Wikipedia talk:WikiProject Mathematics/Archive/2020/Apr

Edit war at Tangent half-angle substitution
User:Nerd271 seems to want the opening sentence of this article to call this substitution the Weierstrass substitution without mentioning that there is any doubt about the justice of that name, or that Euler, who died long before Weierstrass was born, introduced this substitution.

The only people who have less understanding of, or respect for, historical accuracy than authors of mathematics books are those who edit Wikipedia's article about George Washington to say that he chopped down a cherry tree.

Can anyone adduce any respectable evidence that Weierstrass was ever aware of this substitution? (Short answer: no.) (Long answer: I will pay a major fortune, US$5.12 (five dollars and twelve cents, a power of 2) to whoever can do that during April 2020.) Michael Hardy (talk) 18:56, 1 April 2020 (UTC)
 * PS: I had left the article in a state where it refers to the tangent half-angle substitution in the opening sentence and later says some books call it the Weierstrass substitution. Michael Hardy (talk) 18:58, 1 April 2020 (UTC)


 * The source you used contains nothing more than a general-interest biography of Euler. I searched it for the book that was mentioned in the citation, but it was simply not there. Unlike what its name might suggest, it is not a depository of Euler's works. Claims that cannot be supported by the citations that follow should be removed. Please see WP:VERIFY. In addition, this method is commonly known as the 'Weierstrass substitution' and the page should have that name per WP:COMMONNAME. Nerd271 (talk) 19:03, 1 April 2020 (UTC)
 * For convenience, let's keep the discussion on the article's talk page. Nerd271 (talk) 19:10, 1 April 2020 (UTC)

Notability of "Integer solutions of elliptic curves"?
Hi, I'd like to seek input on whether the captioned title would be considered notable, given the works of previous mathematicians. Thanks. TLOM (The Lord of Math) (Message) 07:45, 4 April 2020 (UTC)
 * This is not only highly notable, but also well covered in Wikipedia, see Elliptic curve, and the subsection Elliptic curve. D.Lazard (talk) 08:32, 4 April 2020 (UTC)
 * Maybe the better question is whether rational points on an elliptic curve should exist as a separate article. I’m inclined to say yes; there is even a textbook on the topic . —- Taku (talk) 11:17, 4 April 2020 (UTC)

Spam article on possibly notable topic

 * I am bumping this back to the talk page from the archive, since an AfD has been opened and the page creator left a comment here. --JBL (talk) 13:21, 4 April 2020 (UTC)

Draft:Word-representable graph was written by an editor who is a name match for the claimed inventor of the term, whose research also dominates the references. Is this actually a valid topic, or is it vanity spam? Guy (help!) 09:38, 5 February 2020 (UTC)
 * I don't recognize it. But that doesn't mean it doesn't exist.  — Arthur Rubin  (talk) 09:47, 5 February 2020 (UTC)
 * This is a real topic and Kitaev is a real mathematician. It is fairly new (introduced in the last 15 or so years) and Kitaev has been heavily involved in studying and promoting it (along with a varied group of coauthors), but glancing through MathSciNet I see a dozen or more papers about this topic in non-spam journals by sets of authors that do not include Kitaev.  --JBL (talk) 12:44, 5 February 2020 (UTC)
 * (Probably I should give a COI notice that Kitaev wrote a letter of recommendation for me 10 years ago when I applied to post-docs, though we haven't had significant contact since.) --JBL (talk) 12:45, 5 February 2020 (UTC)
 * Are you thinking of Alexei Kitaev? That's a different Kitaev than S. Kitaev, from what I can tell. 67.198.37.16 (talk) 01:09, 25 February 2020 (UTC)
 * What a deeply bizarre question; I don't even know how to begin to respond. --JBL (talk) 01:39, 25 February 2020 (UTC)
 * I really don’t think it’s a spam. It is actually quite nice that the article is written by the originator of the subject, since that person must know the best. Of course, we have to watch out for a self-promotion but as far as I can tell that’s not an issue here. (It’s only an issue if the topic is fringe; i.e., not something studied in the mainstream mathematics community.) —- Taku (talk) 20:26, 5 February 2020 (UTC)
 * Not spam, but very new topic (mostly developed in the last five years) with limited literature as a result. It's not WP:FRINGE, but probably not mature or well-cited enough to be considered WP-notable as an article subject yet. — MarkH21talk 20:48, 5 February 2020 (UTC)
 * (Cf. User talk:S. Kitaev.) Given my mathematical background, I really cannot tell whether the topic is too new for Wikipedia (e.g., in computing, 5-10 years might be long enough for encyclopedic treatment). Maybe some other editors in the project can weight in? —- Taku (talk) 19:39, 11 February 2020 (UTC)
 * I am somewhat surprised at it being labeled "too new" -- I mean, it is fairly new, but there seems to be an established literature around it, and Kitaev has written a book on the topic. The COI aspect is of the kind that doesn't bother me, personally, much (though YMMV) -- we have a legitimate researcher writing about their legitimate research.  I personally would have just cleaned out the most over-the-top bits (e.g., the bibliography of papers, which is certainly not maintainable long-term) and let it live in mainspace. --JBL (talk) 00:02, 12 February 2020 (UTC)
 * There’s little literature on the subject independent from Kitaev though. — MarkH21talk 04:21, 12 February 2020 (UTC)
 * Like I said, I went through MathSciNet and (filtering out false positives) there are a dozen papers on the topic that do not have him as an author. For my taste, that's well over the "is this a real thing?" line (though again YMMV). --JBL (talk) 14:28, 12 February 2020 (UTC)

