User talk:David Eppstein

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January 2014

Hello, I'm BracketBot. I have automatically detected that your edit to Ju-Chin Chu may have broken the syntax by modifying 1 "[]"s. If you have, don't worry: just edit the page again to fix it. If I misunderstood what happened, or if you have any questions, you can leave a message on my operator's talk page.

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• <ref>[http://www.etaiwannews.com/who/index.php?view=339&category=6&lang=tc Who's Who], eTaiwanNews], retrieved 2014-01-02.</ref><ref name="Nobel">{{cite book | editor = Tore Frängsmyr | title = The

Thanks, BracketBot (talk) 22:51, 2 January 2014 (UTC)

Acceptability of List of quadratic irrational numbers set in a systematic order

When this page had still less explicitly named sources you voted in Wikipedia:Articles for deletion/List of quadratic irrational numbers set in a systematic order that it's unacceptable for the article name space because of WP:OR. In the following discussion in Wikipedia:Deletion review/Log/2013 December 17 I explained further my Keep-position with the simple possibility to add more explicit sources from the linked Wiki-articles, and with WP:CALC and other certain math articles which give also more complex own explicative conclusions (without explicit sources for them). The article Periodic continued fraction already explains that every quadratic irrational is exactly defined by its unique periodic cont. fraction so that a bijection like the one mentioned in the now restored and with more explicit sources added page version

• User:MathLine/List of quadratic irrational numbers set in a systematic order

is therefore possible. Also mathematical topics must be presented here with own words and in regard of

• Wikipedia:What SYNTH is not#SYNTH is not explanation and
• Wikipedia:What SYNTH is not#SYNTH is not presumed,

please allow me now this further question to the article: Is also this latest version still unacceptable due to WP:OR, especially WP:SYNTH? --MathLine (talk) 22:56, 3 January 2014 (UTC)

As far as I can see the topic of your article is to provide a specific enumeration for the quadratic irrