Wikipedia talk:WikiProject Mathematics/Archive/2020/Mar

blockquote?

The Basel problem was solved by a proof that

$\sum _{n=1}^{\infty }{\frac {1}{n^{2}}}={\frac {\pi ^{2}}{6}}.$

The Basel problem was solved by a proof that

$\sum _{n=1}^{\infty }{\frac {1}{n^{2}}}={\frac {\pi ^{2}}{6}}.$

The first statement above has the displayed TeX code indented by a colon at the beginning of the line. That has long been standard usage here. The second uses "blockquote". I've run into several like that today. Is that now considered a standard usage in Wikipedia articles? Michael Hardy (talk) 01:09, 1 March 2020 (UTC)

For non-math typesetting, <blockquote> and {{quote}} are both standard. I've noticed <blockquote> used a few times for math typesetting here too though. — MarkH₂₁^talk 01:14, 1 March 2020 (UTC)

I don't think it is or should become standard, though. —David Eppstein (talk) 01:57, 1 March 2020 (UTC)

There are issues with every solution unfortunately. I don't know the specific circumstances, but using <blockquote>...</blockquote> will avoid the problem of a lack of indentation in material next to a body floating left, like at the picture I inserted above. It's possible that at least some of the cases of this being used in the wild are to try to work around this. Not even <math display="block"> will avoid that. –Deacon Vorbis (carbon • videos) 02:19, 1 March 2020 (UTC)

I've taken the liberty of modifying the above visual to show this problem. I hope no one minds. --Bill Cherowitzo (talk) 22:04, 1 March 2020 (UTC)

I would think the smaller font size of the block quote (carried through into mathematics formulas displayed that way) would be a bigger problem than the faulty indentation of the other styles. —David Eppstein (talk) 02:26, 1 March 2020 (UTC)

Interesting; Chrome reports both as exactly 49.57px tall for me. Likewise, text in blockquotes is displayed at the same size as surrounding text. I'd be curious what's causing the discrepancy. There are certainly a lot of potential places for styling rules to get tweaked. –Deacon Vorbis (carbon • videos) 04:11, 1 March 2020 (UTC)

No idea, but for me on OS X, Chrome, and the MonoBook skin, the block quotes are a little smaller in font size (both text and math) and more noticeably smaller in line spacing. —David Eppstein (talk) 06:34, 1 March 2020 (UTC)

• I'm on Firefox and the font size of the first example is distinctly larger than in the second. My personal preference would actually be to have the font slightly bigger as in the first, but indented as the second. Reyk _YO! 06:42, 1 March 2020 (UTC)
• These are not blockquotes and should not be marked up as such. Fix them as you will where you identify them. --Izno (talk) 21:45, 1 March 2020 (UTC)

User of template:Infobox polychoron.

I was very surprised that Template:Infobox polychoron was only used on the 6 regular polytopes. I'd like to see it used on ther other entries in Category:Polychora, but that may involve adding some parameters, including I think Hypervolume. I'm sure that Hypervolume can be pulled from Coxeter for the regular polytopes. I'd love any suggestions.Naraht (talk) 04:03, 2 March 2020 (UTC)

Forgive my ignorance about this particular template and going slightly off-topic from the original question, but how is this template specialized for 4-polytopes as opposed to polytopes in general? I.e. why isn’t it just Template:Infobox polytope? Likewise, why isn’t the category called Category:4-polytopes according to the WP:COMMONNAME of the corresponding article (which I understand was decided to be n-polytope in general in some older discussions at Talk:Polytope)? — MarkH₂₁^talk 05:00, 2 March 2020 (UTC)

Because it has as parameters Cell List and Face List. a 5-polytope like the 5-cube would need an entry for 4-faces as well. As for commonname, I'd actually prefer that the 4-polytope article be called polychoron, I'm not sure where to get the "Common Name" for this. Coxeter?Naraht (talk) 05:09, 2 March 2020 (UTC)

See Talk:4-polytope#It is entirely inappropriate for this article to be named "Polychoron" (2009), Talk:4-polytope#Pushing nonstandard terminology (2014), and Talk:4-polytope#Polychora again (2015). The move from the neologism "polychoron" to the much more widely used (in professional mathematics) "4-polytope" appears to have happened after the middle discussion. It's not so critical that we move the template in the same way (because its neologism isn't visible to readers) but we should do it anyway. We should certainly not push the neologisms back into view in our articles, for all the reasons discussed in the earlier discussions. (Also, anyone who has spent any effort on the polytope articles knows that they are a mass of original research, reduplicated off-topic material, and decorative but uninformative and off-topic image galleries that needs a power hose to clean out.) —David Eppstein (talk) 06:28, 2 March 2020 (UTC)

Ah, thanks! I'll go ahead and make these template/category moves then. It seems that Polychoron was moved in 2014 based on those discussions to 4-polytope but nobody noticed to do the same to the category. There seems to be strong consensus towards the "n-polytope" nomenclature, which also matches what I usually see in mathematical literature. — MarkH₂₁^talk 08:48, 2 March 2020 (UTC)