I suggest moving the article from draft space to main article immediately. I've never heard of this, but its clearly a good-quality article on something that is rather remarkable and quite interesting. I'm wondering how it might relate string rewriting to graph rewriting. What about directed graphs? So, semi-commutative monoids, e.g. history monoids have word representations and arise with things like parallel communicating finite state machines (which are just directed graphs). There's a bunch of interesting questions that could be posed. (All of mine are trivial.) Sorry I'm easily excitable. 67.198.37.16 (talk) 01:15, 25 February 2020 (UTC)
 * I'm easily excitable. Indeed. --JBL (talk) 01:39, 25 February 2020 (UTC)

For now, I have put the article back at the mainspace (since the initial concern has been proven invalid). It does appear to have a COI concern; so I have put the COI template. —- Taku (talk) 23:14, 27 February 2020 (UTC)

Hi everyone and thanks for your opinions about the page created by me. I was not aware of this discussion but Guy let me know about it yesterday, and he said that I can contribute to it. I was thinking to comment on some of your points which would hopefully clarify the situation. Yes, I’m a real mathematician http://personal.strath.ac.uk/sergey.kitaev/index.html not related in any way to Alexei Kitaev and I indeed wrote a letter of recommendation for JBL in Sept 2011 :) This is my very first contribution to Wiki, and I should admit that I probably violated (unintentionally!) some of the basic principles of Wiki for which I’m sorry. When I was creating the page, I was thinking to produce a high quality, useful page similar to the page about another area of my research interest, namely, https://en.wikipedia.org/wiki/Permutation_pattern, and I thought I’ve succeeded (at least it was appreciated by the many people working in the area), but then problems came along with various issues around Wiki policies. I still don’t see anything wrong with me creating the page, rather than someone else doing this as indeed probably no one knows this subject better than me, and every statement in the article is supported by an explicit reference to a published source, so every one could check that this is not a spam article, e.g. by following the references, or by contacting any of the 35+ researches mentioned on the page (in the references). This is true that I’m involved in the majority of publications in the area so far, but there are many other papers related to the topic that I have no involvement in, and the area is definitely mature enough (with a Springer book published about it, so cannot be WP:TOOSOON) to have a Wiki page dedicated to it (although, of course, I’m biased when saying this). I think it’s indeed a good idea suggested by someone to make the article a bit less technical, or at least to have some intro that can be understood by non-experts. Finally, 67.198.37.16 suggested several interesting ideas for further development of the area which I have no idea about except the case of directed graphs is handled by the notion of semi-transitive orientation. Namely, if your graph is oriented in a semi-transitive way, you can represent it by words, if not then you cannot do it. Thanks again for all your opinions. --S. Kitaev (talk) —Preceding undated comment added 06:24, 3 April 2020‎


