Wikipedia talk:WikiProject Mathematics/Archive/2022/Oct

Working on a draft: Cartwright's Theorem
Hi all,

I am currently working on this draft currently. Please feel free to help me to improve it. Thank you so much for your great help if possible. Also, can I know if the stub holds general importance? Aitzaz Imtiaz (talk) 01:00, 2 October 2022 (UTC)
 * The lead says this is about graph theory and that it is about set theory. Both are incorrect. A hint: when you do something with graphs of functions you are not doing graph theory, and when you are using sets as part of the description of other kinds of mathematical object. you are unlikely to be doing set theory. Where are you getting this incorrect information? It does not appear to be in the sources you are using. The actual mathematical content of the draft stub also appears to be stated in a somewhat incoherent way, making it difficult to understand the actual statement of the theorem without going back to the sources and reading them instead. —David Eppstein (talk) 01:53, 2 October 2022 (UTC)
 * hey thanks! The following is a part of Graph theory, what think, sorry if I am wrong, but basically I tried saying that the following theorem has an application in Set Theory doesn't means it is a part of it. Aitzaz Imtiaz (talk) 02:04, 2 October 2022 (UTC)

Fixed point requested move
Hi all, I requested a move of Fixed point (mathematics) to Fixed point which is currently a disambiguation page for Fixed point (mathematics), Fixed-point arithmetic, and a few other topics. This move is somewhat controversial as several editors have objected that Fixed-point arithmetic precludes Fixed point (mathematics) from being a primary topic. A few months ago a similar move request was closed as "no consensus", so please join in at Talk:Fixed point (mathematics) so that this discussion can reach a definitive conclusion. Mathnerd314159 (talk) 20:46, 6 October 2022 (UTC)

Discussion needs input from editors with subject knowledge
You are invited to join the discussion at Wikipedia:Redirects for discussion/Log/2022 October 8 § Locally small category. &#x0020; The redirects and  currently point to different places (Glossary of category theory and Category (mathematics) respectively). 1234qwer1234qwer4 believes they should target the same place and has nominated them for discussion at RfD to determine what the best target is. That discussion needs input from editors familiar with the topic area. Please comment in the linked discussion rather than here. Thryduulf (talk) 22:13, 8 October 2022 (UTC)

Closed merge discussions
Working on the merging backlog, I recently closed some merge discussions involving mathematics articles. This includes the proposal to merge Polynomials calculating sums of powers of arithmetic progressions into Faulhaber's formula, which I believe had been discussed here some months back. Interested editors are invited to implement the merger! Felix QW (talk) 08:12, 14 October 2022 (UTC)

Move discussion for 142,857
There's a Requested Move for 142,857 to be renamed to 142857 at Talk:142,857. Please join the discussion if you're interested. Thank you. --Paul_012 (talk) 10:58, 14 October 2022 (UTC)


 * If a discussion about whether or not to have a comma in a page name doesn't go to an RfC and at least two ANI threads, I will be very disappointed in Wikipedia. XOR&#39;easter (talk) 18:09, 14 October 2022 (UTC)
 * Awesome - (I am uncertain about the veracity of the following, but maybe there are other reasons for the removal of the comma,    Wakelamp d&#91;@-@&#93;b (talk) 02:17, 18 October 2022 (UTC)

VP Idea discussion on ESL user preferring Britannica to WP
Suggest people comment. I think the points are well made.Village_pump_(idea_lab), I like the way this site handles it (Note its called skeptical science because it's skeptical about anti-climate change science - confuses everyone), THey have basic, advanced, and intermediate levels as tabs. Wakelamp d&#91;@-@&#93;b (talk) 02:36, 18 October 2022 (UTC)
 * I don’t think having several entirely separate articles at different “levels” about each technical topic seems necessary, but many mathematics (and other technical) articles would benefit from having a more accessible top few sections, more figures, more motivation and context, some historical discussion, additional narrative explanation stitching technical details together, and so on. If you find one that you know about, please be WP:BOLD and start making improvements. If you find a specific article that you think should be more accessible than it is but you don’t know enough about the topic to improve it yourself, please start a conversation on the talk page or here. –jacobolus (t) 04:03, 18 October 2022 (UTC)
 * Apologies, there are two similar topics, i meant this.
 * Village pump (idea lab)
 * I have noticed that WIkipedia is no longer appearing first on google search for some maths article (eg algebra) . Links for Algebra
 * Brittanica
 * Simple English
 * Algebra Wakelamp d&#91;@-@&#93;b (talk) 04:53, 18 October 2022 (UTC)
 * This is just your (algorithmically personalized) Google. As a not-logged in user, Wikipedia is the first result for "algebra" in Google, Bing, Yahoo, and DuckDuckGo. –jacobolus (t) 18:39, 18 October 2022 (UTC)
 * @Wakelamp Quoting some of the items in the discussion that you mentioned:
 * I wholeheartedly agree with their sentiment. Some articles are just too technical due to the nature of the topic, and will not be of interest to most mathematics learners.  That does not mean there is a need to "dumb them down".  And on the other hand, other articles more accessible to beginners/laypeople can absolutely have a lead/sections that explain the topic in simpler terms before going into more technical details.  But that should not apply to all mathematics article across the board. PatrickR2 (talk) 05:26, 20 October 2022 (UTC)
 * it's quite tricky to write things for students. It would be nice to ask a mathematics teachers association to review all the article ledes. Wakelamp d&#91;@-@&#93;b (talk) 09:30, 20 October 2022 (UTC)
 * You could pick a few articles and try to ask a math teacher (or a few) who teach those concepts to comment. –jacobolus (t) 16:02, 20 October 2022 (UTC)
 * Good idea, I have sent emails to a few classmates. Wakelamp d&#91;@-@&#93;b (talk) 21:59, 20 October 2022 (UTC)
 * rough rough draft, few links, I haven't copied the latex,  I decided to have a go without a teacher, and then checked.
 * The aim is to provide a mental map by linking between paragraphs, what they know, where it gets them
 * Underlines are just summaries of the point of that section, and are not intended for the article
 * 'Maps to Place in maths
 * In the branch of mathematics called linear algebra,
 * General form - details many readers will skim this, but use simple words for the simple cases and then formal words for the general, many exceptions should be hinted at, or should be mentioned in the body instead, forms map for the article. With  definitions, the aim should be not to list all  exceptions, but hint at them, and mention them in the body.
 * A linear equation has the general form
 * where are the variables (or unknowns), and
 * are the coefficients (or parameters).
 * These coefficient may be arbitrary expressions, provided they do not contain any of the variables (see polynomials). The solutions of a linear equation  are the variable values that make the equality true. Each solution may be interpreted as Cartesian coordinates, and  all solutions may be visualised as forming a line with 2 variables, a plane with 3 variables, and with n variables forming a hyperplane (a subspace of dimension n − 1). A linear equation can also be considered a polynomial of degree 1 which is equal to 0.
 * ' Purpose of the article- Is/Is not, use (The chart shows simultaneous linear equations)
 * 'This article discusses single linear equations with real coefficients and real solutions, but it is applicable to those involving complex numbers,
 * The normal pre-requisites are an understanding  simple algebra, of cartesian co-ordinates, and x-y line charts
 * Linear equations in used all of mathematics, sciences, and finance can be used to approximate non-linear systems, and these equations often involve complex numbers.
 * When there is more than one equation, these are called simultaneous linear equations, or a system of linear equations.
 * Being able to solve and visualize linear equations is needed for the study of simultaneous linear equations,
 * Student students see an example in their text, how readers remember it, map to general form, Equations for students should be in colour in the lede - so it draws their eye, and they are not overwhelmed by the latex.
 * Students are initially taught to solve linear equation in the form
 * y = mx +c,
 * where m is describe as the gradient, and c is where line crosses the y axis crosses, and relation, Expressing this in the form of the original def
 * definition
 * a1x1 + a2x2 + 01 = mx -y +c =0,
 * The term linear equation is often assumed by students to refer to 1 or 2 variables (with the  the solutions forming a line on a chart) but it also applies to 3 variables (the solution forming a plane on an x y z chart) or more, Wakelamp d&#91;@-@&#93;b (talk) 07:27, 21 October 2022 (UTC)
 * There are some amazingly well done technical articles on Wikipedia, but there are also many existing technical articles at all levels which are dramatically less accessible than they could be, and currently mostly serve as a technical reference (or list of sources) for people who have already studied the topic.
 * In my opinion, ideally any technical topic should be made accessible (to a basic degree) to someone with a couple years less technical background than usually assumed for first studying it. So for instance topics usually learned by advanced mathematics undergraduates should be made accessible to first-year physics or computing students. Etc. Not the whole article necessarily, but the basic motivation, some simple examples, the conceptual idea behind the definition, some historical background, etc. The main thing lacking is volunteer effort; it takes a ton of work to write excellent articles for a wide audience.
 * (This is not only a problem on Wikipedia. Mathematics as a field is notorious for not making results accessible to non-specialists.) –jacobolus (t) 16:13, 20 October 2022 (UTC)
