User talk:David Eppstein: Difference between revisions

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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.)

I don’t know where Ph.D is accepted; WP tends to favor PhD somewhat, though Ph.D. is acceptable, but I draw the line at failing to decide and using just one full stop. Chris the speller yack 22:25, 30 December 2025 (UTC)[reply]

It should have been obvious in Hee Oh that that was a typo and that the intended formatting was Ph.D. —David Eppstein (talk) 22:35, 30 December 2025 (UTC)[reply]
(delurk) I was ready to agree with Chris (without having read David’s response), when I happened to see Ph.D in an article I saw for unrelated reasons in the New York Times. It’s in today’s issue, called “She Tried to Kill a President. He Loved Her Anyway.” —Trovatore (talk) 22:56, 30 December 2025 (UTC)[reply]

Sometimes even the Gray Lady nods? I agree with Chris that we should use an even number of dots. —David Eppstein (talk) 23:05, 30 December 2025 (UTC)[reply]

FWIW MOS:ABBREV is the place that suggests PhD is preferred, or at least one of them. (But this seems to be a MOS guideline that not so many follow.) Russ Woodroofe (talk) 23:53, 30 December 2025 (UTC)[reply]

It also seems to apply only to usage “in tight quarters such as citations, tables, and lists”. —David Eppstein (talk) 23:55, 30 December 2025 (UTC)[reply]

I read the advice there as giving the preferred form of the abbreviation, which should certainly be used in tight quarters. That is, I think the section head “Abbreviations widely used in Wikipedia” is important. It says that _many_ of them should be spelled out otherwise; I think that PhD is an exception. OTOH, are we getting a local consensus for :Ph:D: ? Russ Woodroofe (talk) 02:10, 31 December 2025 (UTC)[reply]

Is it actually widely used in Wikipedia, though? Or would it be without editors like Chris going around enforcing this sort of thing? —David Eppstein (talk) 02:12, 31 December 2025 (UTC)[reply]
So “.P.hD” it is, then. —JBL (talk) 00:18, 31 December 2025 (UTC)[reply]

Or “Ph:D” —JBL (talk) 00:27, 31 December 2025 (UTC)[reply]

Ṗ..ḣḊ. —Trovatore (talk) 02:38, 31 December 2025 (UTC)[reply]
That one almost makes sense. —David Eppstein (talk) 01:25, 31 December 2025 (UTC)[reply]

So you are saying that except in tight quarters we should use “Doctor of Philosophy” instead? No, I will go with PhD as the MoS suggests. Chris the speller yack 01:40, 31 December 2025 (UTC)[reply]

MOS:ABBREV does not provide guidance on PhD vs Ph.D., except in tight quarters. That should not be interpreted as saying it should be spelled out (as Philosophiae Doctor for Ph.D., or Doctor of Philosophy for Oxford’s idiosyncratic DPhil), but neither should it be interpreted tendentiously as saying that Ph.D. is forbidden. It is merely a lack of guidance on specific style and spelling choices, just as we have on most other such issues. —David Eppstein (talk) 01:44, 31 December 2025 (UTC)[reply]
Yes, PhD is very widely used in WP. I searched for articles with “received his PhD” and with “received his Ph.D.”, and they are nearly equal, and no, none of that is because I switched from one to the other. I have been fixing cases where one dot was missing, or was until David changed the Hee Oh article back to “Ph.D”, which is simply not acceptable. Please refrain from saying “Chris is going around doing xxx”, which implies a certain aimlessness and recklessness, while I see it as being productive. Changing “Ph.D” to “PhD” is an improvement, as it is changing it to an approved abbreviation, but reverting that change is not an improvement to the article. Chris the speller yack 05:14, 31 December 2025 (UTC)[reply]

reverting that change is not an improvement to the article Chris, David already indicated that was a typo, and fixed it, before their first response here. Take the win? —JBL (talk) 19:21, 31 December 2025 (UTC)[reply]

Minor correction: it was after Chris had pointed out here that it was a typo. —David Eppstein (talk) 19:33, 31 December 2025 (UTC)[reply]
Happy New Year to all! Chris the speller yack 02:28, 1 January 2026 (UTC)[reply]

Thanks! To you as well! —David Eppstein (talk) 06:24, 1 January 2026 (UTC)[reply]

   Send New Year cheer by adding {{subst:Happy New Year fireworks}} to user talk pages.

BhikhariInformer (talk) 17:12, 31 December 2025 (UTC)[reply]

Thank you! —David Eppstein (talk) 06:24, 1 January 2026 (UTC)[reply]
Thanks! Happy new year to you too! —David Eppstein (talk) 06:24, 1 January 2026 (UTC)[reply]

Categories you have created have been nominated for possible deletion, merging, or renaming. A discussion is taking place to decide whether this proposal complies with the categorization guidelines. If you would like to participate in the discussion, you are invited to add your comments at Wikipedia:Categories for discussion/Log/2026 January 2 § Category:Fellows of the Association for Computing Machinery by year on the categories for discussion page. Thank you. SMasonGarrison 04:02, 2 January 2026 (UTC)[reply]

Thank you for your input at this CFD nomination. At the discussion, would you be open to sharing any real-world connection you have to the topic? RevelationDirect (talk) 01:33, 3 January 2026 (UTC)[reply]

Look it up yourself. And while you’re looking up things, see WP:AGF.
But to answer your implied bad-faith accusation: I don’t care about what the article about myself says. I do care about the thousands of other articles I have created on fellows of learned societies, just like any Wikipedia editor who creates articles would care about the maintenance of those articles.
Additionally, I happen to think I am in a position to understand better than some editors how defining this sort of thing is taken to be in academic circles. —David Eppstein (talk) 01:35, 3 January 2026 (UTC)[reply]

I was being intentionally vague prior to re-reading the outing guideline and, I’m afraid that opaque wording left room for misinterpretation. Sorry about that; let me try again:I don’t think you’re acting in bad faith here at all, but advocating only for what you feel is best for the encyclopedia. I also perceive what could be a potential conflict of interest per WP:EXTERNALREL.That nomination is discussing the prestige of an award you appear to have personally won. And one of the ~900 articles that could be impacted is
David Eppstein. Ideally your expertise could strengthen your case while still being transparent: “I work in this field with this relationship to the award and within academic circles it’s treated as defining because …”At the discussion, would you be open to sharing any real-world connection you have to the topic? RevelationDirect (talk) 02:59, 3 January 2026 (UTC)[reply]

Thanks so much for that post, that was perfect! RevelationDirect (talk) 04:31, 3 January 2026 (UTC)[reply]

I was interested to see this edit, particularly as I wasn’t challenging notability. Could you please point me to the policy you are relying on, since in more than 20 years I haven’t referenced a book listing, nor been challenged on removing refs for publications, cheers Jimfbleak – talk to me? 20:22, 3 January 2026 (UTC)[reply]

Let’s start with WP:AUTHOR #3 and #4c: an author with multiple reviews of their books can be notable through those reviews. We should not remove the cause of notability from an article, so we should list the reviews rather than removing them.
We should also consider the fact that, especially on a WP:BLP, all material should be supported by WP:SECONDARYSOURCEs. The books themselves are primary sources. The reviews of those books are secondary. —David Eppstein (talk) 20:25, 3 January 2026 (UTC)[reply]
But you haven’t listed the reviews you are referencing. If you think they are needed for notability (I don’t), surely you should at least mention the reviews you are providing references for? Jimfbleak – talk to me? 20:38, 3 January 2026 (UTC)[reply]

You mean, stating the existence of the reference in the article text? That’s not how references work. If we wrote “this work was reviewed in the American Journal of Archaeology” with a footnote to the review, that footnote would be a primary source for that claim: it is the book review itself, not someone else stating independently that the review was made. When we write that Cooney published the book The Cost of Death (either as prose or in a list of published books), with the same footnote, it is a secondary source for the claim that she published the book, because it is something someone else (the reviewer) wrote, supporting the claim, with evaluative material about the claim (making it a secondary source and not merely a database entry). Similarly, when a subject is notable through the existence of multiple published in-depth sources about the subject (WP:GNG notability), the correct thing to do is to use those sources as footnotes for material in the article, not to add article text saying that they’re notable because of these sources.
Separately, listing reviews of books can be useful to readers who might want to find reliably published opinions about those books. Why destroy that resource? —David Eppstein (talk) 20:44, 3 January 2026 (UTC)[reply]
I’m not challenging the validity of the information, it just seems odd to me that you need to reference the self-evident existence of a book, but not mention in the text the reviews you are relying on for notability Jimfbleak – talk to me? 06:12, 4 January 2026 (UTC)[reply]

It seems strange to me that you think the article text should say something about notability, something that is internal to Wikipedia. We could use the reviews to say something about the content of the books, or how they were received, and leaving them in the article provides an opportunity for future editors to do that if they see fit. But we don’t have to use them that way, and the fact that they also convey notability is not something that should be reader-facing. —David Eppstein (talk) 06:17, 4 January 2026 (UTC)[reply]

A persistent IP user on adding citation needed tags in the lede in Solid. Dedhert.Jr (talk) 07:24, 5 January 2026 (UTC)[reply]

Your revert was a false revert. I am not a vandal. I have cited sources. I advise you to look at the citations before reverting. Its a reputable source. And if not I have 10 more citations that will do the same thing, from mainstream legacy american media. ~2025-34140-84 (talk) 04:29, 6 January 2026 (UTC)[reply]

[Context: Special:Diff/1331313891 on Moving sofa problem.] A newspaper article can be reliable for claims like “Baek claimed a solution” but not for claims like “Baek’s solution is correct”. For that we need peer review in a mathematical journal, not newspaper journalism. —David Eppstein (talk) 06:19, 6 January 2026 (UTC)[reply]

@David Eppstein I do not remember that being official policy anywhere. As far as I am aware. Major legacy news sources reporting on it suffices for the article to say it was solved. Either way I have no doubt the article will be edited by other users in the future to change it to “solved” because reputable sources said so. ~2025-34140-84 (talk) 01:26, 7 January 2026 (UTC)[reply]

You can start with WP:NEWSORG “Scholarly sources and high-quality non-scholarly sources are generally better than news reports for academic topics … Press releases from organizations or journals are often used by newspapers with minimal change; such sources are churnalism and should not be treated differently than the underlying press release.” —David Eppstein (talk) 02:08, 7 January 2026 (UTC)[reply]

If I want to improve the history of any mathematical topics, I might be lost. Because I could not find which sources are reliable and have no knowledge of history. For example, how do I write better novelty about Euler’s characteristic‘s history and background, even though I have found a magazine from Cambridge Press [1], which includes the 20 proofs of Euler’s characteristic in Junkyard, but still I am questioning the better sources? Where should I start? Dedhert.Jr (talk) 02:01, 9 January 2026 (UTC)[reply]

Richeson’s book is probably a decent source for that, but for the early history of this I think the Friedman source already cited is good. Anyway, there are scholarly journals on the history of mathematics such as Historia Mathematica; what you can find in those, or in scholarly monographs like Friedman’s, is probably more careful in its conclusions than popularized treatments like Richeson’s. My web site’s focus is more on the proofs than on their publication, so I don’t think it’s a good source for the history of the problem. For the frequent (but dubious) claim that Descartes found this formula before Euler, see Descartes on Polyhedra and its sources. —David Eppstein (talk) 02:09, 9 January 2026 (UTC)[reply]

Okay. But what about the history of any mathematical topic? Surely, one example of an article is not enough. Dedhert.Jr (talk) 04:14, 9 January 2026 (UTC)[reply]

I think the advice to search for scholarly journals and monographs over popularized treatments is still sound. —David Eppstein (talk) 06:01, 9 January 2026 (UTC)[reply]

A discussion is taking place as to whether the article David M. Diamond, to which you have significantly contributed, is suitable for inclusion in Wikipedia according to Wikipedia’s policies and guidelines or if it should be deleted.

The discussion will take place at Wikipedia:Articles for deletion/David M. Diamond (2nd nomination) until a consensus is reached, and anyone, including you, is welcome to contribute to the discussion. 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.

To customise your preferences for automated AfD notifications for articles to which you’ve significantly contributed (or to opt-out entirely), please visit the configuration page. Delivered by SDZeroBot (talk) 01:01, 10 January 2026 (UTC)[reply]

Hi David Eppstein: I’m noticing that the FAC nomination for “Rules of inference” article is currently being nominated by a philosophy editor and that there are no editors with 3-CNF experience, etc, to keep things consistent with computer science perspectives; could you give it a look when time allows? ErnestKrause (talk) 22:20, 12 January 2026 (UTC)[reply]

Have looked up the transparent version in this image. Since the current user was blocked, I have no idea how to revert the current image to the transparent background. Or can you help me to do it? Many thanks. Dedhert.Jr (talk) 14:13, 14 January 2026 (UTC)[reply]

The original version of that image did not have a transparent background. Unlike Wikipedia article content, there is a concept of ownership for images; they should not be changed to different images, especially not without agreement of the original uploader. If you want an image with a transparent background it should have a different name. —David Eppstein (talk) 18:17, 14 January 2026 (UTC)[reply]
(talk page stalker) @Dedhert.Jr: since there’s a transparent version in the history, you might try requesting a history split with a distinct name.—Odysseus1479 03:08, 15 January 2026 (UTC)[reply]

Indeed there is a transparency. But I rather create it by my own, but I might need its Cartesian coordinates before tracing with Inkscape from Geogebra. Dedhert.Jr (talk) 03:38, 15 January 2026 (UTC)[reply]

If you’re recreating it as a vector graphic (which has numerous advantages anyway), the difference in extension (.SVG vs .PNG) will suffice to avoid a filename conflict.—Odysseus1479 05:03, 15 January 2026 (UTC)[reply]

@Odysseus1479. Okay. A little off-topic here. I have made a different polyhedron File:Cell of the dual snub 24-cell (transparent, symmetry).svg, with recreation by myself. But do I need to write the whole coordinates from unsaved, sandbox, Geogebra 3D? Do I need to write something like “tracing from Geogebra 3D” or similar? From other images I have made, I have written the source for tracing from other Wikimedia images alongside their authors. But in this case? Dedhert.Jr (talk) 15:48, 15 January 2026 (UTC)[reply]

Notice

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

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

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

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

If the proposed deletion has already been carried out, you may request undeletion of the article at any time. Sorry for the template. Bearian (talk) 10:45, 22 January 2026 (UTC)[reply]

I know that the answer is in List of unsolved problems in mathematics, but there might be many unsolved problems that are not ready to be included in the list (WP:NOTABILITY is behind all of this), or, in other words, new unsolved problems are published somewhere else. But have no idea where I can find it. I hope I can collect the unsolved problems in the list I made (about polyhedra), apart from the discussion in Talk:Arithmetic billiards/GA1, the book from Princeton University Press published from the previous year [2], and many more [3]. For the http://openproblemgarden.org/, it’s dubious by telling the promotion titles and empty conjecture statement. Talk:Arithmetic billiards/GA1. Dedhert.Jr (talk) 08:14, 23 January 2026 (UTC)[reply]

Many conferences and workshops have open problem sessions and sometimes these are published. For instance searching for “Open Problems from CCCG” will find many from one particular computational geometry conference. Many are not notable enough to list, though. —David Eppstein (talk) 08:17, 23 January 2026 (UTC)[reply]

“Many are not notable neough to list, though”. Like the problem in 2023 [4] about finding the minimal of a cube’s volume? I hope there is a high possibility to include the problrm in Cube, the same way for unsolved problem about the quasigeodesic of a cube [5]. Dedhert.Jr (talk) 08:30, 23 January 2026 (UTC)[reply]

As a person with a Ph.D. in mathematics, I disagree with your suggestion to refrain from adding spaces. The algorithm in the TeX renderer is not especially good with spaces (for example, when one uses “\left(” for a function argument, it inserts a space before the “(” ). The very reasonable assumption by the makers of the rendering engine is that a human can make much better judgement about the fine-points of spacing, although there are some things that could be better automated (e.g. it could automatically add a slight space between the end of the argument of a square root and the end of the solidus, and it could ensure a slight gap between the end of the solidus and a closing parenthesis following it).

Regarding spacing, it’s standard in well-typeset math texts to use slight extra spaces between factors in an expression to emphasize the application of a power to the preceding factor, and the start of the parenthesis for the next (although this sometimes works out on its own) and between terms in an expression that are themselves complicated, so that each separate term is a bit removed from the complications of the others. Likewise in serial inequalities ( F(x) < G(x) < H(x) ) to make the separately calculated expressions stand away from the relational operators. Finally, it is always necessary for the mathematical variables embedded in running text to be separated by slight extra spaces from the prior and following text: The math variables or embedded formulas should never run-together with the text. None of this latter spacing can be provided by the TeX rendering engine, and the font-templates “math” and “mvar” are (and should be) too dumb to pull it off.

You reverted my prior edits while I was working on far more, so rather than loosing them, I went ahead and inserted them over your reversion. If you want to go into ‘edit-war’ mode, or are offended that I imposed my new edits after you had reverted the prior (fewer) edits in the final section, it’s on you to go in and revert them again. My position on the matter is that math in Wikipedia should be an easy read, and that in this particular case of Sterling’s approximation, which is widely used outside of mathematician-only crowd, it’s even more important for a general audience.
~2026-31703-6 (talk) 20:56, 23 January 2026 (UTC)[reply]

No really don’t do this, it makes things ugly, difficult to edit and maintain, and impossible to keep consistent; even if you disagree about “ugly”, that is still two very good reasons. Surely you can find some actual problem to fix instead? —JBL (talk) 00:42, 24 January 2026 (UTC)[reply]

I saw that you reverted a bunch of edits at WP:SWEEPS2025, which indicated that a bunch of articles were delisted. Was this a misclick, or is there a concern to address? Z1720 (talk) 20:07, 31 January 2026 (UTC)[reply]

Mouse slip. I am currently topic-banned from having anything to do with GAR so a deliberate edit would be a mistake. —David Eppstein (talk) 20:08, 31 January 2026 (UTC)[reply]

Women in Red | February 2026, Vol 12, Issue 2, Nos 358, 359, 361, 362, 363

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—Lajmmoore (talk 22:46, 31 January 2026 (UTC) via MassMessaging[reply]

Your good article nomination of the article Lambek–Moser theorem is under review. See the review page for more information. This may take up to 7 days; feel free to contact the reviewer with any questions you might have. Message delivered by ChristieBot, on behalf of MCE89 — MCE89 (talk) 03:24, 1 February 2026 (UTC)[reply]

I’ve contacted Smith609 (talk · contribs · blocks · protections · deletions · page moves · rights · RfA) and AManWithNoPlan (talk · contribs) for their thoughts on the citation bot’s recent block. sjones23 (talk – contributions) 18:34, 2 February 2026 (UTC)[reply]

I am kind of terrible at color theory, so I doubt picking colors that are closer to monochrome. Furthermore, I reduced the transparency of the surface’s teal color, so one can look the edges behind. Since I use Inkscape by tracing the screenshot polyhedral structure in Geogebra, I have no comments at all and I may have learn something if you give more comments about the color. And to your comment about the edges’ color, this reminds about light blue surfaces with black edges [6]. If you have some time, you won’t mind giving some better portraits? Dedhert.Jr (talk) 01:54, 3 February 2026 (UTC)[reply]

The images in the linked paper (and the triaugmented prism) were all generated using https://prideout.net/blog/svg_wireframes/ — that way I get correct 3d geometry in a vector graphics format, more accurate than trying to trace over a bitmap, but it doesn’t have the fancy lighting and reflection models that you would get from povray, and it is not even very good at z-ordering. So basically all you get is the polygons, in a valid projection, and any coloring model you feel like coding up yourself. The software’s web site does have some code for adding a lighting model but it doesn’t mix well with partial transparency. —David Eppstein (talk) 03:20, 3 February 2026 (UTC)[reply]

If I remember, I have tried to copy your code on File:Triaugmented triangular prism (symmetric view).svg in Visual Code Python. But in the end, I have to import the libraries (or whatever the names are), which end up in failure. Dedhert.Jr (talk) 01:15, 4 February 2026 (UTC)[reply]

icon Please stop attacking other editors, as you did on Talk:Directed acyclic graph. If you continue, you may be blocked from editing. Comment on content, not on other contributors or people. In addition to Talk:Directed acyclic graph, you have shown similar behavior on Talk:Square. I have posted this warning as a friendly reminder and gesture of good will as recommended at WP:CONDUCTDISPUTE. EulerianTrail (talk) 08:20, 4 February 2026 (UTC)[reply]

It is not a personal attack to point out that you added information to directed acyclic graph with a malformatted reference that looked superficially relevant and specific but failed to verify the added information, and to ask you what process led you to use that reference. —David Eppstein (talk) 08:25, 4 February 2026 (UTC)[reply]
@EulerianTrail: what exactly is the attack? Because I dropped by that discussion and see nothing ruder than an old lady at church remarking that the cinnamon rolls served at brunch were undercooked. Headbomb {t · c · p · b} 09:14, 4 February 2026 (UTC)[reply]

Insulting another editor’s judgment, accusing an editor of not reading, and accusing an editor of using LLMs are all personal attacks that do not contribute to the article. Especially when I try to reason with and explain the source. EulerianTrail (talk) 15:24, 4 February 2026 (UTC)[reply]

Asking you questions about how you came to be making bad edits, together with a correct explanation of what is wrong with those edits, is not a personal attack. —JBL (talk) 17:22, 4 February 2026 (UTC)[reply]

Asking how someone came up with an edit is ok to ask. But making specific unfounded accusations is not. EulerianTrail (talk) 17:43, 4 February 2026 (UTC)[reply]

The specific accusation (that you added text not supported by the source) seems well founded; then I see some questions/speculation about how that might have happened. This could be a personal attack if the substantive objection to your edit were missing or incorrect, but that doesn’t seem to be the case. Similarly, if someone writes “This edit is bad for [well specified reasons]; did you use an LLM?” they aren’t being friendly but they are well within the boundaries of WP:NPA, certainly at least as much as a person leaving template warnings on the talk-pages of long-time users. —JBL (talk) 17:50, 4 February 2026 (UTC)[reply]

Hi, what exactly is the meaning of Use dmy dates|cs1-dates=ly|date=January 2024 as opposed to Use dmy dates|date=February 2026 ? Denisarona 09:17, 4 February 2026 (UTC)[reply]

The dmy dates part says to format the publication dates of references like 4 February 2026. The cs1-dates=ly part says to format minor editor-facing dates like access-dates and archived-dates like 2026-02-04. This is one of the styles allowed by MOS:DATEFORMAT. —David Eppstein (talk) 18:06, 4 February 2026 (UTC)[reply]

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