User talk:David Eppstein

Hi, and welcome to my User Talk page! For new discussions, I prefer you add your comments at the very bottom and use a section heading (e.g., by using the "New section" tab at the top of this page). I will respond on this page unless specifically requested otherwise. For discussions concerning specific Wikipedia articles, please include a link to the article, and also a link to any specific edits you wish to discuss. (You can find links for edits by using the "compare selected revisions" button on the history tab for any article.)

Tips for DYK

DYK is supposed to make readers interested in an article. Saying that "... the cube can pass through a hole of itself?" is a doppleganger for the Prince Rupert's cube, or "... the cube can be used for building houses in the Netherlands" which is suitable for Cube houses instead.

Do you have any tips for proposing DYK after GA, even though there are nothing such interesting topics? Unless I could think of targeting the audience like young generations who are into games and toys: "... the cube has many roles in games and toys such as Minecraft and Rubik's cube, respectively?" Dedhert.Jr (talk) 02:14, 7 July 2025 (UTC)

Nevermind. I have nominated it anyway. Dedhert.Jr (talk) 02:26, 7 July 2025 (UTC)

... that there are 11 ways to unfold a cube?

... that cubes have a hexagonal cross-section, used as the floor in Dutch cube houses?

... that cubes appear in the shapes of both crystals and microorganisms? —David Eppstein (talk) 02:38, 7 July 2025 (UTC)

Okay, thanks. I'll add these alternatives under your name. Dedhert.Jr (talk) 02:42, 7 July 2025 (UTC)

Renominated Marmalade

Marmalade was renominated for good article. Floating Orb (talk) 02:24, 7 July 2025 (UTC)

Ok, thanks for letting me know. My preference would be to let someone else take the next review so you get a broader sample of opinions than just mine, but I'll keep an eye on it. —David Eppstein (talk) 02:32, 7 July 2025 (UTC)

Okay thank you. @Chiswick Chap took it already. Floating Orb (talk) 02:33, 7 July 2025 (UTC)

You're in good hands then. He's a very experienced reviewer and has nominated many food articles for GA. —David Eppstein (talk) 02:38, 7 July 2025 (UTC)

Yeah. I actually am reviewing his article Bean. Floating Orb (talk) 02:40, 7 July 2025 (UTC)

Help please? Draft:Otis Chodosh

Title. MathKeduor7 (talk) 07:22, 7 July 2025 (UTC)

Well, I see one well-cited Annals paper and a local teaching award. Which criterion of WP:PROF do you think these or other accomplishments pass, and why? —David Eppstein (talk) 16:45, 7 July 2025 (UTC)

I thought the Annals paper alone was enough for notability per WP:GNG, not WP:PROF. Among the many citations it should have in-depth coverage of his work. And that's why I asked for the help of Gumshoe2 at the Wikipedia talk:WikiProject Mathematics. P.S. Also, he has a recent paper with a lot of citations for his field (I think ~80). Best wishes, MathKeduor7 (talk) 16:58, 7 July 2025 (UTC)

One Annals paper is enough to win the respect of a lot of other mathematicians, but not really enough to convince non-mathematicians here of academic notability. It takes a sustained record of multiple high-citation papers (not really a good match to the citation patterns of pure mathematics), a major national or international award, a named or distinguished professor title, or a society fellowship (like Fellow of the AMS). —David Eppstein (talk) 17:16, 7 July 2025 (UTC)

Okay. It may be WP:TOOSOON. MathKeduor7 (talk) 17:25, 7 July 2025 (UTC)

Nomination of Codenominator function for deletion

A discussion is taking place as to whether the article Codenominator function is suitable for inclusion in Wikipedia according to Wikipedia's policies and guidelines or whether it should be deleted.

The article will be discussed at Wikipedia:Articles for deletion/Codenominator function until a consensus is reached, and anyone, including you, is welcome to contribute to the discussion. The nomination will explain the policies and guidelines which are of concern. The discussion focuses on high-quality evidence and our policies and guidelines.

Users may edit the article during the discussion, including to improve the article to address concerns raised in the discussion. However, do not remove the article-for-deletion notice from the top of the article until the discussion has finished.

—Quantling (talk | contribs) 13:11, 7 July 2025 (UTC)

Paul Zeitz

Notable or not? Bearian (talk) 18:46, 7 July 2025 (UTC)

Talk page stalker comment. The book "The Art and Craft of Problem Solving" shows signs of notability: it looks like it has been assigned reading in some university classes etc; the MAA reviewed it [1]; it is in its third edition from a major publisher [2]. Another review would make the case for book notability more solid. Anyway, a redirect to a stub on the book might be an alternative to deletion, if Zeitz is not notable. Russ Woodroofe (talk) 20:28, 7 July 2025 (UTC)

My opinion is that being a recipient of the Deborah and Franklin Haimo Awards for Distinguished College or University Teaching of Mathematics, as a major national-level academic award, passes WP:PROF#C2, but other editors might disagree. —David Eppstein (talk) 20:32, 7 July 2025 (UTC)

Thank you. Bearian (talk) 09:27, 14 July 2025 (UTC)

Admin and native speaker help, Robert Osserman

"There are a number of mathematical concepts named after him." (zero is a number)

Also, history merge to give credit to Gumshoe2. how? MathKeduor7 (talk) 07:25, 10 July 2025 (UTC)

A history merge (or I think you mean split and then re-merge) would move old versions of entire copies of the Osserman biography into the Keller–Osserman conditions article, not merely the parts of the biography relevant to the new article. I don't think that's what you want. The initial edit summary giving credit should be sufficient. —David Eppstein (talk) 07:31, 10 July 2025 (UTC)

Okay! Thank you! MathKeduor7 (talk) 07:42, 10 July 2025 (UTC)

