April 2013 (UTC)

I did not say that they were completely unconnected, just that it fails to capture the notion. The characterisation of a positive definite function in terms of positive definiteness of the Hessian is a theorem about positive definite functions that happen to be twice continuously differentiable. Other functions exist. Deltahedron (talk) 18:18, 15 April 2013 (UTC)

In terms of fashioning an article on this topic, my first question would be whether these dynamic and group functions can be explained under the same heading as the bilinear or quadratic forms. My second question would be, if they are too distinct for such a description, is there a primary topic between them that would be the thing people most likely expect to find when searching for or linking to "positive definiteness". bd2412 T 18:31, 15 April 2013 (UTC)

The definition in Positive-definite function on a group (usually a locally compact group) is not quite right; the added B(H) coefficients are unneeded and irrelevant generality. The standard definition from times of yore (say in Dixmier's book on C* algebras, Gelfand-Naimark or Mackey's Chicago notes) is for scalar functions on a group with some mild measurabilty or continuity properties (the usual theorem, from Banach's book and Calvin Moore's papers on Borel cohomology, that a Borel homomorphism on a Polish group is continuous). Certainly for the two articles I wrote on representation theory (zonal spherical functions and Plancherel theorem for spherical functions) the wikipedia definition is not helpful, in fact useless, and misses the point entirely (the Gelfand-Naimark-Segal or the Gelfand-Naimark construction). I don't know how that happened. I am not at all surprised. Mathsci (talk) 20:49, 15 April 2013 (UTC)

You are, of course, our resident expert on operator theory, so you're undoubtedly correct and this problem should be fixed (by someone...) Sławomir Biały (talk) 00:31, 17 April 2013 (UTC)

Euler's Doodle

I think I can follow most of the allusions in http://www.google.com/doodles/leonhard-eulers-306th-birthday but I am not sure which of Euler's contributions the animated "O" is supposed to illustrate. Any ideas? Tkuvho (talk) 09:38, 17 April 2013 (UTC)

Euler angles--Salix (talk): 10:04, 17 April 2013 (UTC)

Yep. Such an animation would be a nice addition to the WP article. --Mark viking (talk) 14:21, 17 April 2013 (UTC)

That would be nice, but it is not entirely clear whether this is in the public domain. I just looked through their "store" without conclusive results. Tkuvho (talk) 14:35, 17 April 2013 (UTC)

Google's specific rendition is definitely not in the public domain, but anyone with the ability to make a similar animation is free to do so. bd2412 T 15:24, 17 April 2013 (UTC)

Lucas primality test

Bob Baillie wrote me, asking for help with the article Lucas primality test. In particular:

this wikipedia page
http://en.wikipedia.org/wiki/Lucas_primality_test
does not describe any kind of lucas test at all.
instead, it describes pocklington's theorem.  the whole article needs to be renamed to something else, and the {{number theoretic algorithms}}  template needs to be corrected.

We have Pocklington primality test, LL, and LLR; I'm not sure what should be where and what the best names are. Any thoughts?

CRGreathouse (t | c) 15:13, 17 April 2013 (UTC)

The Lucas test described in

Baillie, R. (1980-10). "Lucas Pseudoprimes" (PDF). Math. Comp. 35 (152): 1391–1417. {{cite journal}}: Check date values in: |date= (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)

seems to be rather different to what the article Lucas primality test claims it to be. The test described in Lucas primality test appears to be an extension of the Fermat primality test (I don't know whether that extension has a specific name). -- Toshio Yamaguchi 16:40, 17 April 2013 (UTC)

The subject is discussed at length in Hugh Williams (1998). Édouard Lucas and primality testing. Wiley. ISBN 0-471-14852-0. Deltahedron (talk) 06:43, 18 April 2013 (UTC)

Equation formatting disagreement

There's a discussion going on at Talk:Sexagesimal on how to format some equations. Please contribute. —David Eppstein (talk) 15:35, 18 April 2013 (UTC)

Polynomial recurrence AfD

The article polynomial recurrence is being considered for deletion. Please add your thoughts here. This article has been discussed at least once before on this page; see this past discussion. Thanks. --JBL (talk) 18:50, 18 April 2013 (UTC)

Idèle vs idele

Is there a consensus on this? It is under discussion at Talk:Adele ring#Idèle vs idele. Deltahedron (talk) 06:32, 18 April 2013 (UTC)

Good question. More generally, do we keep or omit accents? In the place or people names, we keep them. What about mathematical terms? -- Taku (talk) 13:46, 18 April 2013 (UTC)

It would certainly be nice not to have to type them :/ As long as the search function can fuzzily match the two, and that there is no danger of confusion between a word with accented and unaccented characters, I'm not sure there is much to stress about. (Of course, forthcoming examples could prove me wrong.) Rschwieb (talk) 13:44, 19 April 2013 (UTC)

Marilyn's Cross: a hoax or not?

Someone tagged Marilyn's Cross as a possible hoax. Is it? Michael Hardy (talk) 17:36, 19 April 2013 (UTC)

I don't know about hoax, but it seems to be original research. GScholar generated no hits and a general Google search turned up little that was not related to the Wikipedia article and nothing that could be considered independent. There seems to be a conflict of interest, as editor LMcCormick created the knot and created the article. The history of the editor's talk page suggests that there was controversy about this page. In particular, it was claimed that the editor simply renamed a well-known knot (e.g., Borromean Ring) and substituted their own diagram for an already existing illustration at File:Brunnian-3-not-Borromean.png. It does look fishy. --Mark viking (talk) 18:11, 19 April 2013 (UTC)

"Marilyn's Cross" is not found in ZMATH. Deltahedron (talk) 19:18, 19 April 2013 (UTC)

None of the above makes it a hoax, but maybe it makes it a mistake. Michael Hardy (talk) 22:32, 19 April 2013 (UTC)

Proposal to delete our article on an axiom of set theory

Please see Wikipedia:Articles for deletion/Axiom of global choice. Eozhik (talk · contribs) believes that Axiom of global choice is a hoax. Obviously, I disagree. If you have an opinion on this, I urge you to express it on the AfD page. JRSpriggs (talk) 09:28, 21 April 2013 (UTC)

The nomination for deletion was withdrawn after considerable discussion. JRSpriggs (talk) 21:38, 22 April 2013 (UTC)

Domain (mathematics): fixes to ∼ 150 inbound links? Or back to domain of a function with a hatnote?

I do not know what to do with these consequences of those clumsy changes in 2009 (and earlier). And the proposal about deprecation of redirects, which could avoid this kind of situation in the future, also did not attract any support. Incnis Mrsi (talk) 09:26, 23 April 2013 (UTC)

IMO, the easiest solution is to redirect Domain (mathematics) to Domain of a function, and to add to the latter a hat note For other use of "domain" in mathematics, see Domain#Mathematics D.Lazard (talk) 10:03, 23 April 2013 (UTC)

"Namesakes"

This edit was done by a user whose most recent edit history does not mention the following:

• List of things named after Archimedes
• List of things named after Thomas Bayes
• List of things named after Augustin-Louis Cauchy
• List of things named after Arthur Cayley
• List of things named after Richard Dedekind
• List of things named after Gustav Lejeune Dirichlet
• List of things named after Albert Einstein
• List of things named after Euclid
• List of things named after Leonhard Euler
• List of things named after Paul Erdős
• List of things named after Fibonacci
• List of things named after Carl Friedrich Gauss
• List of things named after Charles Hermite
• List of things named after Joseph Louis Lagrange
• List of things named after Adrien-Marie Legendre
• List of things named after Gottfried Leibniz
• List of things named after Pythagoras
• List of things named after Srinivasa Ramanujan
• List of things named after Bernhard Riemann
• List of things named after James Joseph Sylvester
• List of things named after Alfred Tarski
• List of things named after Karl Weierstrass
• List of things named after Hermann Weyl

Michael Hardy (talk) 02:46, 26 April 2013 (UTC)

The new version is neither clearer nor less vague, and also reads awkwardly. I recommend reversion. --JBL (talk) 03:07, 26 April 2013 (UTC)

I've complained there that it is much more vague, to many people namesake means anything or anyone with a name like Leonhard Euler, and not necessarily named after the mathematician. Dmcq (talk) 03:28, 26 April 2013 (UTC)

I've changed the article's title back to List of things named after Leonhard Euler and commented on the article's talk page about my reasons for this. Michael Hardy (talk) 13:49, 26 April 2013 (UTC)

Good job. -AndrewDressel (talk) 21:53, 26 April 2013 (UTC)

Organization of the List of things named after Archimedes

I've just organized the List of things named after Archimedes into sections. Further work could probably be done, possibly including alphabetizing, creating subsections of the "Mathematical concepts" section, further refining the organization, and other things. Some of our lists of (pardon the expression) "namesakes" are organized this way, and I think some are not. Some of those that are not might benefit from such work. Michael Hardy (talk) 14:28, 26 April 2013 (UTC)

Help needed on Tessellation

This is a request for assistance on Tessellation, which has been in a scrappy state for some years. There are clearly several aspects of the mathematics of the subject (such as in higher dimensions, and of non-Euclidean surfaces) that need proper treatment with decent visual examples, citations and intelligible explanation. I have done some work on the basics and on the artistic and historical side, but a mathematician's hand is now required. I'm happy to lend a hand where I can. Chiswick Chap (talk) 15:48, 26 April 2013 (UTC)

Reference spam at Pursuit-evasion

An editor at Pursuit-evasion is adding references that are not used in the text and appear likely to be a conflict of interest. Are they sufficiently significant in the history of this topic to keep in the article? If not, could I have some help keeping them out, please? —David Eppstein (talk) 17:30, 26 April 2013 (UTC)

Ha, and of course one of the references added would be a paper in Chaos, Solitons & Fractals, wouldn't it? --JBL (talk) 22:14, 26 April 2013 (UTC)

I skimmed the two papers that Chiswick Chap reverted. Both concern differential games with a particular dynamics and constraints and the conditions for successful pursuit. My best guess (I know a little about the field, but am far from an expert) is that these are nice little problems, but are not of fundamental significance to different games theory. The papers themselves don't seem to have any bearing on the article. GScholar shows that each paper has 2 citations, and one was published in 1999. I have to agree, this looks like COI and refspam. --Mark viking (talk) 23:00, 26 April 2013 (UTC)

May 2013

Space Wars

Poincaré group

[35] Sadly, editing patterns usual for nationalistic (and other) PoV pushers apparently are acceptable even in purely scientific articles. This editor not only summarily undid the edit I made for no less than 30 minutes, not only did not he put any notice to the talk: Poincaré group, but his edit summary did not point to any concrete problem with an edit consisting of a lot of changes. Incnis Mrsi (talk) 04:34, 15 April 2013 (UTC)

Y'all seem to be working it out just fine. You can also start the talk section by responding to the revert's comments. ᛭ LokiClock (talk) 01:53, 16 April 2013 (UTC)

To where do shapes from Euclidean geometry belong?

The article Euclidean geometry should explain the history and traditional methods. But where should actual things from Euclidean spaces be listed: in Euclidean space #Geometric shapes? Or there are better suggestions?

BTW, there is a list of geometric shapes which, as can be seen in its preamble, is devoted to plane shapes only. I feel that the adjective “geometric” is a misnomer in such case. Incnis Mrsi (talk) 17:54, 18 April 2013 (UTC)

Compounding the problem, there is a List of mathematical shapes which would be better named List of geometric shapes. Perhaps it should be renamed, and the current List of geometric shapes moved to List of planar geometric shapes. RockMagnetist (talk) 17:31, 19 April 2013 (UTC)

BTW neither henagon nor digon are actually “planar”. IMHO list of two-dimensional geometric shapes would be better. I go to create “list of shapes” as a list of list, for both mathematical lists and not so. Incnis Mrsi (talk) 18:20, 19 April 2013 (UTC)

Is Euclidean space relevant to the definition of a manifold?

Two editors object against replacement of “Euclidean space” with “coordinate space” and “real coordinate space” in the Manifold article on pretexts that complex and p-adic manifolds are unheard of, that Euclidean space is a more familiar concept, etc. I do not think that pushing the “Euclidean space” link wherever a reader is expected to be more familiar with this concept is a good practice. See talk: Manifold #"Euclidean space" or "coordinate space"?. Incnis Mrsi (talk) 16:16, 19 April 2013 (UTC)

“Vector” redirects

I retargeted 10 redirects previously bound to Euclidean vector to other targets. Maybe, hatnotes or some content should be added? Or some of misleading redirects were missed? Incnis Mrsi (talk) 15:15, 21 April 2013 (UTC)

I redirected Vector component back to Euclidean vector#Decomposition (a different section than previously). A reader who needs information on what a vector component is probably needs a less abstract and more directly applicable treatment than is found in Basis (linear algebra). I will fix Vector components and Component (vector) to point to the same place for consistency. I added a "more info" link pointing to Basis (linear algebra).--Srleffler (talk) 01:07, 23 April 2013 (UTC)

Going over the rest of your list:

• Physical vector and Vector (physics): I'm not sure that Vector (mathematics and physics) is a better choice than Euclidean vector. If someone is linking to "physical vector" they most likely want the article on Euclidean vectors.
• Vectors and Scalars: I don't have a big problem with this change. Neither target is very good.
• Vector addition, Vector subtraction, and Vector sum: I think Vector space#Definition is an inferior target in this case, for the same reason as for vector component: a reader who needs a link to these concepts likely needs a less abstract introduction to the topic.

These changes are typical of a problem I have seen with mathematics articles on Wikipedia: too damn much of the material is written by and for mathematicians, so that concepts that can be explained simply and directly are instead explained with great generality and abstraction, using concepts and methods that are beyond the level of some readers who might be interested in the topic, and who would have the background to understand it if it were approached differently. The most rigorous explanation is not always the best one pedagogically. Vector components, addition and subtraction are suitable topics for a high school senior, and the directly-linked articles should be at that level, with links to more advanced treatments available from the simpler articles.

I haven't changed any of the other links yet, so we can talk this through first.--Srleffler (talk) 01:32, 23 April 2013 (UTC)

These changes are typical of a problem I have seen with scientific articles on Wikipedia: too damn much accommodation to “what a reader wants to see”, at the expense of precision. It is not especially important for Vector addition/Vector sum and Vector subtraction, but it is quite important for “components”, because these redirects suggest that these are namely Euclidean vectors which have components, not any others. I would prefer to see Physical vector and Vector (physics) as red links (if only because 4-vectors exist), although we should consult WP:WikiProject Physics about this two targets. Incnis Mrsi (talk) 05:48, 23 April 2013 (UTC)

I've reverted pending consensus. Vector component is definitely not better explained by Euclidean vector#Decomposition than by Basis (linear algebra). When a reader is required to know the technical details of how decompositions are performed before the formalism of an article becomes accessible, the linking of the article is often the only clue of where to go to decipher things. A simplification is also not appropriate as a redirect, because redirecting implies the article that would be about that subject is under another title, and Euclidean vector#Decomposition is not the article about vector components. ᛭ LokiClock (talk) 09:48, 23 April 2013 (UTC)

Take another look at the two articles. A reader who is encountering vector components for the first time in high school or first year university is going to find the introduction to Basis (linear algebra) completely impenetrable. In an encyclopedia it is important to treat each topic at the simplest level possible (which varies from topic to topic), before moving into more complicated or abstract aspects of the topic. --Srleffler (talk) 02:23, 24 April 2013 (UTC)

It's not important to treat things at the simplest level possible, it's important to treat them comprehensively. Encyclopedias are not textbooks. Basis (linear algebra) may be impenetrable, but some things are impenetrable because they're new concepts that you have to take the time to wrap your head around. Having learned from it at high school age, I would say it's semipermeable. Now that it has that nice picture, it's a lot less work. Now, I would be mentally impoverished if all the Wikipedia articles I read during that time were subject to every editor's idea of the best way to dumb it down, what I don't need to know, and what my purposes for the information should be. I actually didn't need to understand Euclidean vector components and vector decompositions the most, I needed to know what a basis is and linear combination are. ᛭ LokiClock (talk) 14:21, 25 April 2013 (UTC)

Simplicity and comprehensiveness are not mutually exclusive. We just need to arrange material and links so that a reader is more likely to find simpler material first, if that is appropriate based on the link they clicked. It doesn't make sense to throw a reader looking for information on vector components to an article on a much more general concept, where the first paragraph of the introduction assumes knowledge of half a dozen concepts that may not be familiar. A high school student who has encountered vectors in physics and math class would be immediately put off by Basis (linear algebra). To even get past the first paragraph, you have to understand the concepts of linear independence, linear combination, vector spaces, free modules, and spanning sets. None of these concepts are likely to be familiar. Redirecting vector component to this article is totally crazy.--Srleffler (talk) 22:09, 27 April 2013 (UTC)

I changed vector addition and subtraction to simply redirect to vector space because the operations are conceptually motivated throughout, as a function of vector spaces being algebras. I left vector sum because it might get confused with elements of the direct sum. ᛭ LokiClock (talk) 09:55, 23 April 2013 (UTC)

It should not be necessary to explain vector spaces in order to explain the concept of vector addition and subtraction. This is a bad redirect.--Srleffler (talk) 02:23, 24 April 2013 (UTC)

What? That's all a vector space is, its addition and scalar multiplication. All those figures in vector space are dedicated to explaining what vector addition and scalar multiplication mean intuitively. ᛭ LokiClock (talk) 14:10, 25 April 2013 (UTC)

You're missing the point. Vector space is a more abstract concept than vector addition and multiplication. Start with the simple; move to the abstract later. You probably didn't learn about vector spaces before you learned how to add and subtract vectors. Why would you expect a reader looking for information on vector addition to have to master this much more difficult subject first?--Srleffler (talk) 22:09, 27 April 2013 (UTC)

I support all of the original changes. I'm not sure vector component, component (vector), etc. (in the singular) have a perfect redirect target. Does this mean a component of a vector in a basis, or is it the scalar projection of a vector in some direction (as the term "component" is sometimes used)? Sławomir Biały (talk) 11:33, 23 April 2013 (UTC)

I don't at present have a position on the current status of things but I would like to register a preference that all links under discussion are chosen in opposition to the principle "too damn much accommodation to “what a reader wants to see”, at the expense of precision."" -- most of these links should go to the most elementary, and emphatically not the most general, treatment of the subject in question. If we're not presenting material a reader at the appropriate level (say, a bright high school student) can understand then we're doing things wrong. --JBL (talk) 14:05, 23 April 2013 (UTC)

I would oppose redirecting Vector component to Basis (linear algebra).. I would prefer a redirect to somewhere within Euclidean vector (per JBL). There is also the article Vector projection (to which Scalar projection should probably redirect). Mark M (talk) 14:33, 23 April 2013 (UTC)

“Vector projection” presently has a strong Euclidean bias. If one can reformulate the definition in purely affine terms, specifying that orthogonal projections are a particular case, then it would be a solution. Incnis Mrsi (talk) 07:03, 24 April 2013 (UTC)

I don't see why it should be done in terms of affine geometry. Is there evidence that this notion of vector projection is more common? Sławomir Biały (talk) 11:10, 24 April 2013 (UTC)

It should be done in terms of affine geometry because any orthogonal projection is an affine projection, but any skew (affine) projection is not an orthogonal projection; I believe you knew it yourself. Why should I find evidences that the affine projection “is more common”? Or let us rewrite the percentage article in terms of money on the pretext that this notion of percentage is the most common. Incnis Mrsi (talk) 10:16, 26 April 2013 (UTC)

I'm unaware of any mandate that articles should immediately take the most general perspective possible. A more general notion of projection is already covered at Projection (linear algebra). The article under discussion is about the vector projection in elementary Euclidean geometry. Why is it that you think that readers will expect an article about affine geometry when they type "vector projection" into the search bar? Of the 5000 available on Google books using the term "vector projection", only 36 also include the word "affine". And even in most of those few references, the vector projection is regarded as an Euclidean concept. Sławomir Biały (talk) 11:20, 26 April 2013 (UTC)

It just means that “projection (linear algebra)” is a possible target for redirecting “component (vector)”, but (the present) “vector projection” is not. Bases do exist in spaces which provide no orthogonality. Incnis Mrsi (talk) 11:29, 26 April 2013 (UTC)

I think there's something you're still not understanding. We're meant to be a general encyclopedia, and need to accommodate a wide array of readers, many of whom lack mathematical sophistication but for whom an article on Euclidean vector projection is useful. It is extremely uncommon in the literature to use the exact term "vector projection" to refer to anything but the standard Euclidean notion. I'm not arguing that there aren't more general concepts of projection available; for that there are other articles: projection (linear algebra), projection (mathematics). What I'm asking is, what is the evidence that the exact phrase "vector projection" is used to refer to one of these more general notions? If it is not used in this manner, then clearly we should not take the more general perspective. If there are sources that do use it in ----- WP:WEIGHT to attach to those sources. Sławomir Biały (talk) 11:37, 26 April 2013 (UTC)

Another fine example of the problem of too much focus on the needs of mathematicians. It should not be necessary for a reader to figure out what affine geometry is to get some information on vector components. Vector components is a high-school level topic. Affine geometry is not. --Srleffler (talk) 22:09, 27 April 2013 (UTC)

I am with Srleffler and JBL. Those redirects should go to the elementary articles.

As for Srleffler's remark that "...too damn much of the material is written by and for mathematicians...", Euclidean vector certainly is not written for mathematicians, neither is vector space for that matter. We just need to figure out how to redirect appropriate audiences to appropriate articles. Mct mht (talk) 10:53, 24 April 2013 (UTC)

As there is clearly no consensus for the recent changes in redirect targets, I have reverted the redirects relating to vector components, vector addition/subtraction, and physical vectors. Of special note is Vector (physics) where I disambiguated all article links to that page and found that every one of them intended Euclidean vector. I left Vector theory and Vectors and Scalars pointing to Vector space. I added a "more info" link to Vector space at Euclidean vector#Addition and subtraction, for readers who are looking for a more thorough treatment of the topic.--Srleffler (talk) 01:58, 7 May 2013 (UTC)

---

Please, contribute to this discussion. In short: a WP:CONCEPTDAB article about vectors could become a long-term compromise. Incnis Mrsi (talk) 11:42, 24 April 2013 (UTC)

Describing vectors simply?

Not related to DABs and all, but there were comments above about basis (linear algebra)/vector space as "impenetrable" or overly abstract... To this end I quickly cobbled two diagrams as you can see on talk:basis (linear algebra)#Diagrams and talk:vector space#Diagrams, if case they're any diagrammatic help... Regards, M∧Ŝc²ħεИ_τlk 17:26, 25 April 2013 (UTC)

I think change of basis needs that illustration. ᛭ LokiClock (talk) 12:02, 26 April 2013 (UTC)

I'll take the liberty of adding them (after slight modifications) to that article. Thank you for pointing this out. M∧Ŝc²ħεИ_τlk 22:55, 26 April 2013 (UTC)

Euclidean space, Euclidean vector, and inner product space

There is some overlap between these topics. For example, all three should consider the concept of angle. To which extent should first two articles rely on each other? To which extent should both rely on “inner product space”? This is also related to the question immediately above. Incnis Mrsi (talk) 07:49, 25 April 2013 (UTC)

BTW, I just discovered Euclidean subspace, yet another article full of abominations: see talk: Euclidean subspace. Incnis Mrsi (talk) 06:50, 27 April 2013 (UTC)

Marilyn's Cross marked with Template:Hoax

An editor has listed Marilyn's Cross in Category:Wikipedia suspected hoax articles. Since this appears to be the relevant WikiProject, someone in this project might want to participate in the discussion (if you have not already done so). Hyacinth (talk) 21:16, 22 April 2013 (UTC)

See the discussion two sections above about this article. It is not clear that it is formally a hoax, but it appears that the author may have given her own name to a common knot and then wrote an article about it. If so, then it would qualify as original research, probably non-notable, and possibly redundant. I am not knowledgeable enough about knot theory to make a definitive call on OR and redundancy, but there doesn't seem to be much in the way of independent reliable sources for this article. --Mark viking (talk) 21:53, 22 April 2013 (UTC)

Now renamed to L10a140 link, and the "Marilyn" part greatly de-emphasized. AnonMoos (talk) 13:59, 4 May 2013 (UTC)

Hurwitz's theorem and related articles

This discussion has been closed. Please do not modify it.
The following discussion has been closed. Please do not modify it.
There are discussions taking place about the article Hurwitz's theorem (normed division algebras) and the redirect Hurwitz algebra. A Hurwitz algebra is synonymous with a composition algebra on which there is an existing article (except that a few authors do not require composition algebras to be unital). However, it is claimed that Hurwitz algebra should not redirect to composition algebra but to the related Hurwitz's theorem (normed division algebras) on the grounds that composition algebra is "inadequate" [36], and "There is no content in the Composition algebra article" [37]. Comments of expert editors would be helpful at Talk:Hurwitz_algebra and Talk:Hurwitz's theorem (normed division algebras). Deltahedron (talk) 17:09, 29 April 2013 (UTC) Update: Hurwitz's theorem (normed division algebras) has just been moved to Hurwitz's theorem (composition algebras). Deltahedron (talk) 18:16, 29 April 2013 (UTC) Further update: anyone looking for the discussions will need to look at both Talk:Hurwitz's theorem (composition algebras) (plural) and Talk:Hurwitz's theorem (composition algebra) (singular) as something odd seems to have happened to the redirections. Deltahedron (talk) 19:35, 29 April 2013 (UTC) As you have noticed, the other editor is a bit prickly, but it is very likely that what they have said is accurate (and he has written a large number of high quality articles). You will get much better results by asking questions and considering the replies. Johnuniq (talk) 03:22, 30 April 2013 (UTC) I cannot see that this complaint will serve any purpose, except that Deltahedron might discover that I am among the main content contributors to mathematics articles on wikipedia. I don't accept his claims, which contradict what can be found in standard textbooks. My own view, after having seen him "in action", is that he is not very much in touch with this subject and is being pedantic, while showing almost no interest in adding any serious content. So far in his relatively short wikipedia existence, he has created several short stubs. He apparently has no experience with extended content. Even professionally trained mathematicians have to use sources, in-line citations, etc. Wikipedia is not a source and cannot invent its own rules for mathematical naming, particularly for interdisciplinary subjects such as this one, which is extensively used in geometry and analysis. On the talk page of the article I mention three sources—Jacobson, Faraut & Koranyi and Springer & Veldkamp. All of these are solid sources. What I have written conforms to those sources. In addition, apart from looking at many other books and articles, I read through the long and fascinating book of Daniel Shapiro, essentially on just this topic. Shapiro gives a very detailed account of the history in the zeroth chapter. What I have written in the article reflects that history quite closely and accurately. In particular in his second posthumous article, which I have read and which was icidentally proofread by L. E. Dickson prior to publiscation, Hurwitz introduces the representation of the real Clifford algebra that appeared in later treatments (e.g. Eckmann, Lee, Chevalley). If I were less busy with symmetric cones, the article that required a detailed account of Euclidean Hurwitz algebras, I would summarise that zeroth chapter in the current article. Much of the material is already there in the main body, but it would do no harm to mention the more general Hurwitz matrix systems and the corresponding problem for composition of forms. I also think that a "further directions" section right at the end could be worthwhile. Shapiro discusses the applications to vector fields on spheres, Bott generators in K-theory, composition of quadratic forms in arbitrary characteristic, generalizations of composition algebras, algebraic K-theory, and so on. A short summary of what can be found in this long and fascinating book would be nice. It also has Conway's treatment of composition algebras (a sort of Archimedeans talk I assume). There are other similar general sources, e.g. the AMS Notices article by Eckmann. Worrying about whether the octonions are a real division algebra or a composition algebra is hardly the point. When Jordan, von Neumann and Wigner used Hurwitz's work in 1934, it was through the system of Clifford matrices that Hurwitz defined. These mathematical physicists did not use the terminology "Jordan algebras", but the quantum mechanics term "r-numbers". I have no idea why Deltahedron has become side-tracked by these minor and trifling MOS-issues. He appears to be making very few substantial content contributions. I have encouraged him to get some experience of writing an extended article so that he has a clearer idea of the relation between the main body of an article and its lede. That would clarify how we rely on sources for writing wikipedia articles, even in mathematics. Bristling, acerbic or whatever you like, those are the rules. A brief look at WP:DTTR might also be an idea. Thanks, Mathsci (talk) 11:29, 30 April 2013 (UTC) I don't really care one way or the other. It's particularly hard for a non-expert to get any kind of informed opinion when the discussion is spread over so many different pages. Let me say that both editors involved might do best to step back from the matter of what should redirect where. It simply is not a big issue either way, and it's certainly not worthy of User:Mathsci personalizing it so much. Enough time has been wasted on this trifling question, time that could have been spent far more productively. My perhaps naive view is: Composition algebra should have a link to Hurwitz's theorem (composition algebras) and vice versa. If a reader lands at the "wrong" article via the redirect, then it should be made as easy as possible for the reader to find the "right" article. Sławomir Biały (talk) 12:07, 30 April 2013 (UTC) Yes, both articles have been linked to each other since the second one was created. I do object to my time being wasted on these trivial matters, when I am in the middle of editing. Mathsci (talk) 12:51, 30 April 2013 (UTC) After all this it will be obvious why I have decided to retire from the project. Deltahedron (talk) 18:35, 1 May 2013 (UTC) You know, it doesn't have to end like this. (of course, that would apply to many Shakespeare stuff too.) -- Taku (talk) 00:22, 2 May 2013 (UTC) <comments of community banned user redacted - please do not restore per this arbcom motion> I regret Deltahedron decision, and I hope he will reconsider his decision and come back to the project. WP has not enough good editors in mathematics. I particularly regret that this decision is caused by the inadequate behavior and the personal attacks of another experienced editor (auto proclamed "main content contributor in mathematics") that systematically breaks WP rules to push his point of view. The remaining of this post is devoted to clarify my appreciation of Mathsci's behavior. I have just restored Castello Orsini-Odescalchi's post that user:Mathsci has removed with summary edit: "WP:DENY see Wikipedia:Sockpuppet investigations/Echigo mole". This WP:SPI concerning User:Castello Orsini-Odescalchi has been started by user:Mathsci himself, and, apparently Mathsci considers that this allows him to censure another editor. When I wrote this sentence and I reverted Mathsci's edit, the decision to consider Castello Orsini-Odescalchi's account as a sockpuppet and to block it was not yet taken. D.Lazard (talk) 17:11, 2 May 2013 (UTC) Castello Orsini-Odescalchi's post draws our attention on another break of WP:TALKO by Mathsci, who has removed as personal attack from talk:Deltahedron the explanations by Deltahedron of his decision. The removed text does not contain any personal attack, only a description of Mathsci behavior on WP. On the other hand, above Mathsci's post is full of personal attacks ("he is not very much in touch with this subject and is being pedantic, while showing almost no interest in adding any serious content", "He appears to be making very few substantial content contributions"). About this last attack, Mathsci seems to consider that deep mathematics are more important in WP than encyclopedic content, as I am unable to understand "substantial content" otherwise than "deep mathematics content". About the content of the discussion, I have no opinion, or more exactly, I have an opinion that is similar to that of User:Sławomir Biały. However Mathsci's posts suggest that he want to deny to other editors, less good mathematicians than himself, the right to edit his own articles. WP:OWN is another rule that Mathsci has forgotten. D.Lazard (talk) 10:51, 2 May 2013 (UTC) Castello Orsini-Odescalchi (talk · contribs · logs · block log) is now an indefinitely blocked sockpuppet of the commumity banned user Echigo mole (talk · contribs · logs · block log), a persistent wikihounder who has repeatedly trolled on this page. Because of his disruption (including to mathematics articles and also here), there is an arbcom motion about not restoring or enabling the edits of this particular user. His purpose is to mislead people with malicious comments and that has been going on since 2009 (so about 4 years). It is a case of WP:LTA. Because he socks so persistently, the WP:SPI archives have two separate pages. He has trolled here many times, for example as Southend sofa (talk · contribs · logs · block log) and South Jutland County (talk · contribs · logs · block log). So as far as this sock troll is concerned, please do not feed him. There are no ownership issues involved here. Deltahedron over-reacted and misunderstaood the purpose of a lede. In the case of an extended article, rather than a stub, it should summarise the article in a way that is accessible to the reader. Objections about a trivial naming issue (composition algebra or normed division algebra) were raised even before the initial draft of the article had been completed. Deltahedron then changed the lede so that it bore no relation to the article (a simple redirect that I changed into a fully fledged article). Clifford algebras and representations of finite groups, etc, are almost always first studied or taught over the real or complex numbers. Taking arbitrary coefficients can be done later, but that is rarely done in the first instance. So when the body of an article is about real vector spaces and real quadratic forms, coming from inner products in this case, there is no reason to change the lede to cover fields of arbitrary characteristic. As far as I could tell, Deltahedron's contributions to the lede were unsourced, apart from his own thoughts together with references to other WP articles. However, there were sources, as mentioned above, and it is those that were used (particularly Shapiro) for any kind of historical remarks. Back in 2006 there was a way of writing mathematical articles without sources or inline citations. That is no longer the case. There is no reason to editorialise or make anachronistic remarks in the lede (that's WP:OR and WP:SYNTH), instead of summarising the article. As far as I am aware no content was actually being discussed. I realise that in the world of real or complex semisimple Jordan algebras, R, C, H and O play the same role as division algebras in the classical theory of central simple algebras. Fhis is a tiny part of a much larger theory which I decided to detach when writing it, since it is one of the few self-contained parts of the general theory (it took just 1 or 2 days to write within several weeks for the rest). As TauyaMurata has pointed out, Deltahedron has over-reacted. TakuyaMurata has edited some of the new set of articles, all of them related to Hermitian symmetric spaces. Mathsci (talk) 12:09, 2 May 2013 (UTC) I'm frequently seeing Mathsci's name in places like WP:AN and WP:ANI[38] He seems to have a certain attraction to trouble. I've not paid that much attention to these cases but if his actions result in the loss of a good mathematical editor then that is an overall loss to the project. Some of the discussion at Talk:Hurwitz algebra do show some signs of [{WP:OWN]] "My advice is to wait until I have finished adding the content on Jordan algebras." Our documents are live so anyone can add content at any time. It mathsci wants to work on a draft in userspace that fine. I would not say this is a bad example of WP:OWN but does show a failure of working together. I'm also concern at how rapidly mathsci removes content critical of him, it might be better to let others do this.--Salix (talk): 12:32, 2 May 2013 (UTC) You're "frequently seeing my name"? Really? Go and substantiate things instead of inventing this kind of nonsensical blather. Have you looked at my content editing history? There is no recent block log but a long list of specialist mathematics articles. So we have your wild and inane accusations, which were written without having checked anything, like a small child. Why are you attacking a major content contributor? What is true is that a number of users have been banned or site-banned from wikipedia for reasons unconnected with mathematics article. Many of them have made false accusations concering me. The banned users include all the sockpuppets of Mikemikev and Echigo mole. Others include Captain Occam, TrevelyanL85A2, Zeromus1 and Ferahgo the Assassin. Another recent contributor to this page was the editor Boodlepounce, who now turns out to be a sockpuppet of Echigo mole, a community banned user. Echigo mole, either posing as Algebraic Jordanian or the tongue-tied buffoon Boodlepounce, was out of his depth in these postgraduate mathematics articles. Both sockpuppets are now blocked. That is how the cookie crumbles. Mathsci (talk) 21:04, 5 May 2013 (UTC) The wiki (namely, Wikipedia) is, generally, a rough media. A user (namely, Deltahedron) who apparently collapsed after a couple of personal attacks from another single user, probably, would not live here for long in any other occurrence. But the recent development shows that our community can (and should) deflect Mathsci’s efforts to disregard and shun any criticism of his edits and attitudes, which rises in Wikipedia from time to time. Incnis Mrsi (talk) 13:35, 2 May 2013 (UTC) What does the community think about this removal of an ambox? Anybody can certify that I tried to discuss the matter (the link is accessible from the complementary ambox at composition algebra), not just pushed my agenda. What should I do: to push [rollback] until the opponent started to explain his position? Incnis Mrsi (talk) 08:17, 5 May 2013 (UTC) Please read Faraut & Koranyi. It doesn't take a lot of intelligence to work out that Joe Wolf and Adam Koranyi have been among the major contributors to Hermitian symmetric spaces. My impression from the current lamentable state of the article Jordan algebra is that there is a huge lack of expertise in this area on wikipedia. Sad but true. Your own comments are an example of that. As another example, take the quadratic representation of Jordan algebras or even the definition of quadratic Jordan algebra, a redlink. I have added some content on that in symmetric cone#Quadratic representation. But it cannot be found anywhere else on wkipedia. That is the problem. If you can't be bothered to read Faraut & Koranyo, why make any comment at all? All you're doing is making malicious and sneering remarks about a major contributor. Please stop it. Mathsci (talk) 21:19, 5 May 2013 (UTC) Except for unexplained removal of my subsection header (which facilitated editing), proposals to learn so-and-such sources about a dozen of related concepts, and usual personal remarks, will we see something about specifically composition algebra and Hurwitz algebra (edit | talk | history | links | watch | logs) today? I repeat: the composition algebra article is short of content, while the Hurwitz's theorem (composition algebras) discusses properties of composition algebras unspecific to the real numbers field. I would willingly learn what aforementioned Wolf, Faraut, and Koranyi (or Koranyo?) think about concretely this matter, even in Mathsci’s paraphrase, but I do not see any reason to divert attention to Jordan algebras and related red links to resolve this concrete conflict. It arose about redirecting "Hurwitz algebra" to either "composition algebra" or "Hurwitz's theorem". Incnis Mrsi (talk) 06:57, 6 May 2013 (UTC) Comments by suspected sockpuppetes removed.--Salix (talk): 07:32, 6 May 2013 (UTC)

Direct relation

Should the article titled direct relation exist? Or should it redirect to a section of proportionality (mathematics)? Or something else? I imagine some people can think of meanings of this term in mathematics other than direct proportionality. Michael Hardy (talk) 00:01, 1 May 2013 (UTC)

Redirect to proportionality (mathematics)#Direct proportionality seems like a simple and effective solution but others are welcome to disagree. M∧Ŝc²ħεИ_τlk 00:25, 1 May 2013 (UTC)

Agreed. Also, what's up with the italicization in the lead of that section? --JBL (talk) 01:38, 1 May 2013 (UTC)

The genesis of this article is interesting; this edit completely changed the topic. Should the old version of the article (about something much vaguer) exist? --JBL (talk) 01:43, 1 May 2013 (UTC)

Multiplicative calculus

Multiplicative calculus is the work of a single editor and is essentially a redux of the deleted non-Newtonian calculus. It has recently grown to a whopping 59000 bits. Somebody should keep an eye on this. Tkuvho (talk) 10:30, 1 May 2013 (UTC)

I do wish they would just write that Multiplicative calculus article well instead of having a scrappy intro and justification and turning it into a dumping ground for every reference and trivial fact. That sort of thing is uninformative and deters anyone else from contributing or improving. And sticking in references elsewhere in Wikipedia which are just advocating the methods instead of directly relevant ones cited by people in the field is just annoying too. The article is correctly in Wikipedia and could be made interesting but it is just a dump currently. Dmcq (talk) 12:17, 1 May 2013 (UTC)

Smithpith (talk · contribs) is probably hoping that a large-enough pile of references will prevent his article from being deleted again.

