Wikipedia talk:WikiProject Mathematics/Archive/2026

Proposed move of 1 + 2 + 4 + 8 + ⋯

Allan Nonymous has initiated a formal proposal to move 1 + 2 + 4 + 8 + ⋯ to Geometric Series of 2. If you have opinions regarding this proposed new name for this topic, please express them at Talk:1 + 2 + 4 + 8 + ⋯ § Requested move 1 January 2026. —David Eppstein (talk) 06:14, 1 January 2026 (UTC)

Draft:Q-distribution

Dropping this here to confirm my suspicion that this is not a thing of note in mathematics. Cheers! BD2412 T 01:08, 29 December 2025 (UTC)

I agree — WP:TOOSOON. Malparti (talk) 01:19, 29 December 2025 (UTC)

Is it related to Gaussian q-distribution or Q-Gaussian distribution? Also are these two the same topic? EulerianTrail (talk) 02:00, 29 December 2025 (UTC)

@EulerianTrail: as far as I can tell, there is no obvious link between "Zhao's q-distribution" and the other two. Regarding your other question:

• The q-Gaussian is an important distribution that pops up naturally in various contexts. In particular, there are generalizations of the central limit theorem and of the free central limit theorem where if you consider "mixtures" of independent and of freely independent random variables, you get a q-Gaussian. This is a fairly active domain of research with lots of open conjectures.
• The "Gaussian q" on the other hand, I've never heard of.

I find it a bit problematic that Gaussian q-distribution is named that way... from what I can tell by skimming through the article, this is just a q-analog of the Gaussian — but it's not clear what makes it stand out among the infinity of q-analogs that one can come up with. Some of the expressions are relatively nice, that's one thing... But does it arise naturally like the q-Gaussian does? So why does it get to be the Gaussian q-distribution and not just a Gaussian q-distribution?

Also, after looking at the history of the article I have concerns of WP:PROMO / WP:CITESPAM:

• the only two references that cover the topic are by the same author;
• the article was created shortly after the second of these references was published, by an account who did not contribute anything else to Wikipedia;
• at the time of the creation of the article, the topic an the references most likely weren't WP:NOTABLE.

I wouldn't necessarily have an issue with that if the name of the article was less confusing. But given the similarity with q-Gaussian distribution, I do find that a bit problematic. Malparti (talk) 12:05, 29 December 2025 (UTC)

I would add that the draft purports to call the theory "Zhao's q-distribution"; this Zhao is not mentioned in either Gaussian q-distribution or Q-Gaussian distribution. BD2412 T 23:30, 29 December 2025 (UTC)

Hi @BD2412,

Sorry but I can't follow you. Just to make sure there is not misunderstanding, my point was that:

• the draft you posted here is about Zhao's q-distribution, which is a non-notable probability distribution (at least for now).
• there is no link between Zhao's q-distribution and the two other probability distributions discussed at q-Gaussian distribution and Gaussian q-distribution, respectively. So there is no reason to expect Zhao to be mentioned in either article (that's what confused me).
• The q-Gaussian is definitely a notable distribution. The so-called "Gaussian q-distribution", I'm not so sure.
• I have an issue with the two articles having names that are so similar. In particular, one can come up with infinitely many "Gaussian q-distributions". The q-Gaussian is important enough to justify getting a short name; but who decided that Diaz and Teruel's should also get a short name? And a confusing one at that...
• (and, of course: even if Zhao's q-distribution were notable — which it might become at some point, who knows — the name q-Distribution would not be appropriate for the draft, because it is way too general)

Malparti (talk) 00:53, 30 December 2025 (UTC)

I'm just saying that "Zhao's q-distribution" is not notable enough to be mentioned in connection with anything else titled "q-distribution". The strictly mathematical relationships are beyond my domain of knowledge. BD2412 T 01:07, 30 December 2025 (UTC)

The principal fault of this article in its present form is that it cites only the primary source and no reliable secondary sources. Reliable secondary sources are the things that establish that experts in the field consider the topic notable. I've done some edits today that fix inappropriate links by directing them to the appropriate targets, e.g. a link to Laplace, in a context that made it clear that it was a reference to the Laplace distribution, merely had to get suitably directed, and there were a bunch of those. I also edited for context and for proper terminology. E.g. the term "compensator" I replaced with normalizing constant. That term and other things make me think the writer's native language is not English. Michael Hardy (talk) 00:16, 2 January 2026 (UTC)

Can we stop automatically replacing HTML entities by Unicode characters or vice versa?

Can we make some kind of explicit 'stylevar' type carveout for HTML entities?

@Beland does a lot of minor edits like special:diff/1329043733 to Curvature which replaced {{math|''k'' {{=}} ± κ}} with {{math|''k'' {{=}} ± κ}} using the edit summary "convert special characters found by Wikipedia:Typo Team/moss (via WP:JWB)". This type of edit adds spam to watchlists and article history, but in my opinion has trivial if any benefit, and in some cases can be (trivially) harmful.

Leaving aside that the Greek letter κ should be italicized, Can we make some kind of declaration that any of the following is acceptable, and should be left alone and not automatically twiddled just for the sake of it?

• {{math|''k'' {{=}} ± ''κ''}},
• {{math|1=''k'' = ± ''κ''}},
• {{math|''k'' {{=}} ± ''κ''}},
• {{math|1=''k'' = ± ''κ''}},
• and likewise for other trivial variants which appear identical.

Which specific markup is considered the most legible or easiest to edit is going to depend on editor preference, and may even be context dependent: if each symbol appears once in an article, it might be clearest in the markup to spell out the entity names, but if a specific symbol appears hundreds of times, using the unicode symbol for concision might make the text less cluttered.

Our various help pages recommend using HTML entities, e.g. Help:Displaying a formula § HTML entities, Wikipedia:Manual of Style/Mathematics § Minus sign, and as far as I can tell there is no principled reason to systematically remove them. –jacobolus (t) 09:37, 23 December 2025 (UTC)

On most articles, editors would generally rather have the Unicode characters for WYSIWYG purposes unless they are easily confused with a different character, but on articles with <math>...</math> markup, editors generally prefer to leave HTML entities spelled out so they are searchable in parallel with the LaTeX-style markup. I see &plusmn is on the list of entities to leave alone on math pages but &PlusMinus isn't; I have corrected the error. -- Beland (talk) 15:39, 23 December 2025 (UTC)

I usually go by 'does this help to prevent confusion'? ± is no harder to read than ±, so replacing with ± makes sense. When it comes to κ and κ well κ can be easily be confused with k, so κ makes sense. Headbomb {t · c · p · b} 19:48, 23 December 2025 (UTC)

"editors would generally rather" – I see no evidence for this, at least for mathematical articles. My observation is that using unicode code points directly vs. spelled out as entities is a matter of personal preference, and most people are completely indifferent. Arbitrarily switching from one to another site-wide to enforce one person's preference doesn't seem justified. –jacobolus (t) 22:12, 23 December 2025 (UTC)

I suppose it's more accurate to say the preferences among math editors are mixed; it's not like I go around changing Unicode characters to named HTML entities, so I wouldn't know from personal experience whether or not some math editors would complain about that. I do know that (other than entities we retain for technical or confusion reasons) math articles are the only places I've gotten complains about changing named HTML entities to Unicode characters on the grounds that HTML entities are easier (because LaTeX also names its special characters).

This is not one person's preference and it is not arbitrary. On other pages, many editors have explicitly supported changing HTML entities like &eacute, because they are harder to work with than characters that people can simply type on their keyboards, and many editors are not familiar with HTML entity syntax. Outside of the named entities we are keeping permanently (and exceptions for math articles), I have at some point zeroed out the population of all of them except for &thinsp, &emsp, and &quot. -- Beland (talk) 22:40, 23 December 2025 (UTC)

"harder to work with than characters that people can simply type on their keyboards" – This seems backwards; the ascii entity names can always be typed on any English speaker's keyboard on any platform, whereas other characters are sometimes inaccessible. People with a Mac who are unusually knowledgeable can type the ± symbol via [option, shift, =], but on some platforms it's significantly less convenient (on Windows you need to know to type [alt, 1, 7, 7]), and there are other symbols that are even more challenging to type.

Symbols like é, ü, or ç (or, say, en dashes) are a bit of a special case: they are are very widely supported and the support is reasonably well understood by a large proportion of computer users because they are a basic part of several European languages (and appear in plenty of common loanwords in English). So I can understand someone preferring to read/write markup with e.g. façade and naïveté instead of façade and naïveté. –jacobolus (t) 00:16, 24 December 2025 (UTC)

Sure, I expect the proliferation of hard-to-type symbols is one of the reasons named HTML entities are preferred in math articles by some editors. When I say "on their keyboards" with regard to é and friends, I'm assuming that the people most likely to deal with diacritics have keyboards capable of typing them because they read and write a non-English language proficiently enough to cite non-English sources (which is where most of these appear). Maybe that's not true and it's mostly about the visual comprehensibility of wikitext for everyone.

Maybe it's because it shows up by default on the special character insertion toolbar when editing articles on desktop, maybe it's because most editors don't know about HTML entities or how to express this character using one, or maybe people find it more natural to copy-and-paste (e.g. from a web site they are pulling data from), but outside of math articles, 99%+ of organic instances of ± have been the character and not a named HTML entity. All instances of &plusmn outside of math articles have been converted to the character for a while now. -- Beland (talk) 01:21, 24 December 2025 (UTC)

"All instances of ± outside of math articles have been converted to the character for a while now " – And how did such a conversion benefit anyone? Were there widespread complaints from editors who couldn't figure out how to interpret 3.2 ± 0.1 or whatever?

–jacobolus (t) 03:28, 24 December 2025 (UTC)

I would get thanked for such changes, so I'm guessing more like diffuse relief at not having to deal with less intuitive markup? But this is not what we're talking about here; thin spaces can't be changed to their Unicode equivalent because they are too easily confused with other whitespace characters. -- Beland (talk) 04:28, 24 December 2025 (UTC)

"But this is not what we're talking about here" – Hm? This discussion was explicitly about the replacement of ± by ±, as an example of a wide range of comparable changes.

"diffuse relief" there may also be significant "diffuse" dissatisfaction, but you aren't going to hear about it unless someone thinks it's bothersome enough to revert or spend a lot of time discussing. –jacobolus (t) 05:20, 24 December 2025 (UTC)

It's already been settled; &plusmn and &PlusMinus will be left alone on math articles. -- Beland (talk) 05:35, 24 December 2025 (UTC)

Is there a list of the replacements to be made somewhere? –jacobolus (t) 09:07, 24 December 2025 (UTC)

https://github.com/cdbeland/moss/blob/main/unencode_entities.py has the primary lists of substitutions. Keep in mind that these are suggestions, and sometimes I have to do something other than what is suggested, or put in an exclusionary wrapper like {{not a typo}} or {{math}} or {{lang}}. Both the Greek letters and the "controversial" array are excluded from conversion on pages containing <math>...</math>. The main suggestion-generating script is https://github.com/cdbeland/moss/blob/main/moss_entity_check.py . You can see there that some articles are excluded based on the title (though I am trying to convert those to use {{not a typo}} instead, for separation of data and code) or based on the fact that they have some sort of cleanup tag applied. The script also excludes some wikitext based on context, such as source code and file names. Any unknown numerical HTML entity will generate a suggestion for substitution to the corresponding Unicode character. Any unknown named HTML entity will generate an alert that it needs to be triaged. -- Beland (talk) 19:55, 24 December 2025 (UTC)

Our various help pages recommend using HTML entities: Help:Displaying a formula#HTML entities says: Though Unicode characters are generally preferred, sometimes HTML entities are needed to avoid problems with wikitext or confusion with other characters - unless the page you linked to was incorrect or that you read an older version of this, I fail to see where they recommend using HTML entities, if anything they recommend using Unicode characters. This type of edit adds spam to watchlists and article history - so what? This entire post feels like a personal preference that should be completely ignored. Gonnym (talk) 14:36, 26 December 2025 (UTC)

This text was written by Beland at special:diff/992568739 and merged into the linked page at special:diff/1059057061. I agree, it was one person's personal preference, not necessarily reflective of prevailing practice, which should probably be somewhat rewritten.

"This type of edit adds spam to watchlists and article history" / "so what?" – I think we should avoid making mass trivial changes unless there is a clear benefit to them, and more generally shouldn't gratuitously second-guess the choices made by original page authors unless the change is an obvious improvement. Those kinds of changes end up being a distraction from the work of improving the encyclopedia. (I think they also more or less violate MOS:STYLEVAR, whose purpose is avoiding such types of distraction.) –jacobolus (t) 00:40, 27 December 2025 (UTC)

While we're at it, can we also stop with automatic whitespace edits like special:diff/1329018196 to Centrosymmetric matrix which systematically removed thin spaces changing e.g. 5 × 5 which appears as 5 × 5 to 5 × 5 which appears as 5 × 5. These thin spaces were deliberately inserted by a human to improve the typography, and there's no obvious reason why removing them would make the typography better, or even more "consistent" (whatever standard these are supposed to meet seems to be one that Beland invented themself; the LaTeX version looks like ${\displaystyle 5\times 5}$, which is closer to the thin space version (though the differences are pretty slight, and the difference in text size may make it hard to judge). For clearer comparison:

More information ⁠ ...

Markup	Result
5 × 5	5 × 5
5 × 5	5 × 5
{{tmath|5 \times 5}}	⁠${\displaystyle 5\times 5}$⁠

Close

Overall these edits replace deliberate human effort to get the spacing right with a narrow and artificial concept of "consistency" that doesn't seem worth the significant amounts of minor edit churn.

Some other edits of theirs have the edit summary follow MOS:MATH whitespace; Can someone point out which part of MOS:MATH makes any statement about this? –jacobolus (t) 10:00, 23 December 2025 (UTC)

The same applies to text marked up with {tag|math}}, e.g., don't automatically change <math>\kappa = \pm \kappa</math> to some other markup for ${\displaystyle \kappa =\pm \kappa }$. -- Shmuel (Seymour J.) Metz Username:Chatul (talk) 14:22, 23 December 2025 (UTC)

I agree with both of you. I'm rather annoyed by such minor edits. If we had a preferred way of representing math, it would make sense to converge towards it. Since we don't, this is endless churn that should be discouraged. Tercer (talk) 14:40, 23 December 2025 (UTC)

Guidance against changing between <math>...</math> and {{math}} is already in MOS:FORMULA, and I don't do that unless there is a technical reason or MOS requirement to do so (like MOS:RADICAL or MOS:BBB), so I'm not sure why there's a complaint about this. -- Beland (talk) 16:03, 23 December 2025 (UTC)

The examples in MOS:MATH#Multiplication sign use regular spaces around ×, not thin spaces. Wikipedia:Manual of Style/Dates and numbers specifically says to use regular or full non-breaking space around ×, or for set phrases no spaces and the letter x. This aligns with MOS:MARKUP, which has a general directive to keep markup simple. I interpret that to mean that it's not worth complicating markup to fuss over a pixel or two here or there. Thin spaces in this context would be inconsistent with the MOS and the way × is used on the site 99% of the time.

These edits are not automatic in the sense of being unthinking; I've been carefully researching the general practice and MOS examples for each context where unusual spaces appear. You'll notice in that diff I left a hair space because two characters were actually colliding, and it actually does improve the typography in that instance. In some cases, thin spaces are standard, such as in French punctuation. -- Beland (talk) 15:58, 23 December 2025 (UTC)

The problem I have is that these edits basically express: "the original author of this was wrong and I'm right". Sometimes that might be the case, e.g. if the markup is literally broken, or if there's a lot of inconsistency within the page, or if for whatever reason there's some typography that is banned by Wikipedia (e.g. the {{radic}} template was decided by consensus to be ugly, or, more famously, typographically correct quotation marks and apostrophes are banned in favor of typographically incorrect ones). But most of the time, the original author has more context than someone coming to make automated or semi-automated fixes. When the original author made a deliberate choice to insert a hair space somewhere, or use a thin space instead of a regular text space, our default assumption shouldn't be "the author was just being inconsistent" but rather "the author considered this and made the choice that seemed best to them, and unless we have a compelling reason we shouldn't second-guess them".

I have no problem with people making markup cleanup changes if they're reading along in a random article and the spacing seems wrong to the eye, or if an article is internally inconsistent, or if they're planning to do a significant improvement to a mediocre article, and want to start by adjusting some stylistic features to their preference which they intend to use consistently thereafter. But are mass trivial style twiddles to large numbers of article really adding value? –jacobolus (t) 22:06, 23 December 2025 (UTC)

Many math expressions don't actually have a single "original author", because wikitext is routinely tweaked and reformatted. I'm afraid I don't share your confidence that existing thin spaces are more often than not carefully crafted. I've found hundreds that are obviously incorrect, like adding space before a footnote marker after ordinary (non even italicized) text. I would argue that any use of thin spaces that doesn't have a good justification is banned by MOS:MARKUP. I support that because unusual whitespace characters:

• Can cause failure to match when searching articles (depending on how smart the search tech is and how it is configured)
• Can pollute downstream environments when readers copy-and-paste
• Require more effort for humans and scripts to parse when dealing with wikitext

That said, given your complain in April 2024, when I encounter thin spaces in math articles now, I'm looking into the typographic and mathematical context. For what I'll call two-sided symbols (+-−/×=≠<>∈≥, etc.) in the main prose I have found that these have full spaces when used in the MOS. This is also usually true in articles, but in some contexts (such as superscripts and subscripts) they tend to be unspaced for visual coherence. For example, n + 1 vs. k_n+1. Because I'm using my brain, for example I would not write sinx unspaced like that, because it looks weird. I'm going through articles alphabetically by title; you can't see my todo list, but I've put some of the As and Bs aside because I need to do more research into how Wikipedia uses less-common math notation before I know what our readers are conditioned to expect or if editors have decided there's a particular preferred presentation.

Using thin spaces can look weird to readers who pay attention to typography if they've been seeing lots of examples with full or no spaces (assuming the difference can be distinguished). In addition to conflicting with the MOS pages linked earlier, using thin spaces with ×, for example, is extremely rare. Looking at easy-to-find cases where the operator is surrounded by numerical digits, and counting by number of lines, in the 2025-12-20 database dump, I see 177,633 D × D (65%), 96,068 D×D (35%), and 183 D × D (0.07%). -- Beland (talk) 00:58, 24 December 2025 (UTC)

Examples given in the manual of style are demonstrative, not prescriptive, and there is no consensus anywhere to force all formulas site-wide to precisely follow the markup used in a few examples which were never intended to be a specification. If you want to make an exact "prescriptive math notation style guide", write up a complete version and then submit it as an RFC. –jacobolus (t) 01:02, 24 December 2025 (UTC)

I do interpret examples as persuasive. If there's anywhere that someone with an opinion would have come in and objected to disfavored typography, it's in the MOS, not a random math expression in a random article. Either way, MOS:MARKUP still applies, along with explicit instructions on the spacing around ×. -- Beland (talk) 01:27, 24 December 2025 (UTC)

Aside: this is yet another case where consistency and typographic correctness would be dramatically improved if English Wikipedia would serve a specific reasonably complete math font to every reader's browser vs. relying on each reader's separate built-in fonts according to their platform, browser, and layout "skin". In some fonts, k_n+1 appears too tightly spaced, nearly overlapping, and adding hair spaces would be an improvement, whereas in other fonts, the subscript of k_n+1 is if anything too widely spaced. –jacobolus (t) 01:08, 24 December 2025 (UTC)

• Side point: It was my understanding that in general we do not italicize Greek letters, whether they represent variables or not. My preference is that we should not usually italicize them; there might be exceptions for reasons I'm unaware of. --Trovatore (talk) 17:56, 23 December 2025 (UTC)

  Lower case Greek letters are generally italicized, while upper case usually aren't. –Deacon Vorbis (carbon • videos) 18:35, 23 December 2025 (UTC)

  In LaTeX math lower-case Greek letters are essentially always italicized and there's not even a built-in font for upright ("roman") ones. –jacobolus (t) 20:14, 23 December 2025 (UTC)

There are at least 2 templates that can be used to standardize this, and additionally wrap the numbers and markup to help identify the markup to be left alone by bots like WP:TYPO, etc.