 * As a concrete example, the notion of the "continuity" of the real numbers should be a fundamental idea made accessible at a basic level to a high-school audience, and that article should discuss (early and in as non-technical a way as possible) what continuity means in this context, why the rational numbers are not continuous, and how the real numbers are set up to fix that. The article defines: a real number is a value of a continuous quantity (wikilink on quantity but not "continuous), but continuous is not ever accessibly explained. Though it discusses the topic a few times in different ways, each version is overly technical and full of inaccessible jargon linked to articles which themselves also do not discuss the basic idea. I would have hoped that continuity (mathematics) would explain the basic idea, but it redirects to List of continuity-related mathematical topics which does not provide any basic conceptual description of what continuity means but just links to more advanced articles like continuum (set theory) and linear continuum which circularly describe a continuum as being "like the real numbers", continuous variable which just describes having an uncountable set of values (not quite technically correct, or helpful as a basic idea), continuum (topology) which is absurdly terse and technical, the kind of definition you’d find in a journal paper for an audience of mathematicians, etc. The link real line redirects to number line which again only addresses continuity using inaccessible jargon. The overall result is that an e.g. high school calculus student hearing about the "real numbers" is never going to get a clear answer about what they are or why they exist unless they go find some external source. –jacobolus (t) 16:48, 20 October 2022 (UTC)
 * I agree with your points. On the other hand, if the wikipedia article references these external sources as you mention, it's perfectly fine for interested people to go read these sources to get a better understanding.  Wikipedia is not necessarily in the business of premasticating and regurgitating information to make it accessible to people without the necessary background.  The main thing is to provide links where people can deepen their understanding.  Although I do agree that some articles here are too technical.  (Some technical articles have been transformed (I have in mind one editor in particular, who will remain unnamed here) to a state of technical jargon and presentation that makes them close to unreadable, even by mathematicians). PatrickR2 (talk) 21:07, 20 October 2022 (UTC)
 * Wikipedia is not necessarily in the business of premasticating and regurgitating information to make it accessible to people without the necessary background – where practical Wikipedia absolutely should be in that business. The concept of a real number is regularly taught in late high school or early college, and the article should very broadly accessible, and self-contained enough that someone with an ordinary high school education can follow most of the basic ideas involved without needing to go on a scavenger hunt. It is an utter cop out to pass the buck to other sources, especially since the ones linked in a 'Sources' section are a Cantor paper from the 1870s in German and several graduate level textbooks. jacobolus (t) 21:44, 20 October 2022 (UTC)
 * The problem with WP:BEBOLD is that it is frustrating to put a lot of time in an edit only to have it reverted for lack of WP:RS, especially in areas where many sources are proprietary. The lack of an effective dispute resolution mechanism is also discouraging. --Shmuel (Seymour J.) Metz Username:Chatul (talk) 14:04, 19 October 2022 (UTC)
 * This seems like a bit of a tangent, and is pretty vague. Do you have a concrete example or some more specific detail? What kind of dispute are you thinking of, and how was it resolved? I will grant you that sometimes Wikipedia can be frustrating or discouraging. Getting pseudonymous strangers with widely varying backgrounds to agree can be a challenge.
 * You can certainly also start a talk-page discussion, make an outline, etc. if you don’t want to lead off with putting weeks of work into changes that might be opposed by other wiki authors.
 * What do you mean by “proprietary” sources? Mathematics doesn’t generally involve proprietary material. You can’t patent a mathematical formula or concept, and there are few if any trade secrets per se. Are your sources secret NSA documents or something? Or do you just mean papers in journals that are not freely available online? There is nothing wrong with citing paywalled papers in Wikipedia articles. Someone who really cares can usually find a copy, e.g. through their public library, a university, asking for help online, directly emailing the authors, or sci-hub. –jacobolus (t) 16:10, 19 October 2022 (UTC)
 * @Chatul I feel your annoyance. But then the next day something good happens. The day after that is crud.
 * @Jacobolus "Someone who really cares can usually find a copy, e.g. through their public library, a university, asking for help online, directly emailing the authors, or sci-hub" I agree with what you say, but that is bit bitey. Although "pseudonymous strangers with widely varying backgrounds" made me laugh,
 * So, what has been the past consensus of having a simpler lede? Wakelamp d&#91;@-@&#93;b (talk) 16:34, 19 October 2022 (UTC)
 * Headbomb's answer a month ago was definitive. JBL (talk) 21:18, 19 October 2022 (UTC)
 * I can't find his reply on special search. May I have a link? TA Wakelamp d&#91;@-@&#93;b (talk) 05:15, 20 October 2022 (UTC)
 * It's the first link in this thread, and the first reply in that link. —David Eppstein (talk) 06:01, 20 October 2022 (UTC)
 * @David Eppstein The first link in this thread Village_pump_(idea_lab)
 * Is this what you mean For 1, there's 6 millions+ articles out here. Feel free to start. For 2, that's what the lead section already does. For 3, what skin is best is subjective. That's why we have preferences. Wakelamp d&#91;@-@&#93;b (talk) 07:48, 20 October 2022 (UTC)
 * Yes. JBL (talk) 17:12, 20 October 2022 (UTC)
 * See WP:VPIL for Headbomb's reply. JRSpriggs (talk) 23:16, 20 October 2022 (UTC)
 * I didn't have that problem with articles on Mathematics, but rather with articles on computers. Computer vendors and software vendors often have documents that they consider trade secrets, and even if an editor has a copy, readers cannot verify the relevance of the citation.
 * As for the issues with dispute resolution, the obvious processes explicitly require the consent of all parties. I've thrown in the towel on some topics becaus of that.
 * Mathematic has a different issue. As has been attributed to Albert Einstein, things should be as simple as possible but no simpler. It is difficult to write a concise lead without assuming background knowledge. A lot of articles have leads that I consider too long, but I am by no means sure that it is possible to shorten them while still leaving them intelligible to neophytes. --Shmuel (Seymour J.) Metz Username:Chatul (talk) 16:36, 21 October 2022 (UTC)
 * If unpublished corporate documents are considered trade secrets, Wikipedia articles obviously can’t cite those... See Verifiability. –jacobolus (t) 17:13, 21 October 2022 (UTC)
 * As for the issues with dispute resolution, the obvious processes explicitly require the consent of all parties. I've thrown in the towel on some topics becaus of that.
 * Mathematic has a different issue. As has been attributed to Albert Einstein, things should be as simple as possible but no simpler. It is difficult to write a concise lead without assuming background knowledge. A lot of articles have leads that I consider too long, but I am by no means sure that it is possible to shorten them while still leaving them intelligible to neophytes. --Shmuel (Seymour J.) Metz Username:Chatul (talk) 16:36, 21 October 2022 (UTC)
 * If unpublished corporate documents are considered trade secrets, Wikipedia articles obviously can’t cite those... See Verifiability. –jacobolus (t) 17:13, 21 October 2022 (UTC)