Wikipedia:Articles for deletion/Make New Friends but Keep Discord

Do my arguments make sense? MathKeduor7 (talk) 03:18, 11 July 2025 (UTC)

The notability of individual My Little Pony episodes is a swamp I don't care to wade into. —David Eppstein (talk) 04:54, 11 July 2025 (UTC)

Hahahahahaha, okay. MathKeduor7 (talk) 07:26, 11 July 2025 (UTC)

• What happens to Wikipedia editors who wade into the My Little Pony swamp: [3]. EEng 17:42, 11 July 2025 (UTC)

Pythagorean theorem in China

I don't have a source for this, but it seems the Chinese discovered the Pythagorean theorem first by calculating the diagonal of a square, a specific case... The square was culturally important for them. MathKeduor7 (talk) 05:20, 13 July 2025 (UTC)

Your GA nomination of Square

Hi there, I'm pleased to inform you that I've begun reviewing the article Square you nominated for GA-status according to the criteria. This process may take up to 30 days. Feel free to contact me with any questions or comments you might have during this period. Message delivered by ChristieBot, on behalf of MathKeduor7 -- MathKeduor7 (talk) 08:05, 13 July 2025 (UTC)

I'll read all the sources I can get my hands into. MathKeduor7 (talk) 08:12, 13 July 2025 (UTC)

Aron Katsenelinboigen

I found this unsourced biography that appears to be part of a "walled garden". What do you think? Bearian (talk) 09:28, 14 July 2025 (UTC)

He easily passes WP:AUTHOR. Reviews of his books on JSTOR: [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] —David Eppstein (talk) 16:16, 14 July 2025 (UTC)

Square

Why GA, not FA? MathKeduor7 (talk) 05:57, 15 July 2025 (UTC)

First because even if one wanted FA then GA is a step towards that. But second, because (maybe from an uninformed outside view because I haven't participated much) FA as a process seems much more focused on form over content and it is really the content that I care about. —David Eppstein (talk) 06:19, 15 July 2025 (UTC)

Frankly, Prime number is a good start, or Reversible cellular automaton or Prince Rupert's cube. But I think I let my Cube take the badge. Currently, it's on peer review. Dedhert.Jr (talk) 00:52, 16 July 2025 (UTC)

Everything I looked at is correct and well-sourced, etc. It's an amazing article. I think I'll give speedy GA status to it. MathKeduor7 (talk) 06:00, 15 July 2025 (UTC)

Have a few minutes to look at recent speedy delete nominations?

@David Eppstein: I came across three very recent speedy delete nominations for blatant copyright violations tagged by User:Chippla360. These three nominations were not copyvios. One in fact was an article on a different person. I posted comments on User talk:Chippla360 about these three.

I find that working speedy deletes is something that the user is logging.

What are the proper next steps with respect to the nominator? — ERcheck (talk) 01:09, 16 July 2025 (UTC)

I'm pinging you as I see from the deletion logs that you are actively working the speedy deletes at this time. — ERcheck (talk) 01:10, 16 July 2025 (UTC)

Only the F8s in any consistent way, though if I did run across a copyvio speedy tag for other reasons I would likely check it out (and decline if invalid). Anyway, if they continue to make such mistakes on a longer-term basis or after being warned, the obvious next step would be to take away their NPP privileges per WP:NPRREVOKE. —David Eppstein (talk) 01:11, 16 July 2025 (UTC)

K-set halving line gallery

I'm not sure I understand the 2 point situation; it cites the OEIS page for the sequence, which defines the problem as:

"Let S be a set of n points in the plane. A halving line is a line through two points in S that splits the remaining points into two equal-sized subsets. How many halving lines can S have?"

I don't see anything about general position in the definition on the wiki page or OEIS page... do these need to be updated? BagLuke (talk) 00:33, 17 July 2025 (UTC)

Why are you following the definition in OEIS rather than the sourced definition here? Here, a k-set is defined to be a subset strictly separated from the rest by a line, and a halving line is a line separating a k/2-set.

Maybe the picture is clearer if you look at it in the dual line arrangement, where halving lines become dual to points. The halving lines this article is talking about are points in two-dimensional cells of the arrangement that have exactly n/2 lines above them and n/2 lines below them. The halving lines you are talking about are points at the crossings of two lines where there are (n-2)/2 lines above the crossing and (n-2)/2 lines below the crossing. From left to right across the arrangement, cells of the first kind of halving line alternate with crossings of the second kind of halving line, so the counting is essentially the same (in general position so that you don't have to worry about what happens when a cell is bounded by a vertical line) but the things being counted are not. —David Eppstein (talk) 00:38, 17 July 2025 (UTC)

Ahh, I see. I was going off the definition preceding the sequence as well:

"For the case when k=n/2 (halving lines), the maximum number of combinatorially distinct lines through two points of S that bisect the remaining points when k = 1, 2... is:"

But it looks like it's a relevant sequence, defined in a different context. Thanks! - BagLuke (talk) 00:50, 17 July 2025 (UTC)

I'm looking through papers on halving lines, and even ones which are written in the context of k-sets are defining halving lines exclusively as passing through 2 points of a set of points P (generally, d points, in d = 2) and equally dividing the rest, including the material cited for the k-set page.

The paper "Point Sets with Many k-Sets" says:

"Let n > d ≥ 2, n − d even, and let P be a set of n points in R d in general position (no d + 1 of them lie in the same hyperplane). A hyperplane determined by d points of P is called a halving hyperplane (resp. halving line for d = 2 and halving plane for d = 3) if it has exactly (n − d)/2 points of P on both sides."

And also the pseudoline source, "New algorithms and bounds for halving pseudolines":

"Let P be a set of points in general position in the plane. A halving line of P is a line passing through two points of P and cutting the remaining n − 2 points in a half (almost half if n is odd)."