{{val|5|x|5}} yields 5 × 5. {{times|5|5}} yields 5 × 5. While both produce different spacing (especially in px units (that {{resx}}/{{times}} was originally meant for: "{{val|5|x|5}}: 5 px × 5 px, vs. {{times|5px|5px}}: 5px × 5px), at the very least decorating such instances can allow easy unification/standardization by homologizing the templates.  — sbb (talk) 17:02, 2 January 2026 (UTC)

Category:Fellows of the Association for Computing Machinery is considered for deletion

Please opine. Headbomb {t · c · p · b} 04:50, 3 January 2026 (UTC)

To save anyone who cares to comment one click, the discussion is here: Wikipedia:Categories_for_discussion/Log/2026_January_2#Category:Fellows_of_the_Association_for_Computing_Machinery_by_year. --JBL (talk) 20:46, 3 January 2026 (UTC)

Redundant Definitions in Nemytskii operator

The article on the Nemytskii operator currently defines the operator three times:

- The "Nemytskii superposition operator", defined on maps between arbitrary sets

- The "Nemytskii operator" in Euclidean space, induced by a function satisfying the Carathéodory conditions

- An operator between Lipschitz continuous maps, which isn't explicitly stated to be the Nemytskii operator.

From some quick research, I found a fourth definition of the Nemytskii operator in terms of vector spaces of functions between Banach spaces in "Concrete Functional Calculus", by Dudley and Norvaiša (p. 273), which also explicitly states the terms "superposition operator" and "Nemytskii operator" are used interchangeably.

It seems sensible to me to restructure the article around a single one of these definitions. I am asking here first because I do not feel I am familiar enough with Wikipedia etiquette to judge whether it is appropriate to set out on such a major restructuring on my own, and because I am interested in second opinions on which level of generality would be most appropriate. Yoneda-Emma (talk) 16:32, 8 January 2026 (UTC)

I do not know anything about this subject, but I have some general observations. If these are the same, then you should show that they are the same, begin with the most concrete and work up to the most general. If they are different, then would it be better to split the article rather than downgrading all but one of them. JRSpriggs (talk) 19:33, 8 January 2026 (UTC)

Metric barnstar

As the WikiProject Measurement is now inactive, I thought here was the best place to post this. Would it be all right if I added this barnstar I made to the list of topical barnstars here? - Wikipedia:Barnstars/Topical

Please comment below to let me know what you think. Thank you. Caravansera (talk) 07:19, 5 January 2026 (UTC)

I don't see why not. —David Eppstein (talk) 07:41, 5 January 2026 (UTC)

Seems fine to me. Stepwise Continuous Dysfunction (talk) 21:33, 5 January 2026 (UTC)

Ok, since it's been a week and two users have said it's okay and nobody has objected, I am going to add the metric barnstar to the list of topical barnstars.Caravansera (talk) 18:43, 12 January 2026 (UTC)

Good article reassessment for Newton's theorem of revolving orbits

This is a physics subject, but it's mathematically involved enough that editors active here may want to chime in: Newton's theorem of revolving orbits has been nominated for a good article reassessment. Per the reassessment page, some problems have been resolved but there is still work to do. Stepwise Continuous Dysfunction (talk) 00:54, 14 January 2026 (UTC)

Regret (decision theory)

I am quite confused by the page Regret (decision theory), as it is categorized under both “Game theory” and “Statistics”, while a large part of the article discusses psychology. Should we create a separate Wikipedia page dedicated to regret in mathematics, without any links to regret as a “negative emotion”, as described in Regret (decision theory)? I believe there is sufficient material on mathematical regret to justify a standalone page. Adrien PREVOST (talk) 10:09, 31 December 2025 (UTC)

Regret (decision theory)'s lede and "Anticipated regret" sections certainly don't look mathematical, and an article on regret as a mathematical concept seems sensible. I've taken a cursory look at some sources, and regret is well-defined and studied in game-theory.

Decision theory looks mathematical in itself. Regret in game theory looks similar to regret in decision theory (at present, Regret (game theory) redirects to Regret (decision theory)), so it might be best, instead of creating a new page, to move the psychology sections to Regret or delete it entirely. The Boolean^_Talk 19:23, 1 January 2026 (UTC)

I agree that the psychological material should be moved out and the article refocused on the mathematical optimization aspects of the topic. See also competitive regret and swap regret; this appears to be a big topic in machine learning that our articles don't really cover well. —David Eppstein (talk) 19:48, 1 January 2026 (UTC)

I had a quick look at the article and I actually feel like the "psychological" part of the article is fairly light. If there are particular parts that we feel are too detailed, I wouldn't be against them getting shortened, but I would be opposed to completely removing the "psychological" aspects of regrets from that article. Are there particular paragraphs that are of concern?

This article is primary about regret in the concept of decision theory and game theory. These two fields are at the intersection of mathematics and psychology. They try to use mathematics to model psychological mechanisms. Focusing solely on the mathematical aspects, in my view, would remove the intuition behind the math, and make the article a lot less useful for most readers (especially the lead section, which is generally supposed to be less technical than the rest of the article). 7804j (talk) 11:56, 11 January 2026 (UTC)

I don't think that regret in game theory is at the intersection of maths and psychology. Regret is a very common quantity in game theory, especially in online games where it is the difference between the best achievable from an oracle that knows everything and what the player is doing. When regret appears in papers on online games there is no reference to psychology. Application of regret in those games is absolutely not linked to any psychological stuff.^[1]

We can find such quantity in Reinforcement Learning^[2], learning with experts^[3] and especially in Bandit games^[4] where even in papers on bandits but not on regret they even have to specify that it is not about regret.^[5] There are probably more domains of online learning that use regret that I forget or don't know.

That's why I think it requires its own page with only maths stuff on it. Maybe we can separate the page between regret in decision theory and in game theory? Adrien PREVOST (talk) 00:08, 13 January 2026 (UTC)

It could be that regret in game theory and in decision require two distinct pages.

Regarding the psychological angle: there is for example this paper that's referenced in the current article that talks about the "feeling" of regret (i.e., in a psychological sense) in the context of auctions. But perhaps that's because auctions fall more within the realm of decision theory?

If the game theoretical definition of regret is almost universally understood, as you described, as the "difference between the best achievable from an oracle that knows everything and what the player is doing", I agree with you that it's not about psychology (and thus that it may require a different page than for decision theory). 7804j (talk) 20:59, 14 January 2026 (UTC)

I've looked more closely at the article, and it seems to be trying to say that regret in decision theory has applications in psychology. If that's the case, the psychological content belongs in the article similarly to how the article Calabi-Yau manifold discusses the manifold's importance in string theory, even though, in principle, the Calabi-Yau manifold is a purely mathematical object.

Regret has other applications outside psychology (particularly in machine learning), so the psychology section shouldn't be the article's exclusive focus, but it needn't be removed.

As for the difference between regret in decision theory and regret in game theory, I suspect that no difference exists and that both fields use the same definition. "Regret" appears to be a widespread mathematical term. However, I have been unable to find a source that explicitly references both regret and decision theory, which is what we'd need to provide the correct definition of regret in the context of decision theory. Based on this, I'd propose:

• Cleaning up the article to clarify the relationship between regret and its applications
• Moving the page to Regret (game theory) or Regret (mathematics).
• Writing the lede so it explains regret, then explains its uses

The Boolean^_Talk 23:17, 14 January 2026 (UTC)

Sprague–Grundy non-theorem

Our article on the Sprague–Grundy theorem must be wrong as written. It says "every impartial game under the normal play convention is equivalent to a one-heap game of nim". This is absurd. If there was only one heap, then either it is empty and the first player loses or it is non-empty and the first player can immediately win by taking the whole heap. So the complexity of real nim with multiple heaps would be eliminated. When there are multiple heaps you want to reduce the largest [some] heap to a value which makes the XOR of all the heaps' sizes in binary equal to zero. JRSpriggs (talk) 02:29, 15 January 2026 (UTC)

Oh! No, that's completely right actually. The complexity of nim is encoded in the size of the heap. You can reduce a standard, multiple heap game of nim to a single heap whose size is the binary XOR of all the heaps sizes. MEN KISSING (she/they) T - C - Email me! 02:54, 15 January 2026 (UTC)

I realize now, this needs one clarification (which I hope clears all this up): the only reason that much complexity can be removed at all, is because we're assuming both players are playing optimally. A more complicated game of nim may have more complexity than if it were just a single nim heap, but only if we were to assume the two players might make sub-optimal moves.

Perhaps this point isn't illustrated clearly enough in the article? MEN KISSING (she/they) T - C - Email me! 03:11, 15 January 2026 (UTC)

There's a key word in this sentence: equivalent.

If it meant merely that the game had the same outcome when played in alternation with perfect play, then every game would be equivalent either to a zero-coin nim game (in which the first player always loses) or a one-coin nim game (in which the first player always wins). But that is not what equivalent means here; see Sprague–Grundy theorem#Equivalence.

The equivalence of games X and Y means that for every impartial game Z, the sum of games X + Z has the same outcome (with optimal play) as the sum of games Y + Z. Here the sum is more or less what you do in nim when you have multiple piles: you can move in exactly one of them.

The issue of optimal play is also valid but is part of the definition of equivalence, which is the more subtle and more important point. —David Eppstein (talk) 04:41, 15 January 2026 (UTC)

Yes, yes. A nimber is required, it can't just be either 0 or Star. Otherwise, it wouldn't explain why a nim game of *2 + *1 is a win for the player going first but *1 + *1 is a win for the player going second.

As an aside: I'm surprised Conway's Winning Ways for Your Mathematical Plays isn't used as a source there. Is there a reason for that? If I recall correctly, that book makes a good case for the significance of the theorem in game theory, an area where the article seems to currently be lacking. I'm on something of a self imposed wikibreak, so I don't want to dig in to it right now, but maybe I could poke around there some more in a few days! I've been meaning to get more invested in this WikiProject; I kinda got distracted futzing around at RfD haha. MEN KISSING (she/they) T - C - Email me! 05:03, 15 January 2026 (UTC)

It is unreasonable to presume perfect play. If there are no heaps, then the first player loses. If there is one heap, then the first player can take the whole heap and win. If there are two unequal heaps, then the first player can reduce the larger heap to the same size as the smaller one and win. When there are three heaps, a≤b≤c, then reduce c to b-a [reduce one of them to XOR of the other two]. JRSpriggs (talk) 13:15, 15 January 2026 (UTC)

All of combinatorial game theory is presuming perfect play, haha.

Note that you can also think about a nim game of any number of heaps as being equivalent to two heaps, the second heap being the XOR of all the other heaps aside from the first heap. This checks out under the Sprague-Grundy theorem because XOR is commutative and associative. MEN KISSING (she/they) T - C - Email me! 16:36, 15 January 2026 (UTC)

It is completely reasonable to presume perfect play, in the definition of equivalence. If what you want is games that have the same game play in all situations regardless of perfection, then you are looking at a different and less interesting equivalence relation, isomorphism. —David Eppstein (talk) 18:41, 15 January 2026 (UTC)

I think that you-all are conflating nim with Grundy's game. Although both deal with heaps or piles of objects, they have different rules including different winning conditions. JRSpriggs (talk) 01:02, 16 January 2026 (UTC)

No, that's not what's happening here. Both games are heap games, and although they have different rules, they are both impartial games and the Sprague-Grundy theorem applies just the same.

Grundy's game is actually a great example of how impartial games can be reduced to nim sums! You can convert each Grundy's game heap into a nim heap according to the stack size, and it will remain equivalent under perfect play. The sequence ‹See TfM›

OEIS: A002188 describes the conversion rule. Note that the Sprague-Grundy value is exactly equal to the nim heap stack size you need to convert to.

I'd like to recommend volume 1 of Conway's Winning Ways if you want all of this cleared up. Chapters 3 to 4 I think cover the topic and how it relates to other heap games best. Also, it's just a really fun book. It has my favorite diagram I've ever seen in any mathematical text. MEN KISSING (she/they) T - C - Email me! 01:18, 16 January 2026 (UTC)

That OEIS sequence is labeled "Sprague-Grundy value for Grundy's game when starting with n tokens.". It is describing Grundy's game, not nim. JRSpriggs (talk) 01:33, 16 January 2026 (UTC)

Why are you keeping on talking about Grundy's game? It is nim that the Sprague-Grundy theorem is formulated in terms of, and nim that the Sprague-Grundy theorem article talks about. Where are you seeing Grundy's game used in place of nim? —David Eppstein (talk) 01:38, 16 January 2026 (UTC)

Read reference 2 in the article on Grundy's theorem. Grundy says "The following game with piles of matches is an example:- The move consists of taking any pile and dividing it into two unequal parts. The game is one in which the last mover wins; ...". He is talking about his game, not nim. JRSpriggs (talk) 01:47, 16 January 2026 (UTC)

That's an example of a game whose positions are equivalent (in the specific sense described) to games of nim. It doesn't mean it's the same (isomorphic) game. —David Eppstein (talk) 02:12, 16 January 2026 (UTC)

Yes. MEN KISSING (she/they) T - C - Email me! 01:39, 16 January 2026 (UTC)

The theorem is about normal-play nim where the player to take the last coin wins. Nim is also played in a "misère" version where the player to take the last coin loses, but the Sprague-Grundy theorem applies only to normal-play games, not misère games. For nim both versions have almost the same game play but that is not true for other impartial games. —David Eppstein (talk) 01:20, 16 January 2026 (UTC)

Uncle and ouch. After reading a great deal more of our articles on games, I see that I was wrong, for the most part. But I still have two points: (1) The word equivalent is being used in a very technical sense and I think that the readers should be apprised of that fact where it is first used in the lead of some articles. (2) The theorem does not appear to allow for infinite games. I agree that every game should end in finite time, but that can be achieved by using ordinals which have no infinite descending sequences despite being infinite in the upward direction. Consider a single heap of 2^ω=ω things. I do not think that this would be equivalent to *n for any natural number n. JRSpriggs (talk) 21:03, 16 January 2026 (UTC)

Aw, don't sweat it. Someone was wrong on the internet. It happens all the time! If it didn't happen, we wouldn't need to have Wikipedia at all haha.

The way I understand the Sprague-Grundy theorem, both finiteness and the definition of equivalence are pretty important to justifying the theorem. That would be a good point of improvement.

Winning Ways did also talk about the case of infinite games at length, including an infinite version of the Sprague-Grundy theorem! If you want to learn more about that, I think volume two of the book covers most of that topic. MEN KISSING (she/they) T - C - Email me! 21:40, 16 January 2026 (UTC)

Volume 1 (Games in General), Chapter 11 (Games Infinite and Indefinite), p. 313 (The Infinite Sprague-Grundy and Smith Theories). Every impartial game that is guaranteed to eventually end is equivalent to nim with a single ordinal number pile of coins (in the same sense of equivalence). —David Eppstein (talk) 00:04, 17 January 2026 (UTC)

Unsolved template in Rupert property

Can anyone tell why the unsolved template in Rupert property was deleted, thereby declaring it to be solved (although this looks disputed , yet our article List of unsolved problems in mathematics#Euclidean geometry said the problem remains unsolved? Dedhert.Jr (talk) 04:51, 20 January 2026 (UTC)

A counterexample has been provided (the Noperhedron), but, according to List of unsolved problems in mathematics, the paper describing it is a preprint and has not been published. The Boolean^_Talk 08:27, 20 January 2026 (UTC)

Custom color scheme for mathematics navboxes?

This is what our navboxes currently look like:

It's the default color scheme, and I don't think this is ugly or anything, but I had a thought earlier today that it could be fun to consider having a custom color scheme! As far as I was able to find (although maybe I didn't look hard enough), there hasn't been any proposal to come up with any different colors for mathematics related templates like navboxes in the past.

More than I want to have any specific color change, I just wanted to throw out the idea of having a color change at all. For a specific idea, though, I was thinking a metallic theme could be nice, to make it reminiscent of a whiteboard. The light grey might come across as a bit dull, but maybe the colorlessness is appropriate for a subject without an inherent color.

I could create some mock-ups if the idea seems popular.

What do you guys think? (Have to head to class now, replies may be delayed) MEN KISSING (she/they) T - C - Email me! 23:41, 21 January 2026 (UTC)

I am opposed to custom appearance in general. Pages with unusual style distract readers for no particular benefit. Wikipedia style should be clear but boring. A metallic or white board theme could be good for your personal website. –jacobolus (t) 00:44, 22 January 2026 (UTC)

A metallic or white board theme wouldn't be a good fit for my personal website; I prefer using brash tones of hot pink to complement the deep purple text haha.

In all seriousness, if your concern is that I'm proposing something too flashy and distracting, don't worry. I wouldn't propose something that was so pretty it was ugly, so to speak. Frankly, I'm surprised you think my proposed idea wouldn't be boring; I said "metallic" because what I really wanted to say was light grey. MEN KISSING (she/they) T - C - Email me! 03:12, 22 January 2026 (UTC)

My concern is that the contrast of the blue words on the bluish-purple background may have too low of contrast and should be changed to improve accessibility for color-vision impaired users. EulerianTrail (talk) 01:26, 22 January 2026 (UTC)

The contrast between   and   in the top bar is not extraordinary, but it's also not terrible. I'd have a concern with this color scheme used for paragraphs of text, but I don't think it's a serious issue for a few words in a navbox. The contrast in the other heading parts of the of the navbox with background   seems like plenty. Having relatively lower contrast for this use case compared to the main article is probably somewhat helpful for many readers, insofar as it makes the navbox less distracting. In general if you are concerned about text contrast, I recommend you look at @Myndex's https://apcacontrast.com/ –jacobolus (t) 02:41, 22 January 2026 (UTC)

The contrast ratio is 4.05:1 which does not meet WCAG2.2 AA standard of 4.5:1. I usually use to check what is problematic on a website. EulerianTrail (talk) 02:59, 22 January 2026 (UTC)

I would suggest changing the background text to   which would meet the minimum of WCAG 2.2 Ideally, we would want to change the text color, but that is an issue over what color link text should be and might by outside the scope of the template. Please refer to MOS:CONTRAST which states that wikipedia follows WCAG 2.2 AA for contrast and strives for AAA when possible. EulerianTrail (talk) 03:09, 22 January 2026 (UTC)

If the default color scheme does not meet the minimum WCAG standards then it needs to be changed, regardless of whether we continue to follow the defaults. —David Eppstein (talk) 03:29, 22 January 2026 (UTC)

Unfortunately WCAG 2.x's contrast calculation bears almost no relation to human visual contrast perception. It should frankly never be used for any purpose unless legally mandated; it will happily accept almost completely illegible choices while simultaneously rejecting highly legible ones. Thankfully, @Myndex put in a lot of work making an alternative based on a reasonably accurate model of human vision. It does a significantly better job at predicting perceived contrast, with the result that its assessment of whether something does or doesn't have enough contrast is much more reliable and effective. –jacobolus (t) 04:08, 22 January 2026 (UTC)

I did stare at MOS:COLOR and adjacent guidelines a lot before posting this proposal. I'd like to keep all of that in mind for whatever a potential color change might be. MEN KISSING (she/they) T - C - Email me! 23:53, 22 January 2026 (UTC)

Just keep it as it is. But since the discussion keeps going so far, I have no opinion. I'll leave it for the members above me. Period. Dedhert.Jr (talk) 09:39, 22 January 2026 (UTC)

Square infobox image

There's a discussion about the infobox image used on Square at Talk:Square#Infobox image choice if anyone here would be interested. Daniel Quinlan (talk) 09:34, 24 January 2026 (UTC)

Draft:Best arm identification

Hi ! I'm currently struggling to make my draft less technical, as suggested in the first rejection.