To my way of thinking, it is merely annoying and unnecessary, but probably not harmful. JRSpriggs (talk) 14:18, 1 May 2013 (UTC)

I wish we could just delete this garbage and ban User:Smithpith. His only contribution is his endless self-promotion of this trivial, useless idea, and I'm tired of it. Ozob (talk) 01:24, 2 May 2013 (UTC)

Actually I don't recall this aspect of it. Is User:Smithpith identifiable with one of the authors of "non-Newtonian calculus"? Tkuvho (talk) 08:49, 2 May 2013 (UTC)

Now I see that he signed his name "Michael Grossman" on his talkpage. Tkuvho (talk) 08:51, 2 May 2013 (UTC)

Note that "non-Newtonian calculus", by M. Grossman and R. Katz, earned a whopping 4 citations at MathSciNet since 1972. Tkuvho (talk) 08:53, 2 May 2013 (UTC)

I'm surprised they got that as it looks self published to me, and the editions for sale have a single review by... wait for it... Smithpith. The topic multiplicative calculus is I believe notable enough for inclusion, it is the mess there like a magpies nest that is annoying. Dmcq (talk) 12:23, 2 May 2013 (UTC)

I agree that it's a notable topic. I don't think the Grossman and Katz source should be assigned much weight in that article. Unfortunately, the primary editor of that article has a clear conflict of interests. Someone should root out the dubious references there, eliminate the non-encyclopedic "reception" section, and keep only what can be attributed to reliable secondary sources. Sławomir Biały (talk) 13:26, 2 May 2013 (UTC)

A few months ago the page was a redirect to Product integral where Volterra's work is discussed. Does multiplicative calculus have notability beyond that? Tkuvho (talk) 13:34, 2 May 2013 (UTC)

speaking of product integrals . . .

Can someone add something on product integrals of matrix-valued functions to that article? If it's only about real-valued functions, isn't it essentially instantly reducible to familiar integrals? Michael Hardy (talk) 15:48, 4 May 2013 (UTC)

"Great Feuds in Mathematics" (book)

Would anyone in this WikiProject like to write a Wikipedia article about this book?

• Great Feuds in Mathematics: Ten of the Liveliest Disputes Ever: Hal Hellman: 9780471648772: Amazon.com: Books

—Wavelength (talk) 20:58, 2 May 2013 (UTC)

There's no obvious indication that this book passes WP:Notability (books). Sławomir Biały (talk) 21:25, 2 May 2013 (UTC)

Here are two independent reviews of the book.

• Loci: Convergence | Great Feuds in Mathematics
• Great Feuds in Mathematics: Ten of the Liveliest Disputes Ever | ScienceWriters (www.nasw.org)

—Wavelength (talk) 00:04, 3 May 2013 (UTC)

The NASW review doesn't look very substantial, but there's a also third review at MR2248901, a fourth (behind a paywall that I don't have access to) at Vinculum, a fifth at Journal of the British Society for the History of Mathematics, and a sixth at Science News.—David Eppstein (talk) 00:38, 3 May 2013 (UTC)

Associative algebra #Representations

Such section could be topical without any doubt, but its current content appears to be, at best, misplaced. Incnis Mrsi (talk) 17:47, 3 May 2013 (UTC)

It's a duplicate of Algebra representation and, as usual, should be merged with it except leaving a short paragraph or two. -- Taku (talk) 18:51, 3 May 2013 (UTC)

What does your "duplicate" denote? I do not capture your thought. BTW, the content IMHO can be moved into representation theory. Incnis Mrsi (talk) 19:58, 3 May 2013 (UTC)

English grammar is tricky, isn't it? I meant that section and the article Algebra representation, at first glance, seem like the same topic. The section is about the compatibility conditions; for example, an associate algebra has a natural structure of Lie algebra (i.e., commutator) and so we can look at how two structures are related. I don't know why the discussion is limited to representations (an expert would know), but I don't think it should be merged with representation theory. Perhaps we need tensor product of representations. (the solution is always more stuff.) -- Taku (talk) 13:20, 4 May 2013 (UTC)

Symbol Definitions

A lot of articles use mathematical symbols that I don't remember, or have never seen before. Since they're special characters, they can't be searched. It would be nice if every such symbol was automatically a hyperlink to the page defining it. --70.199.133.145 (talk) 01:38, 4 May 2013 (UTC)

There is List of mathematical symbols and Mathematical operators and symbols in Unicode. Many unicode characters are linked to the corresponding article, is there a specific one your interested in?--Salix (talk): 03:30, 4 May 2013 (UTC)

Salix has provided some useful resources for looking up symbols. But those sources suggest an important point--that any given symbol can represent different things in different contexts. As much as possible, we should strive to explain at first use any notation we use in the math articles that isn't completely obvious. --Mark viking (talk) 03:44, 4 May 2013 (UTC)

Anon: if you copy and paste an unknown symbol into the Wikipedia search box, you can search on it just fine. Many symbols will have an article that explains their meaning. But, I agree with Mark that unobvious symbols should be explained and linked on first use in any given article.--Srleffler (talk) 05:34, 4 May 2013 (UTC)

Wikipedia’s use of the goddamned lucene-search already created a local myth that “special characters can't be searched”. Happily, MediaWiki’s search dialog itself does not depend on lucene with its blatant discrimination against non-letter characters, and may retrieve titles containing whatever characters: even U+0085. Incnis Mrsi (talk) 12:19, 4 May 2013 (UTC)

Wikipedia talk:Articles for creation/Vector Manifold

Dear mathemeticians:

There is an article Wikipedia talk:Articles for creation/Vector Manifold in the Afc just now that could use some attention from someone with mathematical knowledge. —Anne Delong (talk) 01:40, 5 May 2013 (UTC)

Kerala fundamental contributions to calculus

It would be interesting to determine whether http://en.wikipedia.org/w/index.php?title=History_of_calculus&diff=551937571&oldid=546717260 is a helpful edit. Tkuvho (talk) 12:26, 24 April 2013 (UTC)

I'd not give much weight to the source cited there. I have nothing in principle against including mention of the Kerala school there, but adequate sources are needed to give a sense of historical perspective. It's never been clear from more mainstream sources what weight should be assigned to the Indian mathematicians. It doesn't bode well that the source in question claims "imperialist suppression". True or not, this is a classic red flag of fringe science. Sławomir Biały (talk) 14:49, 24 April 2013 (UTC)

1. I agree. The point is that fringe science is worse than the original problem of Eurocentrism (which is what they allege.)
2. We need to challenge the claim that the Kerala school invented calculus in the articles Madhava of Sangamagrama, Mathematical analysis and History of calculus.
3. The primary work cited is : C. T. Rajagopal and M. S. Rangachari (June 1978). "On an untapped source of medieval Keralese Mathematics" and this is a paid article on Springer which I can't see.
4. The claims are based on the astronomy treatise Yuktibhāṣā which has some ingenious and useful infinite series. From this it is claimed that the Kerala school invented calculus. However, infinite series is not calculus. In this case, infinite series is a method of approximating the value of pi etc. to a high degree. It is intended to be used for astronomical computations and is not a systematic mathematical theory.

• Thanks, Anand ^{(talk page)} 12:28, 7 May 2013 (UTC)

The article in question is Rajagopal, C. T.; Rangachari, M. S. On an untapped source of medieval Keralese mathematics. Arch. History Exact Sci. 18 (1977/78), no. 2, 89–102. The article is actually not about Yuktibhāṣā but a newly published text entitled Tantrasaṅgraha-vyākhyā ("Commentary to Tantrasaṅgraha") apparently containing some material in addition to the series for sine and cosine. Tkuvho (talk) 13:27, 7 May 2013 (UTC)

And that article is here - http://math.mit.edu/classes/18.01/F2011/school-of-kerala.pdf ... imagine describing infinite series without modern notation! No wonder someone had to explain to the authors how to interpret the formulae. Still, we find a just bunch of infinite series with no systematic treatment. Thanks, Anand ^{(talk page)} 14:06, 7 May 2013 (UTC)

VisualEditor is coming

The WP:VisualEditor is designed to let people edit without needing to learn wikitext syntax. The articles will look (nearly) the same in the new edit "window" as when you read them (aka WYSIWYG), and changes will show up as you type them, very much like writing a document in a modern word processor. The devs currently expect to deploy the VisualEditor as the new site-wide default editing system in early July 2013.

About 2,000 editors have tried out this early test version so far, and feedback overall has been positive. Right now, the VisualEditor is available only to registered users who opt-in, and it's a bit slow and limited in features. You can do all the basic things like writing or changing sentences, creating or changing section headings, and editing simple bulleted lists. It currently can't either add or remove templates (like fact tags), ref tags, images, categories, or tables (and it will not be turned on for new users until common reference styles and citation templates are supported). These more complex features are being worked on, and the code will be updated as things are worked out. Also, right now you can only use it for articles and user pages. When it's deployed in July, the old editor will still be available and, in fact, the old edit window will be the only option for talk pages (WP:Notifications (aka Echo) is supposed to deal with talk pages).

The developers are asking editors like you to join the alpha testing for the VisualEditor. Please go to Special:Preferences#mw-prefsection-editing and tick the box at the end of the page, where it says "Enable VisualEditor (only in the main namespace and the User namespace)". Save the preferences, and then try fixing a few typos or copyediting a few articles by using the new "Edit" tab instead of the section [Edit] buttons or the old editing window (which will still be present and still work for you, but which will be renamed "Edit source"). Fix a typo or make some changes, and then click the 'save and review' button (at the top of the page). See what works and what doesn't. We really need people who will try this out on 10 or 15 pages and then leave a note Wikipedia:VisualEditor/Feedback about their experiences, especially if something mission-critical isn't working and doesn't seem to be on anyone's radar.

Also, if any of you are involved in template maintenance or documentation about how to edit pages, the VisualEditor will require some extra attention. The devs want to incorporate things like citation templates directly into the editor, which means that they need to know what information goes in which fields. Obviously, the screenshots and instructions for basic editing will need to be completely updated. The old edit window is not going away, so help pages will likely need to cover both the old and the new.

If you have questions and can't find a better place to ask them, then please feel free to leave a message on [[User talk:WhatamIdoing|my user talk page, and perhaps together we'll be able to figure it out. WhatamIdoing (talk) 00:55, 7 May 2013 (UTC)

This appears to be unusable for articles with mathematical equations, due to no support for <math> formulas, no support for superscripts, and no support for entities like &nbsp; and &minus; that are necessary for proper equation formatting. —David Eppstein (talk) 01:09, 7 May 2013 (UTC)

(Regardless of the original question) &nbsp; and &minus; are useful (and I employ them from time to time), but are they necessary, really? Did you ever encounter "texhtml" templates in the code? Incnis Mrsi (talk) 13:15, 7 May 2013 (UTC)

At least in the near term, I suspect that we'll need to use the "Edit Source" button to deal with those things. In the long term, I believe that providing support for mathematical equations is planned. I don't personally expect that to happen before the general rollout, though. We'll see. WhatamIdoing (talk) 14:30, 7 May 2013 (UTC)

Correction: Talk pages are being replaced by mw:Flow, not by Notifications/Echo. This may happen even sooner than the VisualEditor. WhatamIdoing (talk) 14:30, 7 May 2013 (UTC)

Gyrovector space

This is all nonsense, surely? 94.116.38.81 (talk) 14:25, 7 May 2013 (UTC)

Why do you say that? M∧Ŝc²ħεИ_τlk 14:26, 7 May 2013 (UTC)

Any article on a subject which hardly appears in the literature except for arxiv preprints, and has Florentin Smarandache as an authority, looks like WP:FRINGE. But it was a question. Is it sense or nonsense? Does anyone vouch for it? 94.116.38.81 (talk) 14:31, 7 May 2013 (UTC)

For this IP, please see Wikipedia:Sockpuppet investigations/Echigo mole. Mathsci (talk) 14:46, 7 May 2013 (UTC)

Still??... The sockpuppetry lately on this talk page and the other pages you've been writing is ludicrous... Anyway, to answer the initial equation, "gyrovectors" definitely are in the literature: see google books. M∧Ŝc²ħεИ_τlk 14:54, 7 May 2013 (UTC)

Rewrite of Quadratic equation

A significant rewrite of Quadratic equation has occurred over the last two weeks. I don't have the time to look into this in any detail, but at first glance there seem to be some problems. Most odd to me is the removal the section titled "Quadratic formula", as well as any mention of the Quadratic formula from the lead. Also note the non-encyclopedic tone in "For most students, factoring by inspection is the first method of solving quadratic equations ..." What do others think? Paul August ☎ 19:01, 2 May 2013 (UTC)

On the whole, I think we can work with the article in its present form. However, one thing I disagree strongly with is the apparent ghettoization of certain important topics to an "Advanced topics" section. This clearly violates some of our basic principles. Also, obviously the article should state the quadratic formula clearly before deriving it. I think that all of the derivations of this formula should be collected into the same section. If the objective is for earlier sections to be more of an elementary reference, then the earlier sections should not contain derivations. And language specific to the field of education should be confined to a section on education, I think. Sławomir Biały (talk) 19:20, 2 May 2013 (UTC)

Lol "ghettorization". Mct mht (talk) 19:53, 2 May 2013 (UTC)

I think it should be "ghettoization". (I know I should go back to work.) -- Taku (talk) 01:37, 9 May 2013 (UTC)

Tauism rearing its head again

Instead of responding to my comments here, User:Tazerdadog added massive amounts of material here. Attention is required. Tkuvho (talk) 15:21, 7 May 2013 (UTC)

Please note that my actions were in accordance with the discussion here (see the close at the bottom) Tazerdadog (talk) 15:27, 7 May 2013 (UTC)

Should the article exist or not, but the redirect to Pi#In_popular_culture, which does not contain any information on the topic, was certainly an unsatisfactory solution. Incnis Mrsi (talk) 15:30, 7 May 2013 (UTC)

The subsection Pi#In_popular_culture contains precisely the appropriate amount of information (including 4 footnotes) on the "topic" in question. That redirect was the outcome of an earlier RfC. Tkuvho (talk) 15:33, 7 May 2013 (UTC)

Correct me if I am wrong, but more recent RFC's supercede earlier RFC's, no? Tazerdadog (talk) 15:51, 7 May 2013 (UTC)

The RfC has been properly closed now, with the conclusion that the article should not exist, or more precisely that it's not yet ready for mainspace. So the two recent RfCs are in agreement, and given that and the effort expended in the most recent one I hope that editors can accept that and move on. Consensus can change but that's been tested once recently; we don't need to test it again any time soon.--JohnBlackburne^words_deeds 23:40, 8 May 2013 (UTC)

Wikipedia:Disambiguation pages with links/May 2013

I would like to thank the members of this project for your help with mathematics-related disambiguation pages. The list of top-linked pages for May is up, and other than Normed division algebra (with only 19 links), I don't see anything off the bat that is a clear math dab. Still, I would appreciate if some members of this project would glance over the disambig project page and see if there are any other math-related disambig pages to be addressed. Cheers! bd2412 T 02:55, 1 May 2013 (UTC)

Looking at the first 500 or so, terms that I noticed that have some mathematical significance are Likelihood ratio, Singularity, Fitting, Density (disambiguation), Dilation, Rectilinear, Recurrence, Rigidity, Transfinite, and Transition function. --Mark viking (talk) 03:16, 1 May 2013 (UTC)

It seems I missed quite a few. Thank you for checking! bd2412 T 04:13, 1 May 2013 (UTC)

Normed division algebra has been redirected to Normed algebra, also a disambiguation page, with a combined 24 incoming links, making this the most linked-to math disambiguation page. Any assistance in fixing these would be appreciated. Cheers! bd2412 T 02:17, 11 May 2013 (UTC)

‎Conjugation and real inner product on the quaternions

An amazing argument over the so named lengthy in-depth article: see talk: Hurwitz's theorem (composition algebras) #L(a*) = L(a)* and similar. Ironically, the editor who recently removed my ambox as per sources is himself found to distort the notation of Faraut & Koranyi beyond recognition. Incnis Mrsi (talk) 13:14, 6 May 2013 (UTC)

Why post this nonsense when (a) you just made a stupid undergraduate/highschool mistake (poor guesswork) (b) you didn't lift a finger to check the source (b) you did not read what the article said (d) you did not look at my reply. Since you cannot be bothered to read my replies here is the explanation again. The inner product on quaternions is Re ab*= Re b*a. So (L(a)b,c) = Re c*ab= Re (a*c)*b = (b,L(a*)c). So L(a)* = L(a)* by the definition of adjoint on a finite dimensional real inner product space. Why are you wasting time like this and making such silly errors? I meanwhile created Jordan operator algebras. If you make a stupid error, please don't come running here blaming it on others. Mathsci (talk) 13:28, 6 May 2013 (UTC)

And what is this claim about notation? The involution on the quaternions H is standard notation in mathematics. Although I didn't look, it's unsurprisingly the same notation a* as used in the wikipedia article: Quaternion#Conjugation, the_norm, and reciprocal. (Four alternative notations are listed.) Equally well the adjoint on a real inner product space is usually denoted by T* (e.g. in the source). Go ask R.e.b. if you're confused. (The argument in general is as in the text of the article as in the original source, which apparently Icnis Mrsi did not read.) Is there a WP:COMPETENCE problem? Mathsci (talk) 13:35, 6 May 2013 (UTC)

There is anything wrong with * notation for an algebra involution. But there is something seriously wrong in the use of this symbol both for this involution and for adjoint (or, if you prefer, in two different involutive algebras), especially if the latter use was not declared anywhere. I tried to find a reference to adjoint operators in Faraut & Koranyi, but did not find any. IMHO it is their serious shortcoming. But in any case, there were not Faraut & Koranyi who used the raised asterisk in the same formula for two different involutions: they used overline for algebra involution on page 82. Incnis Mrsi (talk) 14:19, 6 May 2013 (UTC)

There is nothing seriously wrong at all. For example exactly the same thing occurs in the article on Hilbert algebras and can be read here. There is an underlying *-algebra with an inner product coming from a trace. Left and right muliplication operators are denoted λ(a) and ρ(a) and satisfy λ(a*) = λ(a)* and ρ(a*) = ρ(a)*, where the second *'s denote the adjoint. All of this is standard notation from the articles of Godement or the standard textbooks of Dixmier (C* algebras and von Neumann algebras) and Dieudonnĕ (Chapter V of his treatise on analysis). The notation actually goes back to Murray & von Neumann in the 1930s. And of couse all of the current notation was invented for another article of Jordan, von Neumann and Wigner from exactly the same period. There they used Hurwitz's work in their classification of formally real Jordan algebras. (At that stage Freudenthal's elementary argument for constructing the exceptional 27 dimensional Jordan algebra was not available.) This is standard bread-and-butter mathematics in operator algebras, the subject started by von Neumann. What I don't understand is that people don't add much mathematical content to wikipedia and when it happens they appear with pitchforks. I wrote almost all the material on Hilbert algebras back in 2008; it was a link in zonal spherical functions, which Godement and Dixmier helped develop. It's also a fairly basic part of von Neumann algebras. Mathsci (talk) 14:56, 6 May 2013 (UTC)

Mathsci, please stop your WP:personal attacks like "you just made a stupid undergraduate/highschool mistake (poor guesswork)" and several others in almost every of your posts. About your argument behind your attacks: WP is not aimed for experts who have read and understood all the literature. For such a mathematical subject, the natural audience is "stupid undergraduate students", or non-mathematicians that want understand the subject, or even use it elsewhere (I think of researchers in mechanics who use quaternions to parameterize the position of a body). Therefore a WP article must be self contained and a reader should not need to read references, except for getting more details, not for understanding the body. If an experienced editor misunderstand something, this is never by incompetence (competence must not be a prerequisite), always because the article is badly written. In fact, if an experienced editor misunderstand something, then almost every reader will do the same. Again, stop to blame other editors and try to use their remarks to correct what is wrongly presented (even if mathematically correct) in your edits: Incnis Mrsi remark shows that, although formally correct, your edits are, in this case, ambiguous, and some edits are required to either change the notation or giving explanations for avoiding misreading. D.Lazard (talk) 15:55, 6 May 2013 (UTC)

There are not personal attacks. The OP simply made an error, probably by accident. I have been busy adding mathematical content. Symmetric cone is a hard article; so to some extent is the filling out of Hermitian symmetric space; Jordan operator algebra is marginally less so. The related article Jordan algebra has no proofs and there are huge gaps in the content, many of which I am adding elsewhere. The objection of the OP was about a proof for nonassociative composition algebras (in particular octonions). In the article this is what appeared:

these properties are proved starting from the polarized version of the identity (a b, a b) = (a, a)(b, b):

$\displaystyle {2(a,b)(c,d)=(ac,bd)+(ad,bc).}$

Setting b = 1 or d = 1 yields L(a*) = L(a)* and R(c*) = R(c)*.

That is the brief summary in the text of the article. To complete the proof, set b = 1 as indicated. Then 2(a,1) (c,d) = (ac,d) + (c,ad). So (L(a),cd) = (ac,d) = (c,(a – 2(a,1)1)d) = (c,L(a*)d). Hence L(a)* = L(a*).

That is quite elementary . In case of doubt there are inline citations to check Faraut & Koranyi's argument. I don't see the purpose of not following the method suggested and instead inventing a flawed definition [39][40] with the edit summary, "Something is apparently bad with the article." Mathsci (talk) 20:20, 6 May 2013 (UTC)

Let's examine your second reply. Here you are mostly providing a lot of information to back up the notation. Providing a lot of information is a good thing, because you're talking to someone who doesn't understand something. Waxing about the woes of Wikipedia is not useful. Consider if Incnis Mrsi were laying out these misunderstandings in the form of a math.stackexchange question. Would your response be appropriate? You don't need to ask why someone's making silly errors and undergraduate mistakes if you're willing to recognize that some people come across things on Wikipedia before they understand them and don't know what not understanding something looks like yet. Now, of course it's not your duty to teach these things to people who are trying to fix something that isn't broken, but it would be much more productive, because it stops them from arguing with you, and it contributes to the overall level of participant WP:COMPETENCE. In that light, the history of the notation is meaningless to someone who expects mathematics to be intelligible on its own merits - you're using the wrong kind of information in your argument. You could instead describe what motivates the notation, what semantics are missing due to the perspective one takes with the objects. Reflect on why you would use the notation yourself, other than the sanctity of tradition. ᛭ LokiClock (talk) 03:01, 7 May 2013 (UTC)

Why did you post this rubbish about my misunderstandings? I perfectly understand what is adjoint operator in a Hilbert space, and know that * is (one of) its standard notation, along ^†, and the preferred one in real analysis. The problem is not my poor erudition, but poorly written articles without appropriate declarations of notation and with clumsy typography. This one initially contained not only "minus signs" made of dashes (–), but also barely readable sequences like a*b*c* (until I inserted thin spaces to indicate priority of operations). The article said that * is the so-and-such concrete operator on the algebra, period. One should not guess about possibly relevant structures in the algebra of all such linear operators, but should read explicit declarations of them. We should educate certain major contributors how articles should be written and how to maintain consistency and legibility of notation. Incnis Mrsi (talk) 06:08, 7 May 2013 (UTC)

I read into Mathsci's point of view, rather than the situation at hand. I'm sure it's meaningless. ᛭ LokiClock (talk) 02:34, 10 May 2013 (UTC)

Whoops… not only I missed this implicit associativity bug, but ported it to composition algebra myself. I am unable not find corresponding piece in Faraut & Koranyi. We certainly observe so named #poor guesswork but in an article this time, which is also known as an WP:original research. My guess is that, although (b* a*) c* and b* (a* c*) have different values, their real part is the same. But it is not here where a real mistake can be found. When I inserted thin spaces, I naïvely expanded Mathsci’s ab* as a b*, but(a (b*), c) = (b* a*, c) is not an identity even for complex numbers! One can check that for a := i, b := 1, c := i : (a (b*), c) = (i, i) = 1, (b* a*, c) = (1 i*, i) = (−i, i) = −1. If Mathsci’s ab* means conjugate of the product ab (which would be a jarring notation), then it is an identity which trivially follows from (ab)* = b* a*. Incnis Mrsi (talk) 07:21, 10 May 2013 (UTC)

You introduced the mistake (Re a)bc with this edit.[41] I have changed the layout now and corrected a typo. The associativity under the trace has to be proved prior to establishing (ab)*=b*a*. The notation for the involution is standard, for example it's in the textbook of Størmer and Hanche-Olsen on Jordan operator algebras or equally well in the various sets of lecture notes of Koecher, Loos et al on Jordan algebras, triple systems and Jordan pairs. It cannot be avoided when discussing the complexification of the Albert algebra, which is needed for the construction of the exceptional bounded symmetric domain. Mathsci (talk) 07:46, 10 May 2013 (UTC)

Me, Incnis Mrsi? Yes, in one instance I replaced an ambiguous expression ab* with misplaced a b*. Do you see how many changes I made with aforementioned edit? Do you really expect that there are users willing to repair articles consisting of loathsome formatting and typography, missing definitions, etc., without making a single mistake? Few users like me exist, who can do such a job and absorb its “social” consequences. I can easily deflect or discard a flame and personal attacks, an ability which many others (such as user:Deltahedron and, probably, user:Echigo mole) do not have. Incnis Mrsi (talk) 08:33, 10 May 2013 (UTC)

Please look down the page for the diff I gave to where (Re a)bc occurs. Mathsci (talk) 08:50, 10 May 2013 (UTC)

I made yet another mistake when tried to disambiguate your cryptic stuff to relieve a reader from the necessity to stop at every inch and guess what exactly did Mathsci attempt to express. You collected as many as two my mistakes, so what? It would be more viable strategy for you to use parentheses in a hope that somebody accurate enough will eventually replace parentheses which a more appealing form of expressing priority of operations, rather than imitate formatting of books and papers lacking an ability (or willingness) to format a parentheses-deficient formula properly. Incnis Mrsi (talk) 10:06, 10 May 2013 (UTC)

Associativity under the trace ((ab)c,1) = (a(bc),1) is a trivial consequence L(a)* = L(a*) and R(a)* = R(a*). It's a way of streamlining a proof and hardly original research. In composition algebra, Icnis Mrsi has introduced content by copy pasting without citing the sources (Faraut & Koranyi or the Roos nots from 1988) and without providing any context or notation. The source has a real inner product and yet Icnis Mrsi proceeds nevertheess with their own generalization to arbitrary characteristic ≠ 2.Icnis Mrsi is perfectly aware that there is a textbook by Daniel Shapiro solely on composition algebras. Why are they not using that? The source of Faraut & Koranyi only discussed real positive definite forms as a tool for classifying simple totally real Jordan algebras. If Icnis Mrsi wants to add content to wikipedia, I suggest that go and read the relevant sources instead of plagiarizing content written by me for another purpose and deciding they can generalize from the reals to any characteristic ≠ 2. Wow, what a way to write wikipedia. I've never done that nor would I even think of doing that. Mathsci (talk) 08:28, 10 May 2013 (UTC)

Give a link to the book, please. I’ll read it. Incnis Mrsi (talk) 08:33, 10 May 2013 (UTC)

You can find it at this link. http://en.bookfi.org/ Mathsci (talk) 08:36, 10 May 2013 (UTC)

I am not interested enough to undertake searches if you are not interested enough to give me a link to the book, for neglecting which you blame me publicly. If you wish me to read the book, then give a link or upload a file to ftp://qq.irccity.ru/incoming/ , please. All Wikipedia content is licensed under GFDL. I have full rights to reuse it if attribution is correctly specified. Incnis Mrsi (talk) 10:06, 10 May 2013 (UTC)

In my humble opinion, there is too much unnecessarily drama here. Can we just move onto a more productive activity?

• The article "was" not badly written. Sure, some notational change could have been made for readability. But so are countless other math articles in Wikipedia. (In fact, many other articles can use more attention.)
• Yes, it would make some people happier if Mathsci is "nicer". Personally, I don't care.

-- Taku (talk) 12:50, 7 May 2013 (UTC)

What means they can use more attention? Taku, I experience a trouble with your English again. Do you want to say that such articles deserve more attention, that they can be improved (or could be made more useful) and this requires an attention, or what? Incnis Mrsi (talk) 13:15, 7 May 2013 (UTC)

Yes, that's what I meant. Some notational choice confused an editor, rightly or not: it only takes some "minor" adjustments to make the notation clearer (which has happened.) I was asking why we can't just move on: fixing problems in other articles or adding fresh new content. -- Taku (talk) 19:08, 7 May 2013 (UTC)

Position paper on tauism?

Recent developments indicate that the τ issue needs to be dealt with. We have a number of questions at the top of this page that deal with FAQ-type issues, so as not to have to give the same answers many times over. Perhaps developing a "position paper" on τ may save editor time in the future. If such a "position paper" is to be developed, I would suggest including at least the following items:

• Both π/2 and 2π are frequently used in math formulas. Thus, replacing π/2 by a single letter would simplify formulas like $\cos({\frac {\pi }{2}}-x)=\sin x$ and the like. Having a single symbol for 2π would similarly simplify certain formulas, as we have been frequently reminded frequently. However, this is very little as far as establishing notability (beyond sensationalist press reports) is concerned. Moreover, π/2 has the additional advantage of corresponding to a meaningful geometric angle explainable to beginners, which is not the case for either π or 2π.
• WPM participants of a variety of interests have opposed the creation of a separate tau page. This is in striking contrast to the uniformity of the tauists' single-minded devotion to a single cause, and the paucity of their contributions to wiki outside tauism.