 * The AfD is here. --JBL (talk) 13:22, 4 April 2020 (UTC)

Roland Richardson
I have just put up an article on this mathematician, chiefly notable for his administrative contributions as a dean at Brown and as secretary of the American Mathematical Society. Someone who is a mathematician could probably put more into it about his mathematical contributions. His PhD was on "Improper Multiple Integrals"; he was a student of James Pierpont at Yale. Brianyoumans (talk) 15:59, 4 April 2020 (UTC)

Draft on Copula
Hi all, I have recently been directed here. I have been trying to write a short article on Copula, and it keeps getting rejected for one or the other reason (https://en.wikipedia.org/wiki/Draft:Copula_in_signal_processing). I would be thankful if someone from WikiProject Mathematics could help. Thanks Robert McClenon for introducing me to this place. Earthianyogi (talk) 17:06, 7 April 2020 (UTC)


 * Hi Earthianyogi, and welcome to the Wikiproject. The draft you wrote looks pretty good, except for the lead/introduction. For technical articles we try to give some context and an informal description of the topic up front. Our guideline for accessibility of technical articles is WP:TECHNICAL; take a look. But before investing in more effort on this, take a look at Copula (probability theory); it is a well-developed article that seems to cover the same topic; that is, what about your draft is specific to signal processing?. If so, you might see if there is any material in your draft worthy of merging into that article. -- 17:35, 7 April 2020 (UTC)

User:Mark viking Thank you for your suggestions. Yes, you are absolutely right that this article is about copula in signal processing. I have read this article Copula (probability theory), and created 2 sections in it as well. One about the use of copula in medicine and other in signal processing. I also made some other edits to this page. I already proposed to merge the two articles, but it seems like many different people with many different opinions have a say on why gets listed on Wikipedia. I was hoping to put a page with the current content on it, and use the help of more experienced editors to improve it. But it seems that I am not getting anywhere... Also, I do not believe that a person with less mathematical understanding would be interested in this article anyways; however, it may not always be the case.

Disambig group algebra
Hi all. I have just turned group algebra into a disambig page as we have two articles group ring and group algebra of a locally compact group (the former a concept in ring theory, the latter in functional analysis). This, quite predictably, resulted in a number of internal links to this new disambig page that need to be disambig'ed. I have done a few but I can also use helps from other editors with free time (or those pretending to have free time). —- Taku (talk) 14:34, 7 April 2020 (UTC)


 * Somehow related: I have split off a section in group algebra of a topological group to stereotype group algebra. I am not sure if this concept is notable (in the sense of Wikipedia) or not. *If* notable, it needs some non-primary references. —- Taku (talk) 15:41, 7 April 2020 (UTC)
 * A similar issue with stereotype space. If no one can find a non-primary ref, I’m planning to nominate those articles for deletion. —- Taku (talk) 19:54, 7 April 2020 (UTC)
 * There is now a dispute on the notability of stereotype space at Talk:Stereotype space between me and the inventor of the concept. I cannot say I am very familiar with this area so inputs from other editors can be useful and welcome. —- Taku (talk) 00:42, 8 April 2020 (UTC)
 * Given the above concern, I have nominated stereotype space for deletion at Articles for deletion/Stereotype space. I don't see a choice here. -- Taku (talk) 12:14, 8 April 2020 (UTC)
 * If possible, please participate in the discussion; opinions from other editors can be helpful here. —- Taku (talk) 14:33, 8 April 2020 (UTC)
 * There is also a dispute at Talk:Group algebra of a locally compact group. —- Taku (talk) 14:39, 8 April 2020 (UTC)

Gentlemen (and ladies), are there mathematicians here? What I see in this discussion needs understanding and explanation by specialists. Eozhik (talk) 15:32, 8 April 2020 (UTC)