Planet Math links
I noticed all of the Planet Math links are now broken (or at least every one I've tried). Does anyone know if this is a temporary situation? If it's a permanent situation, is there any plans to systematically fix it? Walt Pohl (talk) 22:07, 26 October 2022 (UTC)
 * If it is a permanent situation, see Wikipedia talk:WikiProject Mathematics/Archive/2021/May --SilverMatsu (talk) 03:47, 27 October 2022 (UTC)
 * Are there any examples where PlanetMath is the best (or even a particularly good) source for some topic? Another possibility would be to just look for a better source any time PlanetMath is cited. –jacobolus (t) 04:29, 27 October 2022 (UTC)
 * I think they are ok in "External Links" sections, not so much otherwise Gumshoe2 (talk) 04:38, 27 October 2022 (UTC)
 * As external links they could also just be removed without doing much harm. If someone cares enough to add it back, they can look up the proper link. But I’m not sure these are all that helpful for readers. –jacobolus (t) 06:37, 27 October 2022 (UTC)
 * I tend to agree that they are not great; removing or replacing the links is probably the best way forward. - CRGreathouse (t | c) 05:03, 27 October 2022 (UTC)

Template:PlanetMath attribution/doc says that; "This template should be placed on the main page of the article.", but is it possible to place this template on the talk page like Template:Merged-from ? --SilverMatsu (talk) 16:42, 27 October 2022 (UTC)