Feel free to suggest additional items to be included. Tkuvho (talk) 12:11, 8 May 2013 (UTC)

If you write such a paper, please include links to our previous discussions on this topic. And mention that

• any such change in notation would create a larger barrier to learning mathematics for people trained in the new notation since virtually all papers written to date use π instead. JRSpriggs (talk) 12:45, 8 May 2013 (UTC)

Thanks, that's a good point to mention. Tkuvho (talk) 12:47, 8 May 2013 (UTC)

Another point is the cost of such a change of notation, due to communication problems between people using π in their professional activities (recalling that a satellite has been lost because of a confusion between measures in meters and feets, or something like that). D.Lazard (talk) 13:39, 8 May 2013 (UTC)

To Lazard: I believe you are thinking of the Mars Climate Orbiter. That is a very good point. JRSpriggs (talk) 14:34, 8 May 2013 (UTC)

• Possibly also worth mentioning Eagle, Albert (1958). The elliptic functions as they should be. An account, with applications, of the functions in a new canonical form. Cambridge: Galloway and Porter, Ltd. pp. XXVIII, 508. Zbl 0083.07401.. This excellent work argues forcefully that the fundamental constant is π/2, denoted τ and pronounced hi (for Half pI). F.J.C. Loomis (talk) 16:17, 8 May 2013 (UTC)

The review you linked to is in German, but it does mention his use of "hi". As far as Albert Eagle is concerned, his wikipedia page has enough information about his views. Thanks, Anand ^{(talk page)} 16:55, 8 May 2013 (UTC)

• I'm a bit puzzled by this discussion. You seem to be trying to decide whether the public should switch to tau or continue using pi. That's a bit ambitious, isn't it? If the question is whether to create an article on tau, shouldn't you be discussing notability or criteria relevant to merging? RockMagnetist (talk) 21:33, 8 May 2013 (UTC)

• There seems little doubt that the number $\tau =2\pi$ is not notable in itself, only in that there may be a notable tauist movement. I'm beginning to come to the conclusion that the movement is notable, although the assertion (that τ is better than π) is not. However, there I'm sure there isn't a Wikipedia consensus for any of this. Do you (collectively) want to try writing essays on the relevance of the tauist movement to Wikipedia, and see if we can reach consensus? — Arthur Rubin (talk) 22:25, 8 May 2013 (UTC)
• I think there is space for an article about the movement. Old versions of the Tau (2π) [42] have most of the relevant content. As far as the guideline goes simply saying we use pi and most references outside the tau article are undue weight.--Salix (talk): 22:53, 8 May 2013 (UTC)
• I have the impression that most of the newspaper reports about τ are from 2011/12 when this first came up and not that much since, and as with any sensationalist story. For example, many of the references cited in the recent RfC (now closed) give 2013 dates, but these are dates for retrieval of information, whereas the original article often turns out to date from 2011 inspite of appearances. So I don't think the "tau movement" is notable, either, at this time. Of course, if someone like Khan (of the Khan Academy) writes a bestseller about τ, the situation may change. I mentioned another point here. Tkuvho (talk) 07:23, 9 May 2013 (UTC)
• Another point that could be mentioned in the hypothetical position paper is that there has not been any notable reaction to the τ proposal in either the mathematical community or the math education community. Tkuvho (talk) 07:52, 9 May 2013 (UTC)

I propose we add a question to the FAQ at the top of this page, of the following sort. Question: Why is wikipedia lagging behind the rest of the world in not creating an article on τ (2π)? Answer: The proposed new constant lacks notability at this stage. (1) comment on π/2 and 2π. (2) students trained in the new notation would face a barrier in their learning since virtually all of the existing literature uses π. (3) Don't fix it if it ain't broke: introducing alternative units may lead to costly errors, cf. Mars Climate Orbiter. (4) Albert Eagle and π/2. (5) no notable reaction to the τ proposal in either the math community or the math education community. Comments? Tkuvho (talk) 12:36, 9 May 2013 (UTC)

If there is an FAQ entry, I think that the main points are that the notability of τ is not yet established, and the fact that all but a miniscule number of sources use π, so it would make little sense for us to unilaterally change our mathematics articles to use τ instead. The other factors are relevant to mathematics in general (perhaps) but they are not very relevant to Wikipedia. — Carl (CBM · talk) 14:08, 9 May 2013 (UTC)

The last point you made seems to be an answer to a slightly different question: Why hasn't wikipedia switched to τ? That particular question does not seem to be asked that frequently yet :-) If we to stick to the question "why there is no tau article", then perhaps we can just mention that the notability of tau is not yet established, and add in explanation that neither math nor math ed crowd has responded in any notable way. What about mentioning also the notability of τ=π/2 since it appeared in Eagle's book? Tkuvho (talk) 14:15, 9 May 2013 (UTC)

I added a tentative question here. Feel free to add relevant material to the answer. Tkuvho (talk) 15:25, 9 May 2013 (UTC)

Looks good. The pi manifesto which tries to counter the tau manifesto gives some more reasons. E.g. "Any publicity is good publicity" and "They pinpoint formulas that contain 2π while ignoring other formulas that do not." By the way, Albert Eagle was an idiosyncratic author and has tried to redefine quite a few things. Finally τ doesn't seem to be notable at this point of time. Thanks, Anand ^{(talk page)} 16:21, 9 May 2013 (UTC)

Thanks. Feel free to edit the question, but keep in mind the comment (by User:RockMagnetist and User:CBM) that the question should focus on why τ is not notable, rather than whether or not it is a good idea. Tkuvho (talk) 16:41, 9 May 2013 (UTC)

Combinatorial identity

Should we do something to remedy the red-link status of these two items?:

• Combinatorial identity
• List of combinatorial identities

Michael Hardy (talk) 22:45, 10 May 2013 (UTC)

Could be useful. The combinatorial identities we have are spread out over a number of articles such as Combination, Binomial coefficient, Bernoulli number, Bell polynomials, etc. A fairly good, if eclectic, resource for combinatorial identities is Gould's collected notes, a series of eight PDF documents. --Mark viking (talk) 23:24, 10 May 2013 (UTC)

Universal geometric algebra

This is a relatively new article created a couple of weeks ago, but strikes me as very dubious: I've never come across infinite dimensional geometric algebras before, and they make little sense within the rules of the algebra. The sources are all standard sources which deal with the usual finite dimension GAs, except the last which I don't recognise. A search for "Universal geometric algebra" finds nothing like this, except this article. It could be something very new I've just not encountered and which can be found with a better search, but it looks like mostly original research to me.--JohnBlackburne^words_deeds 00:07, 11 May 2013 (UTC)

Did you try to search for vector manifold? Incnis Mrsi (talk) 01:31, 11 May 2013 (UTC)

If the contents are referencing the references faithfully, the contents are probably OK. I can say that the names in the references are "big" within the field (geometric algebra).

@JohnBlackburne Actually I'm a little surprised your search wasn't fruitful. Searching "universal geometric algebra" at googlebooks produces an entire first page of relevant hits. I did not check to see if all 100+ were relevant, but the authors in the first page are also "big" names in the field. Rschwieb (talk) 02:00, 11 May 2013 (UTC)

introduction to statistics

Do we have an article on this topic? I notice that we have Introduction to Statistics, but that's about a TV episode. -- 65.94.76.126 (talk) 04:02, 11 May 2013 (UTC)

I don't think we should have articles like "Introduction to something" because we try to avoid purely expository articles on Wikipedia. What exactly are you looking for? You might want to look at existing stuff on Portal:Statistics or on Wikibooks - wikibooks:Category:Statistics. Thanks, Anand ^{(talk page)} 10:18, 11 May 2013 (UTC)

Well, we do have many "introduction to" articles under physics on Wikipedia, so I was thinking that perhaps something should exist for stats. (or perhaps, some "introduction to" articles should be written in a manner that would be accessible to middle school students with dyscalculia). -- 65.94.76.126 (talk) 03:37, 13 May 2013 (UTC)

I noticed they have created one article each for the approx. 100 episodes of the TV series "Community" and most of the names sound like some standard topic or subject. So not surprising that there is this clash. Thanks, Anand ^{(talk page)} 10:42, 11 May 2013 (UTC)

Yeah, those clashes are quite something. -- 65.94.76.126 (talk) 03:37, 13 May 2013 (UTC)

Eagle on tau

I added a comment on Eagle and tau at pi but it was removed by User:Noleander in this edit. I have the impression that tauists still have not learned to cooperate with WPM. Keep an eye on the page. Tkuvho (talk) 07:15, 12 May 2013 (UTC)

new material at philosophy of mathematics

New material was recently added to the page philosophy of mathematics, under the heading "Platonism Interpreted Through Eastern Thought": Although not a part of the contemporary dialogue in the philosophy of mathematics, the contentions of Eastern thought bear on some of the central questions, in particular, the question: if mathematical objects are real, then where do they reside? The Western philosopher is confused by this question for they envision some world of time and space external to the human mind in which mathematical, and (since it is arbitrary to divide mathematical abstractions from all other abstractions) other abstract objects exist. However, teachings dating possibly as far as the second millennium BC, attributed to the Samkhya philosophy associated with yoga indicate that the "worlds" containing abstract objects such as mathematical entities, exist in the depths of human consciousness. Yoga provides empirical means for "peeling back" or "diving into" (for lack of more precise Western terms) these depths of consciousness, the main technique being samadhi. The contention being that "levels" or "worlds" (lokas) are present in the depths of human consciousness where abstract entities are real objects. These objects are not made of physical matter, but real nonetheless. At these levels, the abstract objects serve central roles in the construction of the reality humans perceive as "the physical world", and hence the intimate connection between mathematics and physics. Moreover, that these objects are buried deep in the inner recesses of human consciousness explains the intuitions of the realist schools of mathematical philosophy. These abstract objects, via a process analogous to reflection, find their way into the imagination of waking human minds and give rise to mathematical insight and intuition, precisely Kant's "a priori" knowledge. In the West, relatively rigid intellectual categories demarcate different forms of abstract understanding, but the abstract objects themselves are not so partitioned in their intrinsic spaces but instead form complex networks of abstractions. Hence, through human history, mathematical, scientific, religious and philosophical insights emerge from the imaginations of different people, and each person's insights provide some legitimate perspective on the subtle relationships existing amongst abstract objects at their own intrinsic levels. However, the verbal and intellectual expressions generated by humans awake in the physical world, even those abstracted into the formal deductive language of mathematics, are but pale, highly distorted versions of the deeper realities they reflect. The abstract entities can be directly experienced in the state of samadhi where their true relationships and relative proportions are directly perceived. When seen in their correct proportions, the depth of shallowness, arbitrariness, and complete lack of perspective of current Western intellectual conceptions in mathematics, science, philosophy and religion becomes apparent. Is this properly sourced? Tkuvho (talk) 09:30, 12 May 2013 (UTC)

This is an essay not relevant to the subject. Samkhya and Yoga are standard schools of Indian philosophy. Thanks, Anand ^{(talk page)} 09:56, 12 May 2013 (UTC)

I can't see the relevance and no citation was supplied so I'll go and remove it. Dmcq (talk) 10:01, 12 May 2013 (UTC)

This looks like original research. There has been work on connecting Eastern philosophies and quantum physics, but the above is not the same thing. An interesting synthesis, but unless there is a reliable source for it, I agree with Dmcq's proposed action. --Mark viking (talk) 16:21, 12 May 2013 (UTC)

zeteo - a database for mathematical references

A few years ago, I set up the website zeteo.info which contains a database of about 20.000 (mostly) mathematical referenes. Its main features are: 1) search for an author and comfortably copy the code of a wiki citation template etc. 2) add new references based on either manual input or bibtex pieces. (See here for a short reference.)

Currently, this site is down because the database is not optimally configured (so the provider shut it down). Moreover, someone keeps adding nonsense to the database (which I filtered out every once in a while).

Since I am busy with other commitments, I personally can unfortunately not take the time to fix these things. I am therefore seeking a way of handing over the (small) burden of maintaining this site to the Wikipedia community, most of all this WikiProject. If anyone has an idea of how this might be accomplished, please let me know. I am happy to share the database and/or source code with anyone who is genuinely interested in this matter. Thanks! Jakob.scholbach (talk) 04:48, 13 May 2013 (UTC)

Hi, I will ask around and see if the IT people at some universities I know can take over maintaining this very valuable resource. In the meantime, however, is it possible to get the source code for parsing BibTeX entries and putting it into a Wikipedia citation template? Ray^Talk 18:30, 13 May 2013 (UTC)

Who are the namesakes of Evans–Hudson flow

I created a new page Robin Lyth Hudson two days back. Who is the other namesake of Evans–Hudson flow i.e the Evans one. I googled it tried Google Scholar but I cannot figure out the other namesake. Any help appreciated. Solomon7968 (talk) 16:53, 13 May 2013 (UTC)

I guess it should be MP Evans - see for example - http://link.springer.com/chapter/10.1007%2FBFb0078055 or http://link.springer.com/article/10.1007/BF00367298 — Preceding unsigned comment added by Anand QED (talk • contribs) 17:15, 13 May 2013 (UTC)

Dynamic Dictionary of Mathematical Functions

I want to draw the attention of the community (specially those that re concerned by special functions) on the Dynamic Dictionary of Mathematical Functions. It provide formulas, "properties, truncated expansions, numerical evaluations, plots, and more" for many elementary elementary and special functions. It should be emphasized that everything is automatically computed at the loading time from the differential equation that defines the function. The order of series expansions and the number of digits of the numerical evaluations may be chosen by the reader. All the digits of the numerical evaluations but the last one are certified. By clicking on a formula, one gets the corresponding latex code (allowing to include the formula in WP). Everything is based on the recent theory of D-finite functions. IMO, this has to be linked as external links in the articles about the functions that are covered by the DDMF. This may also be helpful to expand these articles. D.Lazard (talk) 19:05, 13 May 2013 (UTC)

Nice, thanks for finding! M∧Ŝc²ħεИ_τlk 19:38, 13 May 2013 (UTC)

Agreed, this looks like a great resource. From the DynaMoW page it looks like the engine also supports the Encyclopedia of Combinatorial Structures. Thanks, --Mark viking (talk) 20:30, 13 May 2013 (UTC)

Temporary new name

Look at this talk-page comment. Hyperbola has be temporarily renamed Hyperbola (mathematics) in order to deal with some weird thing that Google does when people search for "hyperbola". Is it possible to contact Google about this? Would there be any hope of a reply from a responsible and competent person as opposed to someone skilled in public relations? Michael Hardy (talk) 12:13, 14 May 2013 (UTC)

There is also a comment about this four sections up on this page. --JBL (talk) 12:21, 14 May 2013 (UTC)

I don't see how pageview statistics could possibly be construed as a justification for renaming articles. The tail is wagging the dog if that's the case. Sławomir Biały (talk) 12:28, 14 May 2013 (UTC)

Agreed. This user's brief history with math articles also does not inspire confidence. --JBL (talk) 12:34, 14 May 2013 (UTC)

Misunderstood what they were up to at first but sill think the page should be moved back and pretty sharpish. There is a big bit about it all at WP:VPT#Relinking Google for SSL https Dmcq (talk) 15:24, 14 May 2013 (UTC)

The article has been returned to its rightful home. --JBL (talk) 04:12, 15 May 2013 (UTC)

COI editor

I'm concerned that there is a mathematics editor Zsoftua (talk · contribs · deleted contribs · logs · filter log · block user · block log) who, for the past few months, has been editing Wikipedia with the apparent intent of including links to the publications of Dmitry Zaitsev. In some cases, these publications appear in rather questionable places, either being self-published or published by rather shady open access journals, and would most likely not pass muster as reliable sources even if there weren't an obvious COI issue. Some of them seem to be in better journals (such as journals maintained by the IEEE), but are being used as primary, rather than secondary sources, against our WP:NOR policy. The affected articles relevant to this project are:

• Matrix decomposition into clans — a new article whose only source that is not self-published appears in a journal of the notorious Scientific Research Publishing outfit.
• Graph theory diff
• Matrix decomposition diff (this was reverted by User:Jitse Niesen with a discussion on the talk page that echoes some of my own concerns)
• Turing completeness diff
• Fuzzy logic diff
• Petri net diff

Should some or all of these edits be reversed? What should be done with Matrix decomposition into clans? Sławomir Biały (talk) 12:43, 14 May 2013 (UTC)

I think so okay, thy're link spamming except for that article. I think though Mathgen which created the fake maths for the paper Scientific Research Publishing accepted has probably enough notability now for an article. Dmcq (talk) 15:09, 14 May 2013 (UTC)

Integral → Definite integral?

Our current article Integral is only about the definite integral. As a result, there is a hatnote linking both to integers and to indefinite integral (and omitting the obviously needed link to integral (disambiguation)). Since the article only deals with the definite integral, wouldn't a more logical configuration be to move this to definite integral and then redirect integral to the disambiguation page? I would do all of this myself, but the move requires administrator powers. Sławomir Biały (talk) 12:55, 14 May 2013 (UTC)

As far as I can see integral does deal with indefinite integration as well just not in depth, and the better change would be to turn indefinite integration into a proper subtopic by removing bits which are just to do with integration in general. I don't think people will look up integral just meaning number often enough to warrant turning it into a disambiguation page. I think pointing definite integral to integral is fine. Dmcq (talk) 13:35, 14 May 2013 (UTC)

Ok, if the main article integral is meant to deal also with the indefinite integral, then I think it's not appropriate for the hatnote to point to antiderivative (as it currently does). In particular, the lead already contains a link to that article. I will undo the recent changes to the hatnote, unless there are objections. Sławomir Biały (talk) 14:16, 14 May 2013 (UTC)

Convolution

An editor seems to be arguing at Talk:Convolution#Discrete convolution that the mathematical definition of the discrete convolution is wrong. Please comment there. Sławomir Biały (talk) 12:24, 9 May 2013 (UTC)

There is now an edit war going on there, with the editor in question now at 4RR. Sławomir Biały (talk) 16:54, 14 May 2013 (UTC)

The edit war is still going on. A third opinion seems to be needed again. Sławomir Biały (talk) 15:34, 15 May 2013 (UTC)

Fixing Google https links to major math articles

As many of you might know, during April/May 2013, even more articles have gained secure-server prefix "https:" in Google links (see essay listing 500 pages: "wp:Google https links"), an unusual feature which Google Search has supported since before 2009. In late March 2013, article "Parabola" switched to Google https-protocol links, and pageviews dropped over 75% (2500 to 620/day) because stats.grok.se no longer was counting https page requests, at the end of March (see: Parabola-views-201303). Also, many other articles, including "Geometry" or "Cone" or "Hexagon" (etc.), switched to Google https, and then "Hyperbola" and in early May, even "Catenary" gained https-prefix in Google. However, Yahoo Search and Bing.com are not affected, and pageviews from them are still counted by stats.grok.se (see: wp:Pageview statistics). Currently there are 2 plans to remove the https-protocol prefix from Google articles:

1. Reset the link-tag for rel="canonical", inside https-protocol pages, such as:
            <link rel="canonical" href="http://en.wikipedia.org/wiki/Catenary">
   That link-tag would be placed inside the generated HTML markup, along with the other link-tags (such as for "edit" or "copyright" or "stylesheet"), and once Google re-indexed each article, then the Google https-protocol link should return to "http:" after a while.
2. Rename each article, temporarily, where the new title would be indexed into Google with typical http-prefix link, and then change each old title to a "soft redirect" linking to the new http title, and once re-indexed, then set the redirect as "__NOINDEX__" to allow Google to "forget" the old title, and then rename back, where the double-renamed title would drop the https-protocol prefix.

Hopefully, the first option, to embed the link-tag for rel="canonical" can be applied soon, by the developers, and there will be less need for double-renaming of pages. However, where accuracy of pageview counts is crucial, then those articles can be renamed, immediately, to begin logging accurate entries (under the new titles) for the actual pageviews being requested by readers. The Google https-protocol prefixes have been trouble for over 7 weeks, since around 25 March 2013, and nothing had been done during the initial 2 months to fix the problems. The developers were certain they had fixed entries of https requests (not omitted all counts), and the low pageviews were a puzzlement (not seen as a warning that all https-prefix views were omitted for 2 months). However, now the reality is becoming clearer. But, remember, once fixes are applied, it might take Google several days, or over a week, to re-index the affected pages. That is the status, so far, and I just wanted people to know that workable solutions are being planned. -Wikid77 (talk) 23:42, 12 May 2013 (UTC)

" where accuracy of pageview counts is crucial," -- what could this possibly mean? --JBL (talk) 00:40, 13 May 2013 (UTC)

Pageview counts matter to some editors who write for reader feedback, rather than just pontificate, and can measure the readership base. Because relatively few people read math articles, the pageviews are more of a concern for important articles, such as the Top 1000 most-viewed pages, including "DNA" or "Oxygen" or "Shakira" or "Albert Einstein". However, some math articles could be expanded to be more interesting, such as "Calculus" which had almost 3,900 views/day. In such cases, inviting general readers to view the page "Calculus" (rewritten with more practical substance) could be measured by clever editors to get that page read among the top 1000 most-viewed pages. The pageview counts are a tool which intelligent, inventive editors can use to focus reader interest. -Wikid77 (talk) 07:57, 16 May 2013 (UTC)

This is altogether the wrong way of going around things I think. We should ask Google to have a facility to refer to the pages on the domain using http: always like they have the facility to always refer to them with www. or not according to the web owners preference. This would get rid of anything like this and probably help people elsewhere too. They can always use canonical for ones which don't follow the standard. I think our messing trying to flush the caches is a waste of our time, we should just leave the problem till it is fixed properly. Dmcq (talk) 13:52, 14 May 2013 (UTC)

Thinking about it more Google would really like such a facility I believe as it would improve their statistics. They would probably also like the option of sites saying they can support https even though they marked everything as normally http so logged in users could have an option to automatically use https as often as possible when using google. Dmcq (talk) 14:08, 14 May 2013 (UTC)

• Attempts to double-rename were reverted and https-prefix returned: The pageview and security-certificate issues were too complex to explain to some admins, and they insisted that temporarily redirecting the titles, even for a few days, was unacceptable, and forced the re-rename of article "Hyperbola" within 2.5 days, which was not long enough for Google to re-index without the https-protocol link. All those math articles have retained the https prefix and lowered the pageviews of wikilinked pages. However, we were able to contact some developers who have fixed the page-request software (at 18:44, 14 May 2013) to again log https-type views as counted by stats.grok.se, returning pageview counts, 2x-3.5x times higher, to the March-2013 levels. At this point, the Google-https links remain, but users can be told to insert "http:" prefix (replace "https"), if they wish to view pages but not via secure-server protocols. -Wikid77 (talk) 07:57, 16 May 2013 (UTC)

• Confirmed https pageviews resumed 14 May 2013: I have run tests (on 15 May 2013) to verify exact pageview counts for either http or https-protocol, pages or images, on both enwiki and dewiki (German WP also fixed). The pageview data logs, such as for stats.grok.se, have been fixed (at 18:44, 14 May 2013) to re-enable the https/ip6 stream to webstatscollector, where Google https-protocol links, for over 300 major enwiki articles (see stats: 201305/Email or 201305/Parabola or 201305/Shakira, and thousands of wikilinked pages), had been 55%-80% under-reported during late March, April and early May (see essay: wp:Google https links). The typical pageview counts, from March 2013, have resumed in pageviews, as 2x-3.5x times higher for https-prefix pages/images, during 15 May 2013. German WP pageviews were also fixed for different pages (see stats: /de/201305/Euklidischer Raum "Euclidean Space" or /de/201305/Oval). All https page requests had been omitted during 26 March 2013 to 18:44, 14 May 2013, and so there will be permanent low spots in the pageview stats of some pages during those 50 days (~7 weeks), for various articles, images, talk-pages, templates or categories which were viewed mostly via https-protocol links on some of those 50 days. Many thousands of pages/images were not affected, and those pageviews will seem relatively stable during that 50-day period. As of 15 May 2013, the http/https pageviews have been re-confirmed to log exactly "to the penny" and so, if a page/image was viewed 7x times during a day, it will show a total of exactly 7 pageviews for that day. -Wikid77 07:57, 16 May 2013 (UTC)

I'm not in favour of messy solutions for temporary problems unless it is really absolutely necessary. If it will be fixed tomorrow anyway without messing around it should just be left. Dmcq (talk) 10:52, 16 May 2013 (UTC)

New Square Matrix article?

A new article has been created at Square matrix, which had previously been a redirect to Matrix (mathematics)#Square matrices. It seems to me like an unnecessary duplication of content.. see the discussion here. Mark M (talk) 08:53, 16 May 2013 (UTC)

House with two rooms

Surely we can do better than this? (e.g., a picture). -- Taku (talk) 11:43, 16 May 2013 (UTC)

Simple proofs for geometric progressions

8.25.32.37 (talk · contribs · 8.25.32.37 WHOIS) has been adding pretty much illegible "simple proof"s for the value of 1/4 + 1/16 + 1/64 + 1/256 + ⋯, 1/2 − 1/4 + 1/8 − 1/16 + ⋯. and 1/2 + 1/4 + 1/8 + 1/16 + ⋯ for some time. I've been removing it, and sometimes pointing to the actual simple proof at geometric series. I would appreciate a second opinion as to whether the "simple" "proof"s should be included in the articles. — Arthur Rubin (talk) 14:46, 17 May 2013 (UTC) ‎

The purported proofs are just variants of the derivation of the formula for the geometric series given in the main article. Of course, these proofs do not establish the convergence of the series. So they're a bit misleading as written. Sławomir Biały (talk) 15:08, 17 May 2013 (UTC)

Template:Unsolved

{{unsolved}}, a template that is used in some mathematics articles to highlight open questions concerning their subject and link to unsolved problems in mathematics, is being proposed for deletion. Please contribute to the discussion at Wikipedia:Templates for discussion/Log/2013 May 18. —David Eppstein (talk) 04:18, 18 May 2013 (UTC)

Pioriginal.gif

file:Pioriginal.gif has been nominated for deletion. There are various issues concerning this illustration in the nomination. -- 65.94.76.126 (talk) 06:51, 18 May 2013 (UTC)

Bugs with new notification feature

I am clueless when it comes to reporting buggy behavior with wikipedia stuff. The recent addition of that notification digit into the console (mine is a zero in a grey box when I have no notifications, and it becomes a red box if there are nonzero notifications) behaves poorly for me, quite possibly because I'm using a different skin than standard. (I'm using "modern".) I would like to be able to report this, but I would appreciate a pointer to the correct place. Thanks! Rschwieb (talk) 13:15, 17 May 2013 (UTC)

The general place for all things related to behaviour of the site’s software is WP:VPT, though for issues with the notification system you can go directly to Wikipedia talk:Notifications.—Emil J. 13:25, 17 May 2013 (UTC)

And check the FAQ there before you decide it is a bug. I am using "modern" too and don't see anything unexpected. Thanks, Anand ^{(talk page)} 14:09, 17 May 2013 (UTC)

Thanks for the pointer. As I expected, it is a known bug. Apparently it's been fixed for Modern users using anything but IE. Rschwieb (talk) 12:09, 19 May 2013 (UTC)

File:Plot of number of primes between consecutive squares.png

File:Plot of number of primes between consecutive squares.png has been nominated for deletion. -- 65.94.76.126 (talk) 07:15, 20 May 2013 (UTC)

Probably a good idea. The license provided is inadequate. PD (ineligible for copyright due to lack of creativity) is a possibility.... — Arthur Rubin (talk) 07:30, 20 May 2013 (UTC)

Category:Hyperdimensional physics

I nominated the above category for deletion but it seems to have gotten no attention so far and could perhaps benefit from attention from other project participants. The discussion is here:

Wikipedia:Categories for discussion/Log/2013 May 17#Category:Hyperdimensional physics

Thanks. --JohnBlackburne^words_deeds 20:07, 20 May 2013 (UTC)

DISPLAYTITLE

I've added a DISPLAYTITLE template to the top of Kalai's 3^d conjecture, and it has no effect. What's wrong? Obviously it would be barbaric to leave the title as it is. Michael Hardy (talk) 18:21, 20 May 2013 (UTC)

Possibly the superscript? M∧Ŝc²ħεИ_τlk 18:35, 20 May 2013 (UTC)

No, I think it's the caret in the article title that isn't present in the displaytitle. —David Eppstein (talk) 18:41, 20 May 2013 (UTC)

I think it's because the HTML code won't convert to canonical form (note the first line in Template:DISPLAYTITLE#Examples). RockMagnetist (talk) 18:44, 20 May 2013 (UTC)

(edit conflict)Considering your post here maybe the page needs to be moved to remove the caret ^ and then the superscripts would function? M∧Ŝc²ħεИ_τlk 18:45, 20 May 2013 (UTC)

user:Ucucha seems to have fixed it. M∧Ŝc²ħεИ_τlk 18:47, 20 May 2013 (UTC)

The problem is discussed at Wikipedia:Village pump (technical)#DISPLAYTITLE is not working. PrimeHunter (talk) 16:07, 21 May 2013 (UTC)

Minimum chi-square estimation

I've just created Minimum chi-square estimation. It needs further work, including references and links from other articles to it. Michael Hardy (talk) 01:21, 22 May 2013 (UTC)

"Shannon capacity" does not define Shannon capacity of a graph.

The article Shannon capacity does not mention graphs at all.

However, the article Lovász number immediately refers to Shannon capacity. In the former article, there is also a subsection Lovasz_number#Shannon_capacity_of_a_graph, and only there can one find the definition of the Shannon capacity of a graph.

Shouldn't that subsection be included in Shannon capacity, or is this concept too distinct from the usual notion of Shannon capacity?

Evilbu (talk) 07:22, 23 May 2013 (UTC)

It seems reasonable to include the definition of Shannon capacity for graphs in the Shannon capacity article. Shannon capacity seems to only discuss single link examples, but there are interesting results in network information theory that should be mentioned, too. --Mark viking (talk) 18:42, 23 May 2013 (UTC)

Template "Library resources about"

The template {{library resources about}} has been added to Number theory by User:SakeUPenn. I do not clearly understand if this external link passes the criteria of WP: external links. This user intends explicitly to add this template to a "multitude of articles" and does not refer in his user page to any official approval by WP. A quick decision is thus necessary to know if this template is convenient for math articles. (I see that the template has been proposed for deletion, that the result was keep, but there is no clear decision about its inclusion in math articles) D.Lazard (talk) 16:14, 23 May 2013 (UTC)

Since the user in question gives the real name "Sarah Kemp", presumably the correct pronoun is "she."--JBL (talk) 16:32, 23 May 2013 (UTC)

My understanding of the outcome of that TfD discussion is that there was to be some RfC about the use of this template before its widespread deployment. Sławomir Biały (talk) 17:18, 23 May 2013 (UTC)

To clarify: I've been instructed to add this template to various mathematics and physics articles as part of a Library internship project. "Multitudes" was a poor word choice on my part, as the scope was never so enormous. The intent was to choose a few specific articles related to faculty or departmental fields of study, this is by no means the entire body of math or physics subject articles. I'm aware I'm using a template that has been the subject of discussion before, not least because of my use of it. My understanding is that after review it is an acceptable template but that the use of it must be modified and downscaled. As concerns have been expressed, I've communicated with my supervisor and I'm putting this project on hiatus until the community reaches conclusions about both the scope of the project and the use of the {{library resources about}} template. I've removed all of the recent edits I made to Mathematics pages and have edited my userpage to better reflect my purpose here. Going forward, I'm happy to address your concerns as best I can. SakeUPenn (talk) 18:32, 23 May 2013 (UTC)

MathOverflow question

Today I asked a question on MathOverflow about Wikipedia, and it's generating several interesting answers that editors here might be interested in: Why don’t more mathematicians improve Wikipedia articles?. Mark M (talk) 19:54, 22 May 2013 (UTC)

To me, the most astonishing thing in the “question” is a mention of WP: Teahouse. I would not like to see that venue razed to the ground, but it should be least recommended to any editor capable to a content work. The “Teahouse” IMHO should stay ahead of only WP:AN/I. The main reason of existence of both aforementioned sectors of Wikipedia is to drain content-incapable and work-unwilling users out of articles, talk pages, and projects, where they could otherwise mess around and disrupt a legitimate communication. Incnis Mrsi (talk) 17:26, 23 May 2013 (UTC)

Well, we clearly disagree about why the Teahouse exists. It is easy to underestimate how daunting the whole Wikipedia-editing world is to new users (especially to experts who are used to having their authority respected), and the Teahouse is intended to be a place where new users get helpful, friendly, and non-bitey advice.. and, as far as I'm aware, it's (unfortunately) one of the few places that reliably does so. Mark M (talk) 09:08, 24 May 2013 (UTC)

I understand your point--if an editor spends most of their time at the Teahouse, they aren't creating useful encyclopedia content. But as a clueless new editor, I found it invaluable for answering my clueless questions in a patient and kindly manner. As you have said in the past, Wikipedia is a rough neighborhood. The Teahouse is a rare sanctuary of civility for editors trying to get their bearings for the first time. --Mark viking (talk) 15:22, 24 May 2013 (UTC)

Polynomial Surface Rotation images useful to the project?

I have made polynomial surface rotations as animated GIF files and released them under a Creative Commons Attribution license, one lower resolution and one higher resolution image of the same rotation. These should be useful illustrations for the project. The URL with license is:

zunzun.com/rotations/

James Phillips, email zunzun@zunzun.com — Preceding unsigned comment added by 108.81.189.144 (talk) 10:26, 25 May 2013 (UTC)

Posting by D.Lazard

Note this thread was originally titled Wikipedia:Arbitration/Requests/Enforcement#D.Lazard and relates to that discussion.--Salix (talk): 10:51, 22 May 2013 (UTC)

I am the object of a request of enforcement submitted to arbitration committee. This request is related to some discussions in this page and the retirement from WP of User:Deltahedron. Some of you may want to comment there. D.Lazard (talk) 14:20, 21 May 2013 (UTC)

@all: Predictably, the complaint already seems to be falling flat. Still, don't let that stop you from dropping by and chipping in. Your contribution may help discourage future spurious complaints from that user in the future. (After all, you might be the target.) Rschwieb (talk) 21:21, 21 May 2013 (UTC

The tribe made its judgement. I do not think that Mathsci now has even 1% chance of ultimately winning something in his crusade against the unrewarding Wikipedia which edited so many “his” articles without “authorisation”. Now it is the time for Mathsci’s friends (I think about Sławomir Biały, but possibly there are others) to persuade him to stop attacking people who aim to improve articles. If the author of an article is a good mathematician, it does not imply that his content is perfect and his exposition is always balanced. Incnis Mrsi (talk) 06:37, 22 May 2013 (UTC)

Its clear from the sockpuppet investigations 1 2 that there has been a good number of sockpuppets attacking Mathsci. When a users first edit is a post here critical of Mathsci then its clearly a case of someone with some history under another name. Whether all the sockpuppets are the same I can't say, its very difficult to tell in sockpuppet cases. I'm not convinced that the endless round of socks and blocks is the best way to deal with the situation. There may be an editor with some mathematical knowledge but little knowledge of the wikipedia system who has managed to get on the wrong side of that system. No one has really take the time to treat the user with a bit of respect explain why constant hounding of Mathsci is bad for the project and what a productive editor would do. There might be a case for a Wikipedia:Clean start but under certain conditions such as non-engagement with mathsci, and admission about alternative usernames used. Its the only way I can think of of ending this drama for good.--Salix (talk): 09:12, 22 May 2013 (UTC)

I tried my best to convince this apparent Echigo_mole/A.K.Nole that when he harasses a legitimate contributor, he becomes at war with the Tribe, and that he must stop it. Unfortunately, he and some other contributors were lost. Indeed, the problem is that Mathsci may become lost for productive editing, too. Someone should convince him that his contributions to articles are appreciated, but not his interaction patterns observed for last four years. Incnis Mrsi (talk) 09:46, 22 May 2013 (UTC)

It was completely inappropriate to start a section with the previous title on this noticeboard per WP:CANVASS. Echigo mole is a long term problem. But discussing one small aspect of his trolling here is not the way to go, Salix alba. It's not appropriate to respond to this trolling by suggesting what I should do as one of the more active mathematical (or classical music) editors on wikipedia. What were you thinking of? As you know, D.Lazard should have informed me about this posting. But courtesy does not seem to be his strong suit at the moment. I think that D.Lazard, author of the BLP Daniel Lazard and seemingly the same person, should probably stick to the subjects that he knows about instead of fraternizing with and lobbying for banned editors. Operator algebras, Jordan operator algebras, Hermitian symmetric spaces, symmetric cones are areas outside his expertise or interests, or so it would seem. I have no idea why he should claim otherwise. Likewise Incnis Mrsi.