Embedded points

Hi all, are there any pages on Wikipedia for embedded points, in the sense of scheme theory: https://stacks.math.columbia.edu/tag/05AJ? Wundzer (talk) 05:08, 3 March 2020 (UTC)

Not that I’m aware of; its a reasonable article to create or perhaps a section of generic point (which somewhat covers specializations of points, but not really). Both Embedded point and Specialization of a point should probably be created at some point. — MarkH₂₁^talk 06:03, 3 March 2020 (UTC)

Embedded prime is is a redirect to Associated prime. "Embedded prime" is also defined in Primary decomposition. As primary decompositions behave well under localization, the generalization to schemes is straightforward. So, I suggest adding a section about this generalization in Primary decomposition (where this generalization is implicitely mentioned). By the way, as associated primes and embedded primes can hardly be defined independently of a primary decomposition, I would suggest to merge Associated prime into Primary decomposition. D.Lazard (talk) 10:23, 3 March 2020 (UTC)

I have changed the target of Embedded point to an anchor in Primary decomposition, where "embedded prime" is defined. D.Lazard (talk) 10:41, 3 March 2020 (UTC)

I don’t think merging associated prime to primary decomposition works, since the former article also covers the non-commutative case (for the Noetherian commutative case, as Lazard pointed out, the two topics are the same). One possibility is to split associated prime into two parts; one part is about a primary module or a prime module in the context of general module theory and then merge the other part (associated primes in the commutative ring theory) to primary decomposition. There is also a matter of decomposition of an injective module over a Noetherian ring, which is a sort of non-commutative primary decomposition, but that’s another matter. Taku (talk) 11:56, 3 March 2020 (UTC)

Draft:Convexity (algebraic geometry)

Hi, my submission for the article https://en.wikipedia.org/wiki/Draft:Convexity_(algebraic_geometry) was declined due to not having sufficient context. Unfortunately, I'm having trouble figuring out how to improve the article so there is enough context available. How can I improve it? I've looked at a couple articles, like Flat module and Algebraic stack for help, but these both have similar introductions. Wundzer (talk) 04:16, 28 February 2020 (UTC)

Did you read MOS:MATH#Article introduction and WP:TECHNICAL? As it is, your introduction is much too technical. I know that the subject is of a highly technical nature, and it seems impossible to explain the interest of the concept to a reader who knows nothing of modern algebraic geometry. But the lead must be roughly understandable to a reader who, for example, has had a graduate course of algebraic geometry. More specifically, it would be useful to explain the relationship between this meaning of "convex" and its meaning in other branches of mathematics (I don't believe that this term has been chosen at random). Also, for a non-specialist like me, it seems that the concept is related with the property of compact analytic manifolds to not have non-constant holomorphic functions that are defined everywhere. Clarifying this in the lead would help to explain the interest of the concept. I believe that it is the lack of informal explanations that has motivated the reject of the draft. D.Lazard (talk) 09:17, 28 February 2020 (UTC)

I don't think the draft is too bad -- indeed many other articles have a similarly technical introduction (and rightfully so, IMO). The overarching problem we have here is that new math articles get reviewed by (in many cases) non-math reviewers who have little to contribute other than formal nitpickings. At least that is my personal experience from the last few articles I have created.

@Wundzer: After incorporating some of D.Lazard's comments, I personally would largely ignore the "too technical" complaint. It would help, I think, if you were to add a few more references, ideally within the text (as is currently the case in two spots). Also, there is a bunch of spots where some punctuation etc. is suboptimal, this could be improved before putting it on main space. If you want, I could weigh in at the discussion whether it is too technical: I don't really think so. Jakob.scholbach (talk) 09:31, 28 February 2020 (UTC)

For being clear, I did not intended to say that the body of the article is too technical. Only that the lead is too technical, and lacks of information that is not purely technical. D.Lazard (talk) 10:13, 28 February 2020 (UTC)

I somewhat agree with D. Lazard here. Some additional context and wikilinks in the lead would help. — MarkH₂₁^talk 10:18, 28 February 2020 (UTC)

The problem here is likely just about the lead itself not giving a good informal explanation of what convexity is in this context and why it is important. I don't understand the material well, but some prose along the lines of

That the first cohomology class of the tangent bundle is zero implies that the variety has a globally generated section. For a variety to support such a globally connected section, the base variety needs to be a single connected region with no holes, i.e., it has properties analogous to the usual convex property in Euclidean geometry. Examples of convex varieties include X, Y and Z. Convex varieties are important in fields like quantum cohomology because they are particularly simple and allow for easier computation of their topological and geometric properties.

would help give context and indicated importance. --{{u|Mark viking}} {Talk} 18:51, 28 February 2020 (UTC)

I'm glad to see so many useful tips! I've updated the introduction and added many more references throughout the article. Hopefully this looks good enough. Wundzer (talk) 20:17, 28 February 2020 (UTC)

Your recent modifications are definitely improvements — thank you! I think "write one level down" is good advice for technical topics like these: the lead, at least, should say something that is helpful to readers who have less background knowledge than the primary audience. If the topic is normally taught in graduate school, then the lead should be comprehensible for advanced undergraduates. Another useful question might be, "How would I provide a preview of this material in a course that is the prerequisite for the one where it is actually taught?" I think Mark viking's suggestion for the kind of prose to include is on the right track. What property of convexity in Euclidean space is being abstracted or generalized here? In other words, why is "convexity" the term that the algebraic geometers chose, rather than anything else? That's the type of question that the lead should be helping to answer.