I added a part, "Example of simple modelling", to show how this problem appears, and an animation of how an algorithm behaves in general.

I got a second rejection suggesting that it should be more comprehensible for people not comfortable with probability. However, I don't know how to even define the problem without using any probability, and at the same time I can't redefine every probability definitions just to state the problem of Best Arm Identification.

Does anyone have a more concrete idea of how to improve the draft ? Adrien PREVOST (talk) 23:42, 22 January 2026 (UTC)

There might be some exaggeration in the criticisms and assuming no familiarity with probability at all would be a tough place to start. Looking over the article, I think most of it looks reasonable and the simple example and applications sections are welcome. I think were it is lacking is in the lead. It assumes that the reader knows what a multi-armed bandit is in the first sentence. You may want to add more context. If this isn't about biological limbs or criminals, what is it about? How would you explain the problem to a high-school or undergraduate student in a minute? You'd might first explain that this can be seen as a problem of picking the most profitable slot machine by trying different machines and analyzing the results, and involves the choice of exploration vs exploitation, etc. It doesn't have the be a huge backgrounder, but some context so that a reader can determine what this article is about and if they are interested in the topic is important for technical articles like this. You might look at chapter 1 of Lattimore's book for inspiration. --{{u|Mark viking}} {Talk} 01:26, 23 January 2026 (UTC)

The issue is probably more that you're talking about things in a less approachable way, and not that you're talking about concepts that are inherently not approachable, nor that you're not giving enough background for the concepts you're talking about.

This paragraph strikes me as a good example:

The stochastic multi-armed bandit (MAB) is a sequential game with one player and ${\displaystyle K}$ actions (arms). Behind each arm ${\displaystyle k\in \{1,\ldots ,K\}}$ lies an unknown distribution ${\displaystyle \nu _{k}}$ with mean ${\displaystyle \mu _{k}}$. Each distribution ${\displaystyle \nu _{k}}$ belongs to a known family ${\displaystyle {\mathcal {D}}}$ (such as the set of Gaussian distributions or Bernoulli distributions). At each time step ${\displaystyle t}$, the player selects an arm ${\displaystyle a_{t}}$ and observes an independent sample ${\displaystyle X_{t}\sim \nu _{a_{t}}}$ from the corresponding distribution.

The core idea you're trying to express here is that it's a sequential game where each turn, you select from one of ${\displaystyle K}$ options, and get a reward depending on the option you took, where the random distributions of each choice are not known. You would do better to explain this concept in more intuitive, non-technical terms, and then establish the notation. MEN KISSING (she/they) T - C - Email me! 02:29, 23 January 2026 (UTC)

What does "branch" mean in the first sentence? Is it a variant of the multi-armed bandit problem, an alternative way of describing the multi-armed bandit problem, or what exactly? Stepwise Continuous Dysfunction (talk) 18:21, 23 January 2026 (UTC)

Bandit games are games where you only get an observation of an arm if you play it. But the objective can be diverse. The most common one is to minimize the regret, and another common one is to find the best arm; we call the multi-armed bandit problem with this objective 'Best arm identification'.

I guess I need to give more explanation on this, but at the same time, from all the pages that I have read the first sentence is to give the general context without having to directly explain each term ? Adrien PREVOST (talk) 20:27, 23 January 2026 (UTC)

Try to give the general context as if you are speaking to a bright undergraduate who has taken the prerequisite classes for the idea you're discussing (but not learned about it yet), rather than a seminar talk where the intended audience already knows the context. --JBL (talk) 00:39, 24 January 2026 (UTC)

I added a few sentences to explain the setting without using mathematical formulas, but this triggered an LLM alert. I have no idea which sentence caused it, and I don't feel motivated to look for the reasons and continue drafting. Feel free to copy the code if you want to work on it. Adrien PREVOST (talk) 11:46, 24 January 2026 (UTC)

Interesting; let me invite RangersRus here to discuss, as I don't see anything particularly LLM-ish about what you've written. --JBL (talk) 17:57, 24 January 2026 (UTC)

Sorry for late arrival, been busy. My rejection reason was basically because the draft very much looked like as if some comprehensive Language AI platform was used to create the draft. RangersRus (talk) 03:19, 25 January 2026 (UTC)

For the avoidance of doubt, let me ask: did you use an LLM or similar tool in constructing the draft? Thanks, --JBL (talk) 18:11, 24 January 2026 (UTC)

I use deepL to translate from french to english Adrien PREVOST (talk) 18:21, 24 January 2026 (UTC)

Ah, that would do it.

You should know, using LLMs for translation is a bit of a hot topic right now. There's at least one AN thread about an ongoing issue regarding it and an active RfC. MEN KISSING (she/they) T - C - Email me! 22:23, 24 January 2026 (UTC)

Sure but it's also quite different from the AfC rejection criterion. --JBL (talk) 22:25, 24 January 2026 (UTC)

Is there a tool to correct English grammar faults that is non-controversial ? Adrien PREVOST (talk) 22:47, 24 January 2026 (UTC)

One can make requests at WP:GOCE (or here, for mathematical articles).

In my opinion this situation is an example of the fundamental problem with these tools: in the hands of a skilled subject-matter expert (who can easily and accurately review the output for validity, source use, bias, etc.), LLMs are just another tool that make translation easier; but in the hands of the unskilled or non-experts, they make de novo writing much easier, and therefore become high-volume garbage generation machines. No one objects in principle to writing of the first kind (to an English-competent but perhaps not fluent subject-matter expert using LLM assistance while translating text within their domain of expertise), it's just very hard to draw a bright line that separates it from the incompetent or malicious having ChatGPT write whole articles for them and posting them verbatim. --JBL (talk) 00:25, 25 January 2026 (UTC)

I would advise just posting the uncorrected text as a draft and then asking here if anyone would like to improve it. Stepwise Continuous Dysfunction (talk) 01:37, 25 January 2026 (UTC)

Proposed deletion of Homogeneous variety

The article Homogeneous variety has been proposed for deletion because of the following concern:

Unsourced for 12 years. Makes no sense; might need an expert to make sense of it.

You may prevent the proposed deletion by removing the {{proposed deletion/dated}} notice, but please explain why in your edit summary or on the article's talk page.

Please consider improving the page to address the issues raised. Removing {{proposed deletion/dated}} will stop the proposed deletion process, but other deletion processes exist. In particular, articles for deletion allows discussion to reach consensus for deletion based on established criteria.

If the proposed deletion has already been carried out, you may request undeletion of the article at any time. Bearian (talk) 10:46, 22 January 2026 (UTC)

I think this is notable enough to want to have an article about it. I corrected the article and added citations and unprodded ; the current version is still very much a stub though. jraimbau (talk) 13:32, 22 January 2026 (UTC)

Thank you! Bearian (talk) 20:54, 25 January 2026 (UTC)

History of the Koch curve

• Koch snowflake § Origin and history

I saw a questionable grammatical edit to this section (well, trading one issue for another really). But looking into this, I'm not sure what's there is especially reflective of the source, and it certainly contradicts what we have in the article lead. I tried to dive into this, but it's not really my strong suit, and it could use another set of eyes if someone feels up to it. –Deacon Vorbis (carbon • videos) 13:47, 26 January 2026 (UTC)

Dependence relation

Can someone please add reliable sources? Bearian (talk) 20:54, 25 January 2026 (UTC)

Is this different from a matroid? Maybe it should just be redirected there? —David Eppstein (talk) 21:22, 25 January 2026 (UTC)

Interesting, I was expecting to find very different content at the link! As described this is not on Brylawski's list of matroid cryptomorphisms but that is not intended to be comprehensive. --JBL (talk) 22:06, 25 January 2026 (UTC)

Both of the examples are matroids, I think? Stepwise Continuous Dysfunction (talk) 03:52, 26 January 2026 (UTC)

If there is a correspondence (via ${\displaystyle a\triangleleft S\leftrightarrow a\in \operatorname {cl} S}$), dependence relations correspond to finitary matroids -- axiom (2) is the finitary condition. The first source I found (at https://doi.org/10.3390/sym15020311) does not mention matroids, but it also does not use the terms "independent", "span", or "basis" as the Wikipedia article does. The Boolean^_Talk 04:54, 26 January 2026 (UTC)

As an article in a mathematics journal that is not listed in MathSciNet I'm skeptical of its reliability. —David Eppstein (talk) 06:06, 26 January 2026 (UTC)

Yes, I don't think we should use it as a source. I was attempting to find a resource that would show how dependence relations are studied. Reliability aside, it doesn't have any noteworthy theorems or results. The Boolean^_Talk 07:55, 26 January 2026 (UTC)

I asked Joe Bonin (an expert in matroid theory) about this; here is a condensed version of his response:

In the finite case, the notion of a dependence relation is of course a trivial reinterpretation of well-known formulations of matroids. What made me think that that isn't completely trivial is that the author is clearly interested in the infinite case (see the second property), and infinite matroids are quite a different animal to deal with. [...] I opened up Dominic Welsh's book to the last chapter on infinite matroids where he says (page 388) "For these the reader familiar with universal algebra and in particular with Cohn [65] will recognize an independence space [one of the types of infinite matroids studied in the 1970s] as a transitive algebraic dependence relation or equivalently as a set ${\displaystyle S}$ equipped with an algebraic closure operator ${\displaystyle \sigma :2^{S}\to 2^{S}}$ which in addition to the usual axioms (S1)-(S4) of Section 1.7 [those are the usual closure axioms for matroids, including Steinitz-MacLane exchange] also satisfies the algebraic condition ..." and that algebraic condition is the second property in the Wiki article. Cohn [65] is P.M. Cohn, Universal Algebra, Harper and Row, 1965. So, the [Wikipedia article Dependence relation] probably has more substance, or at least more connections, than might at first be evident, perhaps more from the view of universal algebra. ...

He suggested that the books of Welsh and Cohn might be usable as sources for this article (neither he nor I owns the book by Cohn). --JBL (talk) 18:28, 28 January 2026 (UTC)

Mathematician#History

Would anyone like to take a crack at making Mathematican#History more systematic and less a dump site of famous names? Stepwise Continuous Dysfunction (talk) 04:11, 25 January 2026 (UTC)

What I would expect to see there, and don't, is something about the roles of mathematicians in society in different eras. —David Eppstein (talk) 05:16, 25 January 2026 (UTC)

Would anyone like to take a crack at cleaning up Baudhayana for encyclopedic tone, unreferenced material, etc.? Stepwise Continuous Dysfunction (talk) 23:02, 27 January 2026 (UTC)

This general area can be a minefield of nationalistic editors, unscholarly sources, language barriers, promotional writing, overblown claims of priority, and dubious dating often based on oral traditions rather than written artifacts. In this particular case, the problem of dates and oral history is quite relevant; the dates are stated more precisely in the article than what I believe is known. His having stated the Pythagorean theorem and of having listed several small Pythagorean triples is well attested in the scholarly literature; see Shulba Sutras § Pythagorean theorem and Pythagorean triples. However, you will also sometimes see claims that he proved or first invented the Pythagorean theorem, or that Pythagoras somehow learned of the theorem from him, that are much less clear. As far as I know there was no notion of proof in the ancient Indian mathematical tradition, there is no documentation of transmission from India to Greece, the theory of transmission to Pythagoras rests on the badly-supported claim that Baudhayana was actually earlier than Pythagoras (the date ranges overlap), and there is strong evidence of the Pythagorean theorem (but again not its proof) being known and used millenia earlier in both Babylon and Egypt. There is some of this currently in the Baudhayana article now, stating in vague terms that his contributions connected to the Pythagorean theorem occurred "centuries before the western mathematics developed". This needs to be handled carefully and encyclopedically. —David Eppstein (talk) 23:50, 27 January 2026 (UTC)

Knowledge related to what is now called the Pythagorean theorem existed in multiple ancient civilizations. Babylonian, Egyptian, Chinese, Indian, and Greek sources all contain results or procedures that reflect aspects of the theorem.The recent addition of claims regarding approximations of π and √2 requires greater historical balance. Approximations of π are documented in ancient Egyptian and Babylonian sources, while an approximation of √2 appears in Babylonian texts centuries before its mention by Baudhāyana and there is nationalist approach happening in the article along with the vedic stuff in astronomy article. Myuoh kaka roi (talk) 09:57, 30 January 2026 (UTC)

Bhāskara II

This entire article has problematic statements with a lot of unreliable sources added in many sections like The Siddhānta-Śiroma and Mathematics and it is there for a long time Myuoh kaka roi (talk) 19:19, 30 January 2026 (UTC)

Comparison with Fourier series in Taylor series

I am not sure the Fourier series is included in Taylor series#Comparison with Fourier series. But is there any relationship between these two series? I prefer to delete this section. Dedhert.Jr (talk) 00:03, 29 January 2026 (UTC)

The Fourier series is more closely related to the Laurent series (like a Taylor series but also including negative exponents), of which it is merely a change of variables. The Taylor series is the best polynomial approximation to a function defined near a specific point, whereas the Laurent series is the best Laurent polynomial (polynomial including negative exponents) approximation to a function defined near a circle. –jacobolus (t) 00:41, 29 January 2026 (UTC)

The section should not be kept as is, but is vaguely recalling something useful from approximation theory. Instead of comparing Taylor series with Fourier series, I think the section should be comparing them with Chebyshev approximation, a polynomial approximation technique over a fixed, finite interval with (IIRC) uniformly bounded error (provided the original function is absolutely continuous). E.g. the following sentences should be readily sourceable if you swap out Fourier series for Chebyshev series:

The computation of Taylor series requires the knowledge of the function on an arbitrary small neighbourhood of a point, whereas the computation of the Fourier series requires knowing the function on its whole domain interval. In a certain sense one could say that the Taylor series is "local" and the Fourier series is "global".

(Chebyshev basis projections over ${\displaystyle x\in [-1,1]}$ are equivalent to Fourier cosine series over ${\displaystyle \theta \in [0,\pi ]}$ under the change of variable ${\displaystyle x=\cos \theta }$, which might explain the confusion here.) Preimage (talk) 12:39, 31 January 2026 (UTC)

As you say, a Chebyshev series is a type of Fourier series under a change of variables (specifically, a Fourier series for an even function on the periodic interval ⁠${\displaystyle [-\pi ,\pi )}$⁠). –jacobolus (t) 15:02, 31 January 2026 (UTC)

@Preimage. I'll see if I can find some sources for writing. Dedhert.Jr (talk) 13:20, 1 February 2026 (UTC)

Infobox images for polyhedra

There has been some dispute about which images should be used in infoboxes on articles about polyhedra. I was under the impression that these should all be from "the green set" (https://commons.wikimedia.org/wiki/Category:Set_of_polyhedra;_green) unless there is a strong reason to prefer another image. Can anyone chime in on this? — LucasBrown 07:34, 2 February 2026 (UTC)

I don't really have an opinion on that but I have seen some back-and-forth on my watchlist over whether to use bitmap or vector versions of these images. (In general for new images of this sort of thing I prefer vector formats but in these specific instances I'm not convinced that the vector images were improvements or enough of an improvement to make the exercise worthwhile.) —David Eppstein (talk) 07:51, 2 February 2026 (UTC)

If someone wants a higher resolution, it should also be entirely possible to re-render all of these POV-ray images. –jacobolus (t) 08:37, 2 February 2026 (UTC)

The pentagonal bipyramid looks like it is being rotated, difficult to perceive the illustration

On the other hand, this bipyramid gives a better perspective. One can think of the bipyramid in general as two pyramids attached base-to-base. Color can be discussed if it is problematic in the case of colorblindness.

I am fine with using any color provided by Wikimedia Commons. However, it is preferable to provide an illustration with a more general perspective of the given polyhedra, and possibly a symmetrical appearance.

This has happened before in some articles. For example, @David Eppstein's illustration for Triaugmented triangular prism has been discussed, generally not recommended because of different color, ought to match the green color with other polyhedral articles, which is traditionally accepted. Another one is Truncated tetrahedron, which replaces the green color from File:Afgeknotte driezijdige piramide.svg. In some cases, I sometimes convert the polyhedral images to green because of better perspective, like Diminished icosahedron and Pentagonal trapezohedron. Dedhert.Jr (talk) 14:54, 2 February 2026 (UTC)

To me the green-and-rust-and-gray coloring of many of the images looks arbitrary, like they took a side trip through a clown factory. What kind of 3d environment would actually produce those colors? Look at the pentagonal bypyramid you linked above. We have a bluish-green top front face, an olive top right face, a rust face behind it, a gray face at the bottom, and no change of color at all from the back faces. Why? I'd rather have something closer to monochrome than something that looks fake. I'm sure they were produced by a valid 3d model in povray but it's a model that doesn't resemble reality and where the deviations from reality have no mathematical significance. —David Eppstein (talk) 18:23, 2 February 2026 (UTC)

Someone could certainly also set up different lighting, material properties, camera angles, etc. and re-render all of these images, if they wanted. Maybe it would be worth pinging the various folks involved in their original creation to ask about the choices they made. –jacobolus (t) 19:23, 2 February 2026 (UTC)

Haha, is a clown factory a factory where clowns work, or a factory that manufactures clowns?

It looks like all of the green set were produced using this code written by User:Cyp in POV-ray. For individual pictures that don't have a great camera angle, the code could just be used again for a new image of the same model.

Making a whole new set of images with tweaked colors is something I could perhaps get behind, but it would probably be a lot of effort re-doing it for all the green set polyhedra. But on that note, maybe it's actually not a good thing for all of the polyhedra to be the same color! For example, for the elongated square gyrobicupola, the image could maybe do a better job of conveying why it's different from the rhombicuboctahedron if the faces were colored similar to how the net is colored in the same infobox.

As much work as it would be, it could be a fun project! MEN KISSING (she/they) T - C - Email me! 03:32, 5 February 2026 (UTC)

Both images of nets have atrocious choices of colors in my opinion, so we shouldn't use those colors as-is if we can choose anything else. –jacobolus (t) 04:01, 5 February 2026 (UTC)

Our article Regular polyhedron has list of polyhedra with mixed colors of shades of green, orange, rust, and heather purple. The tetrahedron use dark green and dark brown, with the edges resembles the almost orthogonal projection. Luckily, I have found a better image and it is nowadays exhibit in both articles Regular tetrahedron and Polyhedron. Dedhert.Jr (talk) 04:52, 5 February 2026 (UTC)

Proposed alternative color scheme for the same image

Current colors

Hmm, yes, those colors aren't so great of a choice.

How about something like this instead? I feel like cool colors would be more fitting for polyhedra in general than warm colors, and I'd like for faces with fewer edges to be lighter (to tell them apart better, and lighter instead of darker so that the truncated cuboctahedron would look less like a soccer ball).