Echigo mole is a community banned editor who has engaged in WP:LTA for over 4 years. His latest "creations" Tautological tau (talk⁺ · tag · contribs · deleted contribs · logs · filter log · block user · block log · CA · CheckUser(log) · investigate · cuwiki) and Gongfermor (talk⁺ · tag · contribs · deleted contribs · logs · filter log · block user · block log · CA · CheckUser(log) · investigate · cuwiki) will be soon be dealt with by checkusers/administrators. Echigo mole barely understands the syntax of graduate level mathematics. His editing is creepy. In the case of abusive editors like him, where lying is fairly common, the appropriate response is WP:DENY. We do not feed the troll. He has edited through more than 250 sockpuppets and ipsocks. This noticeboard is not an appropriate place to discuss this disruptive user. I have been making mathematical edits since 2006. In 2009 User:A.K.Nole, the first account of Echigo mole, trolled on Butcher group. Very little has changed then. His knowledge of mathematics has not increased. Mathsci (talk) 09:50, 22 May 2013 (UTC)

So named “trolling of A.K.Nole in Butcher group” involved such revelations as

“ This edit [43] will be reverted because you copied and pasted material from one article into another. The problem with this edit is that it is not relevant to the stub and the material is completely out of context in this article. You are unwittingly using the notation of Hopf algebras but don't seem to have a clue that you're doing so. If you continue editing tendentiously like this you are probably heading for quite a long block. ” — Mathsci (talk) 07:01, 30 June 2009 (UTC), (full discussion)

It is so similar to the infamous conflict of 2013 that one can note: some things really “very little changed then”. Incnis Mrsi (talk) 10:42, 22 May 2013 (UTC)

From what I remember, in 2009 five mathematical administrators, including three arbitrators or former arbitrators, Charles Matthews, Paul August and YellowMonkey, commented on the ineptness and naivity of Echigo mole/A.K.Nole's attempted edits to mathematical articles. Little has changed since then except that he is a now a community banned sockpuppeteer with a history of lying on-wiki and attempted outing. A.K.Nole's edits to Minimal subtraction scheme were rather typical of the way he edits. Those edits were the usual copy-pasting using text by me with no intermediate understanding. The nature of his disruption was clear enough to administrators then and, after over 250 sockpuppets/ipsocks, it is not in dispute now. His edits related to Jordan algebras are uniformly poor. But per WP:BAN he cannot edit. You could argue with the checkusers, I suppose. I cannot guarantee that they or any administrators would take it seriously. Mathsci (talk) 11:46, 22 May 2013 (UTC)

Anyhow, back to the point. Even though the original posting was inappropriate, we hope you have learned something about the community's evaluation of your behavior. Continuing to pretend that throwing a CANVASS flag invalidates any recommendation toward you would be a transparently antisocial thing to do. We all want a cooperative, productive environment, and not chronicles of your epic feud mixed with wikilawyering. Rschwieb (talk) 17:49, 22 May 2013 (UTC)

J-structure

This article has been effectively blanked by being redirected to Jordan algebra, which fails to explain the (close) connection, and indeed does not currently even mention "J-structure". It is not quite clear whether the article was deemed to be "trolling" because it was already known for some other reason that Gongfermor (talk · contribs) as a banned user: or whether the article as assessed as defective in itself: or indeed whether the article is good but must be deleted as being by a banned user. In any event there seems to be a risk that good content may be lost. Are members of the Mathematics Project able to assess the content as composed by Gongfermor and rescue anything worth preserving? Tautological tau (talk) 17:14, 22 May 2013 (UTC)

Now we have a problem here. As you are the same person as a previously banned user, Echigo mole (see [44]) the policy laid down in WP:BAN applies. In particular the ban applies to all alternative usernames that is sockpuppets. Further Bans apply to all editing, good or bad and Anyone is free to revert any edits made in defiance of a ban, but note This does not mean that edits must be reverted just because they were made by a banned editor.

So as things stand all your edits are in breach of a ban and carry very little weight. Your edits will most probably be reverted, entirely within wikipedia policy. In essence your fighting a loosing battle. Options available: carry on as before, with a continuing round of alternate usernames swiftly blocked and edits swiftly reverted. Or you could walk away find another venue where your contribution will be greeted with more respect, perhaps mathoverflow. The third option is the hardest - a modification of the ban allowing some editing of wikipedia. This would involve discussion on the admin noticeboard WP:AN which might not be very friendly and would probably involve an interaction ban with mathsci and a topic ban on Jordan algebra and related articles. Due to the long history of sockpuppets I'm not very optimistic it would suceed.

As to the mathematical content of J-structure I don't know enough on the topic to judge, only that they do exist and are closely linked to Jordan Algebra. As I can verify the article and the edits are from a banned user a redirect seems an acceptable solution.--Salix (talk): 20:46, 22 May 2013 (UTC)

Is there any reason to believe that User:Gongfermor is a banned user other than one editor's private opinion, based on the unsupported assertion that his work on J-structure is "nonsense"? An authoritative opinion on the value of that article would be useful. Coal scuttle (talk) 21:32, 22 May 2013 (UTC)

Above user now added to SPI.--Salix (talk): 22:18, 22 May 2013 (UTC)

I am surprised that Salix alba is able to be so positive that User:Gongfermor is a ssockpuppet of a bnned user, if he is unable to judge the value of his only contribution. I have stated elsewere why I believe that Mathsci's crtitique of the article was over-hasty. However, these games with puppets and bans are not as important as the mathematical content of the encylopedia, so let us return to the question as posed above, which seems to be worth discussing. Irrespective of the status of the author, are members of the Mathematics Project able to assess the content as composed by Gongfermor [45] and rescue anything worth preserving? Coal scuttle (talk) 06:10, 23 May 2013 (UTC)

I believe WP:DENY is best, but WP:ROPE is also good, so let me violate the former to offer the latter. Wikipedia is an encyclopedia—there is no promise of fairness. Pursuing agendas against other editors is not tolerated because it causes too much disruption to the encyclopedia. If you want to contribute at Wikipedia, you must follow what Salix said—undertake to never mention the other editor and completely avoid all articles where the other editor contributes. User:Elen of the Roads (when an arbitrator) offered to hear your side of the story (search here for "23:35, 10 November 2012"). People are willing to consider any situation providing there is a potential for benefit to the encyclopedia (hint: pursuing another editor would not benefit the encyclopedia). The purpose of this message is to determine whether there is an interest in the encyclopedia, or whether editing is directed towards a particular editor. Johnuniq (talk) 10:45, 23 May 2013 (UTC)

On reflection, this is the right way to go. Apologies to all for the disruption. A.K.Nole (talk) 16:29, 24 May 2013 (UTC)

A discussion on the standard offer is underway at Wikipedia:Administrators' noticeboard#Standard offer for User:A.K.Nole. Input regarding the precise topic areas to be covered is particularly welcome.--Salix (talk): 20:28, 24 May 2013 (UTC)

Protection of this talk page

A good move, but the person in question probably has several sleeper accounts, which are able to pass through. This technical solution is insufficient: we now have eliminate all his accounts one by one, which will not leave him other options but to negotiate unban or to cease activity. Incnis Mrsi (talk) 06:48, 23 May 2013 (UTC)

I disagree with the protection of this page. As the recent edit by the now blocked Coal scuttle shows, protection is likely to have little effect on sockpuppets, while preventing legitimate use of this talk page by accounts that are not autoconfirmed. Sławomir Biały (talk) 23:52, 23 May 2013 (UTC)

I'd like to let it stand for a couple more days. Johnuniq has explained the WP:Standard offer on his talk page. Should the person wish to accept he can comment there and normal service can be resumed. But we do need to make it clear banned users are banned from editing and technical means will be used to enforce the ban.--Salix (talk): 05:55, 24 May 2013 (UTC)

I'm pretty certain the page protection is useless against this one. I fully agree that for sockpuppets like this they should be checked by checkuser and banned as soon as encountered. There is no point standing up for them because they do something that looks okay. Their overall effect is malign, they are a cancer on Wikipedia. Standard offer is a good because people do grow up, but as to this one whatever about their own idea of their competence I'd sooner use the results of predictive text statistics from maths books or text from my latest favorite site Mathgen. Dmcq (talk) 10:09, 24 May 2013 (UTC)

Awesome link :) If you have any passing interest in Python programming language, then I should also let you know about the Kant Python generator which produces similarly amusing bits of Kantian prose... Rschwieb (talk) 14:50, 24 May 2013 (UTC)

Protection now removed. If the user is willing a thread to discuss the WP:Standard offer on WP:AN will start soon. I'll let people know when it does.--Salix (talk): 19:21, 24 May 2013 (UTC)

Unfortunately there has been so much abuse, including the problems around WP:ARBR&I where Echigo mole/A.K.Nole inserted themselves to manufacture disputes on wikipedia, that any attempt to reverse a community ban for WP:LTA is unlikely to have approval from the arbitration committee. People commenting here are unaware of the disruption created by this user. With the account A.K.Nole they have reported a small number of sockpuppets that have already been identified, some not necessarily so far connected with this user (who signed himself "Alex" at one stage when using the shared account The Wiki House). The account Junior Wrangler was tagged as him (he admits to it now). The creators of hoax articles on Aix-en-Provence were identified as him (Silver starfish, Nellie Seamonster, etc.). Just this week he claimed as Ultra snozbarg that he was not Echigo mole but a good faith mathematics editor. But this article in gestation tells a different story.User:Euston arch/sandbox There he mentions "snozbarg" and has links to two of the now deleted hoax articles. A few years back he had email discussions as Quotient group with Shell Kinney, who was on the arbitration committee at the time. He similarly committed himself to not following my edits. But that did not last very long. He has no mathematical skills at a post-graduate level. Recently he simply copied formulas mindlessly from Springer's book on Jordan algebras into an "I want to show that I can edit like Mathsci" article. He did the same thing in the subject of Jordan operator algebras. Not even capable of copying one formula properly because he lacks the intellectual capacity to understand the subject. That kind of "mathematical trolling" is of no benefit to this encyclopedia at all. A normal editor, for example a graduate student doing a Ph.D. in pure mathematics, might have added a sentence written by a known expert (e.g. Kevin McCrimmond) to the main article Jordan algebra. But in this case Echigo mole was not bright enough to figure out that Springer had used Hua's identity (Jordan algebra) as his own personal way of developing the subject, etc, as part of the theory of algebraic groups. But that and the advantages/limitations of Springer's approach are all spelled out in great detail in McCrimmond's writing.

But more seriously Echigo mole has created accounts with my street address Rue Cardinale and has inserted information identifying me in RL on user talk pages, in some cases to users that are now site-banned. Those outing edits are inexcusable. Echigo mole has now admitted to sock trolling in a 2009 arbcom case in which I commented (Abd & WMC). That was first of many such interventions.

So A.K.Nole was given the benefit of the doubt by Shell Kinney and almost immediately abused that. He has caused too much disruption to get a third or fourth chance. His edits to articles on Jordan algebras were senseless: editing completely outside his level of WP:COMPETENCE. His intention just recently was to create a malaise on wikipedia, i.e. a toxic editing environment. The arbcom-related edits are very serious and cannot really be discussed here. They were purely malicious and inflammatory. That is why any attempt to undo a community ban of Echigo mole cannot be at the initiative of this small WikiProject. There are arbcom motions concerning Echigo mole, so a clean start is not possible. The correct place to ask is Wikipedia:Arbitration/Requests/Clarification and Amendment.

BTW from 22-25 May I was in intensive care in the cardiology unit of my local hospital, so could not comment until now. Mathsci (talk) 05:57, 26 May 2013 (UTC)

Get better soon. It is shocking how much disruption a single Mole can create. His abuse of the personal physical address of a fellow editor, if confirmed, is intolerable, and may even be of interest to the police. I invite all WPM participants to express solidarity with User:Mathsci and appreciation of his efforts to contain the said Mole. Tkuvho (talk) 07:43, 26 May 2013 (UTC)

Solidarity with a user talking of anything but the A.K.Nole peril and actively disrupting attempts to negotiate a solution as recently as 5 hours ago, against a (former) puppeteer who apologized for his disruption and is not engaged in any disruption for more than two days? It would be better to wait for a further development of this drama, rather that to express a unilateral support while the situation remains strongly ambiguous. Incnis Mrsi (talk) 08:30, 26 May 2013 (UTC)

Seemingly it was yet another sockpuppet of Echigo Mole raised the sockpuppet investigation against A.K.Nole so that was dismissed. A.K.Nole has accepted an offer which includes staying away from Wikipedia for six months before trying again. Whether they are or are not related and whether I have got that right or wrong, I really think it is best to let the appropriate admins check the possibilities and get on with the process rather than standing up for people identified as having caused disruption. Dmcq (talk) 12:17, 26 May 2013 (UTC)

(edit conflict) His cumulative conduct is unacceptable. Any kind of "apology" at this stage is meaningless: there is no wikipedia code of "apologies," particularly from users known to lie, as is the case with Echigo mole. The account A.K.Nole (talk · contribs · logs · block log) has now been blocked indefinitely by a checkuser. His sockpuppets created the now-deleted hoax articles Baldock Beer Disaster, Letchworth Corset Riot, Robert de Baldoque, La Maison du Guozbongleur, Guozbongleur, John Bargel and Gustave de Zarbouble. His sockpuppets, 20 or more of them, put nonsense into the article The Bulldog. As Keystone Crow (talk · contribs · logs · block log) he cobbled together this idiotic RfAr, immediately nuked by an arbitrator.[46] His agenda has been malicious and he has told blatant lies just in the last few days. He has pretended to have a knowledge of advanced mathematics. What he actually knows goes little beyond service mathematics courses for an undergraduate degree in computer science. Classic WP:NOTHERE. Incnis Mrsi should make his arguments directly to the arbitration committee or other checkusers, not here. Nothing stated by Echigo mole can be taken seriously after what he claimed as Ultra snozbarg (talk · contribs · logs · block log). No different from his dishonesty as Quotient group (talk · contribs · logs · block log). Empty promises. Mathsci (talk) 12:40, 26 May 2013 (UTC)

I think only time will tell if the user has reformed. We should wait six months and review the situation then. The WP:AN discussion was perhaps a bit premature as it should really happen after the six month break, but I felt it appropriate to tell the community what had happened. There are signs that the user is serious, the apologies, the revealing of past socks and the use of the original account which has gone unused since 2009. I hope the user respects the six month break and we have a quite size months, without edits from A.K.Nole or sockpuppets. --Salix (talk): 13:01, 26 May 2013 (UTC)

I cannot see anything happening this year or any time soon. Perhaps in 2015. Here is another hoax article connected with towns between Cambridge and London: Hitchin Signpost Case. Why campaign for a disruption-only community banned user who has his very own arbcom motion related to that disruption. And all these hoax articles. Many sockpuppet accounts remain undeclared (e.g. for 2010). The earliest known edits by Echigo mole using an IP are here.[47] Mathsci (talk) 13:17, 26 May 2013 (UTC)

I think it's best just to report them when you notice. The aim of a troll is to annoy and disrupt so one just has to try and avoid getting worked up. Any more use of Wikipedia by them in that time automatically restarts the period at the very least even if not disruptive. Dmcq (talk) 13:28, 26 May 2013 (UTC)

Help with an issue at Articles for Creation

Please take a look at WT:WikiProject Articles for creation#Optimum strategy for dealing with the backlog - can it be mathematically analysed and could such analysis give a meaningful/useful answer? Roger (Dodger67) (talk) 07:23, 26 May 2013 (UTC)

From the replies in that section, it seems that any mathematical model of the process one would create, probably based on queueing theory, would give different answers depending on what you are trying to optimize. If you are trying to minimize number of backlogged articles, filtering obvious cases at the front will reduce numbers quickly. If you are trying minimize the wait that users endure, is that the average wait time or the maximum wait time? If maximum, then concentrating on the oldest articles makes sense. The strategy used in hospitals and airline counters is a triage stage, followed by first come, first served for the more difficult cases. --Mark viking (talk) 16:22, 26 May 2013 (UTC)

Partial recursive functions are recursively enumerable : true or false ?

More details here: Talk:PR (complexity). --Gzorg (talk) 14:45, 27 May 2013 (UTC)

"Dassund analysis of time series"

Should this new section be a whole section of this relatively short article? Michael Hardy (talk) 04:20, 30 May 2013 (UTC)

Surely not. Boris Tsirelson (talk) 05:07, 30 May 2013 (UTC)

I removed it. There are no relevant google hits for Dassund and "time series". It seems to have been made up. The new section also completely lacked sources, and bore some of the earmarks of original research (such as an irrelevant bio of Joseph Dassund, assuming that this is even a real person). Sławomir Biały (talk) 13:14, 30 May 2013 (UTC)

Stack (mathematics)

In this edit, an article got moved to Stack (mathematicis), with a typo in the last word, which was made to end with "-cis". So I tried to move it to Stack (mathematics) and found that that redirected to a section in another article. I deleted that and did the move; then I restored the edit history of the deleted article, so the two edit histories are now merged. If you look at the edit history of the one that was a redirect, you see that at one point it was a disambiguation page. So if this article is kept under its present title, should we have some disambiguating hatnotes at the top? Michael Hardy (talk) 18:39, 30 May 2013 (UTC)

....and now I've added one disambiguating hatnote. Michael Hardy (talk) 19:14, 30 May 2013 (UTC)

Translations from German

I just did some copy-editing on the new article titled Gerhard Huisken.

New articles created by translating articles from German Wikipedia are not infrequent. Here's a strange thing about them: It seems as if in almost every such case, one thing left untranslated looks like this:

Bd. 45 S. 311–402

It could be translated thus:

volume 45, pages 311–402

I've seen this even in numerous cases where articles written in English were cited.

Something a bit less strange is things like this:

John Smith (* 1950) was a mathematician who . . . . .

I wonder how many readers of English Wikipedia would know immediately what the asterisk means? In an article about a deceased person it would say

Leonhard Euler (* 1707 † 1783) was a Swiss mathematician . . . . .

The seeming near universality of the non-translation of volumes and pages seems a bit puzzling. Michael Hardy (talk) 19:13, 30 May 2013 (UTC)

Jun 2013

Mathematician categories

As I was adding some Category:Women mathematicians into non-gendered parts of the tree, I noticed that Category:American mathematicians, and several others, have by-century trees, but that are sparsely populated. What would think about making those century trees (like Category:20th-century American mathematicians diffusing on the head category, and move all mathematicians into those trees, by century, out of the head cat? Something similar was done recently at Category:American novelists (though there is still some controversy about it). What about here? If not, I might suggest otherwise to delete those cats, as having them as non-diffusing is a bit non-standard (by-century cats are usually diffusing elsewhere in the tree). Best --Obi-Wan Kenobi (talk) 23:24, 21 May 2013 (UTC)

Any thoughts? --Obi-Wan Kenobi (talk) 16:33, 3 June 2013 (UTC)

Yurii Reshetnyak

The new article Yurii Reshetnyak has been proposed for deletion under WP:BLPPROD. Reshetnyak is a very influential figure in geometric analysis and mathematical elasticity. We should have an article about him, even if it's only a stub. Unfortunately most biographical sources appear to be in Russian. Please help to improve the article! Sławomir Biały (talk) 23:02, 2 June 2013 (UTC)

Six operators

The new article titled Six operators definitely needs work! Including links, context, and some explanation of the role and importance of the concept. Michael Hardy (talk) 21:38, 4 June 2013 (UTC)

L. E. J. Brouwer

Someone moved Luitzen Egbertus Jan Brouwer to Bertus Brouwer. I've always heard him called L. E. J. Brouwer, and I'd never heard Bertus Brouwer before. I've moved it to L. E. J. Brouwer. Michael Hardy (talk) 21:59, 4 June 2013 (UTC)

Disambiguation help needed.

Greetings! Expert mathematical help is needed in determining the correct targets for links to the following disambiguation pages:

1. Facet (mathematics) and Facet (geometry) both redirect to Facet (disambiguation), for a total of 138 links.  Done D.Lazard (talk) 16:31, 3 June 2013 (UTC)
2. Normed algebra: 24 links
3. Sum of squares: 18 links
4. Lie bracket: 17 links
5. Primitive polynomial: 17 links  Done D.Lazard (talk) 09:41, 3 June 2013 (UTC)
6. Simple root: 17 links  Done Mark M (talk) 12:55, 3 June 2013 (UTC)

Please also double check to make sure that these terms are indeed ambiguous, and are not susceptible to being presented in a substantive article as a topic an and of themselves. Cheers! bd2412 T 00:18, 3 June 2013 (UTC)

I got to ask: why is Lie bracket a disambig page? Not just a redirect to Lie algebra. (maybe I don't have a good perspective.) -- Taku (talk) 00:54, 3 June 2013 (UTC)

"Lie bracket" by itself is often used to refer to the Lie bracket of vector fields. Although a disambiguation doesn't seem to be necessary. We can do that with a hat note or, even better, mention the algebra of vector fields in the lead of the Lie algebra article, with a link to the relevant notion of Lie bracket. Sławomir Biały (talk) 03:04, 3 June 2013 (UTC)

I agree, per WP:TWODAB; so I redirected Lie bracket to Lie algebra, and put a hatnote. Though the Lie bracket of vector fields is also mentioned later in the article, so I'm not sure if a hatnote is even necessary. Mark M (talk) 08:27, 3 June 2013 (UTC)

Thanks, I appreciate the solution. bd2412 T 12:04, 3 June 2013 (UTC)

For Simple root, there is a strange situation: All articles linking to this dab page are intended for the meaning in group theory (root system), while, IMO, for most people the main topic refers to a root of a polynomial. Both links of the dab page are redirects to sections. Thus I suggest to redirect Simple root to Polynomial#Solving polynomial equations (the target of Simple root (polynomial)) and to add a hatnote to the target section. I believe that it will be more useful for the readers than the symmetric action, which would need less editing work. D.Lazard (talk) 09:41, 3 June 2013 (UTC)

Incoming links can be a tricky indicator, since editors may link to an article merely because it is the existing target, rather than being a primary topic. If "real world" sources on the internet and in print indicate that Polynomial#Solving polynomial equations is the primary target, then this can be redirected per WP:TWODABS. Ideally, a disambiguation page should only exist if there are too many meanings of a term to fit neatly into a hatnote, or if the few meanings that do exist are in equipoise. Cheers! bd2412 T 12:08, 3 June 2013 (UTC)

Okay, I've fixed all of the incoming links to Simple root, and sent all but one to Simple root (root system) (which is a redirect). Only one incoming link was actually intended for Polynomial#Solving polynomial equations, which is where Simple root is now redirected. Mark M (talk) 12:55, 3 June 2013 (UTC)

I have moved the geometric content of Facet (disambiguation) to Facet (geometry), which is now a stub, and redirected Facet (mathematics) to Facet (geometry). There is no reason to tag Facet (geometry) as a dab page, because the different meanings are strongly connected, and a part of the content does not appear elsewhere. D.Lazard (talk) 16:31, 3 June 2013 (UTC)

Fantastic! That leaves only Normed algebra and Sum of squares in the top 500 disambiguation pages. bd2412 T 17:25, 3 June 2013 (UTC)

BTW, I did not find [48] a good move. Unfortunately there are some users who say: if this is a dab page with inbound links, then let us… to disguise a dab page as an article, and disambiguators become happy. I do not think it improves an encyclopedia. Moreover, Bubka42’s edit actually concealed the Normed associative algebra red link which, unlike the current piece of crap, could be a valid encyclopedic topic. May I revert this? Incnis Mrsi (talk) 09:59, 6 June 2013 (UTC)

The over-riding question is whether there is a topic here that is capable of being discussed as an article, or whether there are merely a collection of unrelated terms that happen to share the same name. So far as I can tell from the previous version of the page, there are no title matches at all. It is not as though there is an album titled "Normed Algebra" and bird called the "Normed Algebra" and a person named "Normed Algebra" in the mix. "Normed associative algebra" and "Normed division algebra" are partial title matches, and are therefore not ambiguous to one another. What is left, then, but a single mathematical concept which is merely applied in different ways? bd2412 T 13:24, 6 June 2013 (UTC)

I don't think that your original dab page was truly a disambiguation page either. A normed algebra after all is an algebra with a norm. So the links there were all topics related to this. So I'd suggest reverting the edit if you like, but removing the disambiguation template. Sławomir Biały (talk) 13:51, 6 June 2013 (UTC)

A dab or a stub, but “normed associative algebra” is a more concrete structure which the (ambiguous) wording “normed algebra” usually, but not always, denotes. Recent edits plays this circumstance down. And in any case… fix what occurred at Normed division algebra (edit | talk | history | links | watch | logs), please. I hoped to fuse two dabs into one, but if there is no support for it, then it would be better to restore its original tiny dab page or do something else but redirecting to a strange stub. Incnis Mrsi (talk) 15:23, 6 June 2013 (UTC)

I note that neither Gelfand–Mazur theorem nor Hurwitz's theorem (composition algebras) mention the term "Normed division algebra", which means that they can not be included on any disambiguation page for the unmentioned term (see WP:DABMENTION). To the extent that the phrase "Normed division algebra" is used with respect to either article, it must be discussed in that article before it can be included on a disambiguation page, because disambiguation pages only disambiguate content that is already in the encyclopedia. Without that restriction, we could not be sure that the disambiguation page itself is strictly reporting notable uses. However, since those are the only two links claimed to be associated with the exact phrase, "Normed division algebra", WP:TWODABS also applies. Why not redirect Normed division algebra to whichever of those two links is more likely the primary topic of the term, with a hatnote pointing to the other link? (I take it no one would look for Banach algebra or Composition algebra under the name "Normed division algebra"). bd2412 T 15:40, 6 June 2013 (UTC)

This is because you are preoccupied with a formal (link-structural, mention rules, etc.) well-being of Wikipedia, not semantic one, and push forward your “WP:TWODABS” on any pretext or even without one. If there is no clear WP:PRIMARYTOPIC, then do not enforce your dreams that there should be a primary topic. Let experts to decide it, please. There will be numerous links to a dab and you will be slightly unhappy, but eventually it would be better for readers, believe me. Incnis Mrsi (talk) 17:01, 6 June 2013 (UTC)

If there are distinct and different topics, then it should be no problem to fix the links themselves, so that they point to the intended article, and not to a disambiguation page. Remember, disambiguation pages are a means to an end, not an end in and of themselves. They exist to clear up confusion where a term can mean different things, and should not exist if this confusion can be cleared up without creating an extra page to do it. bd2412 T 17:05, 6 June 2013 (UTC)

Ambox-throwing to sections

Jarble (talk · contribs) (notified) was already well-known to me thanks to his “interesting” work with redirects. Recently he turned attention to mathematics, where can see:

1. Placing {{unreferenced section}} to Real number #Properties section, which unlikely contains anything beyond textbooks on mathematical analysis;
2. Cluttering Quotient ring #Examples with {{unreferenced section}} and {{original research}}(!)

Of course, there may be original researches in mathematical articles, but unlikely a reasonable person could claim that a section consisting of disjoint examples, most of which can be found in textbooks, is an WP:original research. Does anybody think that these edits actually helps to improve 10 affected articles? Incnis Mrsi (talk) 06:14, 6 June 2013 (UTC)

These unreferenced sections should be verified by external sources, if possible. I found several lengthy unreferenced sections, and decided to tag them as needing additional references. Adding additional references to these sections would be helpful to readers, since it would enable them to confirm the validity of the statements that are made. Jarble (talk) 06:26, 6 June 2013 (UTC)

How this makes the list of examples an original research? And how do you imagine an intended “externally verifiable” Real number #Properties where most statements are backed by hundreds of textbooks? A dozen of <ref>s on each statement? With page numbers for each instance, or only a chapter name/number? Incnis Mrsi (talk) 06:39, 6 June 2013 (UTC)

I noted a similar phenomenon at Transcendental number#Sketch of a proof that e is transcendental. The section begins We will now follow the strategy of David Hilbert and ends For detailed information concerning the proofs of the transcendence of π and e see the references and external links. In the references, the first item is David Hilbert, "Über die Transcendenz der Zahlen e und $\pi$", Mathematische Annalen 43:216–219 (1893), which is precisely to the point. It seems clear that the section is adequately supported by a reliable source and that any reader would be able to identify the source being relied on. Spectral sequence (talk) 06:42, 6 June 2013 (UTC)

In that case, an inline citation to that particular article should be added to the section, using the <ref> tag. Jarble (talk) 06:55, 6 June 2013 (UTC)

Pointing out what is hopefully obvious: inconsistent citation style and lack of references are two different things. In this case, there was a reference and a citation to that reference contained in the text. If you don't find the citation adequate, then WP:SOFIXIT becomes an issue. Sławomir Biały (talk) 13:20, 6 June 2013 (UTC)

It is not necessary to give citations for each individual statement in an article provided the material is uncontroversial and widely available in general sources. For such kinds of information, general sources are sufficient. WP:SCICITE has more details about this. The "original research" tag pointed out above is obviously ridiculous. Very likely all of these examples will appear in either the textbook referenced by Lang or the textbook by Dummit and Foote. It seems to me that the onus is on the person placing the template to check the references, and I think there is little likelihood that this happened here. I don't really think that these kind of templates in general improve articles. It's more likely that a {{fact}} tag here or there, preferably accompanied by an explanation on the discussion page, will lead to a reference. The placement of large and disruptive templates to articles seems to have more to do with social psychology than with encyclopedia building. Sławomir Biały (talk) 13:44, 6 June 2013 (UTC)

Those tag-tacking edits should be undone. Mct mht (talk) 16:04, 6 June 2013 (UTC)

For a section with uncontroversial knowledge, WP:SCICITE#Uncontroversial knowledge recommends a citation or two for the entire section, often placed in or after the first sentence. So if a section is completely unreferenced, is it within policy guidelines to ask for a citation for the section, but it is also easy to fix this problem. Such a citation can show a reader where to find more information about a section topic; doing so is in my opinion an important part of encyclopedia building. --Mark viking (talk) 10:46, 8 June 2013 (UTC)

Actually it's sufficient to provide a general reference for an entire article. It isn't strictly necessary to have footnotes to the general references in each section. Most (all?) of the articles under discussion include such references already. I do think that citations generally improve the overall quality of the articles, but I disagree very strongly with the application of templates to enforce what is actually just a style issue (especially templates placed without any discussion on the talk page). Sławomir Biały (talk) 12:55, 8 June 2013 (UTC)

Where is the policy that it is sufficient to provide a general reference for an entire article? Again, WP:SCICITE says this is fine for articles of a few sentences, but longer articles should have citations. I agree with you about the drive-by tagging; when I see uncited sections where the material seems fine and I want to know more, I usually either contact the dominant editor, if there is one, or I post a query on the talk page. --Mark viking (talk) 19:21, 8 June 2013 (UTC)

WP:SCICITE specifically says that general references are adequate when most of the content of an article appears in multiple general sources (e.g., textbooks on the subject), regardless of article length. It may be appropriate in some cases to include a citation in the section, the lead of the article, or in a list of references at the bottom. This has all been standard practice in mathematics articles for a long time. Sławomir Biały (talk) 20:39, 8 June 2013 (UTC)

In general examples should not have original research tags stuck on them because they are counted as illustrations and come under WP:PERTINENCE. They may be made up by an editor and don't need citations however if so they must not bring in any new ideas but simply be an obvious demonstration of what has been said around them. Any new idea in them would of course be subject to the verification policy. For instance if in the addition article we say 5+7 is an addition giving the result 12 that does not need a citation showing an example of 5 and 7 being added. Citations can be good if people want to follow up but that is not the purpose of an example. If someone thinks an example is not straightforward from what has been said then a citation can be called for but sticking in block tags is not the way to get clarification of an example. After all one can always say an illustration doesn't seem right but you don't put in tags saying all the images in an article need citations. Dmcq (talk) 13:38, 8 June 2013 (UTC) +WP:IUP we must not copy peoples examples straight as they are copyright even if they involve mathematics. Dmcq (talk) 13:53, 8 June 2013 (UTC)

Parity of zero is up for peer review

Wikipedia:Peer review/Parity of zero/archive1

That's right, folks, I'm getting back on this horse. Please feel free to chime in! Cheers, Melchoir (talk) 22:17, 8 June 2013 (UTC)

Long-time requests

Looking at the dates embedded in Wikipedia:Requested articles/Mathematics, I see there are some 40 requests dating back to 2005 and one to 2004. Perhaps we should try to clear the backlog? For reference, they are listed below. Spectral sequence (talk) 17:15, 3 June 2013 (UTC)

IMHO, this list is obsolete and the best is to destroy it. There are many topics of much larger importance which are not, or badly, described in WP and which deserve to have a much higher priority, like Multivariate resultant or D-finite function. D.Lazard (talk) 17:59, 3 June 2013 (UTC)

The traditional approach would be to archive very old entries. Charles Matthews (talk) 15:17, 9 June 2013 (UTC)

Calculus of variations

• Deformation theorem

Category theory

• Atomic topos
• Coquasitriangular Hopf algebra
• Ribbon category
• Semi-abelian category (with redirect from Semiabelian category)

Coding theory

• Coding lemma -

Convex analysis / Optimization

• Constrained conjugate gradient / Conjugate gradient with barriers (how does the barrier effects the conjugate gradient solution) -
• Waterfilling theorem -

Cryptography

• Multilinear modular hashing

Differential geometry and topology

• Natural bilinear concomitant -

Dynamical systems

• Zeeman catastrophe machine -

Functional analysis

• Codistribution -
• Convenient analysis -
• Nonlinear operator theory -

Geometry

• Diametral circle
• Diametral lens

Graph theory

• Intrinsically linked graph
• Restriction scaffold problem

Group theory

• Recoupling theory

History of mathematics and other cultural aspects

• Etymology of mathematical notation —

Lie groups, Algebraic groups / Lie algebras

• Primitive invariant -

Mathematical analysis

• Percent recovery

Algebraic number theory

• Brandt module -

Numerical analysis

• Model order reduction -
• Nested dissection algorithm -

Order theory

• Continuous poset -
• Ideal completion -

Probability theory

• Bayesian mapping -
• Luders rule -
• Marked point process -
• Threshold function and their relation to combinatorics/graph theory, number theory, etc. -

Real analysis

• Maharam theorem -

Statistics

• Burstiness -
• Gap statistic -
• Ryan Einot Gabriel Welsch method -
• Tukey B method -

Topology

Algebraic topology

• Witt space -

General topology

• Contiguity space -
• Double fibration -

Uncategorized

• Dynamic subtraction -
• Eigenfilter -

Transformed redirect Cartesian tensor into an article

This should be an article. Cartesian tensors are the first approach to tensors and index notation (at least in my experience).

I wrote this from the perspective of someone with a firm grip on basic vector algebra, and some possible exposure to linear algebra and tensor index notation, but not lots, so there is some preamble on notation and terminology.

It is hoped to bridge the gap between basic (Gibbsian, as it were) vector algebra and tensor analysis.

Feel free to complain about the potentially trillions of typos, or anything, on the talk page and we can improve the article.

There is room for more sections and expansion also. M∧Ŝc²ħεИ_τlk 23:56, 8 June 2013 (UTC)

Could you explain better what does it mean: a tensor in an Euclidean space? There is no such thing as a “tensor which exists in Cartesian coordinates” because a tensor must have a representation in any basis, by its very virtue to be a tensor. Incnis Mrsi (talk) 09:43, 9 June 2013 (UTC)

Fixed, any more specific inaccuracies please take it to the talk page. M∧Ŝc²ħεИ_τlk 09:56, 9 June 2013 (UTC)

Links to fractional-order system

Fractional-order system is a new article. No other articles link to it. Creating some links to it from other articles, and other work, should get done. Michael Hardy (talk) 18:15, 9 June 2013 (UTC)

Sorry if it is a dumb question, Chaos in fractional order system is another new article. Should they not be merged? Solomon7968 18:24, 9 June 2013 (UTC)

Perhaps. Michael Hardy (talk) 19:05, 9 June 2013 (UTC)

Merged. No significance to the example, so I removed it. It might be required to determine whether the statement makes any sense, even if there is insufficient information in the reference to locate it. — Arthur Rubin (talk) 19:49, 9 June 2013 (UTC)

Proposing a merge into fractional dynamics; same subject, that's almost an orphan, as well, but it's better-connected. — Arthur Rubin (talk) 20:59, 9 June 2013 (UTC)

Equality, identity and equation

I have recently rewritten the leads of equality, identity and equation. Before my edits, none of these articles contained any understandable definition of their topic. Instead, either they were too technical (introduction of Peano and extensionality axioms in the first line of the lead) or they contained silly assertions like "An identity is a relation which is tautologically true" or "An equation, in a mathematical context, is generally understood to mean a mathematical statement that asserts the equality of two expressions". Editing these leads, I was faced with the problem of lacking of sources providing general definitions of these basic concepts. In fact, they are too difficult to be accurately defined in elementary textbooks. And more advanced studies, such as in mathematical logic, usually deal with only one aspect of these questions.