I'm a little leery of relying upon MathOverflow as a source. Sure, it's a good forum, and the answers that bubble to the top are usually OK, but when we point to a post there, it's not clear whether we're saying to read the answer with the green checkmark (supposing there is one), all of the answers with positive scores, or what, exactly. I think it's more useful to point directly to the papers and textbooks that get cited in the MathOverflow threads. XOR'easter (talk) 17:46, 29 February 2020 (UTC)

Hi XOR'easter, I added intuition for how convexity in the sense of algebraic geometry generalizes convexity in euclidean geometry. TBH I didn't even think of this point before, so this was a helpful question! Thanks! Also, I usually add links to mathoverflow so people can at least find a starting spot for figuring out why something is true. But, occasionally, including the posts of famous mathematicians is helpful. Should I just link directly to their response? Wundzer (talk) 19:21, 29 February 2020 (UTC)

Notice: since the discussion seems subsided and since I'm not seeing opinions that we need to keep this particular draft outside the mainspace (not in generic terms), I have moved the draft page to mainspace; further work on the lead, as needed, can continue in mainspace. -- Taku (talk) 13:27, 4 March 2020 (UTC)

Proposed merge from Ramification theory of valuations to Ramification group

I proposed a merge here from Ramification theory of valuations to Ramification group. I imagine they're fairly low-traffic pages, so any thoughts would be appreciated! — MarkH₂₁^talk 01:16, 6 March 2020 (UTC)

Proposed deletion of Structure (category theory)

I am proposing deletion of the article Structure (category theory), due to the fact that it seems unfocused/incoherent and has no essential content. Please chime in here. --Jordan Mitchell Barrett (talk) 21:21, 26 February 2020 (UTC)

This is an AfD, not a PROD, but thanks for flagging it here. Andy Dingley (talk) 21:40, 26 February 2020 (UTC)

Sounds like abstract nonsense. ;¬) JRSpriggs (talk) 02:12, 27 February 2020 (UTC)

Better abstract nonsense than Fashionable Nonsense. –Deacon Vorbis (carbon • videos) 02:22, 27 February 2020 (UTC)

Bump! The AfD was relisted and more discussion is needed, since we can’t decide on a merge/redirect target (or outright deletion)! — MarkH₂₁^talk 10:03, 6 March 2020 (UTC)

Script to detect unreliable sources

Main page: User:Headbomb/unreliable

I have (with the help of others) made a small user script to detect and highlight various links to unreliable sources and predatory journals. The idea is that it takes something like

• John Smith "Article of things" Deprecated.com. Accessed 2020-02-14. (John Smith "[https://www.deprecated.com/article Article of things]" ''Deprecated.com''. Accessed 2020-02-14.)

and turns it into something like

• John Smith "Article of things" Deprecated.com. Accessed 2020-02-14.

It will work on a variety of links, including those from {{cite web}}, {{cite journal}} and {{doi}}.

I'm still expanding coverage and tweaking logic, but what's there already works very well (e.g. picking up links to Stack Exchange in List of unsolved problems in fair division). Details and instructions are available at User:Headbomb/unreliable. Questions, comments and requests can be made at User talk:Headbomb/unreliable. Headbomb {t · c · p · b} 22:17, 9 March 2020 (UTC)

Brazilian number

I've just accepted Brazilian number at AfC. This is not a topic I grock at all, so could someone please have a look and see if the content is sensible? – Uanfala (talk) 14:46, 1 March 2020 (UTC)

Thanks for taking on this sort of technical article at AfC. The content looks sensible to me and it looks better documented than many articles of this type. As to whether the topic is notable--it is possible, but I have not checked. --{{u|Mark viking}} {Talk} 19:38, 1 March 2020 (UTC)

Isn't this exactly the same thing as described in the existing article repdigit? —David Eppstein (talk) 20:12, 1 March 2020 (UTC)

I don’t know this type of stuff, but as David Eppstein said, the two articles look about the (essentially) same topic. —- Taku (talk) 20:29, 1 March 2020 (UTC)

It does look like the same thing. I suggest merging them. Reyk _YO! 20:28, 1 March 2020 (UTC)

I'd support a merge. XOR'easter (talk) 22:05, 1 March 2020 (UTC)

Ditto. Afterwards I feel like this should be deleted (the name being something just made-up). --JBL (talk) 22:16, 1 March 2020 (UTC)

Good catch, David! They look the same to me and a merge is the way to go. A redirect is fine; it would need to be there for attribution after a merge and the name Brazilian number occurs in the wild.[1][2] --{{u|Mark viking}} {Talk} 00:26, 2 March 2020 (UTC)

Merged! It could maybe use some list-to-prose conversion, but I think it looks OK for a start. XOR'easter (talk) 02:03, 2 March 2020 (UTC)

I've received a talk page message objecting to the merge of Brazilian number to Repdigit. I'm copying over the relevant parts:

4) I really think that this article merits to have its own article. Why?