I'm having trouble finding any sources defining it any other way, but I am probably missing it. Whatever the case, I feel as if the Wiki page is a bit unclear, and I don't want to step on toes trying to differentiate the two without a source for the definition of the version which doesn't cross points of P. Thanks, - BagLuke (talk) 03:22, 17 July 2025 (UTC)

For the purposes of counting, which is what all those papers are about, they are exactly the same. If you have an alternating sequence of cells and crossings in the dual arrangement, you will always have exactly one more cell than crossing. It doesn't matter whether you count one or whether you count the other.

For the purposes of an article about k-sets, we should stick with a definition that matches the definition of the subject of the article. —David Eppstein (talk) 05:04, 17 July 2025 (UTC)

Since the bounds of the more general k-set problem are the point of interest for the k-set page, would it be better to split it into 2 articles, the other specifically on halving lines and its different representations, along with the halving line problem in the form it most commonly takes which involves 2 point intersections?

I do agree though, the line separating the points into the k-set clearly can't have a point on it. If not it's own page, separating it from the more general "combinatorial bounds" section into its own "halving lines" section and ironing it out there should be sufficient. But I wonder since the bounds of all k-sets are focused on so heavily if the page should have its "Unsolved math" card used for that, and the halving line problem on its own page's card. Thanks, - BagLuke (talk) 05:18, 17 July 2025 (UTC)

I don't think there is a lot of literature that treats the two problems as separate and distinct from each other. —David Eppstein (talk) 05:37, 17 July 2025 (UTC)

Your nomination of Square has passed

Your good article nomination of the article Square has passed; congratulations! See the review page for more information. If the article is eligible to appear in the "Did you know" section of the Main Page, you can nominate it within the next seven days. Message delivered by ChristieBot, on behalf of MathKeduor7 -- MathKeduor7 (talk) 09:06, 17 July 2025 (UTC)

on Coupon collector's problem

the page largely covers the statistical distribution where X is the number of rolls of an n-sided fair die before all faces have occurred at least once.

in this revision, Cosmia Nebula finalised her addition (across several edits throughout January 29) of a section about generating functions, which shows one can compute the kth moment of the distribution by applying the Cauchy-Euler-like operator ${\frac {d}{dx}}x$ k times on the o.g.f. of the kth column of the Stirling subset triangle, then evaluating at $x={\frac {1}{n}}$ and multiplying by $(n-1)!$.

I have been writing a page an introduction to Stirling numbers on the OEISwiki, which has a section on some combinatorial manipulation of statistical distributions; specifically I'm interested in getting (preferably non-alternating) summation forms or asymptotic expansions for their kth-order moments.

I learned about the CCP distribution and decided to add it to (an upcoming revision of) the table, then realised that some other tools I know allow the case for each k to be written as a finite sum, of powers of n times products of gen. harmonic numbers in n

so I would like to check a few things about my edit (which replaces Cosmia's section with my derivation) with you (a better expository writer than me)

• I used the notation from Mircea Dan Rus's paper because it allows it to be written without so many factorial coefficients; is this generally allowed for a Wikipedia page?
• what balance should be struck between the current

'Rewriting the binomial coefficient via the gamma function and expanding as the $\exp$ of the polygamma series (in terms of generalised harmonic numbers)'

and a more complete explanation to one without the requisite background knowledge? or is the destination more important than the journey for Wikipedia purposes?

• in a similar vein, is the identity $\left\{{K \atop i}\right\}(-1)^{K}=\sum _{k=0}^{K}\left\{{K \atop k}\right\}L(k,i)(-1)^{k}$ that's shown, ie.

'matrix-multiplying the subset triangle (with alternating column signs) with the Lah triangle produces itself (with alternating row signs)'

sufficiently rote to just include (see this section of my aforementioned page for the g.f. interpretation of matmul of Stirling-type triangles), or ought that to be explained/linked to an explanation?

• should Cosmia's original formulation be kept? I wouldn't have thought of it and think it's neat, even though I have no idea how one would go on a similar path of deductions from it to my result; I suspect her intention was that it could be entered into Mathematica (et al.) to get the closed forms out.

thank you for your time $.\ . \atop \smile$ Drone Better (talk) 14:44, 17 July 2025 (UTC)

I don't think there is any problem with using notation for a source. But regarding coupon collectors: my main opinion is that the article should emphasize the end result, that you need roughly n ln n draws, over its derivation. That's the part that's important, at least in the applications I've seen. —David Eppstein (talk) 17:02, 17 July 2025 (UTC)

Thank you for your improvements. The current page is a bit derivation-heavy. I would suggest putting the derivations into collapsable boxes so that only interested readers would need to see them. It would look like: {{collapse top|title=Proof|left=true}}...{{collapse bottom}}

It has been used to good effect on many pages, such as the Hahn-Banach. pony in a strange land (talk) 17:46, 17 July 2025 (UTC)

Wrapping multiple images

Is there a policy to restrict user merging available images, wrapping them up into one single image? I am thinking of a new image for Kepler–Poinsot polyhedron by collectively merging four polyhedra

• File:Small stellated dodecahedron constructed by dodecahedron.svg
• File:Great icosahedron constructed by dodecahedron.png
• File:Triakis icosahedron kleetope of the icosahedron in 1.svg
• File:Great stellated dodecahedron with yellow pentagram.svg

for the lead, and the pop-up as well (showing only one in four images instead), as long as I can attribute the authors. Dedhert.Jr (talk) 02:47, 18 July 2025 (UTC)

I think that's within rules, as long as it's properly credited. —David Eppstein (talk) 21:51, 21 July 2025 (UTC)

Okay thanks. I'll download them for now. Dedhert.Jr (talk) 08:31, 22 July 2025 (UTC)

Did I do correctly? [23] I'm struggle by the way, so I probably need a hand. Do you mind? Dedhert.Jr (talk) 09:03, 22 July 2025 (UTC)