Therefore I have tried to write down what I believe to be commonly meant by these words. But I may have omitted some important aspect. More important, the lack of convenient sources makes that a consensus is needed on these fundamental questions. Also, I have not edited the bodies of these articles which need also some attention. D.Lazard (talk) 10:15, 8 June 2013 (UTC)

Your edits were partially wrong. An equation does not differ from an equality, it uses the equality binary relation but has a sense different from that of an identity. An (equality-based) identity is a statement of the form ∀⋯: F(⋯) = G(⋯), where F and G are terms, which must be a theorem in certain theory. An equation is a predicate expression of the form F(⋯) = G(⋯) on one or more variables with the equality as the upper (outer) logical relation, and is not a theorem. Incnis Mrsi (talk) 10:44, 8 June 2013 (UTC)

While "equality" may merely mean that two expressions happen to have the same value (extensionally), "identity" is usually taken to mean that they have the same meaning (intentionality). That is, two things are identical if they are necessarily equal, not merely contingently equal.

Equality is characterized by reflexivity and the substitution property of equality. The substitution property implies symmetry and transitivity among other things. However, the article on equality (mathematics) misstates the substitution property as "For any quantities a and b and any expression F(x), if a=b, then F(a)=F(b).". The correct statement would be "For any quantities a and b and any predicate P(x), if a=b and P(a), then P(b).". JRSpriggs (talk) 12:18, 8 June 2013 (UTC)

This explanation is quite enlightening. Sławomir Biały (talk) 12:43, 8 June 2013 (UTC)

Intention and contingency have their own hard to pin down philosophical definitions. From the point of view of mathematical logic, are you saying that identity is like logical equivalence, something that holds in all models, and that equality is more like material equivalence, which is model-dependent? Thanks, --Mark viking (talk) 18:59, 8 June 2013 (UTC)

First of all, I think the desired word is intension, not intention.

I don't really agree with either JR or Incnis here. Two objects are identical just in case they are the same object; necessity or contingency doesn't enter into it, and axiomatic theories still less (Incnis's claims seem to assume a formalist POV). There is an older usage whereby two expressions are said to be "identically equal" if their values are equal for all values of the free variables, whereas just saying they're "equal" may leave open the possibility that you have a particular set of values in mind for the free variables, and the values are equal for that particular assignment. But this is mostly a convenience in exposition, and shouldn't be overinterpreted. --Trovatore (talk) 19:46, 9 June 2013 (UTC)

As a non-expert in these things, I found your version of the leads to be clear and easy to read. Leads are necessarily summaries and approximations of main articles; I don't think one can address all the mathematical and philosophical subtleties of these concepts in a lead, keep a lead short enough for MOS, and keep a lead understandable for non-experts. Equivalence may be a related concept to deal with. --Mark viking (talk) 19:12, 8 June 2013 (UTC)

I have some concerns about them, frankly.

The first point is cosmetic: The changes use boldface repeatedly, which is contrary to Wikipedia style. The article title, and synonyms redirected to it, should be bolded at first occurrence, but not thereafter. Similarly, be careful of WP:OVERLINK.

More substantively, I doubt that some of the proposed distinctions are really standard, specifically the supposed distinction between equation and equality. The distinction I would make is rather that an equation is a syntactic object, something you can write down, whereas equality is a property or relation. --Trovatore (talk) 21:33, 9 June 2013 (UTC)

I agree with Trovatore. I'm not convinced there is a widely held distinction between "equation" and "equality" (in the same way that "inequality" and "inequation" should probably be merged). I understand there are two uses of two similar words, but I'm not convinced mathematicians (or anyone else) actually use these words in the way described. Mark M (talk) 12:34, 10 June 2013 (UTC)

The difference between equation and equality in the leads seems reasonable to me, at least in common usage. We solve for unknown variables in quadratic or differential equations, and the solutions make both sides satisfy an equality or make both sides equal. Also in computer languages, we test variables or objects for equality, which comes down to determining the truth value of a predicate expression whose variables are already determined or bound at the time of testing. --Mark viking (talk) 15:54, 10 June 2013 (UTC)

Several posts are about the difference, if any, between equation and equality. I agree that opposing them, as in equation is too strong. I am thinking to a better formulation. I agree also that, from a formal point of view there is no syntactic difference between the two notions. But this does not means that they have the same semantic. If the notions would have the same semantic, the two words would be synonymous, and one could find sources talking of the equation $(x+1)^{2}=x^{2}-x+1$, presenting $x^{2}+y^{2}=1$ as the equality of the unit circle or $ax^{2}+bx+c=0$ as the quadratic equality. As these articles are not intended for specialists of formal logic, not even for experimented mathematicians, it is essential to explain the distinction between these two notions that the mathematicians (not the logicians) make in their common usage . And this explanation must not involve high level notions. I have tried to solve this difficult equation :-), but this may certainly be improved. D.Lazard (talk) 18:20, 10 June 2013 (UTC)

I don't think this use of equality as a count noun is very usual. Equality is generally a property; one ordinarily does not speak of an equality at all, and there is certainly no bar against talking about the "equation describing the unit circle". Is it possible that you are being overly influenced by French usage here? --Trovatore (talk) 18:31, 10 June 2013 (UTC)

I think it may be helpful to some readers to draw a distinction between the two concepts.. but I don't see the point in having two separate articles, equation and equality (mathematics). I think this gives the impression that the concepts are more different than they actually are (and the false impression that it is a really important distinction). It think it would be better to explain terminology in a single article. Mark M (talk) 22:17, 10 June 2013 (UTC)

I continue to find this situation problematic. I simply do not believe the purported distinction between "an equality" and "an equation" is standard in English-language mathematics (or, indeed, that it is usual to speak of "an equality" at all). D.Lazard, Mark viking, anyone else who makes this distinction, can you back this up? --Trovatore (talk) 18:23, 12 June 2013 (UTC)

I personally am quite comfortable with the phrase "an equality" as a partial synonym for "an equation", and I am more comfortable with "an inequality" than I am with "an inequation". It seems to me that in good encyclopedic fashion the appropriate thing to do here would be to find one or two reliable sources that either do or do not draw distinctions between these terms, and report on what they have to say, rather than trying to formulate the rules ourselves from scratch. --JBL (talk) 21:43, 12 June 2013 (UTC)

I can believe some sources will use the terms in such a way, but I think the main thrust of the articles should follow common scholarly usage, which I think uses equality primarily as a mass noun rather than a count noun. I agree with you about inequation, a very ugly word that is probably attested somewhere but is definitely not standard. --Trovatore (talk) 21:45, 12 June 2013 (UTC)

You are free to dislike "inequation", but, please, remember that in the context of system of equations solving and real algebraic geometry, both inequation and inequality are commonly used with different standard meanings: $A\neq B$ is an inequation, while $A>B$ and $A\geq B$ are inequalities. D.Lazard (talk) 11:40, 13 June 2013 (UTC)

Can you source that? I do not think the term inequation is really standard at all, in any field. But I don't know all fields of mathematics, so I could be wrong. Oh, MathWorld doesn't count, of course, especially in this sort of case, as it frequently seems to borderline make stuff up in regards to terminology, or at least pull it from idiosyncratic sources. --Trovatore (talk) 16:27, 13 June 2013 (UTC)

Not exactly in reply, but syntactically "inequality" much more resembles "identity" than "equality" or "equation". Sławomir Biały (talk) 18:25, 13 June 2013 (UTC)

In common practice in English-based reliable sources like scholarly articles and books, these terms are in no way interchangeable. In Google scholar, "differential equation" nets 1,810,000 results but "differential equality" nets 593 results. In the other direction, "test for equality" nets 31,300 results but "test for equation" nets get 454 results and most of the first page results are bogus. "Equality predicate" gets 4200 results and "equation predicate" gets 24. --Mark viking (talk) 22:52, 12 June 2013 (UTC)

None of that surprises me. As I said, in my usage, "equality" is a property (or predicate), so it's used as a mass noun. I don't have a problem with treating the property of equality separate from the syntactic object of an equation (or the semantic object of the proposition intended by the equation).

What I don't find convincing is talking about an equality, and distinguishing that from "an equation". It's not implausible that such a distinction could be made, and some authors probably do, but I don't believe it's standard. --Trovatore (talk) 23:52, 12 June 2013 (UTC)

Anatolii Alexeevitch Karatsuba

There is a request for further input at Talk:Anatolii Alexeevitch Karatsuba. Spectral sequence (talk) 21:25, 10 June 2013 (UTC)

New article: Spherical basis

I started it for now. It is incomplete and probably full of typos/inaccuracies, and I intend to finish it soon, but it's been sitting in my userspace for a very long time so for now it's been moved into mainspace allowing others the freedom to edit it, if inclined. M∧Ŝc²ħεИ_τlk 08:30, 12 June 2013 (UTC)

I also redirected spherical tensor, spherical tensor operator, and tensor operator to spherical basis for now. Do people think they should have their own articles? Spherical tensor and Spherical tensor operator makes sense to redirect since the literature seems to explain spherical basis and spherical tensors and spherical tensor operators together. So tensor operator should have its own article? M∧Ŝc²ħεИ_τlk 14:16, 12 June 2013 (UTC)

Would some slightly more concrete examples and material, presumably relating the abstract content you develop to the concrete set of spherical harmonics as perhaps the simplest and well-known such basis, be appropriate? (And then perhaps discussing other possible such concretely-realised basis sets?) Or have I missed the point? Jheald (talk) 18:01, 12 June 2013 (UTC)

Yes, as said, more work is needed, including examples and other applications will be added as I learn them in time. M∧Ŝc²ħεИ_τlk 18:08, 12 June 2013 (UTC)

While tensor operator seems to be used by physicists mostly in the context of tensors under rotation in quantum mechanics, the concept is used in other ways, too. For instance, in image processing, there is the concept of tensor operators for energy tensors, e.g., Energy Tensors: Quadratic, Phase Invariant Image Operators and also in the more general concept of structure tensor. Neither of these necessarily involve 3D rotational invariance/covariance. Tensor operator algebras have also been created for other groups, e.g., Tensor Operator Algebra for Point Groups. I don't think the redirect from tensor operator to spherical basis is a bad move, but if an editor wanted to do so, creating a standalone tensor operator article seems reasonable. --Mark viking (talk) 20:24, 12 June 2013 (UTC)

Yes, I suspected tensor operator would potentially have it's own article for the reasons you mention. It's easy to overwrite a redirect. Thanks, M∧Ŝc²ħεИ_τlk 20:34, 12 June 2013 (UTC)

In the end I split the tensor operator stuff from spherical basis to overwrite tensor operator, for reasons explained here and at Talk:Spherical basis, Talk:Tensor operator. The redirects are changed as stated on these articles. M∧Ŝc²ħεИ_τlk 08:56, 13 June 2013 (UTC)

3x12 = ?

I have a different opinion about what (or who) was silly in Hexadecimal. Incnis Mrsi (talk) 04:09, 9 June 2013 (UTC)

Perhaps you could explain what you think the purpose of the link is? --JBL (talk) 15:52, 9 June 2013 (UTC)

Perhaps, an inhabitant of Unicodified worlds needs a hint to understand the “humour” invented by ASCII-based tribes in prehistoric times before the advent of HTML? Incnis Mrsi (talk) 16:13, 9 June 2013 (UTC)

This is why the "joke" is followed immediately by an explanation, is it not? --JBL (talk) 17:51, 9 June 2013 (UTC)

<hit with="bone"><monolith/></hit> Sławomir Biały (talk) 19:38, 9 June 2013 (UTC)

Is there a reliable source which supports anything at all in the section Hexadecimal#Common_patterns_and_humor? Spectral sequence (talk) 20:54, 10 June 2013 (UTC)

There are a lot of sources (but of dubious reliability) in the main article on this topic, hexspeak. Apparently the original source for this is Kernighan and Pike The Practice of Programming (1999) but I don't have a copy to check. —David Eppstein (talk) 20:54, 12 June 2013 (UTC)

As far as I can see, hexspeak is a random collection of mildly amusing jokes that can be or have been made using hexadecimal notation, sourced only to primary sources, and with no single reliable secondary source to suggest that the list is complete, or representative, or significant. The section Hexadecimal#Common_patterns_and_humor mentions a few of those jokes and recounts some others, all without any sources at all. It seems completely undue. Spectral sequence (talk) 21:17, 12 June 2013 (UTC)

In the absence of any further comment I have boldly deleted the section. Spectral sequence (talk) 18:56, 20 June 2013 (UTC)

An instance of erroneous eponymy

I have created this new section, explaining that the so-called Weierstrass substitution was used by Euler long before Weierstrass was born. I don't know how this came to be called the Weierstrass substitution by respectable authors, but Google Books confirms that it is. Maybe the answer to that last question should be included in the article if it can be found. Did Weierstrass even used this substitution? Where, specifically, is it found in Weierstrass' work. If it isn't there, what source could be cited to confirm that it isn't there? Would this warrant renaming the article? How best should the topic of erroneous nomenclature be treated in Wikipedia? Michael Hardy (talk) 13:06, 17 June 2013 (UTC)

I have never heard of this name for the tangent half-angle substitution and I would never find this article by myself. I have created the redirect Tangent half-angle substitution, and I support to move Weierstrass_substitution to this new page. Also it could be worth to merge this page with Tangent half-angle formula. D.Lazard (talk) 13:58, 17 June 2013 (UTC)

Is there an independent reliable source stating that this substitution was used by Euler? So far, all we have is a reference to Euler E342.V.261 where a substitution equivalent to this appears for one specific case. Michael Hardy may be correct about Euler, and in deed I personally think he is, but we go by what the sources say. It seems to be at best original research by way of synthesis to suggest from this reference alone that Euler was aware of the substitution for general rational functions. It is also unwarranted to assert that the assignment to Weiesrstrass is "erroneous". There may be a good historical reason for it -- we just do not know, because there are no sources cited to support the assertion either way. Whereof one cannot speak, thereof one must be silent. Spectral sequence (talk) 17:03, 17 June 2013 (UTC)

Euler knew that

${\begin{aligned}{\text{if }}y&=\tan {\frac {\theta }{2}}\\[8pt]{\text{then }}{\frac {2y}{1+y^{2}}}&=\sin \theta \\[8pt]{\text{and }}{\frac {1-y^{2}}{1+y^{2}}}&=\cos \theta \\[8pt]{\text{and }}{\frac {2\,dy}{1+y^{2}}}&=d\theta .\end{aligned}}$

Certainly he was aware of that substitution. Whether he knew it could be applied to all or to only some rational functions of sin θ and cos θ, I can't say for sure. Whether Weierstrass knew that, or ever wrote anything about this substitution, I don't know. What we can say is erroneously attributed to Weierstrass is the first use of this substitution. Michael Hardy (talk) 22:51, 17 June 2013 (UTC)

. . . . and I should add: Secondary sources are needed to establish notability, and we certainly have those secondary sources for this substitution. But primary sources are what is needed to establish that a particular author used this substituion. Michael Hardy (talk) 22:52, 17 June 2013 (UTC)

"I don't know". That's exactly my point. Wikipedia reports what reliable sources say, not our personal guesses. Is there a reliable source that says that the name "Weierstrass" is erroneous? The primary source indicates that Euler was aware of one particular use of this substitution. Does any source state that Weierstrass was the first person to use this substitution, which would indeed be an error if so? Perhaps it was named after Weierstrass because he rediscovered it, generalised it, popularised it, used it heavily, or whatever -- I don't know and it seems that you don't either. Saying that the attribution to Weiestrass is "erroneous" appears to be synthesis at best. Spectral sequence (talk) 06:15, 18 June 2013 (UTC)

Additional: I see that you have removed the word "erroneous" anyway so this part of the discussion is perhaps moot. In any event it seems to belong at Talk:Weierstrass substitution, not here. Spectral sequence (talk) 06:23, 18 June 2013 (UTC)

The general points raised do seem worth continuing to discuss here. I prefer the term "unhistorical" to "erroneous". It seems to me that we should use the terminology most commonly used in the current literature, whether or not that happens to be historically accurate. That is what readers expect and will think it odd not to find. We are here to follow, not lead, the scientific literature. We are not here as advocates or to right great wrongs. Spectral sequence (talk) 06:32, 18 June 2013 (UTC)

I wholeheartedly agree with this. Of course, if a good source has a discussion of the history of the name, we can include that somewhere in the article, and that would be valuable. But the name we use in general should be the name that is commonly used. Also, we should remember that many theorems are "known" to some editors by Western names, but known to editors in other countries by completely different names, which makes historical accuracy particularly trick to judge based on personal knowledge. — Carl (CBM · talk) 02:01, 19 June 2013 (UTC)

It seems that "Weierstrass substitution" is not the most common name. Google Scholar provide 26 hits for these words (with quotes) and 70 hits for "tangent half-angle substitution", without taking into account other current locutions like "taking the tangent half-angle as new variable".

This Google search provides also the reference Jean-Pierre Merlet, A Note on the History of Trigonometric Functions, International Symposium on History of Machines and Mechanisms 2004, pp 195-200, which contains the sentence "All the authors seem to agree that this substitution was first used by Weierstrass (1815-1897) and is often called Weierstrass substitution or Weierstrass t-substitution [Stewart 94]". It seems thus that this article may be the reference that it is asked for. Unfortunately, I have not an easy access to the full text of this paper. D.Lazard (talk) 09:50, 19 June 2013 (UTC)

That statement is somewhat suspect. I think the referenced source there is Stewart's Calculus, not exactly the gold standard in historiography of mathematics. Sławomir Biały (talk) 00:43, 20 June 2013 (UTC)

It was an email from Fred Rickey that alerted me to the possibility that this substitution may be nowhere in Weierstrass' writings. In our article titled integral of the secant function, this paper that he wrote is cited, showing that the value of that integral was a celebrated conjecture in the 17th century:

V. Frederick Rickey and Philip M. Tuchinsky, "An Application of Geography to Mathematics: History of the Integral of the Secant", Mathematics Magazine, volume 53, number 3, May 1980, pages 162–166

Michael Hardy (talk) 23:14, 20 June 2013 (UTC)

Schwartz kernel theorem

The article Schwartz kernel theorem looks as if it could use further elaboration including concrete examples. Michael Hardy (talk) 23:00, 20 June 2013 (UTC)

The german version looks good de:Kernsatz von Schwartz. The Legend of Zorro 00:44, 21 June 2013 (UTC)

Linear function

Is "linear function"

(a) a synonym for linear map;

(b) a synonym for linear equation;

(c) could be either (a) or (b), depending on context ?

At the moment there is considerable overlap between our articles on linear function, linear map, linear equation and a new article linear function (mathematics). Any views on what the best resolution is ? Gandalf61 (talk) 10:14, 19 June 2013 (UTC)

It is (c) as far as the use of term is concerned. We had an extensive discusson on that here a while back. Currently it seems to me that the main (and established) articles are linear map and linear equation. The other two in particular the new one should incorporated into them. The new one is probably well meant but essentially an undesired fork. Also to avoid such forks/redundant articles in the future we should integrate some disambiguation mechanism.--Kmhkmh (talk)

P.S.: The recent discussion was: Wikipedia_talk:WikiProject_Mathematics/Archive/2013/Feb#Linear_or_affine?--Kmhkmh (talk) 10:58, 19 June 2013 (UTC)

In my opinion, "linear function" is a synonym for linear map, as stated in that article. There is a relation between "linear equation" and "linear function", as discussed in the section linear equation#Connection with linear functions, but they are different concepts--a linear map is a map from one module to a potentially different module, whereas a linear equation describes a relation among variables and/or a geometric object. The new article linear function (mathematics) actually has a lot of overlap with linear equation and perhaps could be merged into the latter, if there is anything useful to merge. Similarly, linear function could be redirected and merged into linear map, but if this is done, it would be important to make sure that linear map has some sort of elementary explanation before launching into vector spaces and modules. High school students may want to learn about linear functions and the high level algebra would scare them away. --Mark viking (talk) 11:04, 19 June 2013 (UTC)

I think there's a misunderstanding here. Nobody suggested that linear map and linear equation are the same concept - obviously there are not. However in literature, depending on the context, the term "linear function" is used to denote either concept. That was the result of that earlier discussion, you can find concrete exmples for both usages in there.--Kmhkmh (talk) 11:36, 19 June 2013 (UTC)

(Edit conflict) I agree that in many context "linear function" is a synonym for "linear map". But for a polynomial function of degree one, the term of affine function seems not to have a dominant use in analysis. Moreover, it needs implicitly to understand that the field of the reals is both a vector space and an affine space. Also, affine function redirects to affine transformation, which does not consider "functions" as they are viewed in analysis. IMO, the lead of "linear function" must be rewritten as a WP:CONCEPTDAB and must begin like "Depending on the context, a linear function may refer either to a linear map between vector spaces or to a polynomial function of degree one", and link to the new article (possibly renamed linear function (analysis) or linear function (calculus)) for the second meaning. Also, a function is not an equation and linear equation refers to linear algebra, which is not the case for polynomial function of degree one. Thus the proposed merge of these two notions is a nonsense. The possible merge of the present content of linear function into linear map in another question. In any case, the present state of the "well established articles" although formally correct is confusing for the readers. D.Lazard (talk) 11:54, 19 June 2013 (UTC)

Sorry for the confusion. I meant to suggest that the current content of the article linear function (mathematics) has a lot of overlap with the article linear equation and could be merged, not that the two topics in general should be merged. --Mark viking (talk) 12:02, 19 June 2013 (UTC)

I oppose to classifying such stuff as linear function as CONCEPTDABs – there are two sharply distinct meanings. Yes, there is a lot of inbound links and placing a {{disambiguation}} tag would make certain people unhappy, but there are other such cases and, more important, diverging clearly distinct senses via dabs makes Wikipedia better in a long-term perspective. BTW, linearity is another interesting “article”. Incnis Mrsi (talk) 07:35, 20 June 2013 (UTC)

So you oppose what exactly now?--Kmhkmh (talk) 03:02, 21 June 2013 (UTC)

I have been bold, and have rewritten the lead of linear function to take the two meanings into account. If I am not reverted, as I hope, it remains to decide which merges are worth. IMO the present body of linear function duplicates linear map and could be suppressed (linear map is already linked to in the lead). Thus the body may be used to develop the "calculus meaning", that is to merge from linear function (mathematics), but with emphasis on the functional aspects rather than on the various equations of the graph of a linear function, as it is presently done in linear function (mathematics). D.Lazard (talk) 14:13, 19 June 2013 (UTC)

I agree with D.Lazard's approach. There remain several problems with the linear function (mathematics) article. There is the POV problem. The "polynomial" definition is referred to as mainstream mathematics, while the linear map view is considered advanced mathematics (does that editor really think that mainstream mathematics is elementary?). There is considerable confusion in the article between the concepts of function, equation and geometrical lines (for instance, at one point he calls a line a function). After fixing these problems (further discussion will be on the article's talk page) I would also suggest moving the article to linear function (calculus) if there is enough material left to make a viable article. Bill Cherowitzo (talk) 15:00, 19 June 2013 (UTC)

At the moment we have this:

• Linear function (calculus) redirects to Linear function (mathematics). The latter article is very new and in very rough shape
• Linear map
• Linear function
• Affine function redirects to Affine transformation. Focuses on maps between affine spaces

Now, here is my opinion:

• Linear function (mathematics) is an awful way to disambiguate the title because both concepts (linear map, affine function) are in mathematics
• Make Linear function have a lede and two sections, which are summary-style paragraphs about the two versions
• Make Affine function be the page that is now Linear function (mathematics). This can then link to affine map as a more advanced topic lower down.

Since this affects numerous articles, I am not sure where else to discuss it centrally. Thoughts? — Carl (CBM · talk) 15:09, 19 June 2013 (UTC)

Sounds good. What fate do you plan for linear equation ? Gandalf61 (talk) 15:59, 19 June 2013 (UTC)

Since essentially everyone (at least in the US) learns about linear functions (i.e., first-degree polynomial functions) in primary or secondary school and no one calls these objects "affine functions" in this context, it seems to me inappropriate to make affine function the main article about this object. I agree that "linear function (mathematics)" is a useless title; "linear function (calculus)" or "linear function (elementary mathematics)" is very much preferable. Otherwise, I think this is a very good suggested arrangement. --JBL (talk) 16:54, 19 June 2013 (UTC)

Since my above post, the article was moved to linear function (calculus). I also edited linear function itself, any feedback on the talk pages of those articles would be valuable. — Carl (CBM · talk) 20:30, 19 June 2013 (UTC)

BTW, I added the link to affine transformation. But the thing “linear function (calculus)” still misses is functions of several variables. Incnis Mrsi (talk) 13:46, 22 June 2013 (UTC)

Spin matrix (and plural: spin matrices)

Not terribly important, but this term could refer to a number of things, so I created a DAB page. The plural spin matrices used to redirect to Pauli matrices, so I removed double redirects from articles, to spin matrices, to Pauli matrices.

If anyone can think of other "spin mattrices" within pure/applied mathematics (not just the Pauli matrices for quaternions, Clifford/geometric algebra, etc.) then add the article there, higher spin alternating sign matrix is the one and only example.

If anyone disagrees with a DAB page and there is widespread consensus to redirect it somewhere, we could overwrite the spin matrix and spin matrices back towards Pauli matrices, presumably. M∧Ŝc²ħεИ_τlk 22:28, 20 June 2013 (UTC)

Commented at Wikipedia talk: WikiProject Physics ‎#Spin matrix (and plural: spin matrices). Incnis Mrsi (talk) 13:46, 22 June 2013 (UTC)

Empty sum

The statement in Summation#General manipulations

$\sum _{n=s}^{t}f(n)=\sum _{n=t}^{s}f(n)$, for finite s and t.

seems to contradict the article Empty sum and Summation#Special cases. Best wishes, --Quartl (talk) 05:11, 21 June 2013 (UTC)

Indeed. I deleted that line. Boris Tsirelson (talk) 05:46, 21 June 2013 (UTC)

As it says in that section,

$\sum _{n=s}^{j}f(n)+\sum _{n=j+1}^{t}f(n)=\sum _{n=s}^{t}f(n)\,.$

If we replace t by s−1, then we get

$\sum _{n=s}^{j}f(n)+\sum _{n=j+1}^{s-1}f(n)=\sum _{n=s}^{s-1}f(n)=0\,$

which implies

$\sum _{n=s}^{j}f(n)=-\sum _{n=j+1}^{s-1}f(n)\,.$

Right? JRSpriggs (talk) 06:01, 21 June 2013 (UTC)

That is basically the argumentation of empty sum at PlanetMath.. The problem seems to be: what is

$\sum _{n=s}^{j}f(n)$

when j ≤ s-1. The case j = s-1 is defined as zero. Is the case j < s-1 also zero or better left undefined? The WP articles don't answer that question. Best wishes, --Quartl (talk) 06:41, 21 June 2013 (UTC)

I doubt you will find any satisfying answer to that, because it comes up so rarely in practice, and few authors spend time talking about conventions that they will never use. — Carl (CBM · talk) 14:22, 21 June 2013 (UTC)

@Quartl: Can I convince you that the following look different from each other?

s-1

s - 1

s−1

s − 1

Only the last one is correct according to WP:MOSMATH. Michael Hardy (talk) 17:12, 22 June 2013 (UTC)

Sorry, I thought the MOS applies to articles only and you can be a bit less formal on talk pages as long as the meaning is clear. Best wishes, --Quartl (talk) 18:40, 22 June 2013 (UTC)

File:Megaprime found.png

Resolved

 – -- Toshio Yamaguchi 08:29, 20 June 2013 (UTC)

This image is being used at the top of the article megaprime. The description says the image is based on the information at http://primes.utm.edu/primes/lists/all.txt. I don't understand this image. The Y-axis appears to be the number of megaprimes found in a particular year. I don't understand the labeling of the X-axis. As is, I find this image highly confusing. I posted at Talk:Megaprime#File:Megaprime found.png but haven't received any response yet. Can someone who understands the image explain this to me please and perhaps improve the image description in the article? -- Toshio Yamaguchi 07:48, 20 June 2013 (UTC)

Requiring the reader to add 1998 to the label is just silly. The last but one revision of the image (http://upload.wikimedia.org/wikipedia/commons/archive/9/94/20130318131035!Megaprime_found.png) is more sensible, I have no idea why it was immediately reverted by the author, but I’m inclined to rerevert it.—Emil J. 11:14, 20 June 2013 (UTC)

I went ahead as there were no objections.—Emil J. 12:53, 23 June 2013 (UTC)

J. Laurie Snell

Someone has proposed deletion of the article titled J. Laurie Snell. I heard of this guy a lot in the '90s and '00s, and I thought there must be some reason for that. Michael Hardy (talk) 03:42, 21 June 2013 (UTC)

I find this trend highly concerning to ignore. User:RadioFan proded this article twice both time contested, with the rationale "No indication of how this might meet notability guidelines for academics. Lacks citations to significant coverage in reliable sources". A simple Google scholar search shows 4000 citations. I bet he has not done a Google search before prodding these. This type of repeated prodding is very much unconstructive. The Legend of Zorro 04:10, 21 June 2013 (UTC)

Irrespective of the merits of the article, it should not have been proposed for deletion twice [49], [50]. If a PROD is contested, AFD is the appropriate route. Spectral sequence (talk) 11:11, 23 June 2013 (UTC)

Linear function, Linear Equation, Linear Inequality full of errors and inconsistencies and "matheese"

These articles are SO badly written, so inconsistent, so incredibly unhelpful .. AND so important to regular people. Just to mention my qualifications: I have over 35 years of teaching mathematics at every level and a Ph.D. in theoretical mathematics.

A. Constant function is correct.

B1. Linear function is incorrect. This is the definition of a linear mapping from linear algebra on up.

Sources:

• http://planetmath.org/linearfunction (READ LAST LINE)

B2. Linear function (calculus) is mostly incorrect - particularly as it seeks to "include" constant functions with linear functions.

Sources:

• http://www.corestandards.org/assets/CCSSI_Math%20Standards.pdf
• http://www.columbia.edu/itc/sipa/math/linear.html
• http://www.math.okstate.edu/~noell/ebsm/linear.html
• http://www.mathplanet.com/education/pre-algebra/graphing-and-functions/the-slope-of-a-linear-function
• http://planetmath.org/linearfunction (although this article is definitely not "for the people"!)

The person who "fixed" and "renamed" my version (originally called Linear function (mathematics)) apparently did not even bother to look at Constant function and Quadratic function and incredibly where the Linear Function article refers to linear mappings of higher mathematics (linear algebra and above so usually college level), decided that a mainstream (general mathematics) definition of linear function (just put it in any browser or look in the CCSSM) was a calculus level subject. P.S. This was my first and most definitely my ONLY contribution to wikipedia; the incredible arrogance of the various responses and in the end - although I certainly did not object to his making it wikipedia format - the forced "corrections" (see talk).

C. Quadratic function is correct.

D. The article Linear equation is incredibly misleading.

This article is incredibly misleading. You are confusing linear equation (refers to the degree of the polynomial) and linear function (a function whose graph is a line).

Some sources for this:

1. http://tutorial.math.lamar.edu/Classes/Alg/SolveLinearEqns.aspx
2. http://www.purplemath.com/modules/solvelin.htm
3. https://www.khanacademy.org/math/algebra/solving-linear-equations-and-inequalities (I have written to them about the "opposite inconsistency" with linear inequalities as with e.g. MathPlanet.)
4. http://www.webmath.com/solver.html

As I said, the word linear here refers ONLY to the degree of the variables. It has NOTHING to do with the graph or rather the graph of the solution set! (It is implicit in the article that the graph of a linear equation is a line.) This is simply not true. A linear equation is NOT the same as a linear function.'

• Where is a linear equation in 1 variable, e.g. 3x=6? The solution of set of a linear equation in 1 variable is a value or point on the number line, e.g. x=2. This is the form most children see at ages 7 and they are told that they are solving a linear equation in 1 variable and do not understand why they don't "see" a line (since it is not a linear function and has nothing to do with a line).

• A linear equation in 2 variables and a linear function in 2 variables written in general form are the same, i.e. Ax+By=C. The solution set of both is a set of order pairs (x,y) in the plane that form a line. (I note that it is EXTREMELY unfortunate that teachers in middle school insist that Ax+By=C is a linear "function", since it is very difficult after that for children to understand the idea of a function. In its "starting" form as a "mapping", the definition of a function completely separates the roles of independent and dependent variable, which is obviously not true of a linear function in general form. Unless a child goes on to higher mathematics (and we are talking about less than 10% of the entire population of the entire world), this definition of function, i.e. the explicit form, is the ONLY definition he will ever see. If one does go higher, then one sees functions of all kinds (implicit, parametric, vector-parametric) and can actually categorize linear equations in 2 or more variables as implicit functions that can be solved uniquely in explicit form (and this explanation will definitely help you use mathematics software.)

• Where is the "clarifying" example of a linear equation 3 variables? The solution set of a linear equation in 3 variables is a plane in 3D space. You never mention it, yet every child who completes 12 years of school must solve a system of "3 equations in 3 variables" and has NO idea that he is actually finding the intersection point of 3 planes. This is critical. Again, this is not a linear function and has nothing at all to do with a line (since it is a plane.)

Then you can go on to the general definition. But these three are critical to the definition and understanding of linear equation.

Where is the information that a linear equation is never unique?

Linear Inequality Finally, if you properly define linear equation, then you can properly define linear inequality in 1, 2, 3 variables (without mentioning linear functional OMG in the second sentence)!

Some sources for this:

1. http://www.mathplanet.com/education/algebra-1/linear-inequalitites/solving-linear-inequalities
2. http://www.purplemath.com/modules/ineqlin.htm

P.S. I have also written to MathPlanet (who has the opposite inconsistency of Khan):

The following article is incorrect (and inconsistent with another of your articles - see below)

• http://www.mathplanet.com/education/algebra-1/visualizing-linear-functions/linear-equations-in-the-coordinate-plane

A linear equation is a polynomial equation of first degree so a linear equation in respectively 1, 2, 3... variables is: Ax=B, Ax+By=C, Ax+By+Cz=D... where capital letters are constants. A linear inequality is a linear equation in which the equals sign has been replaced by an inequality.

The term linear function in general mathematics is restricted to a polynomial function of first degree: y(x)=mx+b. That is, it is a function whose graph is a line in the plane. It is linear equation in 2 variables when written in general form: ax+by=c.

• The definition in the above referenced article is also inconsistent with your article: http://www.mathplanet.com/education/algebra-1/linear-inequalitites/solving-linear-inequalities

• Further these discrepancies confuse students who (a) have been told that they are solving a linear equation in one variable when they solve e.g. 3x=6 and (b) when they solve a systems of 3 linear equations in 3 unknowns as they think they are finding the intersection of 3 lines (and not 3 planes, which is the correct interpretation).

Thank-you for your consideration. LFS Lfahlberg (talk) 18:04, 22 June 2013 (UTC)Lfahlberg (talk) 15:58, 22 June 2013 (UTC)

As far as that some articles are (still) badly written, I think nobody disagrees. However I don't quite understand your complaints about "correctness" of linear function. First of all you own sources don't agree with your claim, that is http://www.columbia.edu/itc/sipa/math/linear.html includes constant functions under linear functions as well (so does any math book on that subject that I've seen so far). The PlanetMath article is not disproving anything in the WP article either, it merely shows that there is even a 3rd meaning/usage of the term, we haven't covered yet. However given that discrete geometry/linear (incidence) spaces is hardly a particularly popular math subject, WP coverage is still weak in that area and hence the PlanetMath content is still missing.

