Wikipedia talk:WikiProject Mathematics/Archive/2018/Dec

Template:Volume

I went looking for a volume calculator, saw that this template by Patrick had been userspaced as not ready yet, so I patched it up, and put it back in "Template:" namespace. It produces useful output by default (inline), and can also generate table cells, and do controllable rounding. Added documentation for it.

It does not presently support unit output, nor do conversion. Someone who knows that stuff better than I do can probably integrate such features and make it much more versatile. PS: It's also just doing cubic volume basic calculation, not anything like converting L×W×D/H into gallons or whatever.  — SMcCandlish ☏ ¢ 😼  23:04, 2 December 2018 (UTC)

Powers of 10

Although more of interest to Wikipedia:WikiProject Numbers, see the proposal at Talk:Powers of 10#Table length. — Arthur Rubin (talk) 16:26, 4 December 2018 (UTC)

RfC about spelling harmonization for "Equaliser (mathematics)" and "Coequalizer"

An RfC about whether we should harmonize the spelling for the equalizer and coequalizer articles is now available at Talk:Equaliser (mathematics)#RfC: Harmonize spelling with the Coequalizer article?. Members are welcome to provide an opinion there. Merry Christmas and Happy New Year, GeoffreyT2000 (talk) 22:56, 8 December 2018 (UTC)

Greek letter templates

Folks here might be interested in a discussion I've opened at Wikipedia:Templates for discussion/Log/2018 December 3#Greek letter templates. –Deacon Vorbis (carbon • videos) 02:59, 3 December 2018 (UTC)

This discussion has been delisted at 2018 December 11. — D.Lazard (talk) 14:13, 11 December 2018 (UTC)

The lede of our article Pure Mathematics needs help

Our article Pure mathematics is an important article, and the current lede is problematic in several ways. Recent edits there have made things worse. Paul August ☎ 14:10, 24 November 2018 (UTC)

D.Lazard, has now restored the lead to a previous better (though still not great) version, see Talk:Pure mathematics. Paul August ☎ 15:59, 24 November 2018 (UTC)

A draft for a new lead for Pure mathematics is proposed at Talk:Pure mathematics#Draft for a new lead, and a discussion on it is open. D.Lazard (talk) 20:28, 25 November 2018 (UTC)

I'm very late to the discussion but just want to make this point: isn't there a sort of conflict-of-interest type problem? My research activity is clearly categorized as "pure math" and that would make me writing/editing the article of this type akin to writing/editing article on companies or political organizations you work for. -- Taku (talk) 23:14, 4 December 2018 (UTC)

It's a very natural human instinct to describe (and often defend) what you do or what you believe and that's not what you should be doing in Wikipedia. -- Taku (talk) 23:17, 4 December 2018 (UTC)

My two cents is that we welcome subject matter experts like you and D. Lazard as editors who know the field well and have an excellent grasp of good versus dubious sources. I'd only consider it a COI if an editor started citing their own papers or books, or there was some egregious POV problem associated with an editor's field of study. I have editied physics articles, but stay away from particular narrow topics in which I have worked or published. Being aware of one own's personal POV is a good thing, as it encourages us to rely on summarizing good sources, rather than just our own expertise. --{{u|Mark viking}} {Talk} 23:28, 4 December 2018 (UTC)

I am puzzled: where are COI contributions from these experts to that article? "Citing their own papers or books"? What did I miss? Boris Tsirelson (talk) 05:59, 5 December 2018 (UTC)

For the moment I am left meditating about the broad field of meanings, covered by the word interest. Wrt to the notion of conflict I contemplate a citation of J.N. Nestroy (Austrian playwright): Who is stronger, me or me? :) Purgy (talk) 07:22, 5 December 2018 (UTC)

To Boris Tsirelson, I was just thinking (and procrastinating): isn't editing "pure math" is akin to editing an article on a company you work for? If your edits depend on your personal experiences and personal views, that's not neutral: I have some idea and view on what "pure math" is; e.g., it feels more art than engineering to me. But an impression like that is something personal and it seems very inappropriate for *me* to put it in the "pure math" article. Editing typical math articles is not like that since definitions or statements used in those always appear in textbooks and not of my own. Maybe this is a problem of "original research" or "synthesis" than COI. I do believe it's very important that an editor *without* math backgrounds is being involved in developing an article like that. -- Taku (talk) 07:49, 5 December 2018 (UTC)

Does it mean that we mathematicians should not edit the "Mathematics" article? Nor its talk page? Nor participate this wikiproject? May I edit "Probability theory"? "Geometry"? Where is the border of COI? More generally, may someone born in France edit "France"? May I participate in a discussion about "eurocentrism" or "decolonization"? Who may? Boris Tsirelson (talk) 09:23, 5 December 2018 (UTC)

I don’t suppose any of you tried to actually read WP:COI, did you? It contains the answers to these questions. (Try WP:SELFCITE to start.) —JBL (talk) 12:28, 5 December 2018 (UTC)

In fact I did (to some extent). I just wondered, how far from this policy would like to go some of us...   :-)   Boris Tsirelson (talk) 12:58, 5 December 2018 (UTC)

The proposed change to the lead was awful quoting all sorts of things that a high school student would never have heard of. Can I suggest that we try and keep our target audience in mind? We should try and aim the first half of an article at people who might want or need to know something about the topic in the next few months. There's no point in putting something like Hilbert's basis theorem in at the level where a person might start to wonder about the difference between pure and applied mathematics. Dmcq (talk) 13:27, 5 December 2018 (UTC)

This is also the reason that I felt I might actually be unqualified to edit an article like this one (since I might start talking about scheme theory and why Grothendieck was the definition of a genius, etc.) A Japanese person can edit the Japan article in accordance to the COI policy but it would be very concerning if no non-Japanese person is involved in the editing process. I’m just saying this is a delicate matter. —- Taku (talk) 20:46, 14 December 2018 (UTC)

New article

Hi. There's a new article, Automorphism group, which I could use someone with more math expertise to take a look at. Thanks. Onel5969 ^{TT me} 10:15, 14 December 2018 (UTC)

Anything in particular? It’s written by a longtime WPM contributor and at first glance is fine. Maybe the only question I have about it is why it should be a standalone article instead of merged with automrophism. —JBL (talk) 12:32, 14 December 2018 (UTC)

Because the notion makes as collective: it is useful to talk about a Galois group as opposed to each automorphism of a field. (This reminds me to add Galois group to the article). It’s a new article and it can certainly use more attention and expansion. —- Taku (talk) 12:47, 14 December 2018 (UTC)

Incidentally I just noticed transformation group redirects to group action, the article which essentially has nothing on the topic... (probably ok circa 2003, not ok today). I will redirect it to automorphism group for now. —— Taku (talk) 12:55, 14 December 2018 (UTC)

Response to Joel B. Lewis - when reviewing technical articles, whether they be in math, chemistry, astronomy, I always ask for folks with more knowledge to also take a look. I can review it for copyvio, formats, bare urls, notability, but not on the technical accuracy. Thanks for all the feedback (and quickly) btw.Onel5969 ^{TT me} 13:25, 14 December 2018 (UTC)

@TakuyaMurata: of course I understand what is the distinction. But neither article is very long, the contents could fit together inside a single reasonable-sized article and it might make navigation easier for readers. (Sometimes when closely related concepts are split into separate articles, it becomes difficult to figure out which article one should be looking at.) --JBL (talk) 16:20, 14 December 2018 (UTC)

Yes, it’s probably fine if they are in a single page but at the current length of the new article. My thinking was there are enough materials for “automorphism group”. For example, there need to be a discussion on the representability of an automorphism group functor, somewhere in Wikipedia, and it will become a bit awkward and unwieldy to have an extended discussion of this in automorphism. A polynomial and polynomial ring are separate articles in part because of the lengths. In my lofty envision, the new article becomes lengthy one. —- Taku (talk) 21:45, 14 December 2018 (UTC)

Rounding templates nominated for merging

{{Round}}, {{rnd}}, and {{decimals}} have been nominated for merging. You are invited to comment on the discussion at the template's entry on the Templates for discussion page. — JJMC89 (T·C) 07:25, 15 December 2018 (UTC)

Isotropy representation

Dear all,

See User_talk:CASSIOPEIA#Isotropy_representation. There is a concern that there might be a concern that concerns the editors of the project. —- Taku (talk) 14:18, 14 December 2018 (UTC)

Thanks to Mark viking: the issue (that there might be an issue) has been solved. —- Taku (talk) 21:41, 15 December 2018 (UTC)

Stokes' theorem move request

There is an an ongoing move request at the Stokes' theorem talkpage. Calidum 03:39, 17 December 2018 (UTC)

Constructions in hyperbolic geometry

Constructions in hyperbolic geometry is a new article that could use some work. In particular, there is the question of which other articles should link to it. And there are tasks internal to the article. Michael Hardy (talk) 19:26, 17 December 2018 (UTC)

Links to DAB pages

I have collected another batch of articles with mathematics-related links to DAB pages. Expert help in solving these problems would be welcome. Search for 'disam' in read mode, and for '{{d' in edit mode; and if you solve one of these puzzles, post {{done}} here.

Feel free to edit. I have a sneaking suspicion that in a couple of the non-technical articles, either an editor or a source may have been misusing a technical term which they didn't understand. One of the articles which I bookmarked before compiling this list failed to survive WP:AFD, and quite right too.