Looks ok to me. —David Eppstein (talk) 16:41, 22 July 2025 (UTC)

Oh, and one more. Shall I use CC 4.0 License if the images are 3.0, like this one? I mean, if it is controversial, Commons Wikimedia might delete this immediately, and I won't mind if somebody deletes the image I have wrapped up. Dedhert.Jr (talk) 03:58, 9 August 2025 (UTC)

I think you have to keep the same license and credits as the original, because wrapping the images isn't itself a copyright-worthy contribution. But I am not an expert on the subtleties of image licensing so that is more a guess than a certainty. —David Eppstein (talk) 06:00, 9 August 2025 (UTC)

User:I AM NEFERTITI and me

Title. Currently, she can't edit the same articles as me (and vice-versa)... How should I proceed to negotiate with the admins to change that? MathKeduor7 (talk) 05:37, 18 July 2025 (UTC)

If this is about User talk:I AM NEFERTITI#She is my friend, that was four years ago. You should probably start by asking User:Callanecc who imposed the conditions. There are other ways of appealing but they are not very attractive (outcome could easily end up worse rather than better). —David Eppstein (talk) 06:06, 18 July 2025 (UTC)

Thank you!! MathKeduor7 (talk) 06:29, 18 July 2025 (UTC)

Luen-Fai Tam

Any tips on how to create an article about him? He meets WP:PROF, but finding sources is hard. MathKeduor7 (talk) 16:32, 19 July 2025 (UTC)

So far:

• https://www.math.cuhk.edu.hk/people/academic-staff/lftam
• https://scholar.google.com/citations?user=nWrWBVEAAAAJ&hl=en
• https://www.mathgenealogy.org/id.php?id=44453
• https://doi.org/10.1142/S0129167X19020014

Is that enough? MathKeduor7 (talk) 16:34, 19 July 2025 (UTC)

Good citation counts and a special issue devoted to him? That's all I found too but I think it's enough. —David Eppstein (talk) 16:36, 19 July 2025 (UTC)

Thank you! MathKeduor7 (talk) 16:37, 19 July 2025 (UTC)

Vladeck good article discussion

Look man it's been like six months so I don't really care if it makes good article or not anymore but don't disrespect the work I put into this by claiming this is in any way "plagiarism." There's only so many ways to reword basic phrases, and in any case we're talking about what, one, two sentences out of several pages' worth of writing. Choose your words more carefully in the future. PequodOnStationAtLZ (talk) 03:21, 21 July 2025 (UTC)

Context: Talk:Baruch Charney Vladeck/GA1.

Ok, you made me realize I made a minor mistake in the review. When I wrote that the article copied the entire sentence "His father, a fervent Lubavitcher Hasid, died in 1889, leaving Shmuel’s mother a widow with five sons (he being the fourth) and a daughter." from the source, changed only to give Baruch's numbering among the siblings instead of his brother's, I was mistaken. It changed "Shmuel's" to "his" but didn't even change the numbering, making it incorrect when stated about Baruch rather than Shmuel.

Oh, and copying entire sentences without attributing them as quotes is plagiarism, whether you find that statement disrespectful or not. —David Eppstein (talk) 05:51, 21 July 2025 (UTC)

Request for opinion on intuition for chain rule

Please, could you opine on the matter at User talk:Gumshoe2#Intuition about chain rule from elementary calculus? MathKeduor7 (talk) 07:41, 21 July 2025 (UTC)

Sorry, but calculus pedagogy is something many others have much more informed opinions about than I do. (Because I am in a computer science department, it's not something I interact with much.) —David Eppstein (talk) 21:50, 21 July 2025 (UTC)

Okay! Best wishes. MathKeduor7 (talk) 22:09, 21 July 2025 (UTC)

Please stop making disparaging personal comments in edit summaries

You make a routine habit of stuff like calling me "pissy" in your edit summary at special:diff/1301885418. Restoring a long-standing stable style of a page pending discussion is routine, not any kind of problem. If you disagree, (politely) start a talk page discussion. But please stop with comments of this type in edit summaries. It makes working on Wikipedia significantly less pleasant when long-time members take random insulting pot shots for no reason. –jacobolus (t) 12:54, 22 July 2025 (UTC)

You appear to make a routine habit of reversing or contradicting my edits as they appear on your watchlist and then leaving snarky edit summaries or talk page comments about them. The edit immediately before that one on the same article was merely the latest example. I was merely noting it. Try looking in a mirror. —David Eppstein (talk) 16:40, 22 July 2025 (UTC)

Can you explain what specifically you found "snarky"? I am basically never trying to be "snarky", so there's some significant misinterpretation going on if you often feel my comments come across that way.

What I said was: 'the "indent" style was set for sources by user:Waynejayes in 2019, and has been fine for the past 6 years; there's no particularly obvious reason to change it without discussion'

This was not intended to be either "snarky" or "pissy".

I do sometimes revert your changes when I think they are harmful. (In this case, your edit seemed like an apparently arbitrary change to stable article style choices; I revert edits like this because stochastic churn in article style seems counterproductive.) If you have a problem with this, the appropriate response is to start a consensus-seeking discussion. (For example, I am not strongly attached to any particular style, and don't really care whether the reference list here has bullets or not; maybe other editors would agree with you that the bullet style is better.) Insulting me is not an appropriate response.

Comments like the one I am responding to, "Try looking in the mirror.", continue to be unprofessional, overly personal, and against Wikipedia norms and policy. Frankly I expect a lot better from you. –jacobolus (t) 18:17, 22 July 2025 (UTC)

If you don't see the pattern you are leaving in your wake, you don't see it. But each little undo of something unimportant is a little irritation. —David Eppstein (talk) 19:58, 22 July 2025 (UTC)

You constantly revert other people's work, including often productive and valuable contributions. You should likewise expect your own changes to occasionally be reverted, especially when they consist of (in my opinion pointless) style churn without explanation. Having your edits reverted is a normal part of life at Wikipedia, and the accepted way of dealing with that here is to start a discussion.