More importantly more or less all your sources don't really prove much regarding (alleged) "incorrectness" of WP content. They merely "prove" a particular usage of a term but do not disprove alternative usages. Aside from that logical problem they are (at least partially) not really authoritative sources either. PlanetMath is a Wiki like us, so strictly speaking it doesn't even qualify as a source. The various university websites and Khanacademy are ok to a degree but hardly authoritative sources, for that you'd need a standard textbook or some reviewed journal article.--Kmhkmh (talk) 23:57, 22 June 2013 (UTC)

Welcome to Wikipedia! You have brought up several perennial problems which are to be expected from such a system as ours. There are a few things to keep in mind. 1) While you might feel strongly about how certain articles should be, don't forget you are working with a community to build them. 2) Don't forget there are other editors as qualified (maybe a few even more qualified) as you. 3) Be sure to keep assuming good faith! This job requires copious amounts of it. Rschwieb (talk) 00:05, 23 June 2013 (UTC)

I agree with your complaint with linear equation, it sort of wades into the definition from the shallow end instead of having a clear definition section, which tends to compound misunderstanding as the article develops since encyclopedic writing communicates implicitly. It's in such bad condition because there are no users with a vested interest in the article, at least not ones with the reference material to formulate the article properly. Contrast it with Abelian group, which has a more typical structure, one in line with MOS:MATH. I don't know what your complaint with quadratic function is. Neglecting to equate a polynomial of degree at most one with a line is obscuring the concept and truth of the matter - polynomials are curves. The Planetmath article you refer to for linear function is a generalization of an affine map to other incidence structures (without a distinguished origin, the exact analogue wouldn't apply). While it can be mentioned in a generalization section of that article, it's not particularly relevant, as it doesn't inform the reader of any flexibility in the concept vs. the formalism that isn't owed entirely to the generalization from affine spaces to the other incidence structures. ᛭ LokiClock (talk) 02:03, 23 June 2013 (UTC)

1. Firstly, thank you all for replying. My experience with wikipedia in this area has not been good. I appreciate and welcome discussion.
2. I have no complaints at all with either Constant function or Quadratic function and state so specifically. In fact, I state that Linear function should take its natural place between these and not try to be all all things to all people. I do not think that it is useful to consider a constant function as a linear function and broaden the definition explicitly, particularly as there is a separate article on constant functions. To avoid this problem, one could simply state that a linear function ia a polynomial function of first degree and then say that its graph is a inclined line. (I debated about the order of these two sentencea for a long time....) There is a plethora of definitions of linear functions including allowing x=C (which i presume we all agree is not a function). Stating that a square is also a rectangle and so a linear function must include a constant function is again not useful. A rectangle is also a parallelogram and using that analogy one could consider a quadratic function to include linear and constant functions... One could mention that some references include constant function as a linear function even though it is a polynomial of degree 0 because it is a function whose graph is a line... . I firmly object to categorizing a linear function as a calculus topic Linear function (calculus). It only serves to make readers afraid and certainly it not introduced in calculus.
3. I see that the article Linear function has been changed now at least to reflect the possibility of the general math definition. No images or anything... That was my original intention in writing the article that was first utterly disdained as non-wikipedia since it dared to have images and media, then marked for speedy deletion as it supposed duplicated this article which at the time was devoted exclusively to linear mappings and which itself duplicated the article Linear mapping, then it was renamed and completely changed to the article mentioned in the above passage without any hint of allowed discussion (and no I do not consider myself the most qualified, but I certainly am qualified and so I do not consider these good intentions....).
4. An aside... Ask an engineer, what is an "affine map"? Ask him, what is a "linear function"? (I dont dare say ask a regular adult either of these questions although presumably they all passed algebra 1 and studied this stuff for years.)
5. What do you consider a good source? A commercial textbook and at what level would be acceptable here? Tthe Common Core State Standards for Math from the USA, Planet Math, ...? I tried to find a wide variety of online sources to illustrate that fact that the generally accepted definition of a linear function is not that of linear mapping (or operator). I only included planetmath as it tends to start from the highest level and even it considered linear functions as separate topic from linear mappings. I certainly did not mean to imply that we should go their way in wikipedia (argh).
6. Finally my point in writing here is that linear equations and linear functions are fundamental topics. They are the first topics in "algebra" where we lose so many children and hence adults. The term linear in linear equations applies to the degree of the polynomial The term linear function applies to the graph being a line in the plane. (Questions: Would a linear equation include a constant function which is considered to be from R to R? Do we consider the e.g. parametric function of a line in 3d to be a linear function? I dont know.) We need to make this distinction between linear equations and linear functions very clear. We extend these definitions implicitly when talking about linear inequalities, systems of linear equations, quadratic functions, ... If we are not clear and mix simple examples and complicated language, then we are just talking to ourselves.Lfahlberg (talk) 09:46, 23 June 2013 (UTC)

Some examples of "good" sources from Google books, picked at random to give you a head start, with the headings on the topic typed in the search engine (with slight variations):

Linear transformations

• New Foundations in Mathematics: The Geometric Concept of Number, Garret Sobczyk
• Advanced Engineering Mathematics, Peter V. O'Neil
• Advanced Engineering Mathematics, Volume 1, H. C. Taneja
• Advanced Engineering Mathematics, Alan Jeffrey

Linear equation

• Linear Algebra Georgíj Evgenevítsj Shilov
• Convergence of Interations for Linear Equations, Olavi Nevanlinna
• Elementary Linear Algebra: Applications Version, Howard Anton, Chris Rorres
• A First Course in Linear Algebra: With Concurrent Examples A. G. Hamilton
• Matrices and Linear Algebra, Hans Schneider, George Phillip Barker

Affine transformation

• Geometry, David A. Brannan, Matthew F. Esplen, Jeremy J. Gray
• 3D Computer Graphics: A Mathematical Introduction with OpenGL, Samuel R. Buss
• Transformation Groups For Beginners, S. Sergeĭ Vasilʹevich Duzhin, B. Boris Dmitrievich Chebotarevskiĭ

Linear inequality

• Systems of Linear Inequalities, A. S. Solodovnikov
• Advances in Linear Matrix Inequality Methods in Control Laurent El Ghaoui, Silviu-Iulian Niculescu
• Linear Programming and Extensions, George Bernard Dantzig

Linear function

• Linear Functions and Matrix Theory, Bill Jacob
• 'Linear Functional Analysis, Bryan Patrick Rynne, Martin Alexander Youngson
• Applied Functional Analysis: Applications to Mathematical Physics, Eberhard Zeidler
• Mathematics as an Educational Task, Hans Freudenthal

Basically: university textbooks (undergrad, grad), research monographs, papers in peer-reviewed journals, ect. Planet math is not reliable as a wiki, as others have said.

You may also want to see {{cite book}}, {{cite journal}}, {{cite article}}, {{cite webpage}}, for uniform formatting of references (but they're not essential), in case you haven't encountered them already. Best, M∧Ŝc²ħεИ_τlk 10:59, 23 June 2013 (UTC)

---

Excuse me, these are are sources for the topics Linear function and Linear equation? None of these, that is, not one is at the level at which these topics are introduced and at which someone looking up the topic would understand. That is my entire point.Lfahlberg (talk) 11:12, 23 June 2013 (UTC)

---

I am the person who "fixed" and "renamed" an original version, called Linear function (mathematics), and I already looked at Constant function and Quadratic function about half-year ago, during the previous discussion. Moving the article to linear function (calculus) was an emergency measure to prevent creating links to a nonsensical title. Probably the article would be better called linear function (mathematical analysis), linear (affine) function, constant-derivative function, or whatever: I do not object against any title which copes with the ambiguity in any meaningful way. Also, y = b is a “linear” function, but Ax = C is not. Look at piecewise linear function to understand why this definition have more sense than other two possibilities (i.e. excluding constants, or including implicit functions). Also, linear function is a mishap, a stuff which actually may not be an article, and I hope it is a transitional phenomenon. Incnis Mrsi (talk) 11:19, 23 June 2013 (UTC)

---

I knew I should give up when I gave up. It was just reading the article on Linear equation; it said "try again". Nope, now for sure I am out of it. Have at it. Definition of wikipedia math: math articles by and for mathematicians. P.S. I love that you are so certain that y = b is a “linear” function, but Ax = C is not. How can you tell that y = b implies an independent variable and so must be a function. To a non-mathematician, they are exactly the same sentences, particularly when you substitute numbers (and not little and capital letters to confuse them). Lfahlberg (talk) 11:36, 23 June 2013 (UTC)

Up to you, but you shouldn't give up this soon and this easily just because one (me?) or more of us are incompetent.

About sources earlier - you asked what are "good" sources, so I simply (attempted) to answer you question in good faith - those are the typical types of books we add to wikipedia.

So you want to add schoolchildren books to WP for references? M∧Ŝc²ħεИ_τlk 11:56, 23 June 2013 (UTC)

Your in/dependent variables do not make any sense: it was already pronounced at talk: Linear function (calculus)#Independent (?) variable. It is because we, mathematicians, cease to think about variables whenever a construction becomes to belong demonstrably to certain class or set. To you, a “number” or a “function” is something written on a blackboard, paper, or HTML page, i.e. some symbolic notation. To us, member of the WikiProject, a symbolic notation only represents an element. A function is something which is a function due to certain theorem, possibly rather trivial. For example, a polynomial (coefficients of which are numbers) is a function. Or: the composition of two functions, where the codomain of the right-hand one matches the domain of the left-hand one, is also a function. You cannot think as we think, and we have to make great efforts to think as you think. That’s why we do not understand you and you do not understand us. Incnis Mrsi (talk) 11:58, 23 June 2013 (UTC)

---

With these sentences you have absolutely proven what I said: Definition of wikipedia math: math articles by and for mathematicians. And not just mathematicians. Apparently one must be supercilious. Since I am not, that is why I don't understand you. I think that articles in wikipedia should instruct and encourage. Pity the actual reader who comes in thinking he might learn something useful (as with most non-math articles in wikipedia, thank-goodness). Lfahlberg (talk) 12:31, 23 June 2013 (UTC)

To instruct, but not to stuff a reader’s brain with dependent and independent variables only because someone’s dogmatic mind can’t think about functions without these surrogates. One should investigate the structure of variables when deals with coordinate systems, partial derivatives, implicit functions, and so on. Not for what we are speaking about. Incnis Mrsi (talk) 12:42, 23 June 2013 (UTC)

Just a remark: the term linear in linear equation does not refer to a polynomial degree but to the linearity of the map T in an equation T(x) = b, where x is the unknown (vector). Besides scalar linear equations there are linear differential equations, linear integral equations and so on. Feel free to consider de:Lineare Gleichung as a starting point, which I wrote some time ago. Best wishes, --Quartl (talk) 15:15, 23 June 2013 (UTC)

I agree that the linear equation is a bit problematic. I'm still not clear on what the problem is with linear function/linear function (calculus), in spite of all the discussion above. Sławomir Biały (talk) 18:24, 23 June 2013 (UTC)

Sorry, I must be slow on the uptake. It occurs to me that User:Lfahlberg's first attempt at an article was treated a bit unfairly by one of Wikipedia's reviewers (WP:BITE, etc), and then as if to add insult to injury (because of a post here) many mathematics editors started piling on. His or her reaction to all that is understandable. Sometimes that's the way it rolls on Wikipedia. One sometimes unfortunate corollary of being the encyclopedia that anyone can edit is that "anyone makes mistakes", as we all know. "Assuming good faith" is what we're supposed to do, but I'm a bit too cynical for that: I prefer a good sense of humor. In any case, it would be a shame to lose an editor with an interest in improving the accessibility of Wikipedia's mathematics content. Sławomir Biały (talk) 19:52, 23 June 2013 (UTC)

Special:Contributions/99.241.86.114 again

Aside of well-known “latex-to-html” campaign, he is engaged in another crusade: replacing Sⁿ for n-sphere with Sⁿ. See [51] as a recent example. Incnis Mrsi (talk) 11:58, 23 June 2013 (UTC)

For clarity, in this instance it does not appear to be a change in the use of <math> or of {{math}}, only changing of italic S to roman bold S. As this is a symbol and not a variable, neither is in accordance with WP guidelines – it should be simple roman (neither bold nor italic, e.g. S¹ or S¹). Since in this case I think the guidelines give a definite preference, this should be resolvable, and the IP editor should be guided rather than persecuted. — Quondum 17:00, 23 June 2013 (UTC)

Random math article

Hi folks, I was perusing the archives, and happened upon a random math article link, maintained on a separate server by User:Jitse Niesen (operator of User:Jitse's bot). Is it worth adding this to the WP:WPM homepage? Sławomir Biały (talk) 21:38, 21 June 2013 (UTC)

Fun and more useful for the mathematically inclined than the Special:Random link in the sidebar. I think it would be worth adding. --Mark viking (talk) 21:55, 21 June 2013 (UTC)

Actually, I'm a bit pleasantly surprised of the general quality of articles that the random math link generator produces. Overall, they seem to be of a generally higher quality than the articles linked by Special:Random. Sławomir Biały (talk) 22:31, 21 June 2013 (UTC)

Sure, why not? Michael Hardy (talk) 17:16, 22 June 2013 (UTC)

I've gone ahead and added it to Wikipedia:WikiProject Mathematics/Nav, the navbox that appears on the right-hand side of the project page, as this seems to be the most convenient place to have the link. But as always, feel free to change it (or complain about it here :-) Sławomir Biały (talk) 18:21, 24 June 2013 (UTC)

A wild idea: multi-tiered maths articles to match the target audience?

I fairly regularly observe the tension between those who feel math (and physics) articles should be aimed at introductory level (let's say, at least understandable to a senior school child or the non-mathematical layman), and those who feel that that it should address the topic more in line with the serious scholar, say an undergrad or postgrad studying the topic. There seems to be potential value to readers in both domains in WP, but the spread is a bit large to be addressed in a single article (even with the current formula of an "understandable" lead and introductory sections) and is getting more so. The "simple English" version may not adequately address the lower end of the WP spectrum in this sense. Only a part of the problem is that the lower end sometimes expects a pedagogical approach (e.g. linearity above). I think the pedagogical approach should be discouraged in WP, but there may still be a need for an approach with multi-tiered maths reference articles, which cross-reference and complement each other. Would it make sense for Wikiproject Mathematics to pioneer such an idea? — Quondum 17:33, 23 June 2013 (UTC)

There is some precedent for this, having separate "Introduction to X" articles. While this can sometimes work, for example, the two featured articles General relativity and Introduction to general relativity, more often I think what happens is that content becomes too forked and fragmented and we end up with a collection of bad articles rather than one article (which may be good or bad, but at least it's only one to worry about). This was the case until recently for essentially all of our articles on tensors. I think it would be better to focus on bringing existing articles up to standards, especially WP:LEAD and WP:MTAA. If there is enough material to fork, then (and only then) should it be forked. Sławomir Biały (talk) 18:19, 23 June 2013 (UTC)

We do have some multi-tiered articles like this, for instance, Group (mathematics) and Group theory. I agree with Sławomir, however. If possible, single articles are more useful for our readers and give a better overview for the whole topic. There is nothing wrong with having an Introduction or Elememtary usage section to explain how the topic is treated in pre-college courses. More sophisticated users can use the table of contents to skip to the advanced stuff. --Mark viking (talk) 18:50, 23 June 2013 (UTC)

I'm going to renew my point here that that's the wrong distinction between group (mathematics) and group theory. The distinction should be that the former is about groups, whereas the latter is about the theory of groups. That is, an article called group (mathematics) should tell you what a group is, why it's important, and what you do with one. An article called group theory should discuss the work of mathematicians primarily interested in groups themselves.

Now, in practice, to some extent, the two formulations may overlap. Indeed, I think the articles are currently largely written in the way I suggest, with one exception I'll get to. So what I'm talking about here is not so much a proposal to restructure anything, as to adjust how we think about the existing text.

But here's where you see the distinction: Some applications of groups come up inside group theory, some outside. The latter ones (for example, anything from physics) belong in group (mathematics), and not in group theory, no matter how "advanced" they are, because they're about groups, but they're not about group theory.

Just to head off another possible confusion: No, this is not a pure-vs-applied distinction either; groups might show up in some other very pure field, say descriptive set theory. As long as it's not from group theory, it belongs in group (mathematics). --Trovatore (talk) 19:51, 23 June 2013 (UTC)

Thanks for the link to WP:MTAA – it is excellently written. From this it seems that several working options have already been identified; being familiar with these guidelines and essays is really helpful. — Quondum 18:56, 23 June 2013 (UTC)

This approach would be, at best, precocious when WikiProject Mathematics still has not a comprehensive content guideline for articles intended for experts (at least, professionals). Such problems as:

• Which notation to assume well-known?
• How to explicate/declare a notation which is not assumed well-known?
• How to make the notation consistent across articles? (at least closely related ones)
• How to make terminology and definitions consistent across articles?
• How to refer to logical systems used?
• Numerous conflicts related to “spaces” and “vectors”

still wait a solution. When a good content guideline “for adults” appeared, the time to develop content guidelines “for children” will come. BTW, miles of flame at #Linear function, Linear Equation, Linear Inequality full of errors and inconsistencies and "matheese" IMHO shall be simply disregarded: the “problem” is not about certain article, but about disagreement of one editor with a style established here and such Wikipedia fundamental as editing of his articles by other editors. There are problems more important than to satisfy demands to explicate the content according to someone’s favorite textbook and exotic mindset. Incnis Mrsi (talk) 20:24, 23 June 2013 (UTC)

I agree with you on every point, and have already effectively withdrawn my proposal. My reference to the section linked above was merely a recent example of a common tension, I realize now not adequately representative of the usual goodwill request for something that may be understood by entry-level readers. I think that the guidelines already documented are fine for the moment, and will be progressively adapted and fine-tuned through collective experience and collaboration. — Quondum 23:18, 23 June 2013 (UTC)

---

I might ask why a mathematician might read an article in Wikipedia on say e.g. Linear function? If he doesn't remember what a linear function is (and that it is usually called a linear mapping or linear operator), then doesn't he have his own textbook (if he is a student) or his books in his own personal library to look it up? I certainly do (I still own Dunford and Schwartz, the bible on linear operators and it is still in print even though it is as old as I am). I never noticed the incredible uselessness of Wikipedia articles on standard math topics because of course I never used them. I do use Wikipedia all the time and I am INCREDIBLY GRATEFUL that the articles on which I needed information were written so that I could understand them and actually learn something. It is only because I have been working on creating resources for non-mathematicians (who BTW include adults) that I started reading them and this attitude here that only major-in-mathematics university level explanations are acceptable, that mathematics starts with calculus, that only "high-level" textbooks are acceptable resources and that speaking mathematics using normal words and sentences is unacceptable is not right, nor is it the purpose of Wikipedia and it is, of course, the (justifiable) reason that most people are so terrified of mathematics that they refuse to learn anything at all. They are NOT stupid - we are stupid for not explaining mathematics in ways and at a level that they can understand.

I absolutely fail to see why in a single Wikipedia article one cannot start at a basic level of explanation and proceed up the mathematical ladder. I am very sorry Quondum that you have withdrawn your proposal. As a final question I would ask those reading this to ask themselves "Who are the over 1000 people per day who access Linear equation?".

I will add a line from a letter I just received from a colleague (university professor) with a tremendous online math resource (pauls notes) that I use constantly to help me explain mathematics in reply to an email I wrote him to say that he should add the words "in one variable" to his definition where he states: a linear equation is an equation of the form ax+b=0. His response is excellent as he writes:

You are correct of course in your definition and I do cover linear equation in two and three variables later in the material. I suppose the reason that I didn't mention "one variable" at that point (it's been a while since I wrote the notes so I don't recall all my reasoning!) is that most of the students I would get in an Algebra class (also been a while since I've taught Algebra) had trouble doing even basic exponent operations and so I figured let's not "confuse" the issue by mentioning cases that we wouldn't be covering until the end of the semester. Many of the students could handle it but a sizable portion would get locked into me mentioning a case that we weren't going to cover right away and would have trouble getting past that point. That is not to say they are "stupid" or incapable of understanding but they tend to be so "math phobic" that they would spend too much time concentrating on unimportant issues (at the time anyway) and not enough time trying to understand the topic at hand.

Lfahlberg (talk) 15:36, 25 June 2013 (UTC)

Articles are to some extent expected to start at a fairly basic level, see WP:MTAA. I don't think anyone here would disagree that our articles on elementary mathematics are sometimes quite inadequate (even mathematics at the college level is woefully poor in some areas). Someone with extensive professional experience in pedagogy is a boon to the project. I for one think that there is nothing wrong with citing good sources that are not targeted at college majors. Some of our best articles cite a variety of such sources. It's simply ludicrous to suggest that journal articles and higher level texts are "better" than sources aimed at a different audience.

But I think it may have already been pointed out that there isn't really any philosophical agreement among members of the project exactly what mathematics in Wikipedia should look like. Some would adopt a Bourbaki point of view of the subject, and attempt to create a precise and rigorous mathematical cipher. Others may want articles to be read by their peers. Still others want articles that are readable by their students (which may include high school students, college students, graduate students). I also want mathematics articles suitable to be read by my children and nieces and nephews. This is all part of the culture, and often these philosophical differences lead to conflict. That isn't a bad thing: it's an essential part of the process. But it does take getting used to, and sometimes there are some aggressive personalities to deal with. Sławomir Biały (talk) 18:23, 25 June 2013 (UTC)

I fully agree with Sławomir. However, there is an important class of readers that he has omitted, and that is neglected by most WP editors: the readers with a good scientific knowledge who are looking on information on subjects that are outside of their domain of competence. The information that such reader are looking for is frequently very often lacking in the WP article. Several examples that are not far from the example of linear function: In practice, many users, like engineers, use real functions of several real variables; I am unable to find any article on this subject. The article system of linear equations needs to be carefully read to learn that there are very efficients algorithms to solve huge systems (up to millions of equations and variables). An information that is essential for most users of such tools is the possibility of numerical instability. This is not even cited in this article. I could continue with many other examples. When you edit WP, please, keep also in mind this category of users (academics and engineers that need usable information outside their domain of competence). D.Lazard (talk) 22:27, 25 June 2013 (UTC)

Oh, so sorry to chat again here, but this is the stuff of my dreams - cooperation between the communities in writing useful articles. I am a professor of mathematics in the engineering department of my university. My degrees are in theoretical maths and I have spent most of the last 20 years trying to make math understandable and useful for engineers - but first having to learn it myself! (Just a teensy low-low-level example - engineers are always using functions involving parameters and yet this has got to be one of the least well explained areas in mathematics (including the fact that even in WP constants are referred to as parameters). Lfahlberg (talk) 10:26, 26 June 2013 (UTC)

Considering D.Lazard's point above that no article on real multivariable functions exists, I made a clumsy start. Anyone is more than welcome to complain on the talk page. Thanks in advance M∧Ŝc²ħεИ_τlk 13:31, 26 June 2013 (UTC)

It may have been raised before, but is there any reason for Real-valued function when we have Function of a real variable?. Real-valued function (a two-sentence dictionary def) should just redirect to Function of a real variable. M∧Ŝc²ħεИ_τlk 14:17, 26 June 2013 (UTC)

Ummm ... aren't they different things ? A real-valued function is a function to the reals whereas a function of a real variable is, in general, a function from the reals. Even if you restrict "function of a real variable" to be only functions from R and to R, real-valued function is still a more general concept. Gandalf61 (talk) 14:32, 26 June 2013 (UTC)

Whatever. Leave them separate. M∧Ŝc²ħεИ_τlk 16:21, 26 June 2013 (UTC)

Euclidean space: inner product, dot product and Cartesian coordinates

I'm trying to clarify the distinction between an inner product and a dot product in a few related articles, and I want to make sure that I've got the concepts straight. I'm bumping up against the classic problem of trying to determine how much a concept has been defined too concretely (and hence has lost its generality) as a result of the pedagogical process, in this case the general concept being taught in terms of Cartesian coordinates, and being worded in WP to exclude the original, correct and more general (and more abstract) definition. Please correct the following:

• A Euclidean space is an inner product space in which the underlying scalars are the real numbers.
• The dot product is defined as a coordinate-wise sum-of-products of Cartesian component vectors in Rⁿ.
• Since there exist many inner products on component vectors in Rⁿ that do not fit the definition in the previous bullet (i.e. they have a positive-definite symmetric bilinear form that is not represented by a diagonal matrix), not every inner product on Rⁿ is a dot product, even though there is always an isometry with the dot product on Rⁿ.
• Since a Euclidean space in the abstract sense need not be defined in terms of Rⁿ and an associated inner product (even though it is always isomorphic with it), strictly speaking a dot product is not defined on an abstract Euclidean space, only on the Cartesian coordinate vectors of the associated decomposition in terms of any selected orthonormal basis).

I intend to word the articles so that the distinction between a real coordinate space with a dot product and a Euclidean space with an inner product is respected, in general avoiding introducing abstractness. — Quondum 23:21, 23 June 2013 (UTC)

IMHO the main distinction between “inner product” and “dot product” is that the former is a general concept (applicable to complex vector spaces, possibly also to spaces over arbitrary ordered fields and their extensions), whereas the latter is something over not wider than R and usually in finite dimensions. The decision to use one or another should be bases not on coordinate/Euclidean distinction, but on the scope of an article. If the article focuses on such properties as positive-definiteness of the form and derivation of topological structure from it, then the link should be inner product space. If the article focuses on geometrical aspects of Euclidean spaces of low dimensions, physical uses of 2- and 3-vectors, as well as row and column vectors, then the link should be dot product. BTW, is a finite-dimensional ∑_k u_kv_k a “dot product” over an arbitrary field, where it is not an inner product, such as over complex numbers? Incnis Mrsi (talk) 06:15, 24 June 2013 (UTC)

The dot product's formula as a sum of products can be taken as its definition. The components are scalars, not vectors (vector multiplication need not be defined first). But in particular, the dot product has geometric meaning, perhaps clarified by vector projection. Hence it is also defined on abstract Euclidean space. ᛭ LokiClock (talk) 02:02, 26 June 2013 (UTC)

@Incnis: if defined in terms of components, I suppose the dot product would be defined over an arbitrary field. This is how it is defined in dot product, but from your description, it sounds like the Euclidian geometric interpretation is the appropriate definition, and that the component version then would only apply when the vectors have a geometric interpretation (though even geometric is hazy: vector spaces over any fields for which a symmetric bilinear form is defined sometimes seem to be called "geometric"). This would suggest that this article needs rewording, not using the sum-of-products definition. It feels more natural to me, the way a physicist, engineer or geometer would interpret it. The summed products definition would then be called a summed component-wise products or similar, but would not qualify as a dot product. However, people who deal only with matrices might object. Anyhow, the question is whether we should adopt this definition and modify the article.

@LokiClock: You can't have it both ways. But you can define it in terms of the component-wise sum-of-products with the restrictions that the basis is orthonormal in a Euclidean space, and then extend the definition to any Euclidean space. But in that case, it makes sense to do it the other way around: define it geometrically, and then derive the sum-of-products in the special case of an orthonormal basis, not as a matter of definition. My point originally was in effect that the bland component-wise definition is not consistent with the geometric interpretation in general.

So, I guess I should seek consensus on the correct definition of a dot product first, but I guess that discussion should be at the talk page rather. — Quondum 02:46, 26 June 2013 (UTC)

Well, both definitions are correct in the sense that they appear in high quality sources. Sławomir Biały (talk) 07:18, 26 June 2013 (UTC)

Nobody doubts that all three standard definitions of dot product (abstract bilinear form a.k.a. inner product, ∑_k u_kv_k in a Cartesian basis, and the product of the cosine and lengths) are applicable to Eⁿ. The question is whether should we refer to such things as ∑_k u^kv^k = u^Tv for two column vectors as to a dot product, even over non-ordered fields/rings. Incnis Mrsi (talk) 08:50, 26 June 2013 (UTC)

In Cⁿ it's also called dot product by many authors, see for example [52]. Best wishes, --Quartl (talk) 11:12, 26 June 2013 (UTC)

@Quartl: Unfortunately, that definition corresponds to the inner product (a sequilinear form) under the name "dot product", not to a general extension of the dot product to arbitrary fields (a bilinear form). I think that the definition corresponding to the bilinear form over complex numbers occurs as well, especially in physics, but I'd have to check.

@Incnis: A general definition of the dot product in terms of the components just does not make sense, except in the limited (and usually pedagogical setting) where the definition starts "Assume an orthonormal basis for a vector space...". The two definitions currently in dot product are incompatible, and I would suggest that the "algebraic" definition ("an algebraic operation that takes two equal-length sequences of numbers") should be regarded as incorrect even in a Euclidean space, because it fails to assume the orthonormality constraint. As to whether the term should be taken to be synonymous with symmetric bilinear form for arbitrary fields would require a notability check, but I suspect that it might find use over arbitrary fields, e.g. in Clifford algebra. — Quondum 12:14, 26 June 2013 (UTC)

One is free to regard the definition as incorrect, but this is how basically everyone does define it (not just in pedagogical contexts either). If you feel that it's an important qualification, you can add that the coordinates of the vectors are Cartesian coordinates. It would be inappropriate to introduce orthonormal bases, not only because most sources do not, but also since the notion of orthonormality already presupposes the existence of an inner product. Sławomir Biały (talk) 13:10, 26 June 2013 (UTC)

Certainly, orthonormality is, in most general case, derived from a bilinear form, not versa. You do not need concepts of orthogonality and norm to define u^T v: for coordinate space (of finite dimensions) it is defined over an arbitrary field or ring. The problem is that, although the definition is universal to aforementioned conditions, it makes a thing with properties of an inner product space only if scalars possess a total order and commute. Over complex numbers there are both u^T v (a bilinear symmetric form) and u* v (a sesquilinear inner product). The latter is never called a dot product, but what about the former? Incnis Mrsi (talk) 13:43, 26 June 2013 (UTC)

I see the question with dot products in Euclidean spaces as the least difficult. Yes, it is an inner product. Yes, it matches the ∑_k u_kv_k only in orthonormal bases/Cartesian coordinates. No terminological clash: we just define the dot product in an Euclidean space as the same thing as its inner product and the dot product in orthonormal bases. I do not think one should strike through “dot product” and replace it with “inner product” wherever an article has no reference to an orthonormal basis. Incnis Mrsi (talk) 13:43, 26 June 2013 (UTC)

Implicit use of an orthonormal basis is often sufficient to qualify something as a dot product. I'll see what I can do to implement this discussion into the articles concerned. — Quondum 02:20, 27 June 2013 (UTC)

Sign conventions in rotation representations

I’m tired to see numerous edits like [53] in numerous articles related to 3d rotations. Could someone make a page (in Wikipedia: or User: space) with reviews and substantiations for all these sign conventions? It would become easier to revert “correctors” (although this concrete case is not typical) without searching for an inconsistency. Incnis Mrsi (talk) 07:16, 26 June 2013 (UTC)

Ugh, agreed! I was just looking at this. Surely enough people have been over it to ensure it was correct in whatever convention it was using. Rschwieb (talk) 13:54, 26 June 2013 (UTC)

It's easy enough to verify that the x, y, and z rotation matrices are consistent; it's more difficult to determine whether they are in left- or right-handed coordinate systems and whether they are covariant or contravariant representations. A page in Wikipedia:Wikipedia Project Mathematics space would be good, though. — Arthur Rubin (talk) 17:51, 26 June 2013 (UTC)

Mathematical abbreviations are Latin abbreviations, not English

I was told this was the place for discussing content issues concerning mathematics.