Discrete analytic function?
This makes me wonder whether we ought to have an article titled Discrete analytic function. Michael Hardy (talk) 18:56, 7 April 2020 (UTC)
 * The question is whether it is a sufficiently independent topic from circle packing theorem, the main article in this area. —David Eppstein (talk) 19:00, 7 April 2020 (UTC)
 * For now I've redirected it. Michael Hardy (talk) 15:08, 9 April 2020 (UTC)

There is a discussion at Redirects for discussion/Log/2020 April 9 about the primary meaning of the term. D.Lazard (talk) 20:06, 9 April 2020 (UTC)

Containment order
Many times I have heard of a set of sets being partially ordered by inclusion, but I don't know that I've ever heard of its being partially ordered by "containment". Should the article titled Containment order be re-titled Inclusion order or something like that? Michael Hardy (talk) 01:47, 10 April 2020 (UTC)
 * In my experience, the usual term is "reverse inclusion". --Trovatore (talk) 01:48, 10 April 2020 (UTC)
 * Maybe that's because you work in mathematical logic. Could we hear from a topologist? Michael Hardy (talk) 02:41, 10 April 2020 (UTC)
 * I'm not a topologist nor a logician, but both "inclusion order" and "reverse inclusion order" are natural to me while "containment order" is not. Reverse inclusion order and inclusion order are just converse to each other. I don't have any sources for you though, and some should be added before a move is made. — MarkH21talk 05:09, 10 April 2020 (UTC)
 * I'm also not a topologist nor a logician. Nor really an order theorist despite one paper in Order. Anyway, both inclusion and containment (in the formulations "partially ordered by X" and "X order") appear in the literature, but Google scholar hit counts suggest that inclusion is far more frequent. Examining the results shows that "containment" is also more likely to be used for other objects (e.g. geometric shapes) rather than abstract sets. —David Eppstein (talk) 05:44, 10 April 2020 (UTC)
 * Containment order has a particular meaning in geometry, where it means an ordering that can be mapped, preserving a proper inclusion ordering, onto similar shapes in a Euclidean space. Here is a review paper on containment order. I've seen the term used in spatial and GIS contexts, too. With a survey article, this containment is likely notable independent of inclusion. -- 17:22, 10 April 2020 (UTC)

Short descriptions and See-also sections
I suggest to complete MOS:MATH by a section on short descriptions and See also sections. I could be placed as the last subsection of MOS:MATH. Here is a suggestion for this section. According to WP:Short description, every article should have a short description. This allows the reader to know what about is an article without having to open its page.

Sort descriptions are visible at the top of a page on mobile devices, and also on desktop browsers after activation of the relevant gadget (see WP:Short description).

Short descriptions are particularly useful in sections "See also" as they allow to transform automatically an indiscriminate list of links into a more useful annotated list. For example, some see-also sections contain the link If the link is entered as, it becomes
 * Lill's method

Short descriptions must appear in a template short description for being visible in annoted links. Short descriptions are also useful for redirects to a section or an anchor. In this case the short description must appear in the line that follows the magic word " #Redirect ". Please, give your opinion on such an addition in MOS:MATH, and be free to improve my draft.

Adapting the see-also sections this way requires some work, but it is useful not only for readers, but also for project members: the spam items become immediately visible. D.Lazard (talk) 14:06, 13 April 2020 (UTC)
 * This doesn’t seem math-specific at all, should this be in MOS:MATH or elsewhere? Also what about is an article and they allow to transform automatically are somewhat awkward. Using what an article is about and they transform are better. — MarkH21talk 14:18, 13 April 2020 (UTC)
 * The specificity of mathematics, is the high numbers of articles whose title is meaningful only for people who know already the content. For example all articles named "Someone's theorem", "Someone's idendity", and so on (how many members of this project knew Lill's method before my post?). While editing some see-also sections, I was astonished by the number of item that should not be there, and for which this appeared clearly only after having added a short description and an annotated link. D.Lazard (talk) 14:47, 13 April 2020 (UTC)