Apparently this "pattern" is that "Jacob sometimes disagrees with David", plus your own apparent incapacity for ever being contradicted. If you are irritated, I'm sorry, that is not my intention. You should deal with that by starting a respectful and content-focused discussion on the talk page instead of turning your irritation to rudeness. –jacobolus (t) 20:15, 22 July 2025 (UTC)

Respectfulness meaning avoiding phrasing like "random insulting pot shots", "Frankly I expect a lot better from you", and "incapacity for ever being contradicted"? Ok, then. —David Eppstein (talk) 20:18, 22 July 2025 (UTC)

My goal here is to give you a heads up: "hey, cut out the insults". Calling you out for that is not intended to be a personal attack. But I find your behavior to be frequently contrary Wikipedia policy and norms and below the standard I expect of administrators.

Because you are a valuable contributor, most people ignore your disrespect or dance around it, but speaking for myself it's often quite unpleasant. If you really want I can make a more comprehensive survey of your language and behavior toward myself and other editors, and take it to ANI. I'd really rather not though, as I think you are generally a net positive to the project. –jacobolus (t) 20:27, 22 July 2025 (UTC)

To be more explicit: What I would hope for as a response from you to this type of note on your page is something more along the lines of "I'm sorry Jacob. I was frustrated by your revert, but I wasn't trying to offend you. I'll try to watch my words a bit more carefully next time, and if I have a problem I will start a discussion on the article talk page instead of venting in the edit summary." –jacobolus (t) 20:31, 22 July 2025 (UTC)

You first. —David Eppstein (talk) 20:40, 22 July 2025 (UTC)

I will do my best:

I am sorry for calling your comment a "random insulting pot shot". I should have been more explicit in stating that (1) I find your comment personally offensive, and (2) I want you to stop making similar remarks in your edit summaries, but without (3) making any characterization which might imply an understanding of your state of mind. I recognize that it is important to be delicate with my phrasing so I am not misunderstood, and I will try to be more careful and precise next time.

Does that cut it? Or do you want me to apologize for calling you out because I found your language offensive? I'm not going to do that, because I believe calling people out for what I perceive to be bad behavior is my basic civic responsibility as part of a welcoming community, and I take it seriously. –jacobolus (t) 20:58, 22 July 2025 (UTC)

Well, if you're not going to apologize "for calling you out because I found your language offensive" I'm not, either. But I do respect your contributions, find them consistently constructive, apologize that for whatever reason my edit summaries have given you the opposite impression, and will endeavor to be less snarky in any future edit summaries in response to you. —David Eppstein (talk) 21:11, 22 July 2025 (UTC)

Thank you. It's much appreciated. –jacobolus (t) 21:29, 22 July 2025 (UTC)

In appreciation

		The Good Article Rescue Barnstar
		This is presented to you by the GAR process in recognition of your sterling work in helping Addition retain its Good Article status. Please feel free to display the GA icon on your userpage. Keep up the good work! ~~ AirshipJungleman29 (talk) 16:51, 22 July 2025 (UTC)

A little help in graph theory

Hope you don't mind if I request an explanation (or expansion, if you want to) of the graph theory in Cube#As a graph. Also, you might interested in reviewing Wikipedia:Peer review/Cube/archive1, just for the comprehensive as one of FACRs, and it's also an invitation from a reviewer. Dedhert.Jr (talk) 03:47, 23 July 2025 (UTC)

Ok. To begin with, "In the case of the cubical graph, it is the product of two $Q_{2}$" is incorrect; the dimensions add, so the product of two $Q_{2}$ is $Q_{4}$, the graph of a four-dimensional hypercube. The graph of a cube is $Q_{3}=Q_{2}\mathbin {\Box } Q_{1}=Q_{1}\mathbin {\Box } Q_{1}\mathbin {\Box } Q_{1}$. And it's not clear to me what "roughly speaking, it is a graph resembling a square" is intended to mean. —David Eppstein (talk) 03:58, 23 July 2025 (UTC)

Okay. Done? For the roughly speaking, do readers understand what a hypercube graph is all about? That's why I include the description of how $Q_{2}$ should be; perhaps too easy to explain? Dedhert.Jr (talk) 04:12, 23 July 2025 (UTC)

Thank you!

I don't spend a ton of time in your corners of Wikipedia but I still see you helping everyone all the time (that's how it seems at least). Earlier today I clicked to XOR'easter's page to say thanks for doing something a few months ago, but alas, XOR'easter is retired now! I'm regularly inspired by certain knowledgable and dedicated people on here, and now I'm especially glad that so many editors stick around, so here I am writing this ramble-y thanks. I've recommended your list of GAs to a few non-Wikipedian friends who like reading stuff like that, and there have been a few times that we've discussed Gale–Shapley algorithm or Square as if we're having some sort of book club. So thank you! They talk about you as if you're legendary, and usually I say they're right. Crunchydillpickle🥒 (talk) 03:20, 26 July 2025 (UTC)

You're welcome! —David Eppstein (talk) 05:57, 26 July 2025 (UTC)

XOR'easter retired??? Damn, what a loss. Headbomb {t · c · p · b} 14:38, 26 July 2025 (UTC)

Hmm... Now I wonder who will take the continuation of expanding Circle. Dedhert.Jr (talk) 01:55, 29 July 2025 (UTC)

Regular tetrahedron

Do you have any reason to revert this edit? Ignore the user anyway. Dedhert.Jr (talk) 12:01, 26 July 2025 (UTC)

See WP:DENY, User:初櫻野瞳妍緒, Wikipedia:Sockpuppet investigations/Xayahrainie43/Archive, and Wikipedia:Long-term abuse/Xayahrainie43. —David Eppstein (talk) 16:22, 26 July 2025 (UTC)

Dashes

Per WP:MOSDASH, em dashes are to be unspaced and en dashes are to be spaced in plain text. Not a huge deal, but just FYI. --Jprg1966 ^(talk) 06:54, 27 July 2025 (UTC)

Yes, I know, and changing spaced em dashes to one of those two is generally appropriate. But in this example I think there is a good reason to choose spaced en dashes over unspaced em dashes. —David Eppstein (talk) 07:01, 27 July 2025 (UTC)

Goldner-Harary application?

