Talk:Gravitational instanton

Instantons as EFE solutions

At the very least, this claim requires qualification and elaboration, agreed? See exact solutions in general relativity and references therein for what "solution" without qualification should be taken to mean.---CH (talk) 11:04, 3 October 2005 (UTC)

I suppose you mean that I should clarify that they are vacuum solutions. At least I think they are. --MarSch 14:40, 12 October 2005 (UTC)

Citations, plez!

Hi, 131.111.212.12, please take the time to add citations following the templates given in WikiProject GTR citation templates (to assure uniform appearance of citations in the Wikipedia).

I see you have made numerous edits to gtr-related articles which show you have a graduate background (at least), and I am very glad to see knowledgable contributions. I noticed however that they often lack citations or categorizations, and hope you will take the time to consider adding appropriate citations and categories in future! This can be very valuable to serious students by helping them find your contributions in the first place, and in reading more about a given topic if they find it useful or intriguing.

You might also want to consider creating a user page (possibly with a handle other than your user name) and joining WikiProject GTR. ---CH 23:36, 18 December 2005 (UTC)

P.S. Saw some more of your contribs and see you did add some citations--- thanx! But please consider that Prola and links to journal pages will generally not be accessible to most users of the Wikipedia. Many journals do now have a "rolling window" which makes classic papers available freely to any user, but you need to find and give the correct url. If possible, I think we should ensure that all cited links in Wikipedia are useful to all users, including nonacademic users. In some cases, a paper might be so important that a "restricted link" might be better than no link at all, but in those cases, please add a comment apologizing to users who lack the required subscriptions (which as you probably know can be hefty if your institution doesn't pick up the tab). ---CH 23:56, 18 December 2005 (UTC)

Students beware

I extensively edited the Dec 2005 version of this article and had been monitoring it for bad edits, but I am leaving the WP and am now abandoning this article to its fate.

Just wanted to provide notice that I am only responsible (in part) for the last version I edited; see User:Hillman/Archive. I emphatically do not vouch for anything you might see in more recent versions, and have some reason to believe that future versions may present what I would regard as slanted information or misinformation.

Good luck in your search for information, regardless!---CH 00:04, 1 July 2006 (UTC)

Why merge?

What is the motivation to merge the articles Einstein manifold and Gravitational instanton? Pierreback 21:29, 5 June 2007 (UTC)

They seem to be different names for the same thing. R.e.b. 03:14, 7 June 2007 (UTC)

The only difference being that 'gravitational instanton' is four-dimensional? Anyhow, the article 'gravitational instanton' is very hard to read for a mathematican. But perhaps the Einstein manifold article can be split into two different sections? Pierreback 00:19, 8 June 2007 (UTC)

This is because there is hardly any article! I've tried to give at least minimal explanations, but the core of it was and remains just three groups of formulas without as much as an explanation of the notation used! Anyway, I believe that it's better to keep these two articles separate, firstly, because of two completely different target audiences, and secondly, because Einstein manifolds are usually assumed to be compact and require rather different techniques. If you look at Besse's book, he spends only one chapter on the non-compact case, and does not even define what a gravitational instanton is. Arcfrk 01:01, 8 June 2007 (UTC)

There is no point in merging the two articles, not because they have different audiences (I think both articles should have value both for mathematicians and physicists), but because they are different topics. Gravitational instantons are not only usually 4-dimensional, but they are also usually assumed to be self-dual, and also ALE or ALF. Differential geometers are interested in non-compact Einstein manifolds (much has changed since the book of Besse), and would regard gravitational instantons as a special case. However, that does not mean that this should be a subsection or subarticle of Einstein manifold because gravitation instantons have a different motivation and different goals, most notably in quantum gravity. I've had a first shot at improving Einstein manifold. I'll do a bit of editing here and remove the merge tag. Geometry guy 17:28, 24 June 2007 (UTC)

Some general comments

The paper cited for the the fact that orbifold blowups lead to Eguchi-Hanson does not explain, merely mention this fact. As this is "common" knowledge among string theorists, maybe some lecture notes should be cited here. The article should expalin the difference between Taub-NUT and Eguchi-Hanson. If I find time I will work on it. —Preceding unsigned comment added by 128.131.48.130 (talk) 12:58, 4 August 2010 (UTC)

Move Eguchi–Hanson space

Seems obvious that most of the section on the Eguchi–Hanson metric can be moved to the currently-stubby Eguchi–Hanson space article. The will help shorten this article, and make it more focused. 67.198.37.16 (talk) 04:36, 7 May 2019 (UTC)