Discussion on primary podcast source vs. Notices of the AMS and Math Genealogy for doctoral advisors
A user has removed the advisor of Eric Weinstein cited to both the Notices of the AMS and the Math Genealogy Project on the basis that the subject himself stated in a podcast that he had no advisor. I have opened a discussion here, and participation on which source to use is welcome. — MarkH21talk 13:25, 14 April 2020 (UTC)

Confusing statement
Please see Talk:Ammann–Beenker tiling. Feedback is welcome. Toshio Yamaguchi (talk) 18:28, 14 April 2020 (UTC)

Statistics question at Talk:2019–20 coronavirus pandemic
Some attention from statistics-inclined Wikipedians would be helpful for resolving the question at Talk:2019–20 coronavirus pandemic. Thanks! &#123;{u&#124; Sdkb  }&#125;  talk 22:49, 15 April 2020 (UTC)


 * The curves labelled 1 and 2 might be correct. The other curves (3, 4, 5, and 6) are certainly wrong. They all refer to the number of cases. What they all leave out is the number of deaths which is the significant difference between mitigation by social distancing and the lack thereof. JRSpriggs (talk) 10:42, 16 April 2020 (UTC)
 * To keep discussion centralized, could you please copy your comment over to the pandemic article? It's not going to be seen here. &#123;{u&#124; Sdkb  }&#125;  talk 08:11, 17 April 2020 (UTC)

Notability of Carol number and Kynea number
Back in 2009, the former was AFD-ed at Articles_for_deletion/Carol_number with a no-consensus result. A decade on, it doesn't look like these numbers are any more notable, and the sourcing remains questionable. Should they be (re)nominated? Boldly merged ref the AFD? ~Hydronium~Hydroxide~(Talk)~ 15:09, 17 April 2020 (UTC)


 * I am surprised that that discussion was closed as no consensus -- to me, it looks like there was a weak consensus to delete. It might be worth another swing at AfD.  (Merging the two would also be an improvement.) --JBL (talk) 15:36, 17 April 2020 (UTC)
 * Both of them could be selectively merged to near-square prime, which could also incorporate some material from Landau's problems. XOR&#39;easter (talk) 14:00, 18 April 2020 (UTC)

Self-promotional additions to Riemann zeta function
These additions to Riemann zeta function appear self-promotional (compare the names of the reference author and the Wikipedia editor). Are they appropriate for the article or WP:UNDUE? —David Eppstein (talk) 18:45, 18 April 2020 (UTC)
 * Surely the standards for what is due weight regarding the Riemann zeta function are pretty high. I'm doubtful that work which is new and virtually uncited could qualify, even though it appears to be reliably published. XOR&#39;easter (talk) 18:50, 18 April 2020 (UTC)
 * It seems undue, and the preceding reference (2017 unpublished Researchgate reference) is an even worse offender. I’ve removed them for now. — MarkH21talk 19:04, 18 April 2020 (UTC)
 * Thanks. XOR&#39;easter (talk) 19:44, 18 April 2020 (UTC)
 * Yes, thanks! I agree with this removal also. —David Eppstein (talk) 20:07, 18 April 2020 (UTC)

Navbox: Functional analysis
Template:Functional analysis has been largely expanded since several years by and. Its size has more than doubled. The result provides a huge and almost indiscriminate collection of links, often shortened in a confusing way for saving some space (for example, one of the links is displayed as "Grothendieck"). IMO, searching an article in this template is not easier than searching it by any other standard mean, and its present state is absolutely not useful. This template must be dramatically reduced and restructured for being useful for non-specialists. I would be tempted to nominate it for deletion per as WP:TNT, but I am not a specialist of this area. Some other advices are thus needed. (The template's talk is empty). D.Lazard (talk) 15:04, 19 April 2020 (UTC)
 * An example of the silliness of the template is that it contains a link to List of Banach spaces, and, nevertheless, the articles of this list appear in the template, and are distributed in several sections. D.Lazard (talk) 15:18, 19 April 2020 (UTC)
 * I agree that a purge of items in this template would benefit those new to those field, but make it less useful for those who are more knowledgeable in it. We need a solution that will make the template useful for all people.Mgkrupa (talk) 15:53, 19 April 2020 (UTC)
 * We could greatly reduce the size of this template by splitting it up into sub-templates like with Template:2019–20 coronavirus pandemic. Say by placing