I noticed a preposterous claim as I read the page Limit: "In formulas, limit is usually abbreviated as lim as in lim(an) = a". It sounds like lim is an abbreviation of limit when it in fact is a abbreviation of limes. You could believe that this was an exception but after reading several other articles such as Natural logarithm (with ln = logaritmus naturalis), logarithm (with log = logaritmus), Sine (with sin = sinus) there seems to be a policy of denying history here. In the history section of sine the sceptic reader gets altered that sin is short for sinus and not sine, but thats about it. I think it needs to be clarified in each article what the abbreviation stands for when it's used for the first time. --Immunmotbluescreen (talk) 12:26, 22 June 2013 (UTC)

Are you a history of science expert? Okay, start please from explicating the tale how an ignorant Arabic-to-Latin translator invented a nonsensical term “sinus”. Incnis Mrsi (talk) 13:46, 22 June 2013 (UTC)

I have no problem pointing out what the abbreviations derive from, if it can be appropriately sourced. I also don't see what's wrong with the passage you quoted. Is limit abbreviated in some other way you want to have the article point out? Sławomir Biały (talk) 14:19, 22 June 2013 (UTC)

Obviously you would want it to be "usually abbreviated as lim (for limes) as in lim...". Since everybody knows that this is the case there is no need to have a source.--Immunmotbluescreen (talk) 20:12, 28 June 2013 (UTC)

Because saying "usually abbreviated as lim (for limes)" is in no way confusing to a typical English reader?? Sławomir Biały (talk) 20:50, 28 June 2013 (UTC)

Mathematical terms are not Latin abbreviations. Their etymology or history is not a part of their definition or expositions. Thanks, Anand ^{(talk page)} 16:08, 22 June 2013 (UTC)

Not there terms but the abbreviations--Immunmotbluescreen (talk) 20:12, 28 June 2013 (UTC)

The claim that limit is abbreviated lim is not preposterous at all: it is entirely correct. Are you suggesting that limit is abbreviated as anything else? A discussion about why those three letters are used might be appropriate provided of course that it was supported by reliable sources. There are other cases in natural English and in mathematics where abbreviations derive from Latin or indeed other languages. For example, "for example" is abbreviated "e.g.". To suggest that all mathematical abbreviations are Latin is simply incorrect. Many twentieth century abbreviations derive directly from German (Z) or English, (glb, hcf, Tor). Spectral sequence (talk) 16:23, 22 June 2013 (UTC)

Technically it is correct but as I said it confuses the reader to believe that lim is an abbreviation of limit. It only goes one way. Maybe not all but the most common and old mathematics. --Immunmotbluescreen (talk) 20:12, 28 June 2013 (UTC)

"lim" may originally have been an abbreviation of "limes", but that doesn't mean it is an abbreviation of only the Latin word. And when one writes

$\dim \ker(T)+\dim \,\operatorname {Im} (T)=n,\,$

the abbreviation "ker" quite obviously comes from a Germanic root, not from Latin. One cannot claim any generality for a statement that there is only one language from which mathematical abbreviations are ultimately derived. Michael Hardy (talk) 17:42, 22 June 2013 (UTC)

Not to mention the abbreviations a.e., a.s., l.i.m. (limit in measure) which all derive from English, p.p. and cadlag which derive from French. Sławomir Biały (talk) 19:57, 22 June 2013 (UTC)

I am not sure of the correctness of the above interpretation of "ln" as an abbreviation of "logaritmus naturalis". In fact, for French mathematicians, "ln" is an abbreviation of "logarithme népérien" (Neperian logarithm). An historical research or a reliable source would be needed to decide which etymology is correct. D.Lazard (talk) 20:46, 22 June 2013 (UTC)

Actually, within mathematics lim only stands for limes. The face that English derives from French which derives from Latin and happen to have similar words does not alter what the abbreviation stands for. --Immunmotbluescreen (talk) 20:12, 28 June 2013 (UTC)

Is there a reliable source for this extraordinary assertion? Spectral sequence (talk) 20:30, 28 June 2013 (UTC)

Google books finds quite a few [54]. For instance, it's in Florian Cajori's History of Mathematical Notation [55]. —David Eppstein (talk) 20:35, 28 June 2013 (UTC)

There's no question about the etymology of "lim". What's debatable, however, is the assertion that "within mathematics lim only stands for limes". How many mathematicians think of "lim" as standing for "limes"? Should this perspective be emphasized in an encyclopedia article on the topic (outside of the history section)? Sławomir Biały (talk) 20:49, 28 June 2013 (UTC)

Immunmotbluescreen's assertion has several components: (1) that English derives from French (which is false) (2) that lim is short for limes (which is true) (3) that in mathematical writings lim derives only from Latin limes and never derives from French limite or English limit (which is extraordinary). Cajori observes that Cauchy used lim. and Cajori makes it clear that Cauchy was writing in French, not Latin. So let me repeat my question. We have yet to see a reliable source that supports the assertion that "lim" is an abbreviation only for Latin limes and explicitly states that it is not an abbreviation for French limite or English limit. In the opposite direction, there are certainly English-language sources that show that limit is abbreviated lim, for example, [56], [57], [58], ... The "only" part of the assertion has no demonstrated support. Spectral sequence (talk) 20:58, 28 June 2013 (UTC)

Why do we even need to talk about this? I'm just going to repeat my suggestion from below — change "abbreviated by" to "denoted by" and be done with it, except maybe in the history section. Who cares what it stands for, in a discussion of the mathematics? --Trovatore (talk) 21:00, 28 June 2013 (UTC)

We only need to talk about it because one particular user appears determined to advance a personal view about this subject even thought they have produced no sources to support their unusual views. Trovatore's suggestion seems perfectly adequate to me. Spectral sequence (talk) 21:04, 28 June 2013 (UTC)

Good grief. I've gone ahead and implemented this minor wording change. Sławomir Biały (talk) 21:20, 28 June 2013 (UTC)

This discussion appears to be the continuation by the original poster of the tendentiously-named Wikipedia:Village_pump_(policy)#Rampant_arrogance_in_articles_about_mathematics. Spectral sequence (talk) 20:52, 22 June 2013 (UTC)

For the most part, these complaints can be resolved simply by removing any claim that the short forms are abbreviations for anything in particular. For example, rather than saying that limit is "abbreviated" as lim in formulas, say that it is "denoted" as lim. What if anything lim is short for is not really important to understanding limits. However, if sourceable, it could be explained that lim originally abbreviated limes, in a separate "etymology" or "history of notation" section. --Trovatore (talk) 22:29, 22 June 2013 (UTC)

For consensus, I agree with everything Trovatore just said. M∧Ŝc²ħεИ_τlk 11:14, 23 June 2013 (UTC)

Review of trolling vandal edits requested

These edits are few in number, but seem intent on subtle (under-the-radar) and lately not-so-subtle (provocative) degradation of WP math content. The first five edits and the last (as of now) have remained unreverted. Could someone check these? I don't feel confident enough in these areas to be sure that every edit constitutes vandalism, though they seem to me to be. The very small number of edits under a named account all apparently being vandalism suggests the possibility of several socks being operated in parallel. — Quondum 01:59, 24 June 2013 (UTC)

https://en.wikipedia.org/w/index.php?title=Divergence_of_the_sum_of_the_reciprocals_of_the_primes&diff=561289321, given in isolation, is anything but certainly not a good-faith edit. Let us wait for several next edits to determine whether the operator has any positive intentions. In my considered opinion, after yet one edit such as replacement of “x” with “65” the account shall be blocked without further deliberations and investigated by WP:CheckUsers. Incnis Mrsi (talk) 06:15, 24 June 2013 (UTC)

I tend to agree, but I've reverted all but one of his remaining edits, and given a final warning. (One of the edits was actually good.) — Arthur Rubin (talk) 08:01, 24 June 2013 (UTC)

FYI Endohiraku (talk · contribs · deleted contribs · logs · filter log · block user · block log) is his new, active sock. Feel free to track and/or block it, but I will not help anymore because I’m disappointed and upset about rampant incompetence and dickery of the people related with sock hunting. Note that I do not refer to CheckUsers themselves. Incnis Mrsi (talk) 06:56, 25 June 2013 (UTC)

Incnis Mrsi has reverted a closure by an SPI clerk on an SPI report page (started by me). He added the editor above. When Incnis Mrsi reverted the close, only one of three edits was odd, so there was no clear pointer to sockpuppetry, beyond circumstantial evidence (recently created account, same section of article). However, they seemed to have some mathematical understanding of the error in the previous proof (dependence on k) and looked as if they were shortening the argument. In those circumstances, adding comments here about "rampant incompetence and dickery of the people related with sock hunting" is inappropriate. Even the posting above is premature. When reverted by the SPI clerk Rschen774 for reverting an administrative close, Incnis Mrsi complained on the clerk's page.[59] The clerk responded:[60] "Well that's not a very good attitude to have. As Mathsci stated, you are welcome to open a new report. However, you should not be reverting the actions of a clerk." Determining sockpuppetry requires patience and carefully reasoned arguments with diffs. Sometimes it takes days or weeks to find out whether an account is a sockpuppet. Even after they restored their 3rd edit, it's still too early to tell. Mathsci (talk) 07:31, 25 June 2013 (UTC)

If someone still has a doubt, I repeat: compare Endohiraku, a brand-new account, and Pirokiazuma, a recently blocked account with previous evidences of sockpuppetry. Not only an interest to the same article, but the same clumsy use of “this” and edit summaries ended with full stop (.), rather atypical syntax for Wikipedians. Incnis Mrsi (talk) 11:09, 25 June 2013 (UTC)

I had a look there and I think the proof that keeps getting messed up should really be phrased in much simpler terms, somebody seems to think they should refer to set difference and cardinality and stick in loads of tiny subscripts in something that should be perfectly easily accessible to high school children.. Dmcq (talk) 13:16, 25 June 2013 (UTC)

I tend to think that the subscript k makes sense. But I'm an expert in mathematics, not in readability. — Arthur Rubin (talk) 18:26, 25 June 2013 (UTC)

If you take k as a constant defined at the beginning there's no point repeating it throughout the proof. The only variable is x. Dmcq (talk) 18:46, 25 June 2013 (UTC)

For what it's worth, I agree. The number k is fixed throughout the portion of the proof where the bound is relevant. I think the original $M_{x}$ should be restored, for clarity, but that also it should be emphasized that k is fixed. Sławomir Biały (talk) 19:01, 25 June 2013 (UTC)

I've implemented a change along these lines. Sławomir Biały (talk) 19:08, 25 June 2013 (UTC)

(edit conflict)The addition of the subscript does make sense. Pirokiazuma missed the dependence on k, while Endohiroku drew attention to it. Can that really br the same person?

Independently of all this, the problem with the article being edited is that it is not properly sourced. It's easy enough to do. Not all the proofs given, e.g. that of Erdos, are in the unique source (I looked at the pages listed). I haven't checked what's in Hardy & Wright, but that's a classic source. It would be good to add a few inline citations. And yes, the article should be accessible to high school students.

Although Kww blocked the suspected sockpuppet, I cannot see any overwhelming reason for it to be a sockpuppet. In this case there were problems not only with the mathematics of the 3rd edit (identical to the 4th) but with the grammar. I reverted both these edits. English is not the native language of the editor: they are struggling. I have no idea why in that edit they changed a short and simple statement to a short and cryptic riddle. Indeed closer examination shows that what Endohiraku added[61] is essentially the same as what Arthur Rubin spelled out in this subsequent edit.[62] But in any event there was really too little data to infer anything. Mathsci (talk) 18:51, 25 June 2013 (UTC)

English is not the native language of the Randy and this, as Mathsci inferred, explains his/her attitude? Where (and when) my English was insufficient to edit an article boldly, I started from posting to the talk page. And I did not attempt to deride the people who started to discuss the matter. It is the (general) WP:competence problem, not a language problem. Just drop it and let’s revert any “cryptic riddle” until Randy realized that his/her changes have no chance without a preliminary discussion. Incnis Mrsi (talk) 02:56, 26 June 2013 (UTC)

Incnis Mrsi has been given advice by the SPI clerk Rschen and by the checkuser Deskana about how to report sockpuppets. Articles on primes attract all sorts of editors, including some with delusions. What might have prevented some of these problems and the recent set of edits (even by regulars here) is for the article to have been properly sourced with a smattering of inline citations. It is true that the subject is elementary pre-university mathematics that any Tom, Dick or Igor can do, but that's no reason not to have sources that cover all the content. Mathsci (talk) 04:29, 26 June 2013 (UTC)

• A further obvious sockpuppet has edited the article, again with an incorrect "simplification" of the Erdos proof. An SPI report was filed with a request for CU. The underlying IP has now been blocked. Mathsci (talk) 06:31, 29 June 2013 (UTC)

Move proposal

I propose to rename

• Real multivariable function → Functions of several real variables (many real variables to one real/complex etc.variable)
• Several complex variables → Functions of several complex variables (many complex variables to any real/one complex etc. variable)

since the titles are clearer and match. If needed, other articles which may split from them could have more refined names like "complex-valued functions of several real variables" etc. Any objections? Feel free to call me a hypocrite for bad naming of real multivariable function/several real variables if you must. M∧Ŝc²ħεИ_τlk 08:27, 27 June 2013 (UTC)

"Several complex variables" is a branch of analysis, so a move of that article is not appropriate. As to the first, the proposed target is inconsistent with our naming conventions for articles, and should be "Function of several real variables" if anything. Sławomir Biały (talk) 11:54, 27 June 2013 (UTC)

I seemed to have over-copy/pasted, several complex variables is supposed to read in the brackets "many complex variables to one complex variable". Anyway, in which case I don't see why "several complex variables" couldn't be renamed to "function of several complex variables", but it's not essential and I'll leave it alone, and move Real multivariable function → Function of several real variables. M∧Ŝc²ħεИ_τlk 18:42, 27 June 2013 (UTC)

There is an entire area of mathematics called "Several complex variables". This is what the article is about (or should be about). Sławomir Biały (talk) 18:55, 27 June 2013 (UTC)

OK, sorry, I've never actually come across that as a title, I've always read/been taught it as "complex analysis". M∧Ŝc²ħεИ_τlk 19:10, 27 June 2013 (UTC)

Yep, it even has its own top-level Mathematics Subject Classification: MSC 32-XX "Several complex variables and analytic spaces". Sławomir Biały (talk) 19:30, 27 June 2013 (UTC)

Proposed contents for pages on Linear function, Linear equation and Line (geometry)

I invite you to look at these pages: Linear function, Linear equation and Line (geometry). I have translated them from wiki pages I was creating. (Please do not judge the folder name wikipedia. My host demanded a folder name before I was prepared for such a request and I already have a PMwiki called wiki on that domain so that was the first folder name that came to my brain. I was already in a long, long chat with the host about getting the math content to render. This site is just a sandbox where I can work on wikipedia type articles in peace. Gave up on clean urls.)

Please consider adding this content to the corresponding English wikipages.

Some notes (I know I am verbose).

1. The contents of the pages in my sandbox contain information that my kids (pupils and students), their parents and professionals from other fields with whom I collaborate,... always seem to be confused about. So I think it important to include them on wikipedia pages. Also many of the international wikipedia pages are directly translated from the en.wikipedia pages. So the en.wikipedia pages rather "set the standard".
2. I think that the equations for lines in the current article Linear equation should be moved to Line (geometry) (I did not include all of the formulas from there and added others from other dimensional spaces) and that perhaps some of the general information about geometry in Line (geometry) could be moved to Geometry. That being said, I must confess to loving great circles and not only suggesting that they go on the Line (geometry) page but wanting to have them above the fold (visible when opened) to create some interest about lines not just among the little ones, but among adults. (I find great circle routes fascinatingly counter-intuitive.)
3. I do not know how to make svg images (nor am I really interested in learning -I always hated Corel Draw). So I cannot do that at all. I make all my images in GeoGebra or Sage and I hope to create a youtube channel showing how to do this for images in the wikipedia pages (I am the voice of the youtube geogebra channel.) But within the png format I can change almost anything anybody thinks needs changing.
4. The pages I am asking you to look at render well on a big monitor, a netbook monitor, an ipad and even on my droid phone (although there the images come out above the text...)
5. Finally, even if we do not agree to change the en.wikipedia pages, any comments and suggestions on these pages would be greatly appreciated (ignore the mk interface and write in english on the talk pages.)

Thank-you for your consideration. Lfahlberg (talk) 09:12, 28 June 2013 (UTC)

I’ll try comment all this sequentially:

1. (I do not understand the point)
2. Lfahlberg possibly does not understand the difference between an equation and a geometric shape, but it does not imply that there is no difference. First of all, interpretation of a shape as an equation assumes a coordinate system, whereas line (geometry) is a concept more fundamental than coordinates. An attempt to dump all these into one large heap will result in a great logical confusion and destructured exposition, a thing which I really detest. Second, Lfahlberg referred to a great circle not in vain, apparently in a paradoxical insight. A line in general is not necessarily a line in an Euclidean or affine space. Geometric spaces without affine coordinates exits, aren’t they? Please, try to realize what does it mean before resuming the discussion.
3. Any videos how to make drawings in a software which can’t export anything in a vector form will not be appreciated here. I even will insist on censoring of these “educational” stuff, if it appeared, both here and on Commons.
4. Accessibility of a general content (text and images) is not a problem topical to this Wikiproject. Accessibility of formulae is, indeed.
5. Finally, why user talk:Lfahlberg would be a place for a forum worse than mk.wikipedia? BTW, repeating new threads about the same thing from the same person are boring. When I posted several related threads, I made each of them with === === and combined under a single == == header. Incnis Mrsi (talk) 10:09, 28 June 2013 (UTC)

If Lfahlberg wishes, I could produce SVG images for what is needed. BTW, hope this section on planes and hyperplanes is not too painful. Regards. M∧Ŝc²ħεИ_τlk 10:22, 28 June 2013 (UTC)

The current article Linear function (calculus) already has too much on linear equations or, well, whatever general form and parametric form are. The article should really focus on properties of functions, not properties of equations or parameterizations of lines. I am going to open a discussion about that on the article's talk page. — Carl (CBM · talk) 11:31, 28 June 2013 (UTC)

Ex nihilo

The article titled Ex nihilo contains this one-sentence paragraph:

In mathematics, ex nihilo can refer to an answer to a question provided with no working, thus appearing to have developed "out of nothing".

It seems to me that that falls short of infallibility. Michael Hardy (talk) 17:58, 22 June 2013 (UTC)

I removed it. — Quondum 12:56, 29 June 2013 (UTC)

Highly totient number?

Making use of the new random math article link, I happened upon Highly totient number. I have never heard of this and a base Google search turned up nothing unrelated to Wikipedia. Google scholar generated only one hit, Masser, D. W., and Peter Shiu. "On sparsely totient numbers" Pacific J. Math 121 (1986): 407-426. There is an OEIS sequence, but it again references the WP article. Right now the topic looks not too notable to me, but I could be missing something. The article content seems fine; if notability is lacking, perhaps it could be merged into Euler's totient function#Some values of the function. Thoughts?

Thanks, --Mark viking (talk) 04:54, 27 June 2013 (UTC)

The only reference is to planetmath, which isn't good enough. A merge to Euler's totient function seems reasonable. M∧Ŝc²ħεИ_τlk 06:02, 27 June 2013 (UTC)

There is probably something to add to Euler's totient function on totient numbers (ie values of the function) where this could be included. Spectral sequence (talk) 16:57, 28 June 2013 (UTC)

There appears to be a problem, in that the Masser & Shiu reference gives a different definition for highly totient number (and conjectures that in fact they are precisely the primes). The Planet Math link given does not work for me. Although the definition in the article makes sense and actually seems quite interesting, I can find no reliable source that mentions this concept. I has been going to transfer the test to Euler's totient function#Totient numbers but will not do so unless I can find a reference for it. Spectral sequence (talk) 20:41, 29 June 2013 (UTC)

Jul 2013

Comments requested

Perhaps you'd like to weigh in here, so that the review can be conducted appropriately. Regards, FoCuSandLeArN (talk) 17:55, 27 June 2013 (UTC)

AfC entry on the infamous Boubaker polynomials, created by and edited by Tunsian IP addresses (with a newly registered account joining in the fun). This is the same pattern as M. Boubaker's previous attempts to create this article. Sławomir Biały (talk) 19:04, 27 June 2013 (UTC)

Boubaker is definitely back, socks and all. See Lattice Compatibility Theory and Wikipedia:Articles for deletion/Lattice Compatibility Theory. Sławomir Biały (talk) 19:25, 1 July 2013 (UTC)

Template: Functions

I made a medium-sized sidebar for concepts related to functions. It links to several articles written in the “this thing is used for so and such” style, three written by me and one by Maschen, but now there is a sufficient number of these articles to make a navbox. Also note title= pop-ups in the “by domain and codomain” section.

Could somebody review it? May I start to transclude it to articles? Incnis Mrsi (talk) 16:28, 30 June 2013 (UTC)

Needs some work. Putting text in the image field has spacing issues. Also, old-style HTML attributes only accept integers (without the "px"). Those parameters (cellpadding, cellspacing) should not be used without their companion CSS counterparts in the style(s) parameter anyway. — Edokter (talk) — 17:45, 30 June 2013 (UTC)

Incnis Mrsi - you should be prepared that people will complain about sidebars and probably request them to be navboxes as footers (see for example template talk:Tensors#Navboxes should be at the bottom). The reasons are that

• all links in it can be seen at a glance,
• takes up less space when expanded and no images on the right-side of the article will be pushed around (see for example notation for differentiation),
• pictures can be placed in the top-right corner of the article in the lead.

Just some thoughts. Thanks for its creation, M∧Ŝc²ħεИ_τlk 09:17, 1 July 2013 (UTC)

I am far less interested in what Jorge Stolfi thinks about this than in what you think about this. “Less space when expanded” – doubtful, “no images on the right-side of the article will be pushed around” – let’s hope that the sidebar will not placed by imbeciles. Pictures – yes, then can, so what? Incnis Mrsi (talk) 09:59, 1 July 2013 (UTC)

The tensor template was not converted to a footer only because of Jorge Stolfi's unpersuasive personal opinions, there were suggestions from others, and the new layout does look like an improvement. This is not something that should generally be done - just providing a pointer for something else to consider. M∧Ŝc²ħεИ_τlk 10:22, 1 July 2013 (UTC)

While I appreciate what the template is trying to achieve, I find the arrow notation to be kludgy and unattractive. This has not been improved by the recent change from a single glyph → to the two glyphs —›. (This will not stand for Wikipedia's cadre of unicode consortium hatchetmen, but my principal objection is that it is simply ugly.) Why not simply link the relevant articles? (A more attractive graphical solution would be to use LaTeX to produce an image, and then use the {{Image label}} template to insert links to the image, but maybe this is overkill.) Sławomir Biały (talk) 20:51, 1 July 2013 (UTC)

I actually like Incnis' original idea of arrows from and to the spaces, as well as the overall layout. But since most other people will object, it should probably just be the usual layout of links in collapsed entries like template:calculus (boring but at least effective). M∧Ŝc²ħεИ_τlk 20:59, 1 July 2013 (UTC)

Names of some of these articles are too verbose to fit into the table. Did you notice the table structure, I hope? Image labels is a stillborn idea: non-distinctive boldface for → in my sans serif was exactly the reason why I replaced it with other characters that have distinctive boldface variants. Incnis Mrsi (talk) 17:49, 2 July 2013 (UTC)

Must we justify every single use of Escher's drawing separately?

At Poincaré disk model, Werieth (talk · contribs) removed the link to M. C. Escher, Circle Limit III, 1959 saying "files are missing non-free use rationale's for this article". But a rationale for Hyperbolic geometry is listed and the example there is more specifically an instance of the Poincaré disk model of hyperbolic geometry. So do we really have to generate a separate justification for this article? JRSpriggs (talk) 01:55, 3 July 2013 (UTC)

Yeah, I think so. I don't think you have to be particularly original — if the justification for the hyperbolic-geometry article works just as well for this one, then just copy it, changing anything that needs changing. Unfortunately there are a lot of folks that don't believe in fair use at all (or at least don't think it should be used in en.wiki, which is admittedly not the same thing), and as a consequence the rules are IMO unnecessarily restrictive, but nevertheless the rules. --Trovatore (talk) 02:03, 3 July 2013 (UTC)

For better or worse, the answer is yes. This is a combination of several factors: (1) Escher's works are all copyrighted. Although his works may seem older, he worked from 1937 until later that century, and modern copyright law has extended the copyrights from that era until far in the future. (2) The WP:NFCC policy is very strict and has the bureaucratic requirement of a separate rationale for each use. Having been previously involved on some of those pages, I can say (without judgment) that some editors have very strong feelings about it and are unlikely to make "exceptions".

I think it is often sufficient to link to the article on one of Escher's works. Although this adds an inconvenience to the reader, because they have to click to see the work, it eliminates most of the hassle of WP:NFCC. If a image is desired in a math article, the key is to include sourced commentary that specifically discusses the image, and add a rationale to the image page pointing out that commentary. — Carl (CBM · talk) 02:07, 3 July 2013 (UTC)

Unfortunately, unlike some of his other works, we do not have an article on M.C.Escher's circle limit III even though it is shown in his biography.

Another anomaly is that a rationale is listed for Tessellation, but the picture is not actually shown in the article on Tessellation. Also that rationale is interrupted by the {{Non-free 2D art}} template instead of being placed after it like the other rationales. JRSpriggs (talk) 02:57, 3 July 2013 (UTC)

I believe there are enough scholarly publications specifically about Circle Limit III to make it sufficiently notable for a stand-alone article, if someone wants to take the time and effort to make it one. —David Eppstein (talk) 03:22, 3 July 2013 (UTC)

Ok, done. —David Eppstein (talk) 07:28, 3 July 2013 (UTC)

Thanks to David Eppstein for creating Circle Limit III and fixing our image file's description. I added a link to the new article to Poincaré disk model to replace the direct invocation of image which was removed. I hope that keeps everyone happy. JRSpriggs (talk) 11:58, 3 July 2013 (UTC)

Quasi-separated morphism

Quasi-separated morphism is currently a redirect to Quasi-separated: I think it should be the other way round, but can't do the move. Spectral sequence (talk) 06:43, 6 July 2013 (UTC)

Change Similarity transformation redirect

Similarity transformation is supposed to link to the matrix similarity article, surely. It did at one time, then it was changed in subsequent edits. I'm going to change it back to matrix similarity, but does anyone have other ideas? M∧Ŝc²ħεИ_τlk 11:52, 4 July 2013 (UTC)

There is no idea of transformation in matrix similarity. On the other hand, "Similarity (geometry) [is] a shape-preserving transformation" (quote from similarity (disambiguation)). Therefore, IMO, your edit is wrong, and I'll revert it. D.Lazard (talk) 12:36, 4 July 2013 (UTC)

A similarity transformation is a matrix transformation of the form A -> P A P^-1.

Examples include:

• transformation of co-ordinate axes to the principal axes of the inertia spheroid, diagonalising the inertia matrix (Moment of inertia#Principal axes, or Principal Components Analysis in statistics);
• transformations to normal mode co-ordinates, diagonalising a quadratic form;
• transformations to "good quantum number" bases in quantum mechanics, diagonalising the Hamiltonian;
• use of rotors/quaternions/spin-matrices to effect rotations.

So of course Maschen is correct in that being where the redirect ought to point. Jheald (talk) 13:03, 4 July 2013 (UTC)

The acid test is to see what articles link to the page, and in what context, eg: Dirac equation, Positive-definite matrix, Representation theory of the Lorentz group, etc. Jheald (talk) 13:14, 4 July 2013 (UTC)

Similarity transformation is a common term in physics for what is essentially a change in basis. Maschen is correct that for physicists at least, it should redirect to matrix similarity. But D.Lazard is correct too, in that for math folk similarity transformation is first and foremost a geometric concept, one that everyone learns in high school. Wherever the redirect points to, there should be a hatnote pointing to the other major use of the term Similarity transformation. --Mark viking (talk) 14:24, 4 July 2013 (UTC)

I would qualify that. "Similarity" is a geometric concept that is taught in school -- whether two triangles are similar, etc. But I don't think I ever heard the phrase "similarity transformation" used in that connection. On the other hand for matrices and operators, similarity transformation is a very precise concept, and this is the phrase invariably used for it. Jheald (talk) 14:39, 4 July 2013 (UTC)

But here's a scientific dictionary that gives both senses [63], so it looks like we should probably have a dab page. Jheald (talk) 14:44, 4 July 2013 (UTC)

Or better, by WP:2DABS, this could be solved by hatnotes. In fact the dab page similarity (disambiguation) already exists and clearly distinguishes between these two meanings.

Jheald, A similarity transformation in geometry is an equally precise concept, referred to by precisely this name. It is a transformation of a geometric space (by default the Euclidean plane) that takes every shape to a similar shape. Similarity transformations are special cases of affine transformations and of Möbius transformations. Sometimes they are referred to just as "similarities", but that is more ambiguous, because "similarity" may also be the property of being similar. The change to this redirect broke one of the wikilinks in affine transformation, for instance, which was expecting to refer to the geometric concept. —David Eppstein (talk) 17:25, 4 July 2013 (UTC)

Sorry for breaking any links... Anyway since the term "similarity transformation" appears to be torn between a few articles why don't we just create a DAB page specifically for similarity transformation (yes, I know there is similarity (disambiguation) but that one is much more general) - with the links

• Similarity (geometry)
• Matrix similarity
• Affine transformation
• Möbius transformation

and "see also" pointers to transformation, similarity (disambiguation)? M∧Ŝc²ħεИ_τlk 18:30, 4 July 2013 (UTC)

Affine transformation should be a see-also, not a main link, and I'm not sure Möbius needs to be listed there at all. —David Eppstein (talk) 19:06, 4 July 2013 (UTC)

Done. M∧Ŝc²ħεИ_τlk 09:35, 6 July 2013 (UTC)

I've done a dab pass through the various links. I routed links for the Euclidean geometry concept through Similarity transformation (geometry), in case anyone wants to expand this, or point it to a specific part of the Similarity (geometry) article. Jheald (talk) 15:52, 7 July 2013 (UTC)

Thanks for doing that and sorry to create work for others, I didn't get round to fixing those myself through the "what links here" function in the toolbox... M∧Ŝc²ħεИ_τlk 21:46, 7 July 2013 (UTC)

Differentiable map is undefined

Differentiable map redirects to smooth function, which does not discuss or define differentiation of a continuous map between manifolds. ᛭ LokiClock (talk) 19:51, 6 July 2013 (UTC)

How do you get the redirect to go to the smooth functions between manifolds paragraph? AHusain314 02:21, 7 July 2013 (UTC)

Click on the Differentiable map link, then click on the "Redirected from" link at the top of the linked Smooth function article. Edit the redirect page to have the content #REDIRECT [[Smooth functions#Smooth functions between manifolds]]. However, this seems to be the wrong destination, as LokiClock points out: differentiable and smooth are not synonyms. — Quondum 03:00, 7 July 2013 (UTC)

I have redirected Differentiable map to Differentiable function, which is the correct target. However, this article unduly emphasizes on the univariate case and would need to be rewritten for better taking the multivariate case into account. D.Lazard (talk) 08:02, 7 July 2013 (UTC)

modular group visualization

I made a video showing how the Klein's j-invariant is invariant under tau->-1/tau in SL(2,R), and I would be happy to provide the movie file if someone else could convert it to an animation for this page:

Here it is on youtube: http://www.youtube.com/watch?v=kvQ7e2AiE2g

http://en.wikipedia.org/wiki/Modular_group

tryptographer (talk) 18:32, 7 July 2013 (UTC)

Transformed the redirect Irreducible representation into an article

Even just looking at the edit history, and more importantly after a discussion on my talk page, this is a desperately needed article and would help fill gaps in WP on group theory in theoretical physics and chemistry. I thought that at least something of a definition with some links and sources (to be moved inline) is far better than the annoying redirect to simple module, and decided put the draft in mainspace so others with expertise/interests in group theory can see and/or edit it. Needs a lot of work which I'll hopefully get to finish (recently busy...). M∧Ŝc²ħεИ_τlk 21:46, 7 July 2013 (UTC)

An irrep cannot be decomposed into a (non-trivial) tensor product, you said? You will write great textbooks some day in a distant future, but now start from learning the representation theory, please. Representation theory of the Lorentz group gives good examples, where e.g. the 4-vector representation is a tensor product of two complex conjugate spinor ones. The latter are projective reps of of the Lorentz group though, but for SL(2, C) they are true representations. And, surprisingly… the 4-vector rep has no invariant subspaces! Incnis Mrsi (talk) 03:46, 8 July 2013 (UTC)

Well, I can't follow the WP version of representation theory of the Lorentz group too easily, and there is a section on this to be expanded. If the irrep can be decomposed, doesn't that mean invariance is broken, somehow? Anyway it's something else I'll try to clear up soon... M∧Ŝc²ħεИ_τlk 05:49, 8 July 2013 (UTC)

I have written quite a lot of content on the topic of unitary representation theory. The article being discussed here seems like some sort of essay. It seems quite confused even in the lede. Groups like SL(2,C) are the complexifications of compact Lie groups like SU(2). The irreducible representations of compact Lie groups, in particular the classical groups, are a natural development of nineteenth century invariant theory. That subject was covered in the book of Felix Klein on the icosahedron and culminated in the work of Schur and Weyl. That theory was used in elementary particle theory by numerous authors. For finite groups it was used in crystallography. Infinite-dimensional irreducible representations, for example of the Heisenberg group, have played a central role in quantum mechanics (and later dual resonance models and String theory). Much of that development, also historically originating in the work of Weyl and von Neumann, is described in the lectures and books of George W. Mackey, which contain numerous instances of the applications of representation theory.

The current article gives a confused view of the topic and not enough sources. The statements on tensor products are strange. For finite groups or compact Lie groups, the irreducible representations of a direct product arise from taking tensor products of irreducible representations of the factors. In general, except in special cases, tensor products of irreducible representations are rarely reducible. The decomposition rules are generalizations of the Clebsch-Gordan formulas. For classical simple groups they can be described for fundamental representations (the Brauer-Weyl rule) or by the combinatorics of the Littlewood-Richardson rule and its generalizations.

Perhaps a good place to start is using a source like "The Scope and History of Commutative and Noncommutative Harmonic Analysis" by George Mackey. There is also no shortage of books with titles like "Lie groups for physicists". Mathsci (talk) 06:41, 8 July 2013 (UTC)

If the article and me are confused, then no surprise, but I wrote from Wigner, Tung, Weinberg, and Atkins (of course there could be more sources, but it's certainly better than nothing). The tensor product bit in the lead will be cut out, but all the sources just mentioned do give the similarity transformation and block matrix, so if nothing else I can't see why that would be wrong.

Apart from the sources and external links already there - the article may as well be scrapped and restarted... M∧Ŝc²ħεИ_τlk 07:37, 8 July 2013 (UTC)

It seems like the errors have been for the most part corrected. I'm not personally keen on the emphasis of the article on physics (a la Wigner), but I think it's obviously better that this article exist (irrespective of its general condition) than for it to be a redirect. It seems much more likely that someone will improve the article now that it exists. Sławomir Biały (talk) 20:07, 8 July 2013 (UTC)

Worse than the emphasis on physics, Maschen’s version is exclusively focused on groups. It is exactly as incorrect as the simple module redirect it recently replaced. The article has to be, at first, restructured to cope with this problem. Incnis Mrsi (talk) 13:30, 9 July 2013 (UTC)

@Incnis Mrsi: Slightly off-topic, but at WP:RD/MA (here) I have recently been trying to understand exactly what it means for spin representations to be called "projective", in terms of the definition given in the article projective representation. Despite valiant efforts by Sławomir Biały (talk · contribs) and an anonymous IP, I'm still not quite there yet. I'd be very grateful for any further clarifications anyone felt like offering there. Jheald (talk) 08:39, 8 July 2013 (UTC)

No longer an issue. All sorted out now. Jheald (talk) 13:40, 8 July 2013 (UTC)

"Reiteration" rule of inference

In mathematical logic, "reiteration" is a rule of inference. See our article on the deduction theorem#Virtual rules of inference and propositional calculus#Argument. However, Reiteration is at present merely a redirect to the musical concept Tremolo. I think we need at least a disambiguation (or hat note) here, and possibly an article. What do you-all think? JRSpriggs (talk) 10:52, 11 July 2013 (UTC)

I created a hatnote at Tremolo to point to the mathematical articles you link here, although a DAB page may be better if more than two pages are involved. M∧Ŝc²ħεИ_τlk 11:10, 11 July 2013 (UTC)

Maschen, as usually I see you running well ahead of schedule. Incnis Mrsi (talk) 11:14, 11 July 2013 (UTC)

Regardless of “virtual rules of inference”, the musical redirect on a word from a non-specific vocabulary is bad. Overwrite it with a dab boldly. Incnis Mrsi (talk) 11:14, 11 July 2013 (UTC)

As you can now see, my edit has been reverted. Let's just proceed with a DAB page. M∧Ŝc²ħεИ_τlk 13:51, 11 July 2013 (UTC)

Done. WikiProject Music has also been notified. Rather than trying and failing and wasting people's time fixing my errors, I'll leave it to the members of this project and WikiProject Music to fix any incoming links and double redirects to reiteration, as and when they are inclined. M∧Ŝc²ħεИ_τlk 14:05, 11 July 2013 (UTC)

Just in case someone wants to help with sourcing for 'Continuum hypothesis'

Please see Talk:Continuum hypothesis#Result by Laszlo Patai. -- Toshio Yamaguchi 13:16, 11 July 2013 (UTC)

Visual Editor changing how italics and superscripts interact

The new visual editor is much discussed, but theres one subtile change which affects html format maths equations. In this revision [64] its changed ''x''_''s'' to ''x_s''. Other changed have ''F''^''i''0 (Fⁱ⁰) to ''Fⁱ''⁰ (Fⁱ⁰) splitting one compound superscript into two. Other diffs on other articles have done the reverse. None of the edits actually change how the equation appear, so I'm not sure its a big issue. Its done to about 10 edits a day all of which seem to be tracked in and edit filter.[65] Anyway if anyone is interested in the issue there is a buzilla T52938.--Salix (talk): 22:31, 11 July 2013 (UTC)

I reported this to them back in June, it is bug 50291. — Carl (CBM · talk) 01:30, 12 July 2013 (UTC)

I have just realised that I am not using VE, presumably because I'm using an unsupported browser. Are other Project members using it for mathematical articles, and what are their reactions? Is there any risk that it will become compulsory and that I'll suddenly find myself unable to edit? Spectral sequence (talk) 17:11, 16 July 2013 (UTC)

canonical

Here is an old version of the article titled canonical. Here is the imbecilic current version. It was imperfect before, but written by somewhat literate people. Now it's just dishonest. Work on this is needed. Michael Hardy (talk) 05:55, 13 July 2013 (UTC)

The erosion of that article happened in several stages. First, apparently based on discussions on the talk page, it was converted to a dab. Then most of the disambiguation entries were removed. We can argue about whether the edit summary of that last edit was correct, but it was clearly a destructive edit. Sławomir Biały (talk) 06:16, 13 July 2013 (UTC)

IMHO the most imbecilic thing of the current version is this content dispute template on a WP:disambiguation page. Being serious, trace to which articles was the original content transferred, please, before starting a pointless flame. Incnis Mrsi (talk) 06:19, 13 July 2013 (UTC)

Well originally these were linked in the dab page. But now they aren't anymore. It's all well and good that this content exists somewhere, but not so good if readers are unable to find it. Sławomir Biały (talk) 06:27, 13 July 2013 (UTC)

This is highly inappropriate conduct from an administrator. I suggest User:Michael Hardy familiarises himself with correct template usage, and tone down the language. StAnselm (talk) 06:47, 13 July 2013 (UTC)

The solution is to replace, in canonical (disambiguation), the entry canonical form by canonical (mathematics) and to write this article, which should describe the various meanings of this word in mathematics. This article should link to canonical form but also define canonical morphism and canonical isomorphism (the unique morphism such that ...) for which I have found nothing in WP. The "Mathematics" section Here could be a starting stub for this article. D.Lazard (talk) 10:52, 13 July 2013 (UTC)

Systemic real numbers bias

One can easily notice that most math articles of en.wikipedia show a strong preference to the real numbers field. And not only in differential geometry where real numbers are deeply entrenched in most primary sources, but in other disciplines too, not excluding algebra. When the bias is explicated, it sometimes has grotesque forms such as presenting general facts as relevant to real numbers only: recall the scandal with the former “Euclidean subspace” article. But there is also a cryptic, more dangerous form of real bias where the field of scalars is not named at all in the relevant context: for example, see the Spin group article which discusses an accidental isomorphism of the Spin(2) and its action of R². I think that any article that presents a real-specific fact must have a mention of R in the appropriate place. Incnis Mrsi (talk) 14:33, 9 July 2013 (UTC)

About the "Euclidean scandal"... I, personally, would be glad to say (on my lectures) that the n-dim Euclidean space is (by definition) an affine space with (some additional structure). However I do not think this terminology is standard. Some mathematicians use both "vector Euclidean space" and "affine Euclidean space"; some use "Euclidean space" (by default, vector!) and "affine Euclidean space"; many use only "Euclidean space" (by default, vector); and very few use "Euclidean space" (by default, affine). Correct me if I am mistaken; I would be happier to be mistaken than right. Boris Tsirelson (talk) 15:18, 9 July 2013 (UTC)

This is sort of like complaining about a "systemic pine-tree bias" in the forests of Russia. I don't think there's any way around the fact that the reals are probably the most used field in math and physics, and therefore the most familiar and most prolific in texts. The complaint about leaving the assumption invisible is fair enough. Isn't the solution just to obviate the field being used? Rschwieb (talk) 16:51, 9 July 2013 (UTC)

How is it related to Tsirel’s comment? Incnis Mrsi (talk) 11:14, 11 July 2013 (UTC)

Dear @Incnis: I apparently made an indentation mistake. Please next time skip the process of writing comments feigning that you could not figure out that a certain comment was directed at you, and continue with addressing the comment. It will save all of us reading/writing time. Thanks. Rschwieb (talk) 13:23, 11 July 2013 (UTC)

Could you just fix the indentation instead of explaining than you made a mistake? Incnis Mrsi (talk) 13:41, 11 July 2013 (UTC)

Dear @Incnis: The answer is no. When the intention is abundantly clear, as it is here, I am not going to fix it. I thought I made that clear in my previous comment. Since I have abundant confidence in your ability to understand the intention, I won't fritter away time playing the "edit-Incnis's-nit" game in the future. Please stop trying to get me to play the game. Thank you for understanding. Rschwieb (talk) 11:32, 17 July 2013 (UTC)

Well, the reals are a pretty amazing field: They're the only Archimedean completion of the rationals, and so they (quite naturally) have a distinguished role in mathematics. It's always good to state your context and assumptions, but I think it's indisputable that R is more important than, say, Q₄₁. Ozob (talk) 03:02, 11 July 2013 (UTC)

This is more of a mathoverflow issue. If you raise the issue there, make sure to give your sources, be specific (with examples), and avoid subjective and argumentative comments. If you do so, please provide a link. Tkuvho (talk) 08:06, 11 July 2013 (UTC)

Please, make yourself familiar with http://mathoverflow.net/help/on-topic, and specifically the paragraphs about “well-defined questions” and “not a discussion forum”. Anyone asking a question on whether R is more important than Q₄₁ can count on my vote to close as “primarily opinion-based”.—Emil J. 11:08, 11 July 2013 (UTC)

I disappointed about the observed lack of serious consideration from the WikiProject’s members. Nobody refutes that R is important, but these are not real numbers that generates the overwhelming majority of abstract mathematical structures (the concept of metric space is the only structure I can remember that directly depends on reals). There is no guideline how to explicate the dependence on the field (or ring) of scalars, and there is nothing good with this in the present stage of Wikipedia. Incnis Mrsi (talk) 11:14, 11 July 2013 (UTC)

WP:MTAA. Making things as general as possible is all very well, but often what is most helpful to readers at least initially is something much more concrete and specific -- particularly if they need the maths, but don't have a maths background, and have not taken courses that might be standard in a mathematics degree but may not typically be found in degrees in other disciplines.

