Wikipedia talk:WikiProject Mathematics/Archive/2019/Nov

Geometrization

The article titled Classification of manifolds says some manifolds are geometrizable and some are not, and the article titled Geometrization conjecture seems to suggest that that means a manifold admits a "geometric structure". The concept is not defined in either article, and Geometric structure redirects to an article in which that term appears once, without a definition, and the word geometrizable occurs twice, also without a definition. Can someone put a definition at some appropriate place in those articles? Michael Hardy (talk) 17:38, 29 October 2019 (UTC)

Isn't it (almost) defined in "Geometrization conjecture#The eight Thurston geometries" (plus the previous text)? Boris Tsirelson (talk) 22:50, 29 October 2019 (UTC)

Should the page Geometric structure be a disambiguation page? Th eredirect to differentiable manifold is certainly not acceptable, and I feel many mathematical concepts can qualify as describing some kind of geometric structure, and none of them is quite general enough to be a redirect. For example, a few that are relevant to the above discussion are :

* (G,X)-structure ;

* model geometries as described in Geometrization conjecture#The eight Thurston geometries ;

* Riemannian manifolds.

That might mean disambiguating a few links here and there but this seems much better than the current situation. jraimbau (talk) 09:14, 1 November 2019 (UTC)

Book "Differential Geometric Structures" by Walter A. Poor, 2007; annotation: Useful for independent study and as a reference work, this introduction to differential geometry features many examples and exercises. It defines geometric structure by specifying the parallel transport in an appropriate fiber bundle, focusing on the simplest cases of linear parallel transport in a vector bundle.

The treatment opens with an introductory chapter on fiber bundles that proceeds to examinations of connection theory for vector bundles and Riemannian vector bundles. Additional topics include the role of harmonic theory, geometric vector fields on Riemannian manifolds, Lie groups, symmetric spaces, and symplectic and Hermitian vector bundles. A consideration of other differential geometric structures concludes the text, including surveys of characteristic classes of principal bundles, Cartan connections, and spin structures.

Also Sect.2 in lectures Geometric structures by Werner Ballmann.

Also Terry Tao about Shing-Tung Yau, “What is a Geometric Structure”. Boris Tsirelson (talk) 10:26, 1 November 2019 (UTC)

Infinity article lead, technical correctness vs common language

Can someone else take a look at the lead of Infinity? It's gone through several changes recently and it's a balancing act between being technically correct and being common language. I suppose I lean farther towards being technically correct than towards using common language, since I think that the common language surrounding "infinity" is often be misleading (e.g. "it cannot be counted or measured even in principle").

More eyes are always welcome. — MarkH21 (talk) 23:28, 7 November 2019 (UTC)

I have edited the article before reading this thread. The begin of the disputed sentence is "In common language". Here is my edit summary which summarizes wle my opinion: This is about common language. It is therefore nonsensical to try introducing mathematical accuracy. "Number" without link would be fine except that it may be confusing for people knowing of infinite numbers. So I put "common number", but I will be fine if "common" is removed. On the other hand, I am strongly against linking. D.Lazard (talk) 23:40, 7 November 2019 (UTC)

An idea: for everyday usage, can we just follow dictionaries (if not urban dictionary)? Trying to come up with a *right* definition is a bit of original research after all. -- Taku (talk) 23:58, 7 November 2019 (UTC)

I agree with both D.Lazard and TakuyaMurata. Paul August ☎ 00:19, 8 November 2019 (UTC)

I guess my feeling is that we don't write encyclopedia articles to document "common language", and I have a general dislike of sourcing Wikipedia content from dictionaries, which I feel usually misses the point. Dictionaries, like encyclopedias, are tertiary sources, and we should be using primarily secondary sources.

The "larger than any common number" language is -- better than some other possibilities, but not ideal. What's a "common" number? Is that a precise notion? Isn't, say, Graham's number larger than any "common" number? The "larger than any natural number" language at least had the advantage of being meaningful and correct for just about any mathematical notion of infinity I can think of.

Which brings me to maybe the more difficult point, which is deciding what exactly the infinity article is supposed to be about. Right now there's a division between infinity and infinity (philosophy), which I suppose means that infinity itself is supposed to be about mathematics (and possibly natural science). To me this is a slightly artificial division; the proximate cause of the biggest philosophical disputes within mathematics has almost always been related to the treatment of infinity. I would support a merge of these articles, and that might change my view of the lead sentence, though I have no good candidate language for such a sentence. --Trovatore (talk) 02:57, 8 November 2019 (UTC)

I think it would be best if this discussion were to continue on Talk:Infinity, where there is a related discussion. Paul August ☎ 12:00, 8 November 2019 (UTC)

User:Math-drafts

This is an announcement that I have created an alternative account of mine: User:Math-drafts to move some of old drafts in the [[Draft:]] namespace to the subpages of that user page. While I am in control of the account, the draft pages in that user page are meant to belong to the community and all the editors should feel free to edit them as fit (including moving to mainspace or even deleting them). This alternative account itself will never make an edit.