AfD for Strictly non-palindromic number
See Articles for deletion/Strictly non-palindromic number, where I have stated why I believe that the term fails the notability guideline. GeoffreyT2000 (talk) 01:01, 29 October 2022 (UTC)

Page name ∂∂̅-lemma
I've just made a new page at ∂∂̅-lemma but am preemptively posting in case people have opinions about the name. It is technically the valid unicode for expressing a character with an overline, except the italic nature of ∂ as a unicode symbol causes it to be rendered slightly off (and it may be bad practice to have wikipedia pages whose names are such esoteric combined unicode characters). Alternatives are ddc-lemma or ddbar-lemma or deldelbar-lemma or ∂∂bar-lemma. The first one is an alternative mathematical name $$dd^c$$-lemma, whereas the others are just phonetic. If anyone has a particularly strong objection then feel free to move the page to one of the suggested names. Tazerenix (talk) 06:23, 27 October 2022 (UTC)


 * Thanks for making the page! It is a very good addition. The title rendering strikes me as very strange, so I think there must be a better alternative. If I had to choose myself, I would suggest "d-dbar lemma" but this is obviously also not perfect.
 * Side note, the second paragraph is wrong, its characterization of the Poincaré lemma is of the form "A implies A" since the conclusion is just rephrasing the assumptions – exactness is the very meaning of being zero in De Rham cohomology, no lemma needed! The Poincaré lemma says that any closed differential form on Euclidean space is exact. Gumshoe2 (talk) 08:10, 27 October 2022 (UTC)
 * Yes thanks. I guess it should just be compared to just the notion of an exact differential form. Tazerenix (talk) 09:03, 27 October 2022 (UTC)
 * I don't have expertise in this area, but just a general question about presentation. I see some mathematics articles quote theorems and try to give full proofs of them. Other articles don't give proofs and instead give authoritative references where proofs can be found.  Unless a result is really simple and has a one or two line proof that can help the reader better grasp the concepts involved, I was under the impression that it is in general preferable to give external references instead of proofs in wikipedia itself? (I can't quote the guidelines about this, but I thought that was covered somewhere.) PatrickR2 (talk) 06:50, 28 October 2022 (UTC)
 * You should try to make the article legible and useful to readers. If the proof is long, tedious, and not very insightful, you can refer to an outside source, hide it by default (e.g. using Template:Collapse or similar), or move it to a footnote. If the proof is shorter / more insightful, you could put it directly in the article body copy. What is most useful and/or most legible is a judgment call, and sometimes there might be disagreement. If you can’t reach consensus, asking here is a good way to get more eyes on it. –jacobolus (t) 07:01, 28 October 2022 (UTC)
 * There is some discussion at WikiProject Mathematics/Proofs. –jacobolus (t) 07:04, 28 October 2022 (UTC)
 * Thanks for the link. PatrickR2 (talk) 18:51, 28 October 2022 (UTC)
 * In this case the topic is of interest because of its applicability to Kahler manifolds. The most interesting part of the lemma, apart from the fact that it is true and very useful, is how the proof relies on the Kahler identities and Hodge decomposition. This is demonstrated in how the failure of the lemma is used to study non-Kahler manifolds (as mentioned on the page). Thus it seems of particular interest to produce the proof (which despite not being one or two lines, is still only 6 or 7 lines). Also the lemma is similar in theme to the Poincare lemma and Dolbeault-Grothendieck lemma, both of which appear with full (and in fact more technical/detailed, albeit slightly more elementary) proofs. Tazerenix (talk) 06:14, 29 October 2022 (UTC)
 * The characters ∂∂̅ probably fall under the "Symbols (avoid them)" part of WP:TSC. Either ddbar lemma, ddbar-lemma, or d-dbar lemma (as suggested by ) strike me as the best alternatives. — MarkH21talk 00:31, 29 October 2022 (UTC)
 * I've moved the page to ddbar lemma. Thanks for the comments. Tazerenix (talk) 06:01, 29 October 2022 (UTC)