[24]

Once again, I may not be good at graph theory, but I think I found something interesting in its application. If this is otherwise, then I guess this graph is not ready for a good candidate like Frucht graph, like you said. Dedhert.Jr (talk) 15:21, 28 July 2025 (UTC)

I have no idea about that paper.

Coincidentally I just saw a talk this morning that mentioned this graph at the SIAM Conference on Computational Geometric Design. It was as a counterexample for a certain construction for generating 3d shapes from their skeletons. If a set of points on the sphere had the Goldner–Harary graph as their Delaunay triangulation then the construction would not have worked, but fortunately the Goldner–Harary graph does not describe an inscribable polyhedron (See Thm 2.2.1 of this dissertation) and therefore cannot be realized as a Delaunay triangulation. —David Eppstein (talk) 17:37, 28 July 2025 (UTC)

Well that paper is basically about Goldner–Harary graph's new quantum pattern for Alzheimer's disease. But okay, then.

Anyway, I wonder if I could use a dissertation for citation, but they might be revised from time to time. I'll see what I can do. Dedhert.Jr (talk) 01:51, 29 July 2025 (UTC)

Doctoral theses are generally fine for citations. Master's theses can sometimes be used with caution. Bachelor's theses probably not. —David Eppstein (talk) 02:03, 29 July 2025 (UTC)

CFD re Native American mathematicians

Greetings, I was happy (though not surprised) to see your name turn up all over the edit history for Jennifer McLoud-Mann. So I thought you might be interested to know that another editor recently created a new Category:21st-century Native American mathematicians expressly for her article, which is being discussed for renaming. Regards, Anomalous+0 (talk) 23:58, 28 July 2025 (UTC)

DYK for Alhazen's problem

On 30 July 2025, Did you know was updated with a fact from the article Alhazen's problem, which you recently created, substantially expanded, or brought to good article status. The fact was ... that Leonardo da Vinci invented a device to solve Alhazen's problem, instead of finding a mathematical solution? The nomination discussion and review may be seen at Template:Did you know nominations/Alhazen's problem. You are welcome to check how many pageviews the nominated article or articles got while on the front page (here's how, Alhazen's problem), and the hook may be added to the statistics page after its run on the Main Page has completed. Finally, if you know of an interesting fact from another recently created article, then please feel free to suggest it on the Did you know talk page.

 — Chris Woodrich (talk) 00:02, 30 July 2025 (UTC)

Your nomination of Yao's principle is under review

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Your nomination of Yao's principle is on hold

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Your nomination of Matroid parity problem is under review

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Your nomination of Parallelohedron is under review

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Your nomination of Yao's principle has passed

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Women in Red August 2025

Women in Red | August 2025, Vol 11, Issue 8, Nos. 326, 327, 344, 345, 346 Online events: New: Alphabet run O & P | Indigenous women | Film and stage Continuing, year-long initiatives: #1day1woman | Music Announcements: Wikipedia:Developing Countries WikiContest runs 1 July 2025 until 30 September 2025 Tip of the month: Read the essay Determining Native American and Indigenous Canadian identities to understand the criteria for status as Native American or Indigenous Canadian Other ways to participate: Become a member. You can always opt-out of notifications. Join the conversations on our talkpage. Help us plan future events and add any general ideas on developing the project. Follow us on social media: Instagram | Pinterest

--Rosiestep (talk) 14:48, 30 July 2025 (UTC) via MassMessaging

Your nomination of Parallelohedron has passed

Your good article nomination of the article Parallelohedron has passed; congratulations! See the review page for more information. If the article is eligible to appear in the "Did you know" section of the Main Page, you can nominate it within the next seven days. Message delivered by ChristieBot, on behalf of Dedhert.Jr -- Dedhert.Jr (talk) 04:01, 31 July 2025 (UTC)

Alphabet (formal language)

I added a new section Alphabet_(formal_languages)#Unambiguity, along the lines of Talk:Alphabet_(formal_languages)#What_does_it_mean_by_"indivisible"? and User_talk:David_Eppstein/2025b#Alphabet_(formal_languages):_indivisibility, and would appreciate any comments from you very much.

In particular, I think that, if the notions of Free monoid and Kleene star don't coincide (as claimed in the new section), several articles about formal language issues would have to be changed, or at least reviewed. I don't dare to start that task without some prior confirmation. - Jochen Burghardt (talk) 18:27, 31 July 2025 (UTC)

This entire section comes across as an essay-like synthesis of sources that fundamentally misunderstands the definitions.

But in general, formal languages are sets of finite sequences of symbols from some alphabet. What you deem "unambiguity" is merely that they are sequences of symbols, not concatenations of strings that may themselves be concatenated from other strings.

Your "if epsilon in Sigma" paragraph is just wrong. You can certainly have an alphabet whose members are strings and which includes the empty string. All that means is that the strings over that alphabet are sequences whose individual elements are strings. The elements of the elements are something else. So ["", "Jochen", "Burghhardt"] is a string, whose individual elements are strings. You could write it as [ [], [J, o, c, h, e, n], [B, u, r, g, h, h, a, r, d, t]] if you prefer. The fact that the empty string is an element of this sequence does not cause it to have length different from 3. The fact that the other elements are themselves sequences also does not cause it to have length different from 3.