• 4.1) This article “Brazilian number” comes from the French Wikipédia article "Nombre brésilien": link below:

https://fr.wikipedia.org/wiki/Nombre_br%C3%A9silien

• 4.2) This submission "Brazilian number" is like other mathematical articles that concern number theory such as palindromic numbers, prime numbers, self numbers, Fermat numbers, Mersenne numbers, repunits, transcendental numbers, ... there is an introduction, followed by an history presentation, then different paragraphs that detailed the properties of these numbers. The structure of this article is perfect for beeing independent.
• 4.3) The Brazilian number section I have written is here 12 times greater than the original article about repdigits, this is not balanced; when there is a complement on an article, the complement is always smaller than the original text. Here, it is clearly the opposite and this cannot be good for understanding the whole article.
• 4.4) There are in the “Brazilian number” text 28 Wikipedia references (in blue) towards mathematical terms or famous mathematicians, and ten references or external links towards historical articles. I don't forget the 18 links to OEIS sequences related with Brazilian numbers. That proves that this article can (must) be autonomous.
• 4.5) About mathematical angle, all Brazilian numbers are repdigits but the converse is false. I remark also that you use my definition of Brazilian numbers to explain repdigits (thanks).
• 4.6) To finish, repdigits belong rather to recreative mathematics and Brazilian belong rather to number theory.

Hence, please, only one question, why don't you create a Brazilian number article independent as in French Wikipédia? There is no sens to put this structured article of 102 lines at the end of the repdigit article of only 7 lines...

Merci for your answer.

Best regards.

OSS117 (talk) 18:30, 2 March 2020 (UTC)

Inviting Mark viking, David Eppstein, Taku, Reyk, XOR'easter, and JBL to comment. – Uanfala (talk) 23:00, 2 March 2020 (UTC)

So it appears to me that OSS117 is incorrect on point 4.5; unless I'm missing something, Brazilian numbers are exactly the same as repdigits. (They're not the same as repunits, which might be the source of the confusion?)

If I'm right about that, then surely there should be only one article, and the question is which title should be used. I agree with point 4.6 that "repdigits" looks like an article about recreational math. If these numbers are thought to have a wider number-theoretic importance than that, then that would be an argument for putting the article at Brazilian number. --Trovatore (talk) 23:15, 2 March 2020 (UTC)

Point 4.1 is irrelevant; Wikipedias in different languages have different inclusion standards. Point 4.3 doesn't seem like a problem (the only difficulty in the reading is not a lack of balance, but the choppiness of using lists instead of prose). I don't understand point 4.4 at all. Point 4.5 is an argument that Brazilian numbers belong in an article on repdigits, being a special case of them. 7 lines on repdigits plus 102 lines on Brazilian numbers is 109 lines on repdigits. As for point 4.6, neither term seems more recreational than the other to me. XOR'easter (talk) 23:57, 2 March 2020 (UTC)

(edit conflict)On 4.5, I thought that their point is that one would implicitly fix a base a priori. But then the repdigits in a fixed base would be a proper subset of the Brazilian numbers, which is the opposite of the claim in 4.5. So I’m also unsure by what is meant by 4.5.

On 4.6, I don’t see evidence that Brazilian numbers are more researched in mainstream number theory.

Surely the existence of bluelinks in the article and a French Wikipedia article are irrelevant. — MarkH₂₁^talk 00:04, 3 March 2020 (UTC)

There is a tiny technical difference: the restriction $b<n-1$ in the quoted Olympiad problem means that the digit sequence 11 (and only that digit sequence) counts as a repdigit but not as Brazilian. (This is necessary to prevent all numbers from being Brazilian.) I don't think that difference is enough to spin out two separate articles, nor to argue that one variation is recreational and the other not (as if that is somehow a pejorative). But probably we should at least clarify that difference in the article. —David Eppstein (talk) 08:16, 3 March 2020 (UTC)

• I still think the merge was the correct outcome. Reyk _YO! 08:21, 3 March 2020 (UTC)

Hello, merci to everybody, I appreciate your answers and I'll answer to all your remarks with much details this evening (in France). OSS117 (talk) 08:58, 3 March 2020 (UTC)

Bonjour to everybody. I have read with much attention all you have written after that Uanfala put my remarks, and I try to explain with mathematical arguments why merge "repdigit" and "Brazilian number" does not look like mathematically correct.

I answer point after point to all your remarks.