Please let me know if there is any issue. —- Taku (talk) 09:14, 7 November 2019 (UTC)

By "issue", I mean this. WP:NOTWEBHOST is a policy and, because of the technical nature, I need the project's help to ensure that I am not using Wikipedia as my personal web host. -- Taku (talk) 22:54, 8 November 2019 (UTC)

Thanks for the clarification. NOTWEBHOST is mostly about disallowing significant non-encyclopedic uses of WP wiki pages. Because all the pages under User:Math-drafts are for the explicit purpose of community development of potentially long-term draft articles and the improvement of the encyclopedia, I don't see there being any problem with that policy. --{{u|Mark viking}} {Talk} 23:57, 8 November 2019 (UTC)

Unfortunately, NOTWEBHOST is not the concern we are allowed to summarily dismiss; see User_talk:TakuyaMurata#Suggestion. So, I really need to ask the project to ensure there is absolutely no violation of this policy (which has a very severe consequences). -- Taku (talk) 00:41, 9 November 2019 (UTC)

Any sufficiency advanced math draft pages are indistinguishable from spammy scientific personal notes. So, this project has to been in charge of that policy not being violated (as non-math editors cannot do the task); not only for drafts started by me. —- Taku (talk) 02:07, 9 November 2019 (UTC)

I concur with Mark viking here. Highly technical drafts can take a while to develop; they benefit from being available for multiple math-inclined people to work on. Keeping them somewhere that isn't attached to a specific person's name is good for that. XOR'easter (talk) 15:29, 9 November 2019 (UTC)

A math template at TfD

Folks here may be interested in the discussion at Wikipedia:Templates for discussion/Log/2019 November 10#Template:Mabs. –Deacon Vorbis (carbon • videos) 19:19, 10 November 2019 (UTC)

Notability/sourceability?

For your consideration: the new article Dubner's conjecture. The Dubner in question is Harvey Dubner, the subject of an old (2007) but weakly referenced biography. Do appropriate sources exist? --JBL (talk) 16:18, 17 November 2019 (UTC)

Hmm. I'm not finding anything that suggests people other than Dubner worked on this conjecture. XOR'easter (talk) 16:53, 17 November 2019 (UTC)

Still not turning up anything of substance; the closest is the Delahaye item already linked in the article, which is a pop-science story that has a sidebar on "la nouvelle conjecture de Dubner". Just for fun — I did find an old NYT piece that appears to mention Dubner himself. XOR'easter (talk) 20:44, 17 November 2019 (UTC)

Fun find. I think it's plausible that Dubner could be notable (though I was disappointed not to find a substantive obituary anywhere, so maybe not). The conjecture (in J. Recreational Math) seems much less likely. --JBL (talk) 13:37, 18 November 2019 (UTC)

MR numbers not rendering properly in citation templates

See discussion at Help talk:Citation Style 1#MR numbers not rendering properly. —David Eppstein (talk) 07:10, 21 November 2019 (UTC)

Please comment. This will also likely affect {{MR}}. Headbomb {t · c · p · b} 20:14, 21 November 2019 (UTC)

Structural Ramsey theory

Hi all, I have been writing the article Draft:Structural Ramsey theory, and have just submitted it for review. I have done my best to give a complete account, and provide adequate context and references. I would appreciate if anyone could give feedback and/or review.

--Jordan Mitchell Barrett (talk) 09:52, 30 November 2019 (UTC)

Welcome to Wikipedia, and nice work! The article is well structured and well-referenced. I have two minor suggestions. First, WP writing is a little different than the usual mathematical writing in that it is a bit more formal--use of "we", "us", "note that", etc. is discouraged, as discussed in MOS:MATH#TONE. Second, for non-experts in this topic, in the introduction section you may want to briefly explain or wiki link what an r-coloring is. --{{u|Mark viking}} {Talk} 11:37, 30 November 2019 (UTC)

Thanks Mark viking for your feedback - I fixed up the tone to be more in line with the style, and explained some of the conventions I use (including r-colouring). I expect this article will not be read much by those outside advanced mathematics, but still best to make it as accessible as possible. --Jordan Mitchell Barrett (talk) 21:26, 30 November 2019 (UTC)

Gave a quick spitshine to the refs, btw. Headbomb {t · c · p · b} 11:46, 30 November 2019 (UTC)

Thanks Headbomb. --Jordan Mitchell Barrett (talk) 21:26, 30 November 2019 (UTC)