Wikipedia talk:WikiProject Mathematics/Archive/2015/Feb

Irreducibility (mathematics) needs help in a bad way

Irreducibility (mathematics) is awful as a disambiguation page, and really should either be moved to Irreducibility (disambiguation) and simplified to conform with MOS:DAB, or turned back into an article describing the primary usage of this term with respect to mathematics. Cheers! bd2412 T 18:59, 1 February 2015 (UTC)

I confess that I'm responsible for turning the page into a disambig page. I do believe there is no uniform definition of "irreducibility" in mathematics, aside from the usual English sense of "not reducible". For example, "irreducible" as in irreducible representation, one as in irreducible polynomial and one as in irreducible component (of a topological space) have nothing in common. -- Taku (talk) 00:53, 2 February 2015 (UTC)

It's not a disambiguation page. It's possibly been mislabelled as such, but it's really a collection of distinct but related uses of a term in mathematical discourse. It would certainly be ideal for someone to link to a more specific meaning of the term in mathematics, but (as often is the case) the usage of a term in mathematics often has more to do with analogies than "this usage or that one". Such pages are useful and important, but should not be treated like "disambiguation pages". If their designation as such confuses various editors, then re-designate them to a more appropriate category. Such pages are very useful and should be allowed and encouraged to stay. Taku has my full support here. Sławomir Biały (talk) 01:06, 2 February 2015 (UTC)

Ok. How do you call that page then? I have just fixed some incoming links (most of times to irreducible representation). The fix was no-brainer. It's very unhelpful for us to direct the readers to Irreducibility (mathematics) instead of "irreducible representaion", when the latter is meant in linking the term. I can ask: on what occasions do we want to have a link to Irreducibility (mathematics)? "A page that must not be linked" is more or less a disambig page. -- Taku (talk) 01:22, 2 February 2015 (UTC)

The title "Irreducibility (mathematics)" seems perfectly reasonable as a title for such a page. Why should there even be a question? I think the issue is that there is some template on that page that tells all the dab-droids that it's a disambiguation page. Remove that template, and the problem is solved, as far as I can tell. Of course, we should link as many things to a specific page as possible, using discretion. But it's wrong to say that each and every time for which the concept of irreducibility appears in a mathematics article that it needs to be completely nailed down to one of the articles. That's what a "disambiguation" page entails, and that's clearly not what we have here. Sławomir Biały (talk) 01:45, 2 February 2015 (UTC)

User:R.e.b. has fixed the problem by replacing the dab template by {{sia}}. It's not really a dab, because the thing that is ambiguous is not the word "irreducibility" but the concept: what kind of decompositions are we talking about? Set index articles are the right way to handle conceptual rather than verbal ambiguities, and don't have such severe formatting and linking constraints as dabs. —David Eppstein (talk) 02:25, 2 February 2015 (UTC)

Yes, SIA was the answer to my question (though why we need to have a distinction is beyond me, reminding me of tax code). To Sławomir, no, I think it is "wrong" to have a link to irreducibility (mathematics), because readers have to look at the list and choose the correct destination. Doesn't that make the page precise a disambig page? (or SIA as some would prefer). Anyway, the problem has been solved so it's ok now. -- Taku (talk) 12:28, 2 February 2015 (UTC)

Lewis Carroll

The page currently contains the following material:

Speculation on Dodgson's sexuality[edit] Dodgson's nephew and biographer Stuart Dodgson Collingwood wrote: And now as to the secondary causes which attracted him to children. First, I think children appealed to him because he was pre-eminently a teacher, and he saw in their unspoiled minds the best material for him to work upon. In later years one of his favourite recreations was to lecture at schools on logic; he used to give personal attention to each of his pupils, and one can well imagine with what eager anticipation the children would have looked forward to the visits of a schoolmaster who knew how to make even the dullest subjects interesting and amusing.[73] Despite comments like this, and the fact that his pictures of children were taken with a parent in attendance (many in the Liddell garden),[39] modern psychological interpretations of Dodgson's friendships with young girls and of his related work—especially his photographs of nude or semi-nude girls—have led some late twentieth century biographers to speculate that he was a paedophile, including Morton N. Cohen in his Lewis Carroll: A Biography (1995),[74] Donald Thomas in his Lewis Carroll: A Portrait with Background (1995), and Michael Bakewell in his Lewis Carroll: A Biography (1996). All of these works more or less assume that Dodgson was a paedophile, albeit a repressed and celibate one.[page needed] Cohen, in particular, claims Dodgson's "sexual energies sought unconventional outlets", and further writes: We cannot know to what extent sexual urges lay behind Charles's preference for drawing and photographing children in the nude. He contended the preference was entirely aesthetic. But given his emotional attachment to children as well as his aesthetic appreciation of their forms, his assertion that his interest was strictly artistic is naïve. He probably felt more than he dared acknowledge, even to himself.[page needed] Cohen goes on to note that Dodgson "apparently convinced many of his friends that his attachment to the nude female child form was free of any eroticism", but adds that "later generations look beneath the surface" (p. 229). He and other biographers[who?] argue that Dodgson may have wanted to marry the 11-year-old Alice Liddell, and that this was the cause of the unexplained "break" with the family in June 1863,[26] an event for which other explanations are offered. Biographers Derek Hudson and Roger Lancelyn Green (Green also having edited Dodgson's diaries and papers) stop short of identifying Dodgson as a paedophile, but concur that he had a passion for small female children and next to no interest in the adult world; in the last ten years[dated info] several other writers and scholars have challenged the evidentiary basis for Cohen's and others' speculations regarding this interest of Dodgson. In addition to the biographical works that have drawn the foregoing conclusion, there are modern artistic interpretations of his life and work that do so as well, in particular, Dennis Potter in his play Alice and his screenplay for the motion picture Dreamchild, and Robert Wilson in his film Alice. In a 2015 BBC programme The Secret World of Lewis Carroll experts indicated their belief that a photograph of a naked teenage girl, was the oldest Liddell girl Lorina, and was the work of Dodgson. The programme speculated that this was the possible cause of the break in the relationship between him and the Liddell family. Will Self in the same programme called Dodgson 'a heavily repressed paedophile. Without a doubt.' [75][76]

Note the abundance of footnotes. How much of this should be retained? Tkuvho (talk) 16:52, 2 February 2015 (UTC)

What does this have to do with the Mathematics project or mathematics? Dodgson may have been a mathematician among other things, but his biography does not have our rating template. JRSpriggs (talk) 04:45, 3 February 2015 (UTC)

Well I think it should. He did important work both in mathematics and logic. Tkuvho (talk) 14:18, 3 February 2015 (UTC)

I think this discussion is better kept at Talk:Lewis Carroll. Ozob (talk) 14:26, 3 February 2015 (UTC)

M-theory

Hello mathematicians,

I just wanted to let you all know that M-theory is currently a featured article candidate. While this is not exactly a math topic, it's related to some very exciting areas of modern mathematics such as geometric representation theory, categorification, and noncommutative geometry.

It would be great if someone here could review the article. Even if you're not an expert on math or physics, I would love to hear your views and whether you find the writing accessible.

Thanks. Polytope24 (talk) 05:01, 4 February 2015 (UTC)

Help with Covering in topology/graph theory

Hi all, I've got a handful of links that go to the disambiguation page Covering in a mathematical sense but I can't figure out which article they need to point to. Could I interest a local math maven in taking a look?

List of articles with ambiguous links to "covering"

Thanks, --JaGa^talk 21:39, 6 February 2015 (UTC)

 Done D.Lazard (talk) 10:56, 7 February 2015 (UTC)

Lie algebra extension

Do we have an article on Lie algebra extensions (under some unexpected name) or perhaps a section on it? In case we don't, and if nobody is in the process of writing one, I might write one. It would parallel group extension. YohanN7 (talk) 16:07, 5 February 2015 (UTC)

There is a section Affine Lie algebra#Classifying the central extensions, but I do not know of any standalone articles. --Mark viking (talk) 19:59, 5 February 2015 (UTC)

Thanks. For a start, I have rewritten Wigner's theorem from scratch. There are clearly connections between the subjects due to the projective representations popping up as a result of Wigner's theorem. YohanN7 (talk) 12:14, 7 February 2015 (UTC)

Navbox for "classes" of matrices?