* Point 4.1: "is irrelevant" (twice). Often in French Wikipédia, for mathematical articles, we write (in French) "this article comes partially or totally from the article XXX of English Wikipedia" and French Wikipédia never thinks that to propose an article coming from English Wikipedia is irrelevant; on the contrary, we are happy to use it and when possible to improve this article; hence, here, it was just an information to you.

* Point 4.2: No remark you have done.

* Point 4.3: Sorry, I have problem (English is not my native language, but I have less problem with mathematical English) to well understand this sentence "(the only difficulty in the reading is not a lack of balance, but the choppiness of using lists instead of prose) " even with help of a dictionary. What I remark is that initial repdigits article has only 7 lines and Brazilian number article has 102 lines, so it is mathematically odd to merge the second with the first. If you want, I can write later more lines about repdigits.

* Point 4.4: is very clear and details the number of distinct references; that proves that the structure of the Brazilian number article is enough correct to be autonomous, as other similar Wikipedia articles in Number Theory as palindromic numbers, prime numbers, self numbers, Fermat numbers, Mersenne numbers, repunits, transcendental numbers… and this article respects also the rules of Wikipedia.

* Point 4.5: "Brazilian numbers are exactly the same as repdigits." Non, Brazilian Numbers are repdigits in some base, yes, but not all repdigits are Brazilian; the counterexamples are 1, 2, 3, 4, 5, 6, 9 and 11. Again, I read " 7 lines on repdigits plus 102 lines on Brazilian numbers is 109 lines on repdigits", these are two distinct sets with not the same position; in addition: 7 (little) + 102 (large) = 109 (little).

* Point 4.6: In Brazilian numbers theory, there exist theorems about Fermat numbers, Mersenne numbers, Sophie Germain primes, twin primes... there are connections with Goormaghtigh conjecture or equation of Nagell-Ljunggren or other Diophantine equations studied by Kustaa Inkeri,... In repdigits, there are references with numerology 666 or 777, never in Brazilian numbers. These are two distinct mathematical words.

Please, I propose other new last comments.

* I know it is "irrelevant" but in French Wikipédia there are two distinct articles for "nombres uniformes" and "nombres brésiliens".

* In French Wikipédia, I have realized a lot of work to put blue links towards the article "Nombre brésilien" for around 200 numbers, and also I have created some paragraphs about Brazilian numbers in existing articles, for example for primes, Sophie Germain primes… With the merge of Repdigits + Brazilian numbers in English Wikipedia, it will be no interesting to improve here some articles.

* Also, in Mathematics, we say 20 is Brazilian (that means that = 22 in base 9), but we never say 20 is repdigit; also, we say 43 is a Brazilian prime (because = 111 in base 6) but we don't say 43 is a prime repdigit. There exists a constant of Brazilian primes, there is not a constant of repdigit primes. These are two distinct concepts.

So, for all these miscellaneous reasons, I sincerely think that the merge is not a correct outcome, and must create confusion between these two mathematical concepts; I read what you wrote before Umfala posts my remarks; of course to create blue links between the two articles Repdigit and Brazilian Numbers would be necessary.

Thanks for reading, not forget that English is not my native language.

OSS117 (talk) 18:57, 3 March 2020 (UTC)

Good evening,

Please, nobody?

Some new comments about your merge of the proposed draft "Brazilian number" of 102 lines with the existing "Repdigit" article of 7 lines.

When a internet user looks for "repdigit" and finds English wiki article, he reads the content:

1. History (yes, but it is the history of Brazilian numbers)

2. Some first properties (of course, but these are first properties of Brazilian numbers)

3. Primes and repunits (linked to Brazilian numbers not to repdigits)

4. Non-Brazilian composite numbers (sequence = 4, 6, 9, 25, 49, 169, 289, 361, 529,... )

5. Numbers several times Brazilian (it is not "numbers several times repunits").

6. See also (towards repunits, yes it is right here)

7. References: the 1st reference is for repdigit (it is right), but the references 2, 3, 4, 5, 6, 7, 8 and 9 relate Brazilian numbers.

Thanks for your comments.

OSS117 (talk) 21:50, 4 March 2020 (UTC)

• I still think the merge was the correct outcome. —David Eppstein (talk) 21:55, 4 March 2020 (UTC)

I agree with everyone else that there should be only one article here. (Of course that does not forbid editing the merged article!) --JBL (talk) 10:32, 5 March 2020 (UTC)

Also it might be useful to see more evidence regarding which title it should appear under ("repdigit" vs "Brazilian number"). --Trovatore (talk) 18:41, 5 March 2020 (UTC)

"Brazilian number" is such an obviously terrible name .... Yes, I know, that's not relevant to how article name decisions get made here. --JBL (talk) 18:57, 5 March 2020 (UTC)

Hello,

First, the draft “Brazilian number” was not accepted by English Wikipedia because “This submission provides insufficient context for those unfamiliar with the subject matter”. !!!!!!!!