On a related note, Incis, I saw you recently replaced SO(3) with SO(3,R) and SO(n) with SO(n,F) in the examples section of Projective representation (diff) I am not sure that this was terribly useful. The point surely of an examples section like this is to present the material applied to particularly important and familiar cases. SO(n), and SO(3) in particular, is the case of key importance, because this corresponds to rotation of everyday Euclidean spaces, and in particular the 3D space in which we live. Also, because orthogonality is particularly associated with real matrices -- the relevant corresponding concept for complex matrices is usually unitarity instead. So in this case SO(n) and SO(3) were entirely appropriate, and were what should have been used. Making the notation more complicated than this just makes the article more opaque and more forbidding to likely readers, for no gain that they are likely to appreciate. Jheald (talk) 12:59, 11 July 2013 (UTC)

@User:Jheald: Accepted modern theories such as quantum mechanics emphatically deny that the world "in which we live", as you put it, has the structure of a vector space over a field built using Dedekind cuts, so in a way the tenor of your comment confirms some of User:Incnis Mrsi's concerns. Tkuvho (talk) 13:13, 11 July 2013 (UTC)

(ec) Part of the skill of making a mathematical model (or a physical model) is choosing the right variables, that transform in the right way. For a vast swathe of applications, that means a classical conventional real space. Besides, User:Incnis Mrsi's obfuscations to that article wouldn't help anyone understand quantum mechanics any better. Jheald (talk) 13:23, 11 July 2013 (UTC)

To which article? Incnis Mrsi (talk) 13:41, 11 July 2013 (UTC)

Really?? It seems I miss something important in quantum theory... Could you tell a bit more on this point?

I'd say, the question is, whether or not real numbers are significantly more notable than others. Boris Tsirelson (talk) 13:20, 11 July 2013 (UTC)

I don't think anyone disagrees the reals are significantly more notable. First of all, the 90+% of people who are not mathematically minded only "know" about two or maybe three fields, and the reals is definitely going to be one of them (even if they have a poor conception of it.) And then even among mathematicians, R is still regarded as a significant field. I think the question(s) are more along the lines of "Do we need to broaden some articles away from R?" and then "If so, which ones?". Rschwieb (talk) 13:32, 11 July 2013 (UTC)

@User:Tsirel: In our article Introduction to quantum mechanics, one finds the following: "Some aspects of quantum mechanics can seem counter-intuitive or even paradoxical, because they describe behaviour quite different than that seen at larger length scales." Meanwhile, the real line assumes scale homogeneity and infinite divisibility, and therefore does not reflect the phenomena on very small scales. I am sure you are aware of this, and I agree, along with User:Incnis Mrsi, that as you put it the "real numbers are significantly more notable than others". Tkuvho (talk) 13:29, 11 July 2013 (UTC)

No, sorry, this is an oversimplification. It is well-understood that the quantum/classical border is related not to the size of the objects, but to decoherence. True, decoherence is typically very strong for large objects and weak for small objects. However, this is not a failure of scale homoheneity of the space. Quantum physics is evidently scale inhomogeneous, indeed. But not the space (unless you come to such ideas as the Planck scale foam). Boris Tsirelson (talk) 14:52, 11 July 2013 (UTC)

Are you arguing that physical space is scale homogeneous? I wonder how you know that :-) What happens exactly on the scale below the smallest string? Tkuvho (talk) 15:03, 11 July 2013 (UTC)

BTW I do not trust in “the space-time”. Although Lorentz symmetry is observable in numerous its manifestations, there are little evidences that “points of the space-time” actually have sense on a fundamental level. What is certain is that there is no observable evidences of the scale symmetry. Incnis Mrsi (talk) 15:07, 11 July 2013 (UTC)

"modern theories such as quantum mechanics emphatically deny" is one thing, and "there are little evidences" is a quite different thing. :-) Boris Tsirelson (talk) 16:21, 11 July 2013 (UTC)

Formulation of a projective representation over an arbitrary field belonged to the article long before my edit. I stressed that the choice of real numbers has nothing to do with the double cover stuff, but the concrete rotation group is 3-dimensional and real, not any else. How the article become opaque from the edit when the wikilink rotation group SO(3) lies behind the symbols? Incnis Mrsi (talk) 13:41, 11 July 2013 (UTC)

It sounds to me like you want to be able to do all of mathematics (well, the part of mathematics that requires fields) over an arbitrary ground field k. It won't work. You cannot even expect the same behavior from R and C (compare real differentiable functions to complex differentiable functions); let alone Q_p and R(x) and F_p and so many others. It's nice to unify things where possible and where it retains clarity, and there are plenty of situations that could be treated in a unified way that aren't currently in Wikipedia; but you can't expect to banish the mention of specific fields, even in those contexts where the definitions don't require a specific field. Ozob (talk) 13:42, 11 July 2013 (UTC)

@User:Ozob: I am not sure why such a rush to refute User:Incnis Mrsi. It may be more helpful to ask for a clarification of what he wishes to improve, for example, in the case of the Spin group. I personally have the impression that the real case is the most important case here, but perhaps I am not sufficiently familiar with the literature. Some examples would be helpful. But the sarcasm and animosity that's coming from a number of editors is a bit puzzling. Does it make people lose sleep just to conceive of the idea that there might be a systemic bias in favor of the reals? Tkuvho (talk) 13:51, 11 July 2013 (UTC)

Despite my opposition to User:Incnis Mrsi on the issue of Euclidean space apropos of our article manifold, I agree with the contention that Spin group (and other similar articles in group theory) should be quite clear from the outset what the relevant field is. However, I also agree with Rschweib's "sarcasm" (as you put it) to a certain extent. I would not characterize this as a systemic bias, but rather just poor encyclopedia writing. For example, I would not want to see the article spin group rewritten from the perspective of group schemes, although at a minimum the field(s) involved should be emphasized. I think the "bias" in restricting to the real field (and complex field as well) in many cases is consistent with the appropriate WP:WEIGHT. This is essentially what I have already said at Talk:Manifold when a similar issue was raised. Sławomir Biały (talk) 14:08, 11 July 2013 (UTC)

(edit conflict) The content on algebraic groups is not great on wikipedia even over the complex numbers. Where for example is the fixed point theorem for solvable groups acting on a projective variety? (is it hidden away somewhere in Borel subgroup?) There are plenty of sources (Chevalley, Borel, Humphreys). As far as differential geometry is concerned, one fairly common way to give a clear exposition is to use matrix groups (so algebraic if compact). Otherwise there is an unnecessary and off-putting amount of preparatory material required to define Lie groups and the exponential map. The problem already arises in defining connections, principal fiber bundles, etc. But, as in the writings of Arnold or Postnikov, matrix groups (and their homogeneous spaces) are very concrete and give examples which can be worked out explicitly. Another example is that of spin structure and the Dirac operator on a manifold. As far as projective representations are concerned, the first main application concerns projective unitary representations of locally compact Abelian groups (Segal, Shale, Weil's 1964 Acta paper). When the group is Rⁿ this is the usual setting of quantum mechanics, the harmonic oscillator, etc, but equally well it could be a group of adeles. So change of fields occurs in the group being represented, not in the projective unitary group. Mathsci (talk) 14:52, 11 July 2013 (UTC)

I do not understand in this eloquence whether do you think that Spin(n) is a real-only construct, or… it ought to become so for the Sake of Accessibility? Incnis Mrsi (talk) 14:41, 11 July 2013 (UTC)

What "eloquence"? The standard method of constructing the spin group and spin representations is to define them using the real Clifford algebra of an even-dimensional real inner product space. Given an underlying complex structure on that space, there is a canonical irreducible module on which the Clifford algebra acts faithfully (the exterior algebra of the complex inner product space). The complexification can therefore be identified with the algebra of all endomorphisms of that module and the spin group with (the identity component of) the group of orthogonal operators in the real Clifford algebra that normalize the Clifford multiplication operators. The algebra and module are Z₂-graded and the Spin group acts irreducibly on the even and odd parts of the module. The action by conjugation on the Clifford multiplication operators gives a homomorphism onto the special orthogonal group. That is just the double cover by the spin group. The group Spin_c also appears in a similar way in the complexified Clifford algebra. This is all standard stuff that is used as algebraic background for the Atiyah-Singer index theorem for example. Of course Clifford algebras can be defined more generally, but there is no comparable application in topology, geometry or representation theory. Over a general field, even in characteristic zero, there is the problem of defining the Lie algebra: that is dealt with in treatments of algebraic groups, Chevalley bases, divided powers, etc, and is more involved. It is an adaptation/rephrasing/generalization of the theory over the real and complex numbers. Mathsci (talk) 08:47, 12 July 2013 (UTC)

Well, Spin(n) is certainly not a real-only construct—quite the contrary—and nor should it become so for the sake of accessibility. Indeed, the complex spin groups are actually easier to understand than the real analogs, and should not be overlooked. I agreed with the contention that it should be made clear which field(s) are involved at which times in the article spin group. But I have consistently objected to the view that our articles should always assume the maximally general point of view from the outset, which is what the OP seems to believe (in this and other threads). This has as much to do with accessibility as it does to other concerns such as WP:WEIGHT. Sławomir Biały (talk) 15:30, 11 July 2013 (UTC)

Leave the maximal generality to Bourbaki. :-) Boris Tsirelson (talk) 16:24, 11 July 2013 (UTC)

Not really my suggestion. I do think Bourbaki's style in incompatible with Wikipedia, but I don't think that they dwell excessively on generality (by modern standards). For the purposes of the present thread, I think Grothendieck's relative perspective goes way too far in that direction though. Sławomir Biały (talk) 18:05, 11 July 2013 (UTC)

For Lie groups, chapter IX of Bourbaki and Vol V of Dieudonné's treatise on analysis are just on compact Lie groups, their complexifications and real forms. They are not very different for fairly obvious reasons. Both are useful sources (sometimes even just the exercises). And yes, the structure of the complexified Clifford algebra is easier than that of the real Clifford algebra. But people who write articles are supposed to know that (or at least I would hope so). Mathsci (talk) 20:59, 11 July 2013 (UTC)

LoL. I am not an ignorant person and know (or at least heard) about these adventures more than Ozob expects. No sane person can assert that Analysis does not depend on the field. “You cannot even expect the same behavior from R and C” is an obvious strawman argument which leads to nothing. It is me who inserted “the mention of specific fields” numerous times (including quite recent navbox and linked articles), and it would be bizarre to expect that somebody here insists on “banishing” it. Incnis Mrsi (talk) 14:41, 11 July 2013 (UTC)

Then, to be entirely honest, I have no idea what this discussion is about. If there are articles that are unclear about their use of the real numbers, then they should be clarified. If there are articles that omit interesting material about fields other than the real numbers, then they should be expanded. What more is there to say? Ozob (talk) 02:22, 12 July 2013 (UTC)

If you still have no idea what an active discussion with numerous participants is about, then I can suppose an acute enumeration syndrome on your side. A Wikipedian prone to this syndrome writes article like: of trees, there are pine trees, birch trees, oak trees, … instead of describing the trunk, branches, leaves, and root. Until you become able to understand that, for example, a vector space is not “a real vector space OR a complex vector space OR a vector space over rationals OR a vector space over a finite field OR a vector space over a non-Archimedean field OR …”, you should abstain from sarcastic comments in such discussions at all. Incnis Mrsi (talk) 04:46, 12 July 2013 (UTC)

I am going to sit out the rest of this discussion, since it appears to be unrelated to writing an encyclopedia. Ozob (talk) 13:50, 12 July 2013 (UTC)

These comments bear no relation to how mathematics articles are written on WP. Teichmüller theory for example is described in the complex case. There is also a p-adic version, but I don't think it's mentioned anywhere on wikipedia, even in Schottky group. Mathsci (talk) 05:32, 12 July 2013 (UTC)

Really don’t you think so? Even after reading hatnotes?

I agree that Ozob’s comments have little to do with how mathematical articles are written on WP. But Wikipedians affected by the enumeration syndrome are not a rare phenomenon. Many articles on computing and chemistry, for examples, are rather clueless in their explanations and verbose in enumerations. Incnis Mrsi (talk) 06:03, 12 July 2013 (UTC)

@User:Incnis Mrsi: Could you be a bit more specific on how one would go about staying away from the "enumeration syndrome" in the case of Spin(n), for example? I added a brief clarification in the lede that we are using the real group SO(n)=SO(n,R). Does that solve the problem, or do you envision a different approach to Spin(n)? It is not entirely clear to me how one would go about correcting a possible "systemic bias in favor of R" in this case. Tkuvho (talk) 07:33, 12 July 2013 (UTC)

How is SL related to the case? BTW, note that Sławomir thinks that Spin is not a #real-only object. So, at least complexifications should be explicated in the article. Incnis Mrsi (talk) 08:10, 12 July 2013 (UTC)

I corrected it. Tkuvho (talk) 08:11, 12 July 2013 (UTC)

I doubt it anybody would object if a section is added to Spin(n) to cover the complex case. I must admit I am not too familiar with this case. Is this a double cover of SO(n,C)? Perhaps the problem could be solved by linking to that page. Tkuvho (talk) 08:14, 12 July 2013 (UTC)

Yes, it is. IMHO for any field Spin doubly covers SO, even for fields with discrete topology, although I am not too familiar with this case. Incnis Mrsi (talk) 09:20, 12 July 2013 (UTC)

As User:Mathsci's edit just reminded me, there is the important case of the group Spin^c, particularly useful in 4-manifold theory since such a bundle always exists in this case, providing the framework for Seiberg-Witten theory. This should certainly be mentioned at the spin(n) page. Tkuvho (talk) 08:56, 12 July 2013 (UTC)

If I remember correctly, Spin^c is a structure on vector bundles that involves recently mentioned projective reps, not a specific Lie group. It possibly would be more topical in Spinor or other articles about spinor geometry, not in article about the group. Does orientation (vector space) belong to general linear group or so, indeed? Incnis Mrsi (talk) 09:20, 12 July 2013 (UTC)

You do not remember correctly. Spin_c is the group of unitaries in the complexified Clifford algebra normalizing the Clifford multiplication operators. It is a central extension of the special orthogonal group by U(1) = T. In terms of the Spin group it is the quotient of Spin × U(1) by the diagonal copy of Z₂. It is also the canonical central extension of the special orthogonal group by T obtained by pulling back the central extension of the projective unitary group of the spin module. All this is very standard. Mathsci (talk) 14:01, 13 July 2013 (UTC)

I added some material on this at Spin_group#Complex_case. Help in formatting this properly would be appreciated. Tkuvho (talk) 09:10, 12 July 2013 (UTC)

The articles Symplectic group, Orthogonal group, and Special linear group all consider them as groups defined over arbitrary fields. It stands to reason that the same should be done in Spin group. In fact, the division presented in Symplectic group seems relevant here, due to the differing perspectives on the Spin groups, as Lie groups over R or C, or as linear algebraic groups over F. Also, note that there is some overlap with the article Spinor. Mark M (talk) 09:21, 12 July 2013 (UTC)

Articles should be developed so the first few sections are accessible to someone who is new to the area. IF a particular topic is normally only mentioned in connection with the reals in introductory texts then that is the level to aim for. The more general case can go further down the article. The lead should mention the more complex bit at the end, but should also be mainly aimed at beginners. We are not in the business of writing articles that are only readable by people who already know everything about the topic. The target audience for the first few sections should determine how they are written not the perfectitude of the exposition. Dmcq (talk) 09:32, 12 July 2013 (UTC)

Somebody should add the standard downloadable reference, "Algebraic theory of spinors and Clifford algebras" by Claude Chevalley (Collected Works, Vol 2). A short accessible description of the construction of Spin can be extracted in the real and complex case (see the summary above) and added to the article. That would cover the main applications in geometry, including Spin and Spin_c. Then in a section at the end of the article entitled perhaps "Spin groups for arbitrary fields," a brief summary of the material on that topic in Chevalley's book could be given (perhaps assuming for simplicity that the characteristic is not 2). Possibly some material on the Witt group and quadratic forms might be necessary (cf Shimura's book, Arithmetic of quadratic forms). Mathsci (talk) 10:10, 12 July 2013 (UTC)

The article Orthogonal group is an example of the imbecility of giving the generalization to general fields before the usual case, for a notion that was primarily defined only over the reals. It follows from the first sentence of this article that there are several groups O(n,R) and that the Lorentz and symplectic groups are orthogonal groups. In fact, it is not said that the matrix of the quadratic or bilinear form should be the identity matrix on some bases. It is not even said that the bilinear form must be non degenerated. D.Lazard (talk) 10:31, 13 July 2013 (UTC)

If an imbecility is demonstrated here, then it is an assertion that a symplectic group can be derived from a quadratic or a symmetric bilinear form. Omission of non-degeneracy is actually a gaffe in the article; it is the only valid point in Lazard’s posting. The question with Lorentz group is explained in the lead after several paragraphs: search for the word “definite”. Incnis Mrsi (talk) 11:11, 13 July 2013 (UTC)

The orthogonal group of a quadratic form can be defined whether or not the form is non-degenerate. This is explicitly done on page 13 of Lam Introduction to quadratic forms over fields (2005), pages 7-8 of Knus Quadratic and Hermitian forms over rings (1991) or page 19 of Cassels Rational quadratic forms (1978). It seems unlikely that all of these otherwise reliable sources would have made the same "gaffe". Spectral sequence (talk) 11:25, 13 July 2013 (UTC)

Then, there are no valid points. Incnis Mrsi (talk) 11:34, 13 July 2013 (UTC)

In response to D.Lazard's comment, I reworded the opening paragraph of Orthogonal group to emphasize the real case, but also keep the standard generalization to arbitrary fields. Is the opening paragraph now reduced in its "imbicility" levels? Mark M (talk) 11:57, 17 July 2013 (UTC)

Merge Duodecimal and Base-13

Duodecimal and Base 13 should be merged and a new page accurately describing a true base-12 number system should be created. While it may be that the system has been historically labeled as "duodecimal", the article technically describes a base-13 number system, not base-12. A discussion on the merger has been created on its talk page.
David Lones (talk) 23:34, 17 July 2013 (UTC)

There is no problem with the article. David Lones was misinterpreting the content of Duodecimal, i.e. base twelve. JRSpriggs (talk) 03:42, 18 July 2013 (UTC)

Move discussion (single digits)

See Talk:1 (number)#Requested move for a discussion that you may be interested in. -- 76.65.128.222 (talk) 05:52, 18 July 2013 (UTC)

Substitutions (a mess)

I moved Weierstrass substitution to Tangent half-angle substitution because

• It was introduced by Euler, who died before Weierstrass was born;
• The only moderately authoritative source I know of that calls it the Weierstass substitution is Stewart's calculus textbook;
• Fred Rickey, a mathematicians who has searched through Weierstrass' writings for any mention of this substitution, says it's not there.

Then in the course of fixing links to that page, I found this mess:

• We have one page called Substitution (algebra), which is about plugging in particular values in an expression. I question the idea that that's what the title "Substitution (algebra) should be about.
• We have another page called Substitution of variables, for which an appropriate title might be "Substitution (algebra)".
• We have yet another page called Plugging in. This is on the same topic as Substitution (algebra).
• We have a disambiguation page titled Substitution, and we had a redirect titled Substitutions that pointed, NOT at Substitution, but at Substitute, another disambiguation page. I've redirected it to Substitution, and put hatnotes atop both disambiguation pages informing the reader of the other page's existence.

Sigh.

Now we have a mess to clean up.

I think we ought to

• move Substitution of variables to Substitution (algebra);
• redirect Plugging in and Substitution of variables;
• fix the links to those pages.

Michael Hardy (talk) 16:47, 13 July 2013 (UTC)

Bravo for great detective work on the so-called Weierstrass substitution. Tkuvho (talk) 08:36, 19 July 2013 (UTC)

First variation

First variation could use some additional motivation. Tkuvho (talk) 08:35, 19 July 2013 (UTC)

Request for help from AfC

Please help review Wikipedia talk:Articles for creation/KSSOLV - the main issue is whether this software "toolbox" is notable or not. Thanks Roger (Dodger67) (talk) 10:36, 19 July 2013 (UTC)

Mathematics Library (IA collection) ‎

Is Mathematics Library (IA collection) a notable web resource? I don't see any significant coverage in reliable sources that are independent of the subject, but a group of editors, apparently with no interest other than this resource and its creator Hamid Naderi Yeganeh, seems to disagree. Spectral sequence (talk) 19:05, 19 July 2013 (UTC)

Now at Wikipedia:Articles for deletion/Mathematics Library (IA collection). Spectral sequence (talk) 07:51, 21 July 2013 (UTC)

There is also a Wikipedia article on Hamid Naderi Yeganeh which suffers from notability concerns as well. I have nominated that article for deletion as well: Wikipedia:Articles for deletion/Hamid Naderi Yeganeh. Moreover, I have noticed that a number of mathematics articles have had links to these self-published items in the collection linked. This seems to be spam, since it is a pretty obvious attempt by Yeganeh to have his name appear in print. Affected articles are: Liouville function, Mertens function, Prime factor, Powerful number, Divisor function, Table of prime factors, Möbius function, Euler's totient function, Table of divisors. My sense is that in many cases the links are redundant with others to more reliable sources like the OEIS. Sławomir Biały (talk) 08:56, 21 July 2013 (UTC)

Wikipedia:About Valid Routine Calculations

Members of this WikiProject may be interested in the new essay Wikipedia:About Valid Routine Calculations. I think the author would probably value input and suggestions. Yaris678 (talk) 17:11, 22 July 2013 (UTC)

That essay has some issues, and I don't think it in any way accurately reflects the many discussions that WP:CALC has been subject to. For instance, it is typically not valid to do units conversion without preserving significant digits. The example in the essay is a source that says "5300 meters" with the conversion to "17,388 ft" (while it arguably should be "17,000 ft"). Also, averaging data is not always appropriate when the data is drawn from different sources (there was a discussion about this somewhere), since different data collection methodologies make taking an average a novel synthesis. These are just the things that jump out at me. Sławomir Biały (talk) 10:18, 25 July 2013 (UTC)

KSSOLV: The AfD needs additional input

Dear mathematicians: Here is a new mathematics article: KSSOLV. I am concerned that three of the five sources are closely connected with the subject, and I don't know enough about the subject to tell if it is properly sourced or not. It certainly isn't of any use to an average Wikipedia reader, and I wonder if it contains detail that should have been saved for a journal article. Can someone check it out? Thanks. —Anne Delong (talk) 20:23, 24 July 2013 (UTC)

I see it was deleted under WP:CSD#G11. I don't think I agree that it was a speedy deletion candidate, although I probably would have voted weakly to delete it on the grounds of marginal notability at an AfD. Sławomir Biały (talk) 10:09, 25 July 2013 (UTC)

The page stated clearly that the software was unveiled 10 days ago. How much notability can it have garnered since? Tkuvho (talk) 14:21, 25 July 2013 (UTC)

It was unveiled in 2009, and announced in the ACM Transactions on Mathematical Software [66]. But that paper only has a handful of citations, hence "marginal notability". Sławomir Biały (talk) 15:03, 25 July 2013 (UTC)

This article has been created in main space and is now up for deletion discussion at Wikipedia:Articles for deletion/KSSOLV --Mark viking (talk) 23:26, 27 July 2013 (UTC)

Centered polyhedral number

Comments at Talk:Centered polyhedral number on whether this is an appropriate article title would be welcome. Spectral sequence (talk) 15:20, 28 July 2013 (UTC)

Extension:Math/Roadmap

There has been a discussion reciently on wikitech-l about the "Long term strategy for math on wikipedia", and there is an mw:Extension:Math/Roadmap document. Its all to do with MathJax, MathML various rendering methods and probably maths support in the visual editor. Theres a Google Summer of Code person working on the later so there should hopefully be some support for maths in VE soon.--Salix (talk): 17:05, 25 July 2013 (UTC)

The meta:Extension:Math/Roadmap link goes to a nonexistent page and I was unsuccessful in searching for the correct page. Is this the correct link? Thanks, --Mark viking (talk) 17:20, 25 July 2013 (UTC)

Sorry, wrong interwiki. The GSoC page is mw:User:Jiabao wu/GSoC 2013 Application a very early VE demo is mw:VisualEditor:TestMath very far from final product. --Salix (talk): 17:28, 25 July 2013 (UTC)

Salix, could you point me to some postings that explain what all this can change for readers? When will the end of (currently the default) retarded PNG renderer come in sight? Incnis Mrsi (talk) 18:36, 25 July 2013 (UTC)

I really don't know, it looks like there just tossing ideas about at the moment. The mailing list is more interesting than the roadmap. One chap has proposed a way of making MathJax available for all readers even anons. There is another idea for a faster way of rendering using HTML5 canvas. Unlikely texvc will die completely as its stable and compatible with even ancient browsers. Speed, download size, browser support and fonts are the big downsides for MathJax. Some are keen on MathML but I've been waiting 10 years for browsers support so I have my doubts on that. It might be good to put the case of better maths rendering from the maths community.--Salix (talk): 19:42, 25 July 2013 (UTC)

Is there any clear statement about whether, when and how mathematics editing will be supported under VE for articles and under Flow for talk pages? I'm getting rather disturbed by the lack of any credible commitment on the part of WMF to supporting mathematics for readers and editors. Perhaps we as mathematics editors should be thinking of taking our work elsewhere? Spectral sequence (talk) 17:03, 26 July 2013 (UTC)

I think the plan is to develop the math plugin for VE during the GSoC, when thats done we'll at least have an ability to enter the latex code, there may be live preview of the formula as you type, there may also be some form of editing visual editing of formula. When it works with VE it will work with Flow.--Salix (talk): 08:13, 27 July 2013 (UTC)

Thanks for that, but without being rude, is that anything other than a personal prediction? In other words, are you speaking for WMF, or do you know of an "official" plan or public commitment anywhere that we can refer to? Spectral sequence (talk) 11:52, 27 July 2013 (UTC)

I thought I would stick my head over the parapet to say what message I personally am getting from the whole VE thing at User_talk:Jimbo Wales#One mathematician's view of VE. Spectral sequence (talk) 21:27, 27 July 2013 (UTC)

Can I just say: if possible, it's better not to take the matter too personally. (actually this applies every time, everywhere.) Math articles/editors are not really the focus of WMF: they want more female editors and stuff from museums and aren't too interested in redoing Bourbaki and beyond! It's much better to keep making small improvements, than thinking of collective bargaining. -- Taku (talk) 22:15, 27 July 2013 (UTC)

I was unsure whether I was going to be able to make any kind of contribution, small or otherwise. It seems, thanks to Salix and Sławomir for finding out, that it will still be possible. But it seemed it might be helpful to flag up that, whatever message the WMF think they are trying to send, this is the message that is coming through to me personally: that message is they do not care about people like me, as you also suggest. And that seems an odd message to send to a volunteer contributor. Spectral sequence (talk) 06:31, 28 July 2013 (UTC)

(unindented) The message is clear: I've been (we've been) waiting SO long for better math support like commutative diagrams. (can anyone just install a package?) And what we get is VE, which is, you know, basically stupid as far as math content are concerned: a reader find an error in a formula, but he will not be able to fix the error himself! Maybe I got so used to indifference and disinterest from the "management" side that it doesn't cause me much grief. Anyway, my point still stands: from 100 years from now, Wikipedia may not exist, WMF may not exist, but I do believe the content being created and maintained here every day will remain in a certain form thanks to the free license (cc-by-sa). So, our focus should be on the content not on the management people. -- Taku (talk) 22:15, 28 July 2013 (UTC)

Just to add more griping to yours, the avowed purpose of WP:VE is to encourage more people to edit Wikipedia, people for whom the oh-so-difficult syntax of editing Wiki source is an obstruction, since there has been a problem of retaining new editors. But the reasons most editors leave have nothing to do with the editing syntax, but (in my experience) with social aspects of Wikipedia—and WP:VE perversely even acknowledges this. Visual Editor is a technical solution for the wrong problem. I predict that, contrary to the aims of the WMF, it will not encourage more quality editors to stay with the project. Instead it will result in a net negative effect: a greater share of the contributions to the project will be poor, incoherent, or outright vandalism. But this is consistent with the purpose of VE which seems to be to encourage more edits from the lazy and incompetent. Sławomir Biały (talk) 23:09, 28 July 2013 (UTC)

Readers of this thread may like to read the message from User:Jimbo Wales here in which he makes the unabmiguous commitment that The source editor will remain available so nothing about mathematical editing needs to change at all. Spectral sequence (talk) 16:37, 29 July 2013 (UTC)

Requested move: Medial

The page Medial describes medial magma or medial groupoid in abstract algebra. However, most of the pages linking there seem to intend Lateral and medial in anatomy, not any concept in mathematics. Therefore, I have requested that the page be renamed. Please see Talk:Medial#Requested move. Cnilep (talk) 02:16, 30 July 2013 (UTC)

Incoherent section in Permutation matrix

Since 4 November 2006 incoherent section Permutation matrix#Solving for P was not removed in spite of note in Talk page! It is very interesting nonsense: if this solving method is correct, then some open problems may be solved very quickly, for example, graph isomorphism problem.--Tim32 (talk) 13:38, 28 July 2013 (UTC)

I wouldn't say it's incoherent, but it's not very explicit about the hypothesis that A (and so also B) must have distinct eigenvalues. Sławomir Biały (talk) 13:53, 28 July 2013 (UTC)

"No strong opinion on whether this section belongs on Wikipedia, but I think maybe no" (History page). Yes, this section looks like WP:OR. Any reference is necessary.--Tim32 (talk) 08:58, 29 July 2013 (UTC)

Just to reinforce the message of my edit summary, I wouldn't object to the removal of the section entirely. Even if it can be sourced, it's clearly placing undue weight on a fairly routine observation. It might be worth a single sentence mention, but probably no more than that. Sławomir Biały (talk)

I deleted the section. I'm finding it very difficult to come up with an application for this. -- Jitse Niesen (talk) 09:32, 30 July 2013 (UTC)

Categorizing three requested mathematics articles

I would like to add the three redlinks in Lists of unsolved problems in mathematics (namely Taniyama's problems, Unsolved Problems on Mathematics for the 21st Century and DARPA's math challenges) to Wikipedia:Requested articles/Mathematics, but I am unsure under which heading I should place them. (Yes, there is the section Uncategorized, but I would like to place them in a more appropriate section). Any suggestions? -- Toshio Yamaguchi 14:48, 29 July 2013 (UTC)

Added. -- Toshio Yamaguchi 11:48, 31 July 2013 (UTC)

Retiring

Thanks for your good works. Kiefer.Wolfowitz 15:10, 31 July 2013 (UTC)

Aug 2013

Wikipedia talk:WikiProject Mathematics/Archive/2013/Aug

Sep 2013

Wikipedia talk:WikiProject Mathematics/Archive/2013/Sep

Oct 2013

Wikipedia talk:WikiProject Mathematics/Archive/2013/Oct

Nov 2013

Wikipedia talk:WikiProject Mathematics/Archive/2013/Nov

Dec 2013

Wikipedia talk:WikiProject Mathematics/Archive/2013/Dec