Given that we have this neat navbox for prime number classes, I wonder if we should create a similar one for different types of matrizes. However, I'm not a mathematician (just an economist ;-) ), so apart from the ones commonly seen in economics, I don't know which of these matrices are important, let alone how to categorize a navbox. Is it a good idea though? --bender235 (talk) 15:02, 26 January 2015 (UTC)

I made Template:Prime number classes but don't think I know enough to make a proper version for matrices. I like the idea though. List of matrices may help with the grouping if somebody wants to give it a go. PrimeHunter (talk) 15:17, 26 January 2015 (UTC)

On second thought, I will make a crude version based on just copying most of List of matrices. I will post later when a draft is ready. PrimeHunter (talk) 15:24, 26 January 2015 (UTC)

I have created {{Matrix classes}} based entirely on copying every link (including red links and links with the same target) in List of matrices. Others are very welcome to make improvements. PrimeHunter (talk) 16:22, 26 January 2015 (UTC)

I think the template needs a little more focus. Right now it has too many different kinds of matrices; most of the entries have no relationship to each other besides the fact that they're matrices. A comprehensive navbox would be too big, and a suitably sized navbox is necessarily more focused. I think it would useful to have a template that discussed types of matrices that are generally of interest within linear algebra proper (sparse, banded, Hermitian, idempotent, etc.) and left out matrices which are of interest because they arise in applications (DFT, Bezout, adjacency, etc.). Ozob (talk) 04:00, 27 January 2015 (UTC)

And it looks like this:

YohanN7 (talk) 07:07, 27 January 2015 (UTC)

To give a perspective, the box looks too large, to me. I suppose it is probably hard to decide on what to include and what to exclude. (The choice would likely reflect editor's background.) -- Taku (talk) 04:30, 29 January 2015 (UTC)

Please be bold and make any improvements. I haven't added it to any articles but just wanted to quickly make a framework for others by indiscriminately copying the whole list without evaluating anything or looking for other groupings or potential additions in Category:Matrices. PrimeHunter (talk) 00:51, 8 February 2015 (UTC)

That is like asking someone to do the work for you. Will not happen. I like the thing. But it is too large, so I ask you to rinse out some. (Like stuff you've never heard of.) It can always be put back later. YohanN7 (talk) 01:02, 8 February 2015 (UTC)

Imaginary point

The article titled imaginary point has sat around for years with almost no attention. It lacks references. If the article should indeed exist, could someone cite some geometry textbook there? Michael Hardy (talk) 01:05, 5 February 2015 (UTC)

How about merging it to rational point? I have put tags proposing the merger. -- Taku (talk) 01:24, 5 February 2015 (UTC)

Call me arrogant if you like, but I can't shake the feeling that there is good reason that there are no solid references: the concept as defined in the stub appears (to me, at least) to be mathematical nonsense in the purely geometric context. I've expounded at Talk:Imaginary point. —Quondum 02:18, 8 February 2015 (UTC)

Is this award for real or is it a hoax?

Please see Stampacchia Medal. The external links do not seem to go anywhere. Is this a hoax? Having an award for such a narrow field as Calculus of variations seems unlikely to me. JRSpriggs (talk) 02:57, 8 February 2015 (UTC)

Check all the links. One of the references is [1] and one of the the external links (only linked on the pdf icon due to a syntax error) is page 17 of [2]. Clearly not a hoax. PrimeHunter (talk) 03:21, 8 February 2015 (UTC)

Here is the announcement of this year's prize by VARANA. It is real. Calculus of variations is a huge field, as it is basically calculus in infinite dimensions. It forms the foundation for both classical and quantum field theories in physics. --Mark viking (talk) 03:34, 8 February 2015 (UTC)

Thanks. Someone who knows Italian should fix the majority of the links which do not go anywhere. JRSpriggs (talk) 03:51, 8 February 2015 (UTC)

Draft help needed

Hermann Mayer is writing a draft about Rouben V. Ambartzumian and asked for help via IRC. The subject seems notable with sources such as this, but the draft is a CV that's largely based on Ambartzumian's own publications, not on what third-party coverage we have. Getting full access to the references would be a significant effort for me; thus I'd prefer if someone else could give Hermann Mayer a helping hand and improve the draft so that it can be accepted. Huon (talk) 23:55, 8 February 2015 (UTC)