Second, I learn later that this draft “has been created”...but I understand this draft has been merged with repunit because "Isn't this exactly the same thing as described in the existing article repunit?"

I put another last explanation that shows that merge was not the correct outcome.

• The first twenty repdigits in the encyclopedia of sequences OEIS are:

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 22, 33, 44, 55, 66, 77, 88, 99, 111 … (sequence A010785 in the OEIS),

and, in the same encyclopedia,

• The first twenty Brazilian numbers in OEIS are:

7, 8, 10, 12, 13, 14, 15, 16, 18, 20, 21, 22, 24, 26, 27, 28, 30, 31, 32, 33, … (sequence A125134 in the OEIS).

So, there are only four identic terms {7, 8, 22, 33} among the first 20 terms of each sequence. In OEIS, there are more than 100 sequences relative to Brazilian Numbers.

Also, my friends and I don't understand the meaning of "(the only difficulty in the reading is not a lack of balance, but the choppiness of using lists instead of prose)." Please, thanks to explain with other words what this sentence means.

To finish, I read also that "Brazilian number" is " an obviously terrible name".

In these conditions, the best decision is to follow your suggestion "Of course that does not forbid editing the merged article!"

Thanks very much for your help.

OSS117 (talk) 10:19, 7 March 2020 (UTC)

I don't understand the issue here at all. There does seem a distinction between "repdigit" and "Brazilian number"; so the question is whether the distinction warrants a separate article. In Wikipedia, there does not need to exist a one-to-one correspondence between articles and concepts; *essentially* the same but distinct concepts can be treated in the same article; the merger does not mean there is no distinction. Whether ""Brazilian number" is a terrible name" is completely irrelevant. There are way too many terrible names ("integral domain"!) in mathematics I love to correct. -- Taku (talk) 18:58, 7 March 2020 (UTC)

Bonjour Taku, Thanks for your message. Yes, you ask the right "question" but the answer looks like rather subjective here. Some participants have decided 1st March to merge "repdigit" and "Brazilian number". Since, although I wrote a lot of mathematical reasons to explain this merge is a nonsense, the participants think the merge was the correct outcome. Merge a well documented mathematical article of 102 lines at the end of a "repdigit" article of only 7 lines (whose 2 lines for numerology) is also difficult to understand. So, the best issue for this structured mathematical article about "Brazilian number" was to delete this article from the "repunit" article. Very sorry for the time you have lost with this true mathematical article "Brazilian number". OSS117 (talk) 22:28, 9 March 2020 (UTC)

@OSS117: I'm thoroughly confused as to why you deleted the content on Brazilian numbers at Repdigit. As Taku and others point out, the naming is a separate issue from whether they should be merged. I.e. they should be one article, but it could certainly be at the article named Brazilian number rather than Repdigit, with the mention of repdigits coming secondary to that of Brazilian numbers. There's no need to remove all of the content.

Also sorry for not explaining what XOR'easter probably meant earlier by the only difficulty in the reading is not a lack of balance, but the choppiness of using lists instead of prose. Here's my interpretation. C'était essentiellement que: le fait que la majorité de l'article concernait les nombres brésiliens n'était pas une cause de difficulté de lecture, mais le fait que la majorité de l'article a été écrit sous forme de liste était une cause (en fait, la seule cause) de difficulté de lecture. Ici, choppiness signifie qu'une liste présente le matériel dans un rythme très staccato et les faits dans une liste ne coulent pas bien. Les connecteurs logiques en écriture de prose collent ensemble le choppiness (les «saccades» de mots)... — MarkH₂₁^talk 22:35, 9 March 2020 (UTC)

I have restored the content that OSS117 removed. I have also started to try a bit to make it look more like an encyclopedia article. Further help in that regard would be welcome. I continue to feel that the name Brazilian number is incredibly terrible, but it is possible that it would be a better title for the article, given that there are at least two sources that seem to use it. --JBL (talk) 23:08, 9 March 2020 (UTC)

I tried searching Google scholar, but just searching for "Brazilian number" alone found a huge number of false positives (9 out of the first 10 results appeared to be for unrelated topics). Filtering out the results that also included the phrase "base b" may be a little unfair, because work on repdigits might be more likely to not specify a base, but it's more likely to only produce relevant hits. "repdigit" "base b" had 35 hits, and "repdigits" "base b" had 40. "Brazilian number" "base b" had 2 hits, and "Brazilian numbers" "base b" had one. Similarly, MathSciNet has 49 papers that include "repdigit" anywhere, 42 with "repdigits", and none with "Brazilian number" or its plural. I think that makes it clear enough which name is the WP:COMMONNAME. —David Eppstein (talk) 23:44, 9 March 2020 (UTC)

Bonjour, I see you have improved the article repdigit and the merged part Brazilian number. It is a real good job, congratulations. I retain some of your ideas to improve the French Wiki Nombres brésiliens. Thanks to JBL for I am "very welcome to continue contributing to the article". First, I want to improve the French Wiki, and I go back here. What do you prefer? I propose here in this talk page some improvements or precisions that I think it could be interesting for the article and you say yes or no, or I put directly in repdigit article what I think improvements or precisions and then you fix or delete, in the two cases, I shall be ok with all you choose or prefer. Have a nice day. OSS117 (talk) 06:52, 12 March 2020 (UTC)

MathGenealogy deprecated ?