 * all items that relate only to Hilbert spaces (and not more generally to Banach spaces) into their own sub-template,
 * all other items that relate only to Banach spaces (and not to general TVSs) into their own sub-template,
 * all items that do not require a topology (e.g. radial set) into their own sub-template
 * all items related to bornology (i.e. bounded sets) into their own sub-template,
 * all items related to nuclear spaces/operators in their own sub-template,
 * and so forth.Mgkrupa (talk) 15:53, 19 April 2020 (UTC)
 * I was thinking something like this: User:Mgkrupa/Functional analysis proposal. Mgkrupa (talk) 13:14, 20 April 2020 (UTC)
 * This is much better. However, if people add to this new template structure all related items, it may become as awful as the current version. IMO, such a navbox is not useful for experts of the subject; so there is no need to include in the navbox the narrow subjects that are interesting only for experts. Also it seems not useful to mention articles that are easily found as links in other articles. For example, most specific spaces that are listed in List of Banach spaces dot not require an entry in this template. In summary, we are faced to the difficult compromise between exhaustion and usefulness. D.Lazard (talk) 15:39, 20 April 2020 (UTC)
 * I don’t have a concrete proposal but Template:Lie groups, I think, has a right balance; not too many not few items and also uses the “collapse” feature. I am sure we can aim for something similar here (and am willing to spend time no one else is interested). —— Taku (talk) 18:49, 20 April 2020 (UTC)

Gamma function
Would someone be willing to take a look at the recent edits at Gamma function? There's an editor insisting on adding what appears to be (poorly written) OR; I've started a talk page thread but I'm at 3RR and don't see how I can explain it any more clearly. Thanks, –Deacon Vorbis (carbon • videos) 01:21, 24 April 2020 (UTC)
 * I've warned the user for edit warring. They are past 3RR, but I'm going to give them one last bit of good faith to stop and discuss it. -- Kinu t/c 01:25, 24 April 2020 (UTC)

Draft:Copy Detection Pattern
I know that this is a very active project, and so I expect that someone will respond to this request. Can someone either please review this draft, Draft:Copy Detection Pattern, and advise me whether to accept it, or advise me where to request a review of this draft? It appears to me to be reasonable, and I don't see anything obviously wrong with it, so that my thought is to accept it, but I would prefer to have another editor review it, perhaps one who hasn't forgotten as much mathematics as I have. (I still know algebra and calculus, but I learned them in high school.) Robert McClenon (talk) 22:13, 23 April 2020 (UTC)


 * I am not sure mathematics is quite the right topic area, but I also don't know who else to suggest instead! (Maybe, this just reflects how far it is from things I know things about.)  All that said, I looked it over and I didn't see any problems that would prevent acceptance. --JBL (talk) 22:33, 23 April 2020 (UTC)
 * Another reviewer accepted it. I would have accepted it but wanted another opinion, so we agreed, and that is all right.  The author of the article appears to be an academic with knowledge about the subject, and so is a welcome addition to Wikipedia.  Robert McClenon (talk) 00:20, 26 April 2020 (UTC)

Systems of polynomial inequalities
This section describes a method for solving systems of polynomial inequalities, but it provides no references, so I'm not sure if it's accurate. Which references should be cited in this section? Jarble (talk) 18:18, 27 April 2020 (UTC)
 * I have replaced the section by a link to the general algorithm for the problem. D.Lazard (talk) 18:36, 27 April 2020 (UTC)

Disambiguation help
There was a recent move that reshuffled the naming scheme of articles on the topic of range, leading to a large number of links from article-space to the disambiguation page range (mathematics). Most of these have been resolved, but maybe someone else would like to take a look at the few that remain; they are listed here. Thanks, JBL (talk) 21:56, 29 April 2020 (UTC)