(Now that I look at it smaller, the color contrast between the squares could certainly be improved, but this is more for demonstration of what a new color scheme could be). MEN KISSING (she/they) T - C - Email me! 04:57, 5 February 2026 (UTC)

@MEN KISSING. Maybe using three different colors. One is for the eight squares arranged horizontally, the squares from an octagonal prism. You can choose two different colors for the triangles and the other squares. The same can be applied to the net of a rhombicuboctahedron. Dedhert.Jr (talk) 05:00, 5 February 2026 (UTC)

When choosing colors, I would recommend you use a color space which is relevant to human perception. Oklab is a fast-to-compute option, with some nice online implementations (e.g. oklch.com has a convenient UI), but you could also use CIECAM02 or IPT or the like. For this purpose, you should pick colors with roughly comparable and relatively moderate chroma (doesn't have to be identical, but you don't want one color to be much more intense than the others), and varying lightness (because lightness contrast is the most visually salient to humans, so colors of the same lightness tend to blend together even when other attributes differ). You can pick the hues based on personal preference. –jacobolus (t) 20:47, 5 February 2026 (UTC)

To be precise, your chosen colors here are something like

•   oklch(0.77 0.11 213),
•   oklch(0.80 0.09 247),
•   oklch(0.82 0.09 277),
•   oklch(0.91 0.07 166).

I would instead recommend using lightnesses which differ by at least 5 (maybe 0.7, 0.75, 0.8, 0.85), and to the extent possible, uniform chroma. We can keep to this general hue range. Maybe along the lines of

•   oklch(0.70 0.1 200),
•   oklch(0.75 0.1 260),
•   oklch(0.80 0.1 230),
•   oklch(0.85 0.1 170).

–jacobolus (t) 21:06, 5 February 2026 (UTC)

For reference, the "current colors" (with numbers rounded a bit and kept in gamut, for ease of comparison) are along the lines of:

•   oklch(0.87 0.28 142),
•   oklch(0.82 0.17 110),
•   oklch(0.63 0.25 29),
•   oklch(0.45 0.30 265).

The display primary colors are much too intense, the purplish blue is too dark, there isn't enough lightness contrast between the olive and yellowish green colors relative to the lightness contrast between the others, the chroma is much too inconsistent, and the hues are essentially arbitrary. –jacobolus (t) 21:25, 5 February 2026 (UTC)

If we wanted to stick with the (I assume) originally intended green/yellow/red/blue theme, we also could, with something like:

•   oklch(0.73 0.16 159),
•   oklch(0.80 0.16 93),
•   oklch(0.59 0.18 19),
•   oklch(0.66 0.14 236).

Which could look like this:

Edit: though it would probably be better to color alternate squares, along the lines of

–jacobolus (t) 21:46, 5 February 2026 (UTC)

I agree; if we're going to color the polygons of a net we should choose a coloring that makes sense relative to the symmetries of the folded polyhedron. Your alternating square coloring does this; the other colorings with one equatorial band of squares colored differently from the rest do not. —David Eppstein (talk) 00:54, 6 February 2026 (UTC)

@MEN KISSING. Why not? You can trace the edges from a three-dimensional graph drawing with the given coordinates, and choose any color that you want for the surface. Dedhert.Jr (talk) 04:56, 5 February 2026 (UTC)

I'm not sure what your "why not" refers to, general encouragement? Or do you mean why shouldn't all of the polyhedra be green? MEN KISSING (she/they) T - C - Email me! 05:02, 5 February 2026 (UTC)

Oh sorry. I thought you wanted to draw polyhedra without using POV Ray, or other three-dimensional drawing software thingy. Dedhert.Jr (talk) 05:04, 5 February 2026 (UTC)

Ahh, gotcha. If I get enough spare time, I could check out POV-Ray and see if I could get some shapes with fancier colors using Cyp's code. MEN KISSING (she/they) T - C - Email me! 05:07, 5 February 2026 (UTC)

I have successfully installed POV-Ray on my computer and used it to generate images using Cyp's code. However, that code only implements the Platonics, Archimedians, Catalans, prisms, antiprisms, bipyramids, and trapezohedra—it will take me some time to figure out how to implement the numbered Johnson solids, and also how to adjust things like colors, transparency, line widths, and other fanciness. — LucasBrown 17:57, 5 February 2026 (UTC)

@AndrewKepert has extended @Cyp's code to include the Johnsons: User:AndrewKepert/poly.pov. — LucasBrown 18:44, 5 February 2026 (UTC)

One-dimensional symmetry group

If someone could please add sources to this page I would appreciate it. It's been unsourced for 21 years.4meter4 (talk) 20:54, 7 February 2026 (UTC)

Maybe merge with frieze group? —David Eppstein (talk) 21:09, 7 February 2026 (UTC)

Three citations needed in Mayer–Vietoris sequence

For those who are experts in topology, I need assistance for adding three citations for the article Mayer–Vietoris sequence's topics in the following:

• "...many other important (co)homology theories, especially singular (co)homology, are not computable directly from their definition for nontrivial spaces."
• "In general, this does not allow (co)homology groups of a space to be completely computed. However, because many important spaces encountered in topology are topological manifolds, simplicial complexes, or CW complexes, which are constructed by piecing together very simple patches, a theorem such as that of Mayer and Vietoris is potentially of broad and deep applicability."
• "...so in addition to existing in ordinary cohomology theories, it holds in extraordinary cohomology theories (such as topological K-theory and cobordism)."

Regards. Dedhert.Jr (talk) 01:35, 7 February 2026 (UTC)

The first statement is probably supported by the introduction to Chapter 4 in Munkres, Elements of Algebraic Topology. However, the singular homology groups are not immediately computable. One must develop a good deal of singular theory before one can compute the homology of even such a simple spaceas the sphere ... Russ Woodroofe (talk) 14:00, 25 February 2026 (UTC)

Negaton RFD

Back in the middle of the 20th century "negaton" was used in physics for a negative charge (vs "positon" and not equal to "electron", maybe). The term drop out of use for the most part. However it seems like it was picked up for solutions of PDEs related to solitons in the KdV hierarchy. Just in case someone in math wants to rescue this one: Wikipedia:Redirects for discussion/Log/2026 February 4 § Negaton Johnjbarton (talk) 02:32, 5 February 2026 (UTC)

Should be "negatron" with an "r". JRSpriggs (talk) 19:34, 26 February 2026 (UTC)

The KdV thing is "negaton" per sources. eg Rasinariu, C., Sukhatme, U., & Khare, A. (1996). Negaton and positon solutions of the KdV and mKdV hierarchy. Journal of Physics A: Mathematical and General, 29(8), 1803-1823.

The thing in the 1960s was "negaton". Hsue, S. T., Kim, M. U., Langer, L. M., Piel Jr, W. F., & Spejewski, E. H. (1968). The negaton decay of 122Sb. Nuclear Physics A, 117(3), 686-696.

There is also a "negatron" with an 'r', Daugherty, J. K. (1974). Measurement of cosmic ray positron and negatron spectra between 50 and 800 MeV (No. X-660-74-16).

Are we having fun yet? Johnjbarton (talk) 20:46, 26 February 2026 (UTC)

Bayes' theorem#Genetics

I decided to put some time into tidying up the Bayes' theorem article, and I've gotten down to the § Genetics subsection. Does it seem overly long to anyone else? It really only discusses one genetic disorder. Stepwise Continuous Dysfunction (talk) 04:25, 1 March 2026 (UTC)

Nice catch. That is just a random example of Bayes reasoning, nothing foundational about Bayes Theorem or genetics. It goes on way too long, and has undue weight in a general article about Bayes' theorem. I would cut the section way down or likely remove it altogether. --{{u|Mark viking}} {Talk} 04:37, 1 March 2026 (UTC)

I chose the route of cutting it way down. Stepwise Continuous Dysfunction (talk) 22:18, 1 March 2026 (UTC)

Recent edits to Normal distribution by Bert Niehaus

I'm having what I think is turning into a bit of a conflict with @Bert Niehaus. Since that user is an academic in mathematics and since the controversy revolves around the addition of ~bachelor-level material to the article Normal distribution, I though I would ask for third-party input here before going through general-purpose conflict resolution procedures.

In a nutshell: Bert Niehaus insists on adding material to the article which — in my opinion — isn't improving it. This started with a batch of objectively clumsy edits, which I reverted. The reason why I'm saying these edits were "objectively clumsy" is that they created a duplicated section, contained grammatical errors, were unsourced and could legitimately be called "OR" (although I dislike the term). I reached to Bert Niehaus on their talk page to explain why I reverted their edits.

This started a lengthy discussion, both on Bert Niehaus' talk page and on the article talk page. Throughout this discussion, I had the impression of repeating the same thing over and over again, namely:

Wikipedia is a not a textbook; in an article such as "Normal distribution", we should simply give the power series expansion of the CDF of the normal distribution with a reference to a source where it is derived, rather than explain in detail how it is derived on the page. We can mention that it is readily obtained by integrating the power series expansion of the PDF term by term, but there is no need to explain in detail why that can be done.

I stand behind that opinion, especially since in my view a detailed argument would only be helpful to a very small number of readers (before having taken a course in complex analysis, one cannot really understand it; and after having taken such a course, it becomes somewhat trivial; so basically the details of the derivation are only going to be useful to a few math students — when the article "Normal distribution" should be aimed at a very large audience).

During this discussion, Bert Niehaus kept making batches of edits to the article — presumably in good-faith, but without really taking into account what I was saying (or perhaps not understand it, since in their latest edits they added a reference to support a notion [uniform convergence] rather than a statement). Also, I'm presuming good-faith here, but having in mind that I was asking Bert Niehaus to slow down, some of these edits did feel like they could have been trolling (e.g, this edit to the lead).

The current situation on my side is this: I am done talking with that use and do not wish to invest any more time in this. But I also do not think their edits are improving the article. So I am not sure what to do: should I just revert everything mechanically until that user gives up? Or ask for third-party input for edit warring?

14:47, 15 February 2026 (UTC) Malparti (talk) 14:47, 15 February 2026 (UTC)

I can't offer much advice on the best course of action for how you should proceed. But many probability wikipages, especially those for particular distributions, are pretty unwieldy and messy. So it's good to remove material if it is not well-attested to in standard sources like well-recognized probability and statistics textbooks, of which there are many. Anything like original research or original computations should absolutely be removed. Since these pages are so messy, even if the material were to appear somewhere in some random research paper, it is probably good to remove it.

Personally I'm not aware of any reason for interest in the Taylor series for the pdf or cdf of the normal distribution. And taking a quick look through this material, it doesn't seem like any (standard) sources for this have been put forward. So, unless I missed a reference, that means that all this material should be removed. And, regardless, any derivation or calculation details should certainly be removed. Gumshoe2 (talk) 16:10, 15 February 2026 (UTC)

There are definitely some standard sources which include the Taylor series for the CDF, especially older sources mentioning that it is (or used to be) a reasonable way to calculate for small values of ⁠${\displaystyle x}$⁠ (but converges impractically slowly for large ⁠${\displaystyle x}$⁠). It's also in references like Abramowitz & Stegun. I'm not necessarily opposed to including the Taylor series in articles about this or any other special function, as a basic reference topic. But I don't think we should belabor the point, or need a lot of derivation, justification, or explanation, all of which seems like it quickly gets off topic. –jacobolus (t) 23:49, 2 March 2026 (UTC)

The formula for the distribution seems potentially useful, but also like an easy exercise. Given the Taylor series for ${\displaystyle e^{x}}$, it's not hard to find the formula for ${\displaystyle e^{-x^{2}}}$, and from there to get the series for ${\displaystyle \int e^{-x^{2}}dx}$. A section about the Taylor series probably would help statisticians and other such readers, but the benefit would be marginal, and it could make the article more difficult for lay readers. The Boolean^_Talk 21:04, 15 February 2026 (UTC)

Thanks @Gumshoe2 and @The Boolean for your replies, and thanks @Jacobolus @Quantling for your contributions on the article and its talk page. Malparti (talk) 20:11, 2 March 2026 (UTC)

Splitting Distribution (mathematical analysis)

I have put a note at Talk:Distribution (mathematical analysis)#Splitting article suggesting a split. I don't know exactly what the split/fork would look like, but the current article strikes me as pretty useless to almost any likely audience, and so a separate, much more technical, article should be made to cabin most of the functional analysis bafflegab, while an earlier and more reader friendly version is restored. Opinions needed. @PatrickR2:, @Jacobolus:. Sławomir Biały (talk) 21:40, 2 March 2026 (UTC)

Doesn't necessarily have to be a split, but should definitely aim for accessibility to less-technical readers and more narrative context in at least the top few sections. The best bet is probably to start by looking for sources aimed at a broad audience with clear explanations. –jacobolus (t) 23:55, 2 March 2026 (UTC)

I think this old revision, prior to the article being rewritten, is in many ways superior to the current article. But I am reluctant to do a wholesale revert, thus my suggestion of splitting. I just don't know what to do with all of the newer content. It seems like the sort of thing that would be better off in a separate article. Sławomir Biały (talk) 07:51, 3 March 2026 (UTC)

I think the more technical side of things is covered in Spaces of test functions and distributions, which claims in its hatnote (outdatedly) that Distribution (mathematical analysis) covers "more basic information about distributions". So maybe this is already an adequate pair of titles for a split and we don't need a third title as well? —David Eppstein (talk) 08:23, 3 March 2026 (UTC)

Thanks, that seems to point towards a solution. Sławomir Biały (talk) 08:29, 3 March 2026 (UTC)

Ok, I have reverted to an earlier version, with a few small edits for correctness and to link to Spaces of test functions and distributions. Sławomir Biały (talk) 10:19, 4 March 2026 (UTC)

Spectral invariants

Please add reliable sources. Note that if you register for the Unref backlog drive, you can earn a Barnstar! Bearian (talk) 16:48, 6 March 2026 (UTC)

Polyad

This article expanded on the concept of polyads, which are related to category theory. Later, an explanation of a different concept with the same name related to infrared spectroscopy was added. This article is a stub, but should it still be split into separate articles? I'm worried that if we split the article, each article might be moved to the draft space.--SilverMatsu (talk) 23:33, 6 March 2026 (UTC)

Wikipedia articles should be about individual concepts, so different concepts that happen to have the same name should be covered in different articles. --JBL (talk) 00:46, 7 March 2026 (UTC)

Done. — LucasBrown 01:37, 7 March 2026 (UTC)

Thank you. I didn't know how to split the article, so this is helpful.--SilverMatsu (talk) 01:57, 7 March 2026 (UTC)

Does "Multiple identity" mean anything mathematically?

There is a discussion ongoing on whether to disambiguate the phrase, "Multiple identity". BD2412 T 21:08, 7 March 2026 (UTC)

Not in my experience. (It's a pretty standard feature of algebraic structures that the uniqueness of the identity element follows directly from the existence of at least one identity element.) --JBL (talk) 21:13, 7 March 2026 (UTC)

Relation construction

Tagged as unsourced for 16 years, this was recently prodded and then deprodded. Please add reliable sources. Note that if you register for the Unref backlog drive, you can earn a Barnstar! Bearian (talk) 11:07, 7 March 2026 (UTC)

I don't think this article involves a standard usage of terminology worthy of an article, so I think it should go through the deletion process. Ebony Jackson (talk) 17:33, 7 March 2026 (UTC)

I can't find a single example in full-text search of academic papers (Google scholar) or various book corpora of "relational constructibility". Only several web pages at various wikis which are all cross-linked like: "Relation Construction, InterSciWiki"; "Relation Construction", PlanetMath; "Relation Construction", Semantic Web; "Relation Construction", Wikinfo; "Relation Construction", Wikiversity; "Relation Construction", Wikiversity Beta; "Relation Construction", Wikipedia. The phrase "relation construction" appears in various contexts, but I am not finding one used in this specific sense. The person who originally created this and presumably also the cross-linked pages, User:Jon Awbrey, has been indefinitely blocked for disruptive editing, with complaints also about original research. Can probably be safely deleted. –jacobolus (t) 18:16, 7 March 2026 (UTC)

Pinging @Mark viking:, who made an assertion that sources exist when unprodding. --JBL (talk) 19:16, 7 March 2026 (UTC)

The assertion was:

Deprod--looks notable at first glance. A simple WP:BEFORE style search shows hundreds of hits in GScholar. Also see the lengthy article "relation construction" in Grokipedia with dozens of references cited

The "hundreds of hits in GScholar" are a wide range of unrelated uses. I didn't exhaustively read them, so it's plausible that this sense can be found, but I am not motivated to keep searching. The "Grokipedia" page is, predictably for an LLM, a mishmash of hallucinations, misunderstandings, and unrelated things incoherently synthesized. It includes such claims as "The framework of relation construction, as developed in resources like the OEIS Wiki, formalizes how relations interact and combine". Not really very encouraging. –jacobolus (t) 19:35, 7 March 2026 (UTC)

Thanks all, for taking a look. At first glance, it looked like there were enough sources for this PROD to be controversial. Looking more deeply myself--while there are GScholar hits that are valid instances of relation construction in CS+ML, I wasn't able to find a secondary review that brought them together into a coherent topic. It would then be difficult to construct an article without synth. Composition of relations has some of what would be covered in a relation construction article, without the machine learning context. Given those facts, I'd be OK with deletion. --{{u|Mark viking}} {Talk} 21:44, 7 March 2026 (UTC)

Grokipedia should not be trusted for any purpose whatsoever, and this provides a nice example of one reason why. The OEIS wiki has a page called "relation construction"... which is just a copy of the Wikipedia article from 2006. This is just citogenesis with an LLM in the middle. Stepwise Continuous Dysfunction (talk) 21:51, 7 March 2026 (UTC)

See Wikipedia:Articles for deletion/Relation construction. Stepwise Continuous Dysfunction (talk) 22:18, 7 March 2026 (UTC)

RfD needs input from editors with subject matter knowledge

The redirect Symplectic form to the article Symplectic vector space has been listed at redirects for discussion to determine whether its use and function meets the redirect guidelines. Readers of this page are welcome to comment on this redirect at Wikipedia:Redirects for discussion/Log/2026 March 8 § Symplectic form until a consensus is reached. Thryduulf (talk) 00:32, 9 March 2026 (UTC)

Attention needed at Fibrations of graphs

Fibrations of graphs was recently created by Vigna, largely copied from the author's website at . Copyright issues have been resolved, but the article could still use a review from an experienced math editor. I'm not experienced enough to evaluate whether the topic is original research or how much it overlaps with existing articles on similar topics. Thanks. Zeibgeist (talk) 21:34, 3 March 2026 (UTC)

Unsourced in some sections. Try to reduce the technical jargon whenever possible, but it looks fine to me in the later sections. Probably see some more guidelines on Wikipedia, like WP:NOTTEXTBOOK, because of the writing style looks like scientific journals or books; for instance, Roy L. Adler and Brian Marcus define (right-) left-resolving maps (Definition 3.31) where is the "Definition 3.31" anyway, and what does that definition says?