The following edit suggests that the template:MathGenealogy is unnecessary:

template removed from Joachin Lambek

Searching the archives no such suggestion was found. If WikiData includes the link, is it not for articles ? — Rgdboer (talk) 02:13, 9 March 2020 (UTC)

It's already included in the Authority control line (under "MGP") so it's a bit redundant as a separate external link. I would still use it as a reference for information about dissertation and students, though, for instance in this case on the sentence "Lambek supervised 17 doctoral students, and has 73 doctoral descendants as of 2019", which is currently unsourced. One other note: when the MGP id is present on Wikidata, you can use the {{mathgenealogy}} template without any parameters (it will find the id from Wikidata). —David Eppstein (talk) 06:52, 9 March 2020 (UTC)

Ok, so MGP is duplicated by Authority control. Has now been cited inline to support the quoted statement. Thank you for your in-depth response. — Rgdboer (talk) 00:43, 14 March 2020 (UTC)

I, for one, have no idea how to use the Authority control line. I suspect there may be others in this situation. So removing something because it is redundant with the Authority control line seems to me to be inappropriate. JRSpriggs (talk) 07:12, 15 March 2020 (UTC)

As a reader? It's a collection of links to certain other sites on the same person, mostly library catalogs, in a more abbreviated format than the external links section. You can click on them like you would any other link. As an editor? Add {{Authority control}} to the bottom of a biographical article (and if you like add parameters like MGP=id and wait for some gnome to move them to Wikidata where they belong). —David Eppstein (talk) 07:33, 15 March 2020 (UTC)

Converse (logic) and Converse implication

Is there a reason to have these separate articles? They have both been around for a long time. --JBL (talk) 16:40, 10 March 2020 (UTC)

My two cents: Converse implication is more symbolic and visual, such as an engineer might like. Converse (logic) is more verbose and formal in tone, such as a philosopher might like. I think both kinds of description are useful and these two articles could be usefully merged. --{{u|Mark viking}} {Talk} 17:48, 10 March 2020 (UTC)

Same topic, so they should definitely be merged. Converse implication should probably be merged into Converse (logic) since the latter is the more general title (and includes the material on the categorical converse). — MarkH₂₁^talk 01:05, 12 March 2020 (UTC)

I don't think there's much at converse implication worth merging. It could just be done as a redirect. —David Eppstein (talk) 07:35, 15 March 2020 (UTC)

I suppose so, although we could move the half sentence about notation from the lead and use the (very) colorful pictures! — MarkH₂₁^talk 08:32, 15 March 2020 (UTC)

Thanks Marks and David -- I have attempted a comprehensive merge. --JBL (talk) 13:24, 17 March 2020 (UTC)

Proposed inclusion of code snippets

The idea is to include simple code snippets, at the end of each math article, to connect concepts and algorithms. An important aspect of this type of approach is to bind concepts to something practical, encouraging through that, the experimentation of mathematical concepts.

As examples of that suggestion, check Outer product and Dot Product in Linear Algebra.— Preceding unsigned comment added by Alexzumalde (talk • contribs) 11:06, 17 March 2020 (UTC)

Please, add new threads at the bottom of talk pages, and sign your posts there with four tildes (~~~~).

This idea has been widely discussed in Wikipedia. The resulting consensus is that explicit source code is useful only if it adds something to the description of the algorithm in pseudo-code (see MOS:MATH#Algorithms, MOS:CODE, MOS:ALGO). In the article that you have edited, the algorithms are so simple that pseudo-code is not even useful, and anybody who knows any programming language should easily produce himself an implementation similar to yours. Also, your implementation of the dot product is not a good one, as explained in the preceding subsections. So, your addition is not only not useful, but also misleading, as suggesting that it could be used without care. For these reasons, I'll delete your edits. D.Lazard (talk) 12:26, 17 March 2020 (UTC)

"at the end of each math article"...? That would be funny if it weren't so ...irrational. What code snippet would you like to put at the end of article about Euclidean plane? about a homology? about convex function?
Most mathematical concepts and problems are not algorithms, so there is no place and no reason to put any code snippets in most math articles. --CiaPan (talk) 18:20, 18 March 2020 (UTC)

To add to the pile-on, I think it is highly inappropriate to add code snippets for implementations of simple mathematical formulas. And in cases where an article discusses a non-trivial algorithm, pseudocode is a better choice than code. —David Eppstein (talk) 18:47, 18 March 2020 (UTC)

Recent mathematical deletion sorting

In case anyone here isn't already aware of Wikipedia:WikiProject Deletion sorting/Mathematics, we currently have seven ongoing deletion discussions (including new ones on multiplicative calculus and of four Pakistani mathematicians) and one prodded article listed there. Please participate with your opinions. —David Eppstein (talk) 17:46, 18 March 2020 (UTC)

Really, Wikipedia:WikiProject Mathematics/Article alerts is the page people should watch. It covers Delsort and a lot more than Delsort. Updates every day too. Headbomb {t · c · p · b} 19:17, 18 March 2020 (UTC)

Also why tagging pages with {{WP Mathematics}} is important, (or rather whichever of {{maths rating}} or {{maths banner}} applies, because I'm not spending time on remembering which applies, because there is no reason to have two distinct banners and these should be merged). Headbomb {t · c · p · b} 19:23, 18 March 2020 (UTC)

Fundamental theorem of linear algebra

I have open there a discussion for deciding whether Fundamental theorem of linear algebra should be moved, merged or deleted. Suggestions are welcome. D.Lazard (talk) 15:18, 22 March 2020 (UTC)

This seems tricky. I agree that the name is not standard; probably we have it because MathWorld does. Apparently in some texts the trivial result that a linear transformation is determined by its values on a basis is honored with the name FTLA. If something is going to exist at this title, it's not really clear what mathematics it should contain, or what other articles it should point to. Maybe deletion is the best option. --JBL (talk) 20:34, 23 March 2020 (UTC)

Draft:Hyperbolastic Functions

A review of this draft is requested. Should it be accepted?

I don't really understand, but I have forgotten all of the higher math that I learned fifty years ago. Robert McClenon (talk) 03:26, 24 March 2020 (UTC)

If you don't mind Robert McClenon I'm going to add Draft:Modular_Forms_Modulo_2 as well to this request for review. Sulfurboy (talk) 21:42, 24 March 2020 (UTC)

User:Sulfurboy - Why would I object to adding to a request about something that I no longer understand? Robert McClenon (talk) 22:14, 24 March 2020 (UTC)

@Sulfurboy: Without going into the details on the page, the Draft:Modular_Forms_Modulo_2 is a reasonable and notable topic, and the draft seems correct and well-referenced at first glance. However, it should really be part of a Modular forms modulo p article, since a lot of the details mod 2 are the same in the more general mod p theory. — MarkH₂₁^talk 22:31, 24 March 2020 (UTC)

MarkH21, So to clarify, you think it should be named Modular forms modulo? Or was that a typo that created a redlink when you meant another page. Sulfurboy (talk) 23:01, 24 March 2020 (UTC)

@Sulfurboy: there should be a p, so the redlink that I wrote is the article title that I had in mind. The article should then be slightly rewritten to separate the general prime p case from the case of p = 2.

If I have time, I may get around to doing some of that writing. — MarkH₂₁^talk 23:34, 24 March 2020 (UTC)

See also Wikipedia talk:WikiProject Medicine#Draft:Hyperbolastic Functions. WhatamIdoing (talk) 15:31, 25 March 2020 (UTC)

There's yet another draft that requires review from someone with mathematical expertise, Draft:Hb-graphs. --Cerebellum (talk) 01:31, 27 March 2020 (UTC)

I'm not sure why we're putting all of these in one section, but in any case, Cerebellum, I poked around a little, and this doesn't appear sufficiently notable for an article. Just about every reference to it seems to be by the same 3 or so people, which is a good case for WP:TOOSOON. The sources that are already there echo this I think. But if anyone else can find more that I didn't, please chime in. –Deacon Vorbis (carbon • videos) 02:07, 27 March 2020 (UTC)

Normalization

platinum ratio ? 2601:281:CC80:2F50:95AC:31F3:E071:B6A3 (talk) 19:25, 26 March 2020 (UTC)

Please be more specific. To which article are you referring (please provide a link) and what is the problem? JRSpriggs (talk) 05:38, 27 March 2020 (UTC)

It smells like a joke based on the name of Golden ratio to me... --CiaPan (talk) 21:34, 27 March 2020 (UTC)

Symmetric successive over-relaxation

We need to improve formulation of Symmetric successive over-relaxation. --Kulgai (talk) 06:36, 31 March 2020 (UTC)

• That's just one of squillions of mathematics articles with no context and difficult details that are impenetrable to a non-specialist. Reyk _YO! 14:25, 31 March 2020 (UTC)
• Also the two references are not wp:Reliable sources, and I have tagged the article accordingly. D.Lazard (talk) 14:41, 31 March 2020 (UTC)
• Until it's better sourced and demonstrates a need for a separate article, it seems like a merge to Successive over-relaxation (along with {{R with possibilities}}) might be reasonable. As a side note, look at all the code there; should that simply be scrubbed? –Deacon Vorbis (carbon • videos) 14:55, 31 March 2020 (UTC)
  • On the last point, we don't need both common lisp and python examples. The python example is probably more accessible to the average reader and should be the one kept. I'd be in favor of keeping one code example, as pseudocode can be esoteric for those not used to reading it. --{{u|Mark viking}} {Talk} 18:20, 31 March 2020 (UTC)