A sequence of sequences is not the same as a concatenation of sequences.

It is just like, if F_i, are sets, then the set of these sets {F_i} is different from the union of the F_i. —David Eppstein (talk) 18:39, 31 July 2025 (UTC)

Thanks for the fast response.

Unfortunately, you have a point with "an essay-like synthesis".

Concerning strings, your point of view amounts to the use of the free monoid as set of strings (that is, always using a fresh concatenation operation, and a fresh empty-string constant), and I like your illustrative analogy to sets.

But I'm still afraid that this construction differs from the Kleene star. If e.g. $A$ is the set of all upper or lower case letters, then the sequence $[J,o,c,h]$ is an element of $A^{*}$, but, if I understood you right, $[[J,o],[c,h]]$ is not in $A^{*}$ but in $(A^{*})^{*}$, since it isn't a sequence of letters, but a sequence of strings. However, the Kleene star should be idempotent; at least, this is required in Kleene algebra.

If this is right (I'm still not sure), we should review every formal-languages article and avoid the misunderstanding that the set of strings over an alphabet $A$ always equals the Kleene star of $A$. We could begin right here: in Alphabet_(formal_languages)#Notation. - Jochen Burghardt (talk) 10:48, 1 August 2025 (UTC)

@Jochen Burghardt I think that there are two Kleene stars whose type signature differs. The star that is used in regular expressions takes as its argument a set of strings maybe described by another regexp, and produces another set of strings over the same alphabet. The star that is used when we denote the set of all strings as $\Sigma ^{*}$ takes as input a set of symbols (an alphabet) and outputs a set of strings over that alphabet. Or if you prefer you could imagine a hidden type coercion from a set of symbols to a set of one-symbol strings. Or if you prefer you could say that $\Sigma ^{*}$ is merely a notational convention and not really a Kleene star operator at all. —David Eppstein (talk) 15:03, 1 August 2025 (UTC)

That looks reasonable. I think the least editing effort is caused by your first suggestion (two Kleene stars whose type signature differs): We'd just need to add a corresponding paragraph somewhere to Kleene star. All occurrences of "$A^{*}$ is the Kleene star of $A$, also known as the free monoid" (and similar) can remain unchanged. The problem with WP:SYN remains, however. - Jochen Burghardt (talk) 12:21, 4 August 2025 (UTC)

We cannot add any such paragraph without a source. All we need to do is to say that $\Sigma ^{*}$ is the notation for the set of all strings, and not try to call it the Kleene star. We don't need sources to not say something. —David Eppstein (talk) 16:33, 4 August 2025 (UTC)

PS I think the real problem is in the Kleene star article, where it doesn't distinguish between concatenations of given strings and sequences of given characters (two different things). We need that article to be cleaned up to make this distinction properly, first. Once that happens, we can figure out how to discuss stars elsewhere (like in the alphabet article) in a way that is consistent with the cleaned-up article. —David Eppstein (talk) 23:39, 4 August 2025 (UTC)

In Wikipedia, it is not trivial to not say something. Kleene star/What links here lists 103 incoming links (no transclusions, about 10 + 10 via the redirects Kleene closure + Kleene plus). I could check these, and replace "Kleene star" by "Free monoid" where appropriate; this might take 1-2 hours, I guess. However, I'm afraid that many such edits would be reverted (maybe not immediately, but in the future, in good faith, without being aware of this discussion), and new formal-language articles would re-introduce more inappropriate links.

As for a cleanup, I guess there is no source that explicitly mentions the distinction between both uses. However, we should at least be able to provide a citation for each of them separately. For the character case, Hermes is the most explicit source I found so far (see my essay which is still available here), and he doesn't even mention Kleene, let alone Kleene star. For the string case, I'd look at sources about Kleene algebra, near the statement of idempotence of the star.

We could also add distinguishing examples at Kleene star and/or Free monoid; they might not need a source, but help to understand the distinction. - Jochen Burghardt (talk) 15:38, 5 August 2025 (UTC)

Risk, Hazards & Crisis in Public Policy

Is this journal notable – or not? Bearian (talk) 23:02, 4 August 2025 (UTC)

It's in Web of Science, so it passes WP:NJOURNALS. But that is an essay and the actual notability guideline that applies is WP:GNG, which is very difficult for most journals to pass, even when they pass NJOURNALS. It is also very difficult to find GNG-worthy sources about most journals, even when they exist, because they are swamped in searches by all the other sources that cite papers in the journal without providing depth of coverage about the journal. Which is to say, the article doesn't provide evidence of GNG notability, and I didn't find any in searching, but I'm not certain of the nonexistence of good sources. —David Eppstein (talk) 23:32, 4 August 2025 (UTC)

Ok, thank you. Bearian (talk) 18:11, 6 August 2025 (UTC)

Platonic solids credited to Pythagoras

Sorry, but did you know something about the history of these solids? Found in Regular polytope, which stated, "The five Platonic solids were known to them. Pythagoras knew of at least three of them and Theaetetus (c. 417 BC – 369 BC) described all five." I do think this is dubious, but if you have one, I reprimand myself for how fallacious my interpretation is, and I might require the reconsideration of his biography. Dedhert.Jr (talk) 11:11, 5 August 2025 (UTC)

https://muse.jhu.edu/pub/267/edited_volume/chapter/3942740/pdf —David Eppstein (talk) 17:08, 5 August 2025 (UTC)

Spanning Tree Protocol in Cycle (graph theory)

Perhaps surprisingly - I absolutely agree that this is not a topic in graph theory. But perhaps an article about distributed algorithms on graphs?