This reminds me of Affine symmetric group, wherein the content is from the journal under the name WikiJournal of Science. Dedhert.Jr (talk) 10:02, 4 March 2026 (UTC)

There's a clear reference in that phrase, and it's a vast book, so it is fundamental to add a precise reference to a definition, or the reader won't be able to find it without a lot of effort. Vigna (talk) 10:08, 4 March 2026 (UTC)

So you're saying Definition 3.31 is from that book? You can add some notes for more specific location on a page, right after the source. Dedhert.Jr (talk) 10:16, 4 March 2026 (UTC)

There's no original research in the article. It tries to put together a large number of results in the field that are mostly uncorrelated because they were proved independently in different fields—IMHO, 99% value of an encyclopaedia of any kind. Otherwise, you can just read the articles and usually they will be more complete and accurate. Vigna (talk) 10:10, 4 March 2026 (UTC)

And try to avoid "we" or any similar first-person pronoun. See MOS:MATH#NOWE. Dedhert.Jr (talk) 10:17, 4 March 2026 (UTC)

According to MOS:WE, the author's we is an acceptable style. I'm not sure who wrote MOS:MATH#NOWE, but I don't think it reflects a consensus of Wikipedians (of math articles or more generally), and should probably be revised. –jacobolus (t) 16:43, 4 March 2026 (UTC)

Seems like it's been there for a long time (added in 2005 by user:Mjb in special:diff/20575613), but from what I can tell it's just one person's preference/advice, with support from 1 or 2 other people, and there was almost immediate complaint on the talk page with several other editors disagreeing with this advice (but never changing the page to remove it). –jacobolus (t) 16:51, 4 March 2026 (UTC)

Guilty as charged, although FWIW, Wikipedia was a bit more Wild West in those days. At the time, WP:BOLD inspired me to forego discussion and add prescriptive language, knowing that it would eventually be undone or dialed back if it was truly too controversial, especially in a MOS article which would be subject to a fair amount of passive review.

I do stand by the initial statement of fact, though: In contrast to the rest of Wikipedia, mathematics articles do tend to read somewhat jarringly like lectures, rife with violations of WP:NOTED and WP:YOU. It seems prudent to acknowledge this tension, and to encourage contributors to minimize their use of such clichés. (I was mainly reacting to the spate of articles, at the time, which were truly chock full of fluff, and issuing command after command to the reader, and/or which kept switching tone.)

Nowadays I'm more inclined to give some grace and tolerate some pedagogical clichés; adopting an encyclopedic, third-person tone shouldn't sacrifice clarity or usefulness, after all. To that end, although the fibrations of graphs article could benefit from some scrutiny—there are a few instances each of we, note that, and indeed which could be easily rephrased—I'd say overall it's fine. —mjb (talk) 08:52, 10 March 2026 (UTC)

I agree that articles should avoid straying into a chummy informal style.

But the author's we is often clearer and less awkward than replacing it with one or significantly rephrasing, and it is routinely used in mathematical and other technical documents, including in reference works. It isn't necessarily informal or unencyclopedic, and therefore shouldn't be banned.

I think we should generally keep our recommendations about tone/style away from absolutes, and leave judgment to editors, settling disputes case by case by consensus on local talk pages (or by other typical community processes). –jacobolus (t) 18:39, 10 March 2026 (UTC)

Really? This is odd. For some reason, there should be a guideline in Wikipedia where any first-person pronoun should be avoided. I clearly forgot what the manual is. Time flies. Dedhert.Jr (talk) 21:38, 4 March 2026 (UTC)

The justification for avoiding authorial we is apparently that Wikipedia is not a textbook, but that seems like a tenuous inference to me. The ways in which Wikipedia should not be textbook-like don't extend to expunging authorial we, as far as I can tell. Stepwise Continuous Dysfunction (talk) 23:51, 4 March 2026 (UTC)

Ok, we appear to going into the stylistic weeds a bit here, but as far as I can tell no one has raised any issues that would prevent the article from remaining in mainspace. I went ahead and marked the article as reviewed, but I'm happy to engage further if anyone has additional concerns. I also took the liberty of tagging with {{cleanup rewrite}}, since the style of writing throughout the article is definitely more typical of a textbook than the encyclopedic style used on Wikipedia. Additional cleanup work to improve the text would be appreciated. Zeibgeist (talk) 23:58, 4 March 2026 (UTC)

Cross's Theorem

Which is the correct article title: Cross's Theorem or Cross's theorem? Also, I couldn't find many papers Cross's theorem or Vecten's theorem to know which is the WP:Common name. And also, It's linked to the Gregorian calendar (2004), but this is the first time I've seen it in a Wikipedia mathematics article.--SilverMatsu (talk) 03:58, 6 March 2026 (UTC)

As per WP:TITLEFORMAT, "Cross's theorem" is correct. I have moved the page accordingly, and unlinked the 2004. — LucasBrown 06:05, 6 March 2026 (UTC)

Thank you.--SilverMatsu (talk) 22:48, 6 March 2026 (UTC)

@Silvermatsu. Here is the source , where I once reverted my rhetorical question. And the article can have a WP:DYK: "did you know, that Cross's theorem was actually discovered by a UK student". Dedhert.Jr (talk) 13:29, 6 March 2026 (UTC)

And here is another source , which raises a question whether it is reliable. Dedhert.Jr (talk) 13:32, 6 March 2026 (UTC)

Thank you. I see, it seems like the common name for this article should be Cross's theorem.--SilverMatsu (talk) 22:48, 6 March 2026 (UTC)

From reading the sources, saying it was discovered by a UK student is very misleading. It is like saying a student discovered limits or Pythagorean theorem. EulerianTrail (talk) 19:08, 10 March 2026 (UTC)

Pseudomonad

I created Draft:Pseudomonad, but I noticed that Pseudomonad is currently a disambiguation page, so should I rename it to Draft:Pseudomonad (Category theory) or Draft:Pseudo-monad? (Which is better?) By the way, should I also post this question on WT:MICRO?--SilverMatsu (talk) 16:22, 22 January 2026 (UTC)

I think Draft:Pseudomonad (Category theory) would be the best approach and then update the DAB page for the new entry. Pseudo-monad doesn't seem like a common spelling. If you go this way, then nothing needs to be changed on the microbiology side. --{{u|Mark viking}} {Talk} 19:01, 22 January 2026 (UTC)

@Mark viking: Clearly "Pseudomonad (Category theory)" would be incorrect under WP:MOS because of the capitalization of the "C". Michael Hardy (talk) 17:19, 9 March 2026 (UTC)

If you're doing parenthetical disambiguation, it should definitely be Pseudomonad (category theory) . --JBL (talk) 20:00, 22 January 2026 (UTC)

Yes, "pseudomonad (category theory)" is much more clear. Stepwise Continuous Dysfunction (talk) 20:51, 22 January 2026 (UTC)

Thanks everyone for teaching me about the draft title. Since there is already a DAB page, I will send a request to move the draft without creating a redirect.--SilverMatsu (talk) 02:13, 23 January 2026 (UTC)

New title:Draft:Pseudomonad (category theory) --SilverMatsu (talk) 02:38, 23 January 2026 (UTC)

By the way, is there a connection between Pseudomonad and Doctrine (mathematics)?--SilverMatsu (talk) 06:44, 3 February 2026 (UTC)

A doctrine is a kind of pseudomonad. --{{u|Mark viking}} {Talk} 12:21, 3 February 2026 (UTC)

Thank you. I added Pseudomonad to the section of See also in Doctrine (mathematics).--SilverMatsu (talk) 08:28, 4 February 2026 (UTC)

Why "nolimits"?

In the article titled Distribution (mathematical analysis) we find this:

${\displaystyle \mathrm {D} (U)=\bigcup \nolimits _{i}\mathrm {D} _{K_{i}}}$

coded as \mathrm{D}(U) = \bigcup\nolimits_i \mathrm{D}_{K_i} .

If instead the code had been \mathrm{D}(U) = \bigcup_i \mathrm{D}_{K_i} ,

then it would be rendered as follows:

${\displaystyle \mathrm {D} (U)=\bigcup _{i}\mathrm {D} _{K_{i}}}$

Since this is in a "displayed" rather than "inline" setting, I would have used the latter form. This use of \nolimits occurs numerous times in this article. Are there reasons why the version with \nolimits is to be preferred? Michael Hardy (talk) 17:35, 9 March 2026 (UTC)

I'm not responsible for the notation in this article, but to me the current notation (that is, with \nolimits) looks neater. Somehow the dangling ${\displaystyle i}$ looks a bit weird and out of place in the standard displaystyle rendering... I guess whoever wrote the article must have had the same feeling.

Anyway, there is no semantic difference between the two notations so if the \nolimit variant is used consistently throughout the text, I guess MOS:VAR applies. Malparti (talk) 22:56, 9 March 2026 (UTC)

Either one seems fine. Similarly, it should be fine if someone wanted to adopt the convention of writing integrals with an explicit \limits added in some article, so that they render like $${\displaystyle \int \limits _{a}^{b}f(x)\,dx.}$$ (This style is especially common in Russian sources, but also routinely found elsewhere, especially on chalkboards, hand-written notes, or pre-LaTeX publications.) –jacobolus (t) 23:25, 9 March 2026 (UTC)

I sometimes use \limits with integrals when bounds require a complicated expression. Like this:

${\displaystyle {}\quad \int \limits _{x,y\,:\,0\,<\,x\,<\,y\,<\,1}f(x,y)\,d(x,y)}$

Michael Hardy (talk) 17:18, 11 March 2026 (UTC)

Good article reassessment for Representation theory of the Lorentz group

Representation theory of the Lorentz group has been nominated for a good article reassessment. If you are interested in the discussion, please participate by adding your comments to the reassessment page. If concerns are not addressed during the review period, the good article status may be removed from the article. Z1720 (talk) 18:22, 11 March 2026 (UTC)

I put work into this earlier; I have no interest in doing more. The concerns listed in the GAR seem mostly orthogonal to the question of whether the article explains mathematics correctly and well. Stepwise Continuous Dysfunction (talk) 20:22, 11 March 2026 (UTC)

Remove List of Johnson solids from FL.

Anyone can join the discussion here, Wikipedia:Featured list removal candidates/List of Johnson solids/archive1. Dedhert.Jr (talk) 04:48, 12 March 2026 (UTC)

General Duality including Dual Polytopes

WP has articles relating to Dual Polygons and Dual Polyhedra, would something more general on Duality that included higher dimensions be appropriate?Naraht (talk) 14:11, 16 March 2026 (UTC)

You mean like we already have in Duality (mathematics)? —David Eppstein (talk) 17:28, 16 March 2026 (UTC)

A concrete topic that we are missing is the historically first and one of the most important examples, polar duality on the sphere (between points and oriented great circles), which was introduced by Persian astronomer/mathematician Abu Nasr Mansur (a teacher of Al-Biruni) c. 1000 AD, in the form of the polar triangle of a spherical triangle (currently a redirect to a short section of Spherical trigonometry, but should also be a separate article). This later inspired the study of duality in the projective plane, etc. –jacobolus (t) 17:59, 16 March 2026 (UTC)

I had not seen Duality (mathematics), however I will say that article is *incredibly* broad. It feels like making one article for all of the Springfields in the United States.Naraht (talk) 18:33, 16 March 2026 (UTC)

There is a short section Dual polyhedron § Dual polytopes and tessellations; the natural thing to do would be to add content there, and split if it ever became large enough to support that. (I see that Mgnbar wrote the same thing, just a couple minutes more quickly.) --JBL (talk) 18:45, 16 March 2026 (UTC)

There's also List of dualities. But Dual polytope is merely a section of Dual polyhedron. Perhaps you would be interested in adding material to that section? And if it becomes unwieldy, then splitting it off into its own article? Mgnbar (talk) 18:42, 16 March 2026 (UTC)

Functors

there is an open discussion about merging Template:Functors into Template:Category theory. Frietjes (talk) 15:02, 17 March 2026 (UTC)

Why Wikipedia Can't Explain Math

Some food for thought: https://www.youtube.com/watch?v=33y9FMIvcWY. Nosferattus (talk) 04:22, 3 March 2026 (UTC)

I have mentioned this before. See Wikipedia talk:WikiProject Mathematics/Archive/2025/Nov#DFT. If someone wants to improve the article by providing the preliminaries before starting the topic, improving the caption, and illustrations, go ahead. Don't forget to add reliable sources (books and journals) and never add up fishy stuff (original research). Look at the list of articles WP:GA/M and WP:FA#Mathematics if you want some samples for better structure. See WP:MTAU. See WP:BOLD. See WP:RS. See WP:NOTTEXTBOOK. See User:XOR'easter/So, you've decided to write about physics and/or mathematics on Wikipedia. See WP:NOR. Dedhert.Jr (talk) 09:43, 4 March 2026 (UTC)

That's where it was! I thought we had discussed this before (somewhat critically) but couldn't find the discussion in the archives because of the cryptic thread title. —David Eppstein (talk) 00:27, 5 March 2026 (UTC)

I took the introductory text suggested in that discussion and worked it into the lede of Discrete Fourier transform, along with some other reorganization. Stepwise Continuous Dysfunction (talk) 00:53, 5 March 2026 (UTC)

Maybe reorganize all of them. Dedhert.Jr (talk) 07:45, 5 March 2026 (UTC)

All of what? Stepwise Continuous Dysfunction (talk) 17:11, 5 March 2026 (UTC)

Everything. Illustrations and captions. Rewriting the definition to be less technical. Etc. Dedhert.Jr (talk) 00:58, 7 March 2026 (UTC)

I moved the figures down from the lede to a place where they make more sense and get less in the way (particularly when browsing on mobile). Also, I brought over a new illustration from Fast Fourier transform that can probably be improved but is better for the lede than what was there before. I did some cleanup on the Discrete Fourier transform § Definition section, but I don't know how non-technical it can be made. Stepwise Continuous Dysfunction (talk) 04:42, 8 March 2026 (UTC)

It seems kind of misleading to show a continuous graph there. There are some images of Commons showing discrete signals, like File:DFT 2sin(t) + cos(4t) 25 points.svg and File:DFT 2sin(t) + sin(4t).svg. 1234qwer1234qwer4 14:44, 18 March 2026 (UTC)

I would also prefer a graph with a signal that is discrete in a visually obvious way. Thank you for suggesting those. Stepwise Continuous Dysfunction (talk) 19:54, 18 March 2026 (UTC)

Help requested with semi-decidable RfD

The redirect Semi-decidable has been listed at redirects for discussion to determine whether its use and function meets the redirect guidelines. Readers of this page are welcome to comment on this redirect at Wikipedia:Redirects for discussion/Log/2026 March 19 § Semi-decidable until a consensus is reached. Thanks, Legoktm (talk) 03:37, 19 March 2026 (UTC)

Discussion at Talk:Ribet's lemma § Alternative lemma?

 You are invited to join the discussion at Talk:Ribet's lemma § Alternative lemma?, which is within the scope of this WikiProject. I found sources which describe a different Ribet's lemma to that found in the article, and would appreciate editor's input on how to resolve this. Gramix13 (talk) 04:01, 21 March 2026 (UTC)

Bayes' theorem again

In Bayes' theorem § Frequentist interpretations, there is an example about beetles. It has been unsourced since it was added in 2011. The section also has two figures, tree diagrams that don't in any obvious way have a uniquely frequentist interpretation. I am somewhat inclined to remove the diagrams and the text beginning The role of Bayes' theorem can be shown, i.e., everything but the first paragraph. Does anyone have a better idea for what to do with that part of the article? Stepwise Continuous Dysfunction (talk) 01:22, 20 March 2026 (UTC)

I have trimmed that subsection. With three examples already in the article prior to that point, another unsourced one doesn't seem to be worth saving. Stepwise Continuous Dysfunction (talk) 21:06, 22 March 2026 (UTC)

Reliability on lecture notes and online websites

I wonder how reliable the lecture notes are from most universities' sites, take an example like Cameron's Graph Homomorphisms, Combinatorics Study Group Notes in Graph homomorphism. I know that published books and academic journals are considered as WP:RS, but is it possible that any Wikipedian can use lecture notes or online notes from any university for sourcing?

I drop off a similar question but this regarding any online notes from professors alone like Morris' Topology without Tears (although there contains Wikipedia link, which kind of WP:CIRCULAR), or websites generated by a person itself like McCooey's Visual Polyhedron in Snub cube (although I am questioning WP:SPS)? Dedhert.Jr (talk) 11:47, 24 March 2026 (UTC)

According to WP:SPS the sites of professors can be used as a reliable source for their work if their research in the past has been independently published (most likely and easiest is a peer reviewed journal). But that does not really answer lecture notes. Since we are talking about professors, they are subject matter experts not some random person. Note their university acts in a way as a third party to approve or reject a course (although there is not some editorial review).

Since there may not be an editorial review or peer review, often times the same fact can be supported by a book or paper. However, since it is a subject matter source aimed at teaching then it is a good for facts that a book or paper may assume a reader to know without ever stating it (something may be trivial to a mathematician but be nontrivial and unknown to the lay reader). For undergrad material and below, there is almost always a source of some book or site. For grad level, it may be useful still for wiki editors as many professors will cite where results came from although it might be obscure (e.g. Smith [1952] and there are 3 papers by Smith in that year but now you know where to look). But as a big important thing, terminology even in papers by the best mathematicians may change in the field and lecture notes show the common name for a mathematical object (whether the name stay the same or different) and lecture notes have synthesized multiple things in the same terms. Since lecture notes are for teaching the proofs contained in them are often better written, more understandable, and simpler logic than the original proofs. So, a wiki article should not stand alone on lecture notes, but they should be used sparingly to support simple facts (or definitions when a book source may be unavailable). EulerianTrail (talk) 12:19, 24 March 2026 (UTC)

I forgot to mention, there is a very cool journal that publishes peer reviewed lecture notes (thus making them RS since they are published by an independent third party and go through a peer review process): the Journal of Inquiry-Based Learning in Mathematics. EulerianTrail (talk) 12:28, 24 March 2026 (UTC)

Re-inclusion of Reduced Primorials within Primorials page

I recently submitted and edit to the Primorials page, to include a section on Reduced Primorials. After being up for almost 2 weeks, JayBeeElld removed it. See below.

https://en.wikipedia.org/w/index.php?title=Primorial&oldid=prev&diff=1344816580

https://en.wikipedia.org/w/index.php?title=Primorial&diff=prev&oldid=1344333936

I sought justification from him for its removal, which I do not agree with. Subsequently he suggested I make a case here for its re-inclusion, which I am now doing.

https://en.wikipedia.org/wiki/User_talk:JayBeeEll#Contesting_Removal_of_Reduced_Primorials_from_Primorials_page

First, the inclusion of Reduced Primorials is intended to expand the understanding of primorials, as used as conceptual and computational entities within the field of Number Theory. In my work I use them all the time, but many have not heard of them outside of number theory, though they have clear historical usage predating my usage of them.

In fact, I first saw their notation used in these video from May 2013 by Russel Letkeman.

https://www.youtube.com/watch?v=KZ2_CP2Fvl8

https://www.youtube.com/watch?v=KXXfROP1uSY

He referred to the expressions as the "minor primorials", first, second, third, etc.

To be clear, these videos are cited only to document the use of their terminology, and their expressions.

In my work using Zn modular groups, which uses terminology e.g. reduced|residue groups, I felt it was clearer, and more harmonious, to refer to them as reduced primorials, to conceptually promote the idea they are the systematic reductions of the primary primorials values, and have physical relevance to the gap structure of the Zn residues.

See such discussion as:

Distribution of a reduced residue system within a primorial (2012)

https://math.stackexchange.com/questions/546425/distribution-of-a-reduced-residue-system-within-a-primorial#587124

Because I didn't completely understand|like Letkeman's presentation, and had developed, independently from scratch, a more consistent mathematical model for the occurrence of residue gaps, I adopted his reduced primorials forms, to be consistent with their expression, but referred to them as reduced primorials (versus minor, etc), for the reasons stated.

So you see, the use of language around the concepts of reduced residue system, and primorials, has a long history, and is not new, or something I made up. And as I stated in the article, and showed with the Euler's totient function example in it, it's a standard computational form used to calculate these values when n is a primorial.

You can see further their explicit development, and conceptual and computational use, here:

https://www.academia.edu/124141259/Draft_Chapter_2_There_Is_No_Last_Twin_Prime_The_Power_Simplicity_and_Applications_of_Prime_Generator_Theory_PGT_

All I have effectively done is standardize their name, to make it more harmonious with the other language used in the field regarding residue gaps.

Thus, the inclusion of Reduced Primorials expands the understanding and usages of primorials, and adds additional mathematical insight to the topic.

Jabari Zakiya

https://independent.academia.edu/JabariZakiya Jzakiya (talk) 19:43, 24 March 2026 (UTC)

Please support any changes you would like to make with published and reliable sources. YouTube videos, stackexchange discussions, and academia.edu preprints do not qualify as published and reliable sources. The International Journal of Mathematics and Computer Research, which you have not mentioned this time but did mention in your discussion with JBL, is included in Beall's list of predatory journals and is also unreliable.

Unless and until you can provide reliable sources for this material, all the rest of your long messages on this are irrelevant and can be ignored. —David Eppstein (talk) 20:39, 24 March 2026 (UTC)

This is some serious Gatekeeping (communication) to prevent any discussion of the merits of the math. Thank goodness Srinivasa Ramanujan lived over 100 years ago, when he could mail his notes to G. H. Hardy and have them not only accepted and read, but also studied, and acknowledged to be original and important work, which brought his genius to light.

The smugness of these responses are soaked in the insecurity that maybe, just maybe, people know more about a subject than them. Truth is irrelevant. The expansion of knowledge is irrelevant. Only the artificial meta criteria rules, which the Guardians of the Galaxy (film) are self-anointed to deem what, and who, passes through its gates. So sad.

Truth And The World Of Wikipedia Gatekeepers

https://www.npr.org/2012/02/22/147261659/gauging-the-reliability-of-facts-on-wikipedia Jzakiya (talk) 22:15, 24 March 2026 (UTC)

If a modern Ramanujan tried to publish their work in Wikipedia, it would also be inappropriate. Wikipedia is not set up to judge technical work in the same way as Hardy was. "Truth is irrelevant" You have grasped the main idea, but I don't think this is a particularly helpful phrasing. Wikipedia is, like other encyclopedias, a tertiary source, whose content is based on the contents of existing secondary sources. This is indeed a strong type of gatekeeping: not gatekeeping by who the editor is, but by what type of information should be added based on how it is known. Without such a policy, Wikipedia would be no more reliable than every crank's personal blog. As for "self-annointed", you are not entirely off track with that; Wikipedia is a self-organizing community which operates based on community consensus. The relevant policies here were established, by the community, more than 20 years ago, and persist because they are still broadly supported. For more you should read the page you were referred to, Wikipedia:No original research. –jacobolus (t) 22:31, 24 March 2026 (UTC)

Amateur mathematicians can and do still mail professional ones, though these days it's usually email or social media. The einstein problem was solved by something similar, for instance. Sesquilinear (talk) 01:08, 25 March 2026 (UTC)

Recent developments on the Hadwiger–Nelson problem also were kicked off by the discovery of an amateur. In both cases we did get the reliable sources we need, soon after their discoveries. —David Eppstein (talk) 05:22, 25 March 2026 (UTC)

As a sidenote, my impression of WP:SELFCITE is that it's somewhat discouraged to add your own work even if it's published in a reliable source. Sesquilinear (talk) 22:50, 24 March 2026 (UTC)

If you are an expert about a topic, and you cite one of your works which is essential to support a claim made in the article (especially if the cited work is older and highly cited), while also citing other people's works as relevant in a neutral manner, then I don't think there's a big problem. The problem is when people come to Wikipedia with the primary purpose of promoting their own work rather than writing articles, and start littering self-citations around. It gets especially egregious when the source is one of hundreds that would serve just as well for a particular claim, when it's an obscure recent paper in a sketchy journal, or when the person does nothing but add such citations, without making other contributions. –jacobolus (t) 23:33, 24 March 2026 (UTC)

I actually think a hard rule of "don't cite yourself without consensus on Wikipedia" would be a net positive for the project. It would prevent these kinds of endless debates. Sławomir Biały (talk) 07:35, 25 March 2026 (UTC)

I agree with the above reply by David Eppstein and with JBL's comments elsewhere. Without reliable sources, there is nothing to say, and none of the proffered sources are reliable. In short, nothing has changed since this was explained to you in 2011. Stepwise Continuous Dysfunction (talk) 22:15, 24 March 2026 (UTC)

MYS

I cannot access the book 1978 Homology and Cohomology Theory: An Approach Based on Alexander-Spanier Cochains by William S. Massey. If someone has this, would you like to tell me on the connection between Mayer–Vietoris sequence and extraordinary cohomology theories, like topological K-theory and cobordism? Many thanks. Dedhert.Jr (talk) 04:00, 25 March 2026 (UTC)

Your account should have access to the Wikipedia Library collection. It might perhaps be accessible through there? MEN KISSING (she/they) T - C - Email me! 05:18, 25 March 2026 (UTC)

This is not the forum for this type of questions. You may have better luck asking on a site like Math StackExchange. PatrickR2 (talk) 05:28, 25 March 2026 (UTC)

I assume the question is because Dedhert is working on a relevant article, or is verifying a source. It's appropriate to ask, and this page strikes me as one of the best places to ask. MEN KISSING (she/they) T - C - Email me! 05:44, 25 March 2026 (UTC)

Oh yeah. I am working on Mayer–Vietoris sequence, especially on sourcing before someone is interested in disqualifying the quality status by GAR. I just need a better source after I provided it. Dedhert.Jr (talk) 09:48, 25 March 2026 (UTC)

The key point is that in extraordinary cohomology theories, the dimension axiom can fail, but the MVS survives because the diagram ${\displaystyle A\cap B\to A,A\cap B\to B,A\to X,B\to X}$ remains a homotopy pushout, and any generalized cohomology gluing converts homotopy pushouts into long exact sequences. There is a nice spectral interpretation of why this is so: every extraordinary cohomology theory is represented by stable homotopy classes of a space into the n-fold suspension of the spectrum, schematically ${\displaystyle [\Sigma ^{\infty }X;\Sigma ^{n}E]}$. What changes is only the representing spectrum E, not the homotopy scaffolding that converts pushouts into long exact sequences. Sławomir Biały (talk) 08:43, 25 March 2026 (UTC)

@Sławomir Biały. Thank you. I'll use this for sourcing. But I cannot find an exact page. Hope you don't mind. Dedhert.Jr (talk) 09:43, 25 March 2026 (UTC)

Requested move at Talk:Four-vertex theorem#Requested move 12 March 2026

There is a requested move discussion at Talk:Four-vertex theorem#Requested move 12 March 2026 that may be of interest to members of this WikiProject. TarnishedPath^talk 09:27, 29 March 2026 (UTC)

Quotation help needed

At Arrow's impossibility theorem and the related article Independence of irrelevant alternatives, there is an anecdote about the philosopher Sidney Morgenbesser. I am unable to find a source for this anecdote that predates its appearance on Wikipedia (4 February 2004). I did find a source that calls it apocryphal. If anyone wants to try their luck at finding references that are not potentially circular, please do; at the moment, I am inclined to think the quotes should be trimmed entirely. Stepwise Continuous Dysfunction (talk) 23:13, 28 March 2026 (UTC)

I found that a user on an old blog referenced the joke in Feb 20, 2003. I will continue looking to try to find a more reliable source, but at least we now know it is not circular. EulerianTrail (talk) 01:16, 29 March 2026 (UTC)

I did some more looking and it seems like to find any better source, I would have to go to the library in person. Also since it is a joke, Morgenbesser could have told it but would have little reason to publish it, but I could be wrong.

Therefore, I think the best thing to do now is cite it as an apocryphal quote using the source that you found. It is still notable as it is quoted as a humorous story in research papers for the topic. It makes the article more relatable and understandable to the lay reader. EulerianTrail (talk) 01:38, 29 March 2026 (UTC)

Kotz (1983) says: "An example involving a choice between three pies has been suggested by P. Halmos (see Gardner, 1974)" –jacobolus (t) 01:41, 29 March 2026 (UTC)

Here's Gardner's column (as republished in his book Time Travel and Other Mathematical Bewilderments):

Paul R. Halmos once suggested a delightful interpretation of the matrix. Let A, B, and C stand for apple pie, blueberry pie, and cherry pie. A certain restaurant offers only two of them at any given meal. The rows show how a customer ranks the pies with respect to three properties, say taste, freshness, and size of slice. It is perfectly rational, says Halmos, for the customer to prefer apple pie to blueberry, blueberry to cherry, and cherry to apple. In his Adventures of a Mathematician (Scribner, 1976) Stanislaw Ulam speaks of having discovered the nontransitivity of such preferences when he was eight or nine, and of later realizing that it prevented one from ranking great mathematicians in a linear order of relative merit.

–jacobolus (t) 01:48, 29 March 2026 (UTC)

Something closer to the version in the article appears in Blyth (1972) "Some Probability Paradoxes in Choice from Among Random Alternatives" JSTOR 2284383 (who credits the idea about pies to Halmos):

This same disagreement, which in the present example happened only for the group judgment, might happen within an individual: Suppose that apple, blueberry, and cherry pie provide him with random amounts ⁠${\displaystyle L_{3}}$⁠, ⁠${\displaystyle L_{2}}$⁠, ⁠${\displaystyle L_{1}}$⁠ of "satisfaction", whose distribution he knows to satisfy (4.4). Offered a choice of ⁠${\displaystyle A}$⁠ or ⁠${\displaystyle C}$⁠ in the cafeteria every day at lunch, he always chooses ⁠${\displaystyle A}$⁠, reasoning that this is more likely to give him the greater satisfaction. But one day they also offer ⁠${\displaystyle B}$⁠, and he remarks "seeing that you also have ⁠${\displaystyle B}$⁠, I'll take ⁠${\displaystyle C}$⁠ instead of ⁠${\displaystyle A}$⁠", reasoning that of the three, ⁠${\displaystyle C}$⁠ has the best chance of giving him the greatest satisfaction.

–jacobolus (t) 01:56, 29 March 2026 (UTC)

Another Gardner column (also republished in Time Travel ...) discusses Blyth's paper:

Blyth has an even more mind-blowing way of dramatizing the paradox. Every night, a statistician eats at a restaurant that offers apple pie and cherry pie. He rates his satisfaction with each kind of pie in values 1 through 6. The apple pie is uniformly 3 (spinner A); the cherry varies in the manner of spinner C. Naturally, the statistician always takes apple. Occasionally the restaurant has blueberry pie. Its satisfaction varies in the manner of spinner B.

Waitress: Shall I bring your apple pie?
Statistician: No. Seeing that today you also have blueberry, I'll take the cherry.

The waitress would consider that a joke. Actually, the statistician is rationally maximizing his expectation of satisfaction. (An error. See Addendum.) Is there any paradox that points up more spectacularly the kinds of difficulty Carnap's followers must overcome in their efforts to advance his program?

...

Addendum
Many readers quite properly chided me for carelessness when I described Colin R. Blyth's paradox of the man and the three pies. It was I (not Blyth) who said that the man's decision was to maximize his "expectation of satisfaction." What he is maximizing is, in Blyth's words, "his best chance" of getting the most satisfying pie. It is a subtle but important difference. Both the dining statistician and the doctor have a choice between two intents: maximizing their average of satisfaction in the long run or maximizing their chance of getting the best pie or drug on a particular occasion.

To put it another way, Blyth's pie eater is minimizing his regret: the probability that he will see a better pie on the next table. His doctor counterpart, as Paul Chernick suggested, could be trying to avoid a malpractice suit that might result if a dissatisfied patient went to another doctor and got more effective treatment. "Is the case of a scientist closer to that of a player in the spinner game," asked George Mavrodes, "or is it closer to that of the statistical pie eater? . . . I do not know the answer to that question."

John F. Hamilton, Jr., revised the dialogue between the waitress and the statistician as follows:

Waitress: Which pie will be better tonight, A or B?
Statistician: The odds are on A.
Waitress: What about A and C?
Statistician: Again, A will probably win.
Waitress: I see, you mean A will probably be the best of all.
Statistician: No, actually C has the greatest chance of being the best.
Waitress: Okay, cut the funny stuff. Which pie do you want to order, A or C?
Statistician: Neither. I'll have a slice of B, please.

–jacobolus (t) 04:03, 29 March 2026 (UTC)

Nice finds, everyone! Stepwise Continuous Dysfunction (talk) 04:29, 29 March 2026 (UTC)

To follow up here, I think the attribution to Morgenbesser is spurious and should be removed. We should credit Blyth for the paradox/joke, and possibly Halmos for the idea of turning A, B, C in to pies. Is there an article about similar paradoxes, to which a section about this specific paradox would be relevant to add (we could redirect to it from a title like Three pies paradox)? It seems like a topic worth having a Wikipedia article about, but I'm not sure what the relevant title would be. Maybe it would fit under Intransitivity. –jacobolus (t) 19:06, 29 March 2026 (UTC)

Brahmagupta polynomials

The article’s primary issue is that its content relies almost entirely on a single research paper, which raises concerns about verifiability and balance. Additional reliable sources are required to corroborate the information and ensure a more comprehensive and neutral presentation. At present, the work of E. R. Suryanarayan (University of Rhode Island, Kingston) is used throughout the article, resulting in an overdependence on one source. Myuoh kaka roi (talk) 16:53, 29 March 2026 (UTC)

From a quick search, the "Brahmagupta matrix" and "Brahmagupta polynomials" seem to be almost exclusively found in Suryanarayan's papers (sometimes with a coauthor), plus a small handful of other papers that cite them, mostly also in Fibonacci Quarterly. I think there's enough mention that I'd lean toward calling the topic notable, but it's borderline. –jacobolus (t) 20:32, 29 March 2026 (UTC)

Fair enough but I am little uncertain whether brahamagupta actually describe matrices in his original works since the matrices that we use today was invented by Arthur Cayley and before him chinese mathematicans did used array-like methods but they didn't used matrices as a whole,same can be said to brahamagupta but the article clearly mentions brahamagupta matrices Myuoh kaka roi (talk) 20:49, 29 March 2026 (UTC)

Brahmagupta did not. As described in the article, the name comes from Brahmagupta's identity. –jacobolus (t) 21:27, 29 March 2026 (UTC)

Thanks for the clarification. Nevertheless, the article requires substantial improvement, particularly with regard to sources. Myuoh kaka roi (talk) 21:59, 29 March 2026 (UTC)

Catalan's constant

An editor has been adding material to Catalan's constant that include unsourced editorializations ("Using these series, calculating Catalan's constant is now about as fast as calculating Apéry's constant") and a "third formula" that, following the sources used for it, was found by someone with the same name as the editor (and is singled out from about 20 different formulas listed in OEIS). More eyes on the article would be welcome. —David Eppstein (talk) 23:55, 16 March 2026 (UTC)

I looked. The changes appear to be legit to me, but were reverted. They consisted of three refs, and the OEIS sequence. The "third formula" is "almost surely" legit; it is stereotypical of the kinds of formulas that Simon Plouffe has been churning out. I recognize them because I published a paper on something very similar. I've seen enough of these to suspect that there's some general formula/algo that can generate identities of this type, but I know not of any work pointing at such. linas (talk) 04:05, 1 April 2026 (UTC)

Finite cardinals and ordinals

It has come to my attention that we don't actually have much content regarding finite cardinal and ordinal numbers—that is, natural numbers considered as cardinals or as ordinals—anywhere. The lead of Ordinal number says that an ordinal number[...] is a generalization of ordinal numerals [...] aimed to extend enumeration to infinite sets. This implies that the article Ordinal numeral is about finite ordinals. However, Ordinal numeral is about words, and has a hatnote that says: For the mathematical concept, see Ordinal number. The situation with cardinals is better. Neither one of Cardinal number and Cardinal numeral suggests that the other one covers finite cardinals. We still have the problem that neither of them covers finite cardinals. The only place where either of these concepts seems to be covered is Natural number § Intuitive concept, and they are both covered there, but poorly.

This is not ideal. These concepts are important to a general audience of lay people, who are familiar with the terms "cardinal number" and "ordinal number", but get flummoxed when they encounter an article like Cardinal number or Ordinal number, since they expected an article about the finite case. To quote Beland, This is horribly confusing! I'm not volunteering to create this important content that we seem to be missing, but I'd like to hear your thoughts on where it belongs: in Cardinal number and Ordinal number, in Natural number, or in new articles dedicated for that? Streded (talk) 11:16, 28 March 2026 (UTC)

A somewhat uninformed opinion from the peanut gallery, but I think a section on natural numbers as finite cardinals vs ordinals would fit most naturally in the natural number article, which already does do some of the required work to distinguish counting things (cardinal number) from putting things into order (ordinal number). It only lacks a consolidated treatment. Sławomir Biały (talk) 11:22, 28 March 2026 (UTC)

Part of what drove me to write this is the realization that articles like Ordinal date link to Ordinal number: An ordinal date [...] consist[s] of a year and an ordinal number, ranging between 1 and 366 [...] representing the multiples of a day, called [...] ordinal day number... I want such articles to have a good target to link to. This makes me a little hesitant to relegate finite ordinals to a section that also discusses finite cardinals. Streded (talk) 11:53, 28 March 2026 (UTC)

I think a simple section like "ordinals and cardinals" could be useful to highlight both concepts and also the differences. I suspect there might be good sources from outside mathematics to help support it (e.g., philosophy), and there is no reason that a link from finite ordinal and finite cardinal can't be to the same section if both are treated in a unified way there. Sławomir Biały (talk) 12:01, 28 March 2026 (UTC)

Good point. If we do that, what should we do about the Intuitive concept section? It seems to be similar to what you're suggesting, but simultaneously more basic and way too abstract. Should that section link to the later section about ordinals and cardinals, instead of Cardinal number and Ordinal number as it currently does? Streded (talk) 12:12, 28 March 2026 (UTC)

I think the best thing to do would be to write the section first. After deciding what basic content to put there, then see if the existing article content should be lightly refactored if it reads as too redundant. Sławomir Biały (talk) 12:23, 28 March 2026 (UTC)

What you are suggesting belongs somewhere in Natural number. The articles Cardinal number and Ordinal number are about mathematical concepts closer to set theory and foundations, presented in a more rigorous fashion. General intuitive information about the finite case for a lay audience does not belong in these last two articles. PatrickR2 (talk) 21:22, 28 March 2026 (UTC)

I recall reading commentary, long ago, that many of the properties of the infinite cardinals/ordinals are reflected in the finite ones, as strange fun-house mirrors. For example, something about a finite analog to the Church-Kleene ordinal, about it getting really hard to find notation to write down ever-larger finite numbers (you can Knuth up-arrow only so far..) I don't recall any more than this, but having a good article on these would be pretty cool. linas (talk) 05:22, 1 April 2026 (UTC)

Include 2 in Category:Metric spaces

Category:Metric spaces is conspicuously incomplete without the empty metric space: the ordered pair whose underlying set is the empty set, S=∅, equipped with the unique function d:∅×∅→R (the empty function): (∅,∅)

Formally, it is straightforward to show that

(∅,∅) = {∅,{∅,∅}} = {∅,{∅}} = 2

⛬ ${\displaystyle 2\in Category:Metricspaces}$

QED ເສລີພາບ (talk) 17:16, 1 April 2026 (UTC)

I don't think 'empty metric space' warrants a page, but we could have a page on the empty topology (or redirect to a section in Discrete space or Trivial topology). The Boolean^_Talk 19:10, 1 April 2026 (UTC)

The empty metric space would have the base space the empty set M={}. The domain of the distance function would be the Cartesian product of the empty set with itself which is also the empty set. So the distance function d={}. So the metric space would be (M,d)=({},{})={{{}},{{},{}}}={{{}}}={1}≠2. This is too trivial to be worth mentioning in the article. JRSpriggs (talk) 20:12, 1 April 2026 (UTC)

You are correct. I missed a bracket. This is quite embarrassing and I'm not sure what to do now. ເສລີພາບ (talk) 20:41, 1 April 2026 (UTC)

Personally I think the particular encoding of Peano arithmetic in set theory is spurious and using it to say things like "2 is a metric space" is a type error. Sesquilinear (talk) 20:38, 1 April 2026 (UTC)

Exactly my opinion as well. —David Eppstein (talk) 22:25, 1 April 2026 (UTC)

Calculus

Do we need any further improvements to this article especially the history section as well as to the History of Calculus article, in order for it to be nominated to B-class Myuoh kaka roi (talk) 18:51, 27 March 2026 (UTC)

B-class does not involve a nomination process; anyone can judge the article to be B-class (or not) and change the assessment. If there is disagreement we can have a discussion on the article talk page. —David Eppstein (talk) 19:17, 27 March 2026 (UTC)

I think B-class is probably a fair assessment. But to my mind the biggest problems are in the Applications section. I don't have any ideas how one would write such a section, but the examples are weirdly scattershot. Calculus is basically used in every quantitative discipline to a greater or lesser extent, and picking up population dynamics as the application of calculus to biology, or Black-Sholes as the application to finance, seems highly suspect. Just reaction rates and radioactive decay in chemistry? Even the physics, which fares a little bit better, is not really good. (e.g., what about thermodynamics/statistical mechanics? quantum mechanics? or... basically anything else.) The problem is that there is no way to give an exhaustive account, but any attempt to drill down starts to look cherry-picked to a greater or lesser extent. [/steps off soapbox] Sławomir Biały (talk) 19:35, 27 March 2026 (UTC)

Anything about History of Calculus article? And I strongly agree that the application section need to be heavily improved Myuoh kaka roi (talk) 19:44, 27 March 2026 (UTC)

I would rate this still as 'C' class. (Remember, the point of the ratings is to help editors prioritize their attention, not to pat ourselves on the back.) It seems pretty undeveloped for such an important topic; we should be trying to give an overview of calculus in all of its various manifestations, rather than just cover a few results from an introductory course. As just one obvious example, there should be more than 1–2 sentences about the topic of differential equations, which are central to all modern science. –jacobolus (t) 19:42, 27 March 2026 (UTC)

Agree with @Jacobolus, but my opinion on the overview of calculus is different. The article should discuss by its subfield, like differential calculus, integral calculus, multivariable calculus, and vector calculus. Differential calculus scopes the limit of a function, which is the basic concept before the derivative of a function and its application. The same thing for integral calculus, which includes the Riemann sum, integrals (definite, indefinite, and improper) and series. And et cera for other subfields. Renaming them numerically like "Calculus I", "Calculus II", and "Calculus III" confines the others like fractional calculus, Malliavin calculus, stochastic calculus, and calculus of variations. As Jacobolus said, we should give an overview of each subfield instead of the definition and theorem, or any concept written formally. Dedhert.Jr (talk) 01:34, 28 March 2026 (UTC)

And for the additional note: Some various calculus can be included in a certain subfield, like stochastic calculus in differential calculus. Dedhert.Jr (talk) 01:39, 28 March 2026 (UTC)

I don't understand what Calculus III, etc. are supposed to mean. –jacobolus (t) 02:14, 28 March 2026 (UTC)

A separating huge amount of calculus topics, according to university classes. Dedhert.Jr (talk) 02:36, 28 March 2026 (UTC)

The contents of our article Calculus should not be determined by the contents or organization of university courses titled "Calculus". –jacobolus (t) 03:33, 28 March 2026 (UTC)

Got it. "Differential calculus", "Integral calculus", "Multivariable calculus", and "Vector calculus" should be the main subfields of calculus. We can write the remaining somewhere else. Those numerically based already exist as redirect articles. Dedhert.Jr (talk) 03:40, 28 March 2026 (UTC)

"Multivariable calculus" and "vector calculus" are basically synonyms. We should also have significant coverage about differential equations, real and complex analysis, numerical analysis, the calculus of variations and functional analysis, maybe matrix calculus, probably some about distributions, etc. –jacobolus (t) 03:57, 28 March 2026 (UTC)

I have started an expansion along those lines. Stepwise Continuous Dysfunction (talk) 07:41, 28 March 2026 (UTC)

Thanks, that looks great! –jacobolus (t) 18:55, 29 March 2026 (UTC)

Calculus § Applications still needs work. Stepwise Continuous Dysfunction (talk) 05:33, 1 April 2026 (UTC)

I tried making some "local" improvements to Calculus § Applications, and perhaps it no longer reads as quite so arbitrary and miscellaneous, but perhaps a more "global" rethinking would help. Stepwise Continuous Dysfunction (talk) 01:51, 2 April 2026 (UTC)

Mathematics has an RfC

Mathematics has an RfC for possible consensus. A discussion is taking place. If you would like to participate in the discussion, you are invited to add your comments on the discussion page. Thank you. GeogSage ^{(⚔Chat?⚔)} 23:15, 30 March 2026 (UTC)

Speaking of which, there's an article about mathematics on Wiktionary with a short explanation. What do you think about that?--SilverMatsu (talk) 16:21, 1 April 2026 (UTC)

The first clause seems a bit awkward and the definition as a whole is too long for a short description; I think, for what short descriptions are actively useful for, "field of study" is probably perfectly fine anyways.

Regardless, probably better to use the talk page for that sort of discussion. Sesquilinear (talk) 23:11, 1 April 2026 (UTC)

Thank you for your reply. Does "talk page" refer to the Wikipedia talk page discussing short descriptions, or the Wiktionary talk page?--SilverMatsu (talk) 01:17, 2 April 2026 (UTC)

I was referring to discussion about the short description, so Talk:Mathematics. Sesquilinear (talk) 01:21, 2 April 2026 (UTC)

Thank you for clarifying.--SilverMatsu (talk) 05:33, 2 April 2026 (UTC)

24-cell

See discussion in Talk:24-cell#Excessive citations. I don't think I have time to deal with these footnotes, and I'm almost giving up because of the tables with multiple footnotes, which are useful. I could only trim unsourced sections. Should have named the title "footnotes" instead of "citations". 😞. Dedhert.Jr (talk) 12:03, 2 April 2026 (UTC)

As for reminder, some sections in 24-cell do have a good explanation of some technical terms. Specifically, for the rotations, it is preferable to improve Rotations in 4-dimensional Euclidean space. Dedhert.Jr (talk) 12:08, 2 April 2026 (UTC)

"Surely it can't be that much, I'm about to go take a nap but out of curiosity I'll give it a look", I said to myself, clueless.

"Excessive footnotes" does not nearly do it justice. The footnotes are nested fractal. There are nearly twice as many words in the footnotes as in the article proper. How did this come to pass??? MEN KISSING (she/they) Talk to me, I don't bite! - See my edits 13:45, 2 April 2026 (UTC)

It used to be even worse. —David Eppstein (talk) 16:21, 2 April 2026 (UTC)

Whoever made this has a bright future in the cosmic horror genre. I'm certainly more shaken than I expected to be. Streded (talk) 17:52, 2 April 2026 (UTC)

The Wikiversity article on the 24-cell still goes up to fx. Sesquilinear (talk) 22:15, 2 April 2026 (UTC)

The citations are also broken in the Notes section. The Boolean^_Talk 21:14, 2 April 2026 (UTC)

I think the fundamental problem is that these were made as the idiosyncratic record of one person's personal research project rather than by trying to summarize the content of existing reliable sources. The resulting page(s) have some interesting and even insightful features, but they are hard to work on collaboratively in the style of typical Wikipedia articles. –jacobolus (t) 21:36, 2 April 2026 (UTC)

In that case, it might be best to just delete these sections and develop the page from there. I agree that much of the information is interesting, but it would take longer to sift through to see what's sourced and what's worthy of the article than to write a new section. The Boolean^_Talk 21:54, 2 April 2026 (UTC)

Agreed, Wikipedia footnotes are not supposed to be a place for original survey papers. Elestrophe (talk) 22:54, 2 April 2026 (UTC)

I took the bold, perhaps excessive, step of cutting out the editorial footnotes entirely. It's better to build them up as needed based on what books and articles say about the 24-cell than try to cut a passion project down to size one step at a time, particularly when the footnote graph is cyclic. I have also lightly edited the opening paragraphs for clarity. Stepwise Continuous Dysfunction (talk) 23:32, 2 April 2026 (UTC)

Honestly I was thinking of doing the same thing. I just didn't have the heart for it. MEN KISSING (she/they) Talk to me, I don't bite! - See my edits 23:45, 2 April 2026 (UTC)

Wikipedia:Articles for deletion/Deterministic context-free grammar

This AfD is getting out of hand. I feel like this, as the nominator is acting uncivilly toward other users who disagree with their claim. It requires evaluation of assertions that the topic is ill-defined or nonsensical, including ^[1] which was raised by a user at the talk page in 2014. –LaundryPizza03 (dc̄) 05:46, 3 April 2026 (UTC)

Two pages that do not exist

Hi everyone!

I was reading the early mathematical work described in the biographies of Artur Avila and Fernando Codá Marques. They mentioned the Zorich–Kontsevich conjecture (in dynamical systems, 778 results on a Google search) and the Min-Oo conjecture (in differential geometry, 3520 results on Google searching for "Min-Oo" + "conjecture") respectively.

I've added them to Wikipedia:Requested articles/Mathematics. Is anyone interested in starting any of them? I think it would be nice! The Zorich–Kontsevich conjecture statement seems very technical, accessible only to specialists in dynamical systems, but Min-Oo's conjecture seems way more interesting and understandable: https://arxiv.org/pdf/2308.03184

Best, Is Johnson (talk) 17:01, 4 April 2026 (UTC)

Notable assistant/associate professors of mathematics

I want to start articles on notable (by WP:GNG or WP:PROF criteria) assistant or associate professors of mathematics. Today I've started the article about Yevgeny Liokumovich. I am planning on starting one about Elina Robeva later (she was awarded the Aisenstadt Prize in 2023). Please, I would greatly appreciate receiving suggestions of names of notable mathematicians that are not full professors yet. A bonus if they are from poor countries or from other underrepresented groups in mathematics, such as women, for example). Thank you! MathKeduor7 (talk) 21:53, 6 April 2026 (UTC)

Young researcher awards such as the Aisenstadt Prize are often not enough to pass WP:PROF#C2, and for junior faculty there may not be much else yet as indicators of notability. For junior faculty who do not even have these awards, the usual outcome is that they are not considered notable. When you make articles on these people, please start already having in mind what additional evidence you might use to persuade people that they are notable, if you need to persuade them (for instance in an AfD or after an article gets draftified). It needs to be evidence that can be seen and evaluated by non-mathematician Wikipedia editors, such as society fellowships or awards that are not labeled as being for early career researchers. See Wikipedia:Articles for deletion/Si Ying Lee for a case of someone who received an early-career award that I think is more significant than the Aisenstadt Prize (for one thing it is international rather than specific to one country) but was deemed not yet notable in an AfD. We should try to avoid outcomes like that one, because it makes it much more difficult to make an article later even when more evidence of notability has built up.

This is one of the reasons that I prefer creating articles on older and more-established academics (often at the full professor level already). Even for those, there needs to be more justification for notability than a single award that could be argued away as minor and local. —David Eppstein (talk) 22:25, 6 April 2026 (UTC)

Thank you for your reply Professor David Eppstein! I'll embark on other projects at Wikipedia then. By the way, Elina Robeva seems to be highly-cited enough (I don't know, maybe Wikipedia requires more), but I won't start an article on her, as I fear someone would send it for deletion. I wish good edits for everyone! MathKeduor7 (talk) 23:01, 6 April 2026 (UTC)

If you start from the other end of the list you might find more well-established but neglected mathematicians who deserve articles. The earliest Aisenstadt Prize winner without an article, Ian F. Putnam, is clearly notable as an FRSC and Fellow of the AMS (double pass of WP:PROF#C3), for instance. —David Eppstein (talk) 23:59, 6 April 2026 (UTC)

I am going to start an article about him in a few days (and maybe of other Fellows of the AMS)! I need to go to sleep now and I won't have time to edit Wikipedia for a few days. I am very tired right now, but I have two questions: Do you think the Simons Fellowship is enough to pass WP:PROF? If not, should I move the article about Liokumovich to the draft namespace or maybe to a subpage in my user page? (before someone tries to delete it, and so that I could be improving it over time until the notability becomes clear). I think that co-solving an important conjecture by Gromov should be enough for notability, but we are at Wikipedia! Haha ^^. MathKeduor7 (talk) 01:00, 7 April 2026 (UTC)

TWAS fellows working in mathematical sciences might be worth checking: . fgnievinski (talk) 01:02, 7 April 2026 (UTC)

It's a bit off topic, but is there a list anywhere of relatively prominent mathematicians who should clearly have a Wikipedia article but are currently red links? (I'm thinking about people with named chairs, editors of major journals, have had Festschrifts, won major prizes, have many highly cited papers and lots of students, etc.) –jacobolus (t) 02:58, 7 April 2026 (UTC)

Wikipedia:WikiProject Women in Red/Mathematics has some. Stepwise Continuous Dysfunction (talk) 03:25, 7 April 2026 (UTC)

There are a few redlinks at List of presidents of the Institute of Mathematical Statistics and List of members of the National Academy of Sciences (applied mathematical sciences). Stepwise Continuous Dysfunction (talk) 03:30, 7 April 2026 (UTC)

There are a lot of redlinks (all male, I think, if that's relevant for you) at Category talk:Fellows of the American Mathematical Society. —David Eppstein (talk) 05:23, 7 April 2026 (UTC)

Also a lot of redlinks at List_of_International_Congresses_of_Mathematicians_Plenary_and_Invited_Speakers. jraimbau (talk) 20:14, 7 April 2026 (UTC)

Related --- it'd be nice to have the list of speakers on that page separated into plenary and invited lectures.

It might also be nice to separate the invited speakers by section, but that might make it too cluttered, especially since some are cross-listed in multiple sections. Gumshoe2 (talk) 21:20, 7 April 2026 (UTC)

i think those red link mathematicians at Mathematical Society of Japan deserve articles (as the prizes by the MSJ are prestigious). It's quite possible there are already articles on some of them in Japanese Wikipedia; just not here in English Wikipedia Taku (talk) 20:41, 8 April 2026 (UTC)

Question about Lucas primality test

In the example in Lucas primality test, it says "We randomly select an a=17 < n." Does a have to be relatively prime to n? Bubba73 ^{You talkin' to me?} 22:59, 8 April 2026 (UTC)

No. If a is not coprime to n, then n is composite. I think that the test would still work, even if you do not bother to check for coprimeness. You can check that easily by calculating the greatest common divisor of a and n. If it is not 1, then they are not coprime and it is a divisor of n, i.e. a witness that n is not prime. JRSpriggs (talk) 23:28, 8 April 2026 (UTC)

If ⁠${\displaystyle d}$⁠ divides both ⁠${\displaystyle a}$⁠ and ⁠${\displaystyle n}$⁠, then is divides also ⁠${\displaystyle a^{n-1}}$⁠. So, the first part of the test provides "composite". D.Lazard (talk) 13:44, 9 April 2026 (UTC)

scr

I have just added a citation to this paper https://www.sciencedirect.com/science/article/pii/S0021869314004505 to Hyperoctahedral group. Unfortunately the title seems to use the script font \scr that isn't supported here (maybe?). Currently I've swapped it for \mathcal. Does anyone have a better suggestion about how to handle this? --JBL (talk) 18:34, 6 April 2026 (UTC)

𝓐𝓑𝓒𝓓𝓔𝓕𝓖𝓗𝓘𝓙𝓚𝓛𝓜𝓝𝓞𝓟𝓠𝓡𝓢𝓣𝓤𝓥𝓦𝓧𝓨𝓩 Sławomir Biały (talk) 18:42, 6 April 2026 (UTC)

Thank you! --JBL (talk) 18:44, 6 April 2026 (UTC)

I think using mathcal is fine, but in case one day you really need mathscr, note that unicode supports it:

𝒜 ℬ 𝒞 𝒟 ℰ ℱ 𝒢 ℋ ℐ 𝒥 𝒦 ℒ ℳ 𝒩 𝒪 𝒫 𝒬 ℛ 𝒮 𝒯 𝒰 𝒱 𝒲 𝒳 𝒴 𝒵

Malparti (talk) 03:02, 10 April 2026 (UTC)

The Unicode "MATHEMATICAL SCRIPT" symbols are usually rendered as similar to "mathcal". There's no separate "caligraphic" vs. "script" symbols, though presumably you could have separate fonts with each type of lettering, using the same unicode code points, or even one font including multiple variant glyphs for each code point. –jacobolus (t) 03:52, 10 April 2026 (UTC)

The PDF of the paper itself uses mathcal ⁠${\displaystyle {\mathcal {W}}}$⁠, so that should be fine. The flowery script font seems to be a buggy artifact of the web-based presentation on ScienceDirect. Depending on whether you prefer LaTeX or a math template, I'd write one of:

• Wilson, Jennifer C.H. (2014), "⁠${\displaystyle \mathrm {FI} _{\mathcal {W}}}$⁠-modules and stability criteria for representations of classical Weyl groups", Journal of Algebra, 420: 269–332, doi:10.1016/j.jalgebra.2014.08.010
• Wilson, Jennifer C.H. (2014), "FI_𝒲-modules and stability criteria for representations of classical Weyl groups", Journal of Algebra, 420: 269–332, doi:10.1016/j.jalgebra.2014.08.010

You shouldn't use a bold symbol in the subscript, as currently done. –jacobolus (t) 19:00, 6 April 2026 (UTC)

That's extremely odd. I had actually pulled the tex code from MathSciNet, so it's somehow more than just a bug of the presentation at Science Direct. I have opted to go back to the LaTeX version (which also matches the author's other papers on this topic). --JBL (talk) 18:22, 9 April 2026 (UTC)

Requested move at Talk:List of misnamed theorems#Requested move 27 March 2026

There is a requested move discussion at Talk:List of misnamed theorems#Requested move 27 March 2026 that may be of interest to members of this WikiProject. TarnishedPath^talk 10:40, 10 April 2026 (UTC)

EoM blocked?

Apologies if this has been raised already, but is Springer EoM globally down/blocked, or is it just from my location? (E.g.: .) I haven't tried accessing it with a VPN, but haven't been able to access it for several weeks from my location. It might be useful for someone with the right archive-bot-fu to add wayback links if this issue persists and isn't geographically limited. Sławomir Biały (talk) 11:13, 10 April 2026 (UTC)

I wouldn't expect "Error: Server Error" if it was blocked. -- Shmuel (Seymour J.) Metz Username:Chatul (talk) 13:34, 10 April 2026 (UTC)

I've been getting 502 errors myself for a while now. Sesquilinear (talk) 19:04, 10 April 2026 (UTC)

Same for me (from Berlin) and the root page https://encyclopediaofmath.org - Jochen Burghardt (talk) 22:00, 10 April 2026 (UTC)

From my Japan ip address, I can’t access the site either (got the server error). Maybe a temporary outage (if temporary is meant several weeks). Taku (talk) 02:31, 11 April 2026 (UTC)

Put "is encyclopediaofmath.org down" into Google to see that this apparently is a known problem. Johnuniq (talk) 03:19, 11 April 2026 (UTC)

I'd generally recommend citing the physical paper edition. The online edition is rarely if ever non-trivially different anyway, and doesn't seem to have been very actively worked on. –jacobolus (t) 03:44, 11 April 2026 (UTC)

The advantage used to be that it was easily accessible. I think someone should look into adding wayback links. Sławomir Biały (talk) 05:08, 11 April 2026 (UTC)

I thought the paper copies had scans on the Internet Archive, but apparently not. Perhaps they were removed. –jacobolus (t) 05:26, 11 April 2026 (UTC)

Yeah, my issue wasn't so much whether one could in principle access the paper copies. It's that a completely electronic link to a single light-weight web page: it's not so much a problem of WP:V as it is one of reader (and editor!) convenience. For example this is a wayback link of the above article, much more convenient than having to download an entire scanned pdf of a very large book. However, looking at the wayback link, it seems less than ideal because the latex/mathjax doesn't seem to render at all for me. Still, I guess it would be better than getting a 502 error. Sławomir Biały (talk) 05:35, 11 April 2026 (UTC)

Update: they are there after all (but "borrow unavailable", so you can search inside but only view one or two pages). I was spelling it as "encyclopedia" rather than "encyclopaedia" in my search. E.g. volume 1, all volumes. –jacobolus (t) 05:50, 11 April 2026 (UTC)

Grothendieck's relative point of view

I believe the notion described in this article certainly exists, but I think this article needs more references. There seem to be few references that specifically explain Grothendieck's relative point of view.--SilverMatsu (talk) 16:09, 11 April 2026 (UTC)

Category:Metric linear spaces has been nominated for discussion

Category:Metric linear spaces has been nominated for possible deletion, merging, or renaming. A discussion is taking place to decide whether it complies with the categorization guidelines. If you would like to participate in the discussion, you are invited to add your comments at the category's entry on the categories for discussion page. Thank you.

It is a highly technical subject and the discussion hinges on the subject matter. –LaundryPizza03 (dc̄) 07:44, 13 April 2026 (UTC)

Initial segment

Hi, all. There has been a debate as to whether this new article initial segment is a content fork of the existing upper set (an initial segment is also called a lower set) or not. David Eppstein thinks it is while I disagree or rather there is a room for a separate article for the use in set theory. We are at deadlock in the debate and thus can appreciate third opinions, comments, etc. at Talk:Initial segment. Taku (talk) 23:26, 13 April 2026 (UTC)

Capitalization of de La Vallée Poussin

See Talk:Charles Jean de la Vallée Poussin for a move proposal regarding the mathematician who proved the prime number theorem. —David Eppstein (talk) 19:24, 15 April 2026 (UTC)

Participant List

Hi, I just joined so I was just looking at the Participant List. There are lots of names outside of the prescribed alphabetical order. Should this be changed or just left alone? Thank you. SailorKuu (talk) 22:32, 16 April 2026 (UTC)

@SailorKuu. Can you tell what Participant List you are referring to? Dedhert.Jr (talk) 01:55, 17 April 2026 (UTC)

This one: Wikipedia:WikiProject_Mathematics/Participants. @SailorKuu, you can alphabetize it if you want. I don't think anyone pays much attention to that list; many of the common participants here are not listed, and most of those listed are inactive. –jacobolus (t) 02:04, 17 April 2026 (UTC)

With a lot of these names, I feel like Obi Wan "There's a name I haven't heard in a long time." Sławomir Biały (talk) 10:32, 17 April 2026 (UTC)

I think that sorting the list is a great idea. I did not add my user-id because I could not figure out where to add it. But what about capitalization, how should that affect the sort? Should we just sort on the user-id itself or on the person's full name? JRSpriggs (talk) 11:59, 17 April 2026 (UTC)

"one of the greatest living mathematicians" is encyclopedic tone?

Hello. There is one thing that bothers me: I've seem many articles tell some mathematician is one of the greatest living or even greatest of the century and things like that... For example, Terence Tao's article says he "is widely regarded as one of the greatest living mathematicians". I think this is essentially correct, but it's nonetheless meaningless and not written in an encyclopedic tone. I did not dare to remove it, because it cites five sources to support it. But why meaningless? Well, it doesn't convey any useful information, also because: Is he among the top 100? Maybe the top 50? There are many impressive Fields Medallists, Abel Prize winners, Wolf Prize winners, etc... who are still alive. Should we mention at Jean-Pierre Serre, Andrew Wiles, Peter Scholze, Grigori Perelman, John Milnor, Mikhael Gromov, Stephen Smale and so on that they are among the greatest living mathematicians? I think not. Maybe there is some Wikipedia policy already about things like this? Pentakol (talk) 02:13, 16 April 2026 (UTC)

I think "widely regarded" and "one of the" does make it encyclopedic. We don't have to pick the cut-off mark for top-N as "greatest", we just have to find enough secondary sources that make that claim. Tao is particularly popular so I am not surprised that there were multiple citations available for that claim but that doesn't stop us from making the claim for other mathematicians if we can find citations for it. abandeali (talk) 02:42, 16 April 2026 (UTC)

I think saying "widely regarded as greatest" is different than saying "greatest" since the former is stating what many believe which appears to be notable for Terence Tao's case while the latter is unencyclopedic since it is not neutral. EulerianTrail (talk) 14:58, 16 April 2026 (UTC)

I definitely agree with you. I think it's unprofessional and unfair to many other mathematicians, including those you mention, that Tao's popularity in the media allows this to be so easily cited. Notably, it would be just as easy to cite that his fellow mathematicians call him the "Mozart of math" despite this being, as far as the evidence shows, purely a media creation. Gumshoe2 (talk) 14:37, 16 April 2026 (UTC)

It seems to me obviously encyclopedic information that something is widely regarded as an exceptional example. I could imagine that in some cases it could be done as at Emmy Noether ("Noether was described by Pavel Alexandrov, Albert Einstein, Jean Dieudonné, Hermann Weyl, and Norbert Wiener as the most important woman in the history of mathematics. As one of the leading mathematicians of her time ...") but it doesn't strike me as particularly worse that Mike Schmidt is "widely considered to be one of the greatest third basemen in baseball history" or that Pelé is "[w]idely regarded as one of the greatest [soccer] players in history" or that John Maynard Keynes is "known as the "father of macroeconomics" and is one of the most influential economists of the 20th century". --JBL (talk) 19:33, 16 April 2026 (UTC)

Are there any available examples for contemporary figures, especially academics? I think it's very different for figures from past times where there is plenty of available retrospective commentary. Gumshoe2 (talk) 19:59, 16 April 2026 (UTC)

LeBron James: "James is widely considered to be one of the greatest basketball players of all time" abandeali (talk) 20:16, 16 April 2026 (UTC)

There are some about Paul Erdős Erdős that describe him as the greatest among the century he lived. EulerianTrail (talk) 21:18, 16 April 2026 (UTC)

Hi. I am here at the invitation of a friend. Well, about the matter: Every Fields Medal winner alive today is "widely regarded as one of the greatest living mathematicians". Just as every Nobel Prize in Physics winner alive today is "widely regarded as one of the greatest living physicists". There is no need for MOS:PEACOCK language in the articles about them. Just describe Tao's main contributions to mathematics and the major prizes he won. An encyclopedia should be about facts, not opinions. By the way, one of the references given there for the claim https://newsroom.ucla.edu/releases/Terence-Tao-Mozart-of-Math-7252 is a quote by John Garnett, who said "He’s an incredible talent, and probably the best mathematician in the world right now." This is very different from "widely regarded as one of the greatest living mathematicians", it's the opinion of one person and uses the word "probably", so it doesn't source our article's claim. All the references for that claim need to be checked, and maybe the phrase should be reworded or even completely removed. Just my two cents. JLW57 (talk) 12:44, 17 April 2026 (UTC)

Every Fields Medal winner alive today is "widely regarded as one of the greatest living mathematicians". This seems ... definitely wrong? You should test-drive it by a few mathematicians and see if they agree. Certainly it is not verifiable in reliable sources, unlike the statement about Tao (and Schmidt, and Pele, and Noether, and Keynes). probably the best is very similar to one of the greatest; to the extent it's different, it's actually more effusive. The beginning of WP:PEACOCK is ... used without attribution to promote the subject of an article, while neither imparting nor plainly summarizing verifiable information but here the information is certainly verifiable and is being plainly summarized. --JBL (talk) 17:21, 17 April 2026 (UTC)

We can also add (with reliable sources to support the adjectives) that Tao is one of the most famous and influential mathematicians today. Let's add that to his article? There are many other adjectives that can be added and backed by reliable sources ("one of the most decorated", by number of prizes received, for example), one of the most generous with his time (yes)... Not everything that has a source should be added to his article, if we do that it will become ridiculous, specially when it clearly adds nothing (after we tell of his great contributions to mathematics and that he received the Fields Medal, why add that he is great?). It's a bad habit, maybe due to how common it is for fans and commentators of sports to do that? Btw, Lionel Messi once said he never saw Pelé playing (not even videos!). Mathematics and soccer are very different things. Everyone here in this forum has heard about Hilbert or Poincaré. In two hundred years many people will still remember Euclid, Archimedes, Newton, Euler, Gauss, Hilbert, Poincaré, and learn from them directly (by reading them) or indirectly, but no one will care about Pelé or Messi (or some baseball or basketball player): They were people who played sports, had success on them, got famous and rich, but they are not important as Tao, who still will be remembered for years to come. :) P.S. At least one source was removed from there, as it was not of high-quality enough for the claim, and did not support the claim. Well, I have better things to do than discuss this here. I'm not going to interfere. JLW57 (talk) 18:30, 17 April 2026 (UTC)

The facts that Tao is widely esteemed and that particular mathematicians have said superlatives about him are just facts that we can document. So, there's not a problem in principle with language like "widely recognized as a generational talent" or "widely regarded as one of the greatest". I am, however, somewhat dissatisfied with the details of how the Terence Tao article actually does this. First, I'd drop the UCLA newsroom source; that's Tao's university reporting statements by other people who work at Tao's university, i.e., not independent by any margin. Second, the main text of the article doesn't do a very good job of following up on that line. It has a whole subsection about "Recognition", but that just lists a bunch of awards and gives a couple quotes, not really fleshing out the "widely regarded as one of the greatest" statement. If I see in the intro that he is "widely regarded as one of the greatest living mathematicians", and what I see in the article below is that he was an Australian of the Year finalist in 2007, have I learned anything about why mathematicians esteem him? No, no I have not.

So, I don't think there's a fundamental problem, but there are issues of implementation. Stepwise Continuous Dysfunction (talk) 18:29, 17 April 2026 (UTC)

OK, I moved some things around and tried to write an intro paragraph that conveys more about his career. The superlative is now down below and attributed rather than in wiki-voice. Stepwise Continuous Dysfunction (talk) 19:02, 17 April 2026 (UTC)

I find it very satisfactory now, thanks for your edit. Gumshoe2 (talk) 19:20, 17 April 2026 (UTC)

Requested move at Talk:Body relative direction#Requested move 6 April 2026

There is a requested move discussion at Talk:Body relative direction#Requested move 6 April 2026 that may be of interest to members of this WikiProject. TarnishedPath^talk 07:26, 20 April 2026 (UTC)

Some mathematicians bios drafts

Drafts about mathematicians who won blue-linked prizes (or whose drafts say they won):

• Draft:François Delarue
• Draft:Iosif Polterovich
• Draft:Rajula Srivastava
• Draft:Yu Deng
• Draft:Valentin Blomer
• Draft:Otis Chodosh
• Draft:Semyon Dyatlov
• Draft:Zsolt Páles
• Draft:Evgeny Plotkin
• Draft:Mikaela Iacobelli
• Draft:Carina Hong
• Draft:Christoph Schweigert

Some of them may be notable. TammKask (talk) 16:01, 19 April 2026 (UTC)

Yes, I would say that most of these are notable under WP:PROF. Sławomir Biały (talk) 05:18, 20 April 2026 (UTC)

I added those drafts to the Wikipedia:WikiProject Mathematics/List of math draft pages.--SilverMatsu (talk) 23:47, 20 April 2026 (UTC)

Issues with supermanifold

See online discussion at . The article is badly sourced, with problematic definitions, and maybe comes from too much of a physics background to get the mathematics right. I don't understand any of this well enough to make a useful contribution to the article but I hope someone else here does. —David Eppstein (talk) 05:39, 21 April 2026 (UTC)

Markowsky's theorem

According to Thomas & Williams (2019), there appears to be another theorem other than Markowsky's (1976) called Markowsky's theorem. Would I split the article?--SilverMatsu (talk) 03:36, 20 April 2026 (UTC)

If there are two notable theorems by the same name then they should have two separate articles with disambiguated titles. —David Eppstein (talk) 05:11, 20 April 2026 (UTC)

Thank you. It might be better to change the title of Markowsky's theorem to Markowsky's theorem (order theory) or Markowsky's theorem (domain theory), and create a article(draft) such as Markowsky's theorem (lattice theory) or Markowsky's representation theorem.--SilverMatsu (talk) 23:43, 20 April 2026 (UTC)

Those names all seem reasonable to me. I would prefer to avoid the lattice name, though, because of the confusion between order-theoretic lattices and group-theoretic lattices. —David Eppstein (talk) 05:40, 21 April 2026 (UTC)

I moved Markowsky's theorem to Markowsky's theorem (order theory) and created Draft:Markowsky's representation theorem.--SilverMatsu (talk) 01:22, 22 April 2026 (UTC)

It appears the Dab page has been reverted to redirecting to Markowsky's theorem (order theory) because Draft:Markowsky's representation theorem is not yet an article. If the Dab page does not exist, Markowsky's theorem (order theory) may be reverted to Markowsky's theorem as an unnecessary parentheses/disambiguator.--SilverMatsu (talk) 01:59, 23 April 2026 (UTC)

I agree with the revert that it is unnecessary to have a disambig page yet. We can always create it after the draft article is moved to mainspace. Taku (talk) 09:11, 23 April 2026 (UTC)

Wikipedia:Articles for deletion/EML (mathematical operator)

This discussion could probably use more input. Stepwise Continuous Dysfunction (talk) 19:59, 24 April 2026 (UTC)

Really shouldn't have been relisted; 3 clear arguments for deletion, one non-policy keep, and three comments that all agree that there's no RS coverage. --JBL (talk) 20:35, 24 April 2026 (UTC)

Probabilistic logic network

The article Probabilistic logic network had its notability questioned years ago on its Talk page, and it's been tagged for quite a while. As written, it seems to cover an AI-related proposal that hasn't really gone anywhere substantial. Many of the Google Scholar hits for the term appear to be about something else (e.g., they don't name the authors who published this idea). The two sources are primary; one of them is the researchers' own wiki, which has since been edited to say that the idea "has been abandoned as of 2021". I don't think we need to document abandonware that was only ever dubiously notable in the first place. So... What should be done with it? Just put it up for deletion? Find somewhere it could be redirected? Stepwise Continuous Dysfunction (talk) 01:49, 20 March 2026 (UTC)

I would be in favor of putting it up for deletion. Malparti (talk) 10:30, 20 March 2026 (UTC)

See now Wikipedia:Articles for deletion/Probabilistic logic network. Stepwise Continuous Dysfunction (talk) 22:43, 20 March 2026 (UTC)

This has been open for about six days now without attracting any !votes one way or the other. Stepwise Continuous Dysfunction (talk) 01:10, 27 March 2026 (UTC)

This was relisted the other day. Further input welcome. Stepwise Continuous Dysfunction (talk) 23:37, 1 April 2026 (UTC)

This is still open, if anyone's interested. Stepwise Continuous Dysfunction (talk) 22:56, 10 April 2026 (UTC)

... Never mind, it's been closed as "no consensus", meaning that despite most of the comments being opposed in one way or another to it existing, it just sits there. Stepwise Continuous Dysfunction (talk) 02:26, 11 April 2026 (UTC)

I missed this discussion, but after reviewing the article and the AfD, I have WP:BLARed Probabilistic logic network. --JBL (talk) 18:24, 25 April 2026 (UTC)

Yoneda extension

Which is a better place to explain this notion: Yoneda's lemma or Kan extension?--SilverMatsu (talk) 15:07, 25 April 2026 (UTC)

I think the Yoneda lemma, since the Kan extension is an extension along any map not just an embedding. Taku (talk) 23:24, 25 April 2026 (UTC)

Thank you for your reply. Done.--SilverMatsu (talk) 23:58, 25 April 2026 (UTC)

Currently, the Yoneda extension seems to be a redirect to the Presheaf (category theory)#Universal property. Would it be better to change the redirect target?--SilverMatsu (talk) 04:19, 27 April 2026 (UTC)

Unreliable source?

Special:Search/"The Universal History of Numbers": I am not sure articles should be citing this book. See Georges Ifrah and in particular https://www.ams.org/notices/200201/rev-dauben.pdf. 1234qwer1234qwer4 21:16, 21 April 2026 (UTC)

There are also "From+One+to+Zero"+"Ifrah" several citations to From One to Zero, apparently an earlier version of the same book. —David Eppstein (talk) 21:58, 21 April 2026 (UTC)

I think the book can be cited in some contexts, but we should take care about it. Where possible it's of course preferable to cite books about history and science written by subject-expert scholars rather than mass-market books written by nonspecialists. –jacobolus (t) 22:08, 21 April 2026 (UTC)

Resources by nonexperts are certainly acceptable (though not ideal). If the review is to be believed, however, Ifrah's book isn't just written by a nonexpert. It has serious issues, even outright fabrications. The Boolean^_Talk 01:47, 22 April 2026 (UTC)

I think it's more a matter of sloppiness than intentional "fabrication". If you get someone who doesn't read any of the languages historical sources are written in, with a bit of an agenda, skimming through primary research papers looking for interesting claims that seem to support their position and then pasting their own interpretation of those uncritically into a book with some additional interpretive speculation, it's easy to drift away from what is supportable. Many Wikipedia articles have similar kinds of problems. –jacobolus (t) 04:56, 22 April 2026 (UTC)

I have been working on a draft to fix various problems with our numeral-system articles, including reliance upon dodgy sources. Stepwise Continuous Dysfunction (talk) 22:45, 23 April 2026 (UTC)

I'm still mucking about with that draft; suggestions welcome. Stepwise Continuous Dysfunction (talk) 01:36, 29 April 2026 (UTC)

Srinivasa or Srinivas?

As far as I know, Srinivasa Ramanujan firstname is way more common rather than Srinivas Ramanujan, which is used today. Dedhert.Jr (talk) 12:35, 26 April 2026 (UTC)

I think "Srinivas" matches the native pronunciation better so I get the motivation. But his name is spelled with a trailing "a" in so many sources that we probably need a strong secondary source to justify using "Srinivas" abandeali (talk) 12:48, 26 April 2026 (UTC)

It's a regional variation. I suppose a reasonable analogue would be 'Geoffrey' vs 'Jeffrey'. 'Srinivasa' would be the more common version where he was from, and as far as I know most English language sources use 'Srinivasa'. MrOllie (talk) 12:52, 26 April 2026 (UTC)

I've moved the article back to Srinivasa Ramanujan. —Kusma (talk) 13:11, 26 April 2026 (UTC)

Offhand, I don't recall reading any source that used "Srinivas" rather than "Srinivasa". Stepwise Continuous Dysfunction (talk) 01:37, 29 April 2026 (UTC)