• Temporal finitism
• Brian Jacob
• Wiener's lemma
• Differential forms on a Riemann surface
• Ptychography
• Singular integral operators of convolution type
• Lévy process
• Bar (diacritic)
• Mikhail Samuilovich Livsic
• Nicholas Young (mathematician)
• Module homomorphism
• Robert Everist Greene
• Incompressible surface
• Redheffer matrix
• Gamma-object

Thanks in advance, Narky Blert (talk) 08:49, 19 December 2018 (UTC)

Thanks, all! I am pleased to be able to report that my 'maths-related issues' bookmark folder is empty, and that I can therefore award this WikiProject my rare 'squeaky clean' rating. (For now. I expect I'll be back later.) Narky Blert (talk) 10:27, 21 December 2018 (UTC)

There's now one more widely linked dab: Parametrization. Typical articles linking to there are Lambda-CDM model and Nonparametric statistics. They generally describe using equations which can be tuned with parameters. That concept is discussed in Parametrization (geometry) but these mentions are not really about geometry. (I already fixed the ones which were.) Any suggestions, please? Certes (talk) 14:34, 26 December 2018 (UTC)

In fact, I have moved Parametrization to Parametrization (geometry), and created the dab page. The reason of this move was that the content of the page was about the process of finding parametric equations of a curve, surface, ... It seems that most links refer to finding parameters for describing a physical process, and the best way for disambiguating these links seems to linking either to Parameter or to one of the pages linked there through the {{main}} template. D.Lazard (talk) 18:57, 26 December 2018 (UTC)

I have just created a stub section Parameter#Modelization, that deserves to be expanded, and used for disambiguating some of the links to Parametrization. D.Lazard (talk) 19:31, 26 December 2018 (UTC)

Thank you for the pointers. I've had another go, using targets such as Parametric equation and Statistical parameter, with plain Parameter as a fallback. Please feel free to fix any I've got wrong, especially any that should go to your new text (or a {{R to section}} to it). Certes (talk) 20:00, 26 December 2018 (UTC)

Requested move: operad theory -> operad

I have requested the move in the title at Talk:Operad theory. The participation to the discussion is very welcome. —- Taku (talk) 07:00, 28 December 2018 (UTC)

The two-sided Laplace transform is one-to-one

I just did this edit, stating the injective nature of the two-sided Laplace transform. Might someone add a proof somewhere in the article? Michael Hardy (talk) 04:26, 26 December 2018 (UTC)

I’m no specialist but is this because there is “inverse Laplace transform” of sort? (just like there is inverse Fourier, which makes a Fourier transform an isomorphism between appropriate function spaces.) —- Taku (talk) 07:47, 28 December 2018 (UTC)

@TakuyaMurata: But no inversion formula is stated in the article, let alone proved. Michael Hardy (talk) 05:57, 29 December 2018 (UTC)

About "appropriate function spaces": it seems, each ${\mathcal {B}}\{f\}$ (two-sided Laplace transform) has its own domain (depending on $f$). Really? Boris Tsirelson (talk) 11:13, 29 December 2018 (UTC)

Change of variable in a polynomial

There are "well known" fast methods for change of variable in a polynomial, but I am unable to find their description in WP. More specifically, I am interested in the fast computation of $p(x+1),$ and more generally of $p(x+r),$ where p is a polynomial of degree n. For such a change of variable, the standard method is a generalization of Horner's rule, which computes $p(x+r)$ with at most $n(n+1)/2$ additions and $n(n+1)/2$ multiplications by r. This method was used by Horner himself, but I ignore how it is called in modern literature. Also, does it exist a faster algorithm (for example using FFT)?

I need this for an article Real root isolation that I am preparing for fixing the mess of Vincent's theorem and Root-finding algorithm#Method based on the Budan–Fourier theorem or Sturm chains. (I have already rewritten, in the same spirit Budan's theorem and the introductory part (before subsections) of Root-finding algorithm#Roots of polynomials). D.Lazard (talk) 10:36, 18 December 2018 (UTC)

I know very little about this field, but shouldn't there be a fast algorithm of the form: Evaluate $p(x+1)$ at $\deg p+1$ points using an FFT; then interpolate? I guess I don't know how the interpolation ought to be done, but probably another FFT? I have no idea where to look for a reference. Ozob (talk) 01:05, 30 December 2018 (UTC)

See https://hal-ens-lyon.archives-ouvertes.fr/ensl-00546102/document and its references (your problem is composition of a polynomial with a monic linear polynomial; it considers composition more generally). —David Eppstein (talk) 01:13, 30 December 2018 (UTC)

What is a "hole"?

I am working on Draft:Hole to create a primary topic article for this subject. I was wondering if there is a mathematical definition of a "hole" suitable for inclusion in a very basic level of article. bd2412 T 03:51, 18 December 2018 (UTC)

@BD2412: Hmm, you could maybe mention something about how homology is a sort of detection of the number of holes in a curve or a surface. That's kind of vague and hand-wavy, but I don't know if you're going to get a precise mathematical definition more than just a pointer to homology for something that can be made more precise. –Deacon Vorbis (carbon • videos) 04:01, 18 December 2018 (UTC)

Yes, I can use that - thanks! bd2412 T 04:13, 18 December 2018 (UTC)

Don't forget Electron hole; not exactly mathematical, but quantum physical at least. Dicklyon (talk) 06:13, 18 December 2018 (UTC)

...And Dirac sea, filling a sea of holes, is more mathematical, in some sense. But. I'm afraid, off-topic. Boris Tsirelson (talk) 11:08, 18 December 2018 (UTC)

None of those would go in a general article called hole. At most they would go in the current hole, which I suppose the plan is to move to hole (disambiguation).

I'm not sure it's necessary to have a general article called hole, but I suppose I have no strong objection either. --Trovatore (talk) 19:38, 18 December 2018 (UTC)

I guess a gap is not exactly the same thing as a hole? --JBL (talk) 20:23, 18 December 2018 (UTC)

With my patent agent's hat on, the USPTO will not accept a claim that includes the word 'hole' without further definition, on the legalistic and rule-bound grounds that you're specifying something that doesn't exist. You have to say 'a surface defining a hole' or the like. The rule is probably buried somewhere within 37 CFR, but I'm not sure I could be bothered to look for it. Narky Blert (talk) 09:00, 19 December 2018 (UTC)

I don't see anything of use in the MPEP. bd2412 T 13:53, 19 December 2018 (UTC)

I never saw much use in MPEP, or in far too many of the USPTO corps of examiners, either. Some of course are excellent; but I once received a first office action in which one of the grounds for rejection was 37 CFR 1.52(b)(1)(ii) – in summary, specification not in English; because it reads 'fibre' not 'fiber'. (a) Check Webster's (b) you are wasting my client's money having to address let alone argue this fatuity. I also remember another case where I got a hopelessly invalid application through to grant simply because the examiner was clueless. Narky Blert (talk) 23:06, 19 December 2018 (UTC)

Isn't that called fraud on the patent office? Shame on you, taking advantage of clueless examiner to get your client an invalid patent. Dicklyon (talk) 03:16, 30 December 2018 (UTC)

Presumably there should be a link to genus (mathematics), which is a sort of the number of holes. (For some reason, biology terminology was hot at one point in the history of mathematics, other examples being class field, germ (mathematics).) -- Taku (talk) 05:07, 19 December 2018 (UTC)

Thanks, I have added that, and noted the contrast between the topological and homological definitions of a hole. bd2412 T 13:54, 19 December 2018 (UTC)

Totally off-topic, but it might appeal to anyone who (like me) retains a juvenile sense of humour. Benjamin Jowett, in his masterly 19th century translation of Plato's Symposium, has the playwright Aristophanes define love as the 'desire and pursuit of the whole'. Narky Blert (talk) 22:09, 19 December 2018 (UTC)

Pentagramma mirificum

The pentagramma mirificum was described by Napier and studied by Gauss, and is now the subject of a Wikipedia article. Only one page links to it. Which others should? Michael Hardy (talk) 05:55, 29 December 2018 (UTC)

Candidates include John Napier, Spherical trigonometry, Star polygon and possibly Vadim Schechtman. Certes (talk) 11:46, 29 December 2018 (UTC)

Also pentagram, surely? —David Eppstein (talk) 07:10, 30 December 2018 (UTC)

Conflicting Maas form definitions

In the lede of Maass cusp form, it seems that Maass cusp forms and Maass wave forms are equivalent, but my non-expert reading of Maass wave form#Definition of a Maass wave form is that the cusp form is a subset of wave forms. Can someone check that apparent contradiction or let me know where I might have gone wrong? Klbrain (talk) 18:15, 30 December 2018 (UTC)

Maass cusp forms are wave forms that vanish at the cusps. See for instance [1], page 364. --{{u|Mark viking}} {Talk} 20:02, 30 December 2018 (UTC)

AwesoMan3000

• AwesoMan3000 (talk · contribs · deleted contribs · logs · filter log · block user · block log)

AwesoMan3000 (talk · contribs) is a prolific editor of mostly mathematical articles. After some questionable edits to 20, I checked some other recent edits and found none unequivocally good. Could someone check me on this? — Arthur Rubin (talk) 19:15, 30 December 2018 (UTC)

I reverted an edit of AwesoMan3000 a couple of weeks ago and looked over their recent edits and had the same impression: nothing really terrible, but not obviously improving things, either. —JBL (talk) 20:46, 30 December 2018 (UTC)

Addendum: the edits to 20 are pointy and terrible.—JBL (talk) 23:43, 30 December 2018 (UTC)