I’m working on the Computer Networks article, and that got me into a little bit of a dispute about removing the Network Science sidebar from the lead of the article on Computer Networks, on the grounds that most (almost all?) of the topics are irrelevant to computer networks. I changed the Cycle (graph theory) article because in looking through the topics, I said to myself, “well that one actually is sort of relevant, I think I’ll make it so by adding some information to it.”

Not really such a good idea, sorry for the trouble. Ngriffeth (talk) 20:35, 6 August 2025 (UTC)

Maria Chudnovsky

Hi,

You reverted my fix of Maria Chudnovsky's Russian name. I reverted it back because the old name was very obviously wrong, but I pressed Publish before writing the full edit summary.

There are sources for it, of course, e.g. https://www.svoboda.org/a/24733447.html . Usually, sources are not written for native names except in unusual cases. This case in not unusual at all—it is a pretty simple Russian name.

Also, the letter ј is never, ever used in the Russian language.

Also, Russian is my mother tongue.

Also, there was no source for the previous spelling of the name, and there couldn't be because it's obviously wrong. Amir E. Aharoni (talk) 20:48, 6 August 2025 (UTC)

Both the Russian and Hebrew names were added by an editor who added non-English names to thousands of articles; in the vast majority of cases these were just made up (unsourced, not grounded in any evidence that the subject has ever used the glyph as a name). Thankfully they have stopped doing that, but doubtless they have left hundreds of errors that no one is ever going to clean up. Since I see no evidence that Chudnovsky has ever professionally or personally used either a Russian or Hebrew version of her name, I have removed them both. ----JBL (talk) 21:13, 6 August 2025 (UTC)

Also, incidentally, a source written in Russian is evidence that someone at some point transliterated her name into Russian a certain way, but it is only weak evidence that that particular string is her Russian name: if someone writes an article about David Eppstein in Russian presumably they will write some string in the Russian Cyrilic alphabet corresponding to his name, but that doesn't mean the resulting string is "his Russian name". (I'm not asserting it's not -- I don't know, probably it actually is -- just that the level of evidence here is weak.) ----JBL (talk) 21:19, 6 August 2025 (UTC)

That is not how it works in Russian, but whatevs, I don't enjoy arguing. Amir E. Aharoni (talk) 21:24, 6 August 2025 (UTC)

How it works on Wikipedia is that we need published sources, regardless of what you think you know.

I could ask Maria (we are coauthors on a soon-to-be-published paper) but that also wouldn't help unless the name appears published somewhere. I agree with JBL's removal.

(As for my name in Cyrillic, I have never lived in a Cyrillic-speaking country so have never used that form. Presumably others have transliterated my name but it is not worthy of inclusion here.) —David Eppstein (talk) 21:38, 6 August 2025 (UTC)

Sorry that was terrible writing on my part; the "it" in "I'm not asserting it's not" was supposed to point back to Chudnovsky. --JBL (talk) 17:31, 8 August 2025 (UTC)

Talk:Adriana Salerno

Greetings. I don't mean to browbeat or put you on the defensive, but my ES was serious: how did this happen? The date changes (thanks for the thanks), image removal, and category changes weren't about "rescue one deadlink and archive the other". I'd just like to better understand where each decision came from. If you'd like to remand this to the article talkpage, that would be grand. I'd just like to understand what happened. Many thanks. JFHJr (㊟) 00:42, 8 August 2025 (UTC)

Your bad faith assumptions are unwarranted. Looks like I merely accidentally edited the wrong version somehow. I think I have fixed it now. —David Eppstein (talk) 00:45, 8 August 2025 (UTC)

No sir, no bad faith. Thanks for your feedback. JFHJr (㊟) 00:58, 8 August 2025 (UTC)

Update re Category:21st-century Native American mathematicians

Hello - Thanks to User:EulerianTrail, this Category now has 5 articles. I thought perhaps you might want to update your comments with regard to renaming vs merging. Anomalous+0 (talk) 21:46, 5 August 2025 (UTC)

I was hoping you would clarify where you come down on this now. It's not entirely clear what you meant by "Merge, but..." - especially after the update you posted. And of course, that was before additional articles were added to the category. Anomalous+0 (talk) 12:30, 8 August 2025 (UTC)

Your nomination of Matroid parity problem is on hold

Your good article nomination of the article Matroid parity problem has been placed on hold, as the article needs some changes. See the review page for more information. If these are addressed within 7 days, the nomination will pass; otherwise, it may fail. Message delivered by ChristieBot, on behalf of Gramix13 -- Gramix13 (talk) 23:07, 8 August 2025 (UTC)

Riemann Hypothesis Solution

Dear buddy, I have good and bad news for you. The good news is that the Riemann Hypothesis is solved. The bad news is you're responsible for vetting the solution as per blocking my edits on the wiki article. I took a screenshot of you locking down the access so you should be prepared to justify that decision. I already stated the solution takes about 1 minute to comprehend, it's simply a matter of realizing zero is a space, not a point and mislocating the notion of 2. "2" resides in the center of zero, it doesn't exist 2 notches outside of zero:

https://github.com/jbreija/Universe/blob/main/init.png https://github.com/jbreija/Universe/blob/main/docs/Riemann_hypothesis_solution

I understand there's thousands of crackpots on the Internet claiming to have solved the Riemann Hypothesis but this is the real deal and the evidence is self-explanatory, there's no need for peer review at all. I read your wiki bio and you're operating way out of your league and have absolutely no idea of it. Anyways, bye bye, I don't edit wiki articles or care about this website. 69.14.4.153 (talk) 19:06, 9 August 2025 (UTC)

Screenshots are unnecessary; the edit history of the Riemann hypothesis article, showing you violate WP:3RR and insult other editors, is not likely to be hidden any time soon. So far you are merely locked out from that one article. —David Eppstein (talk) 19:16, 9 August 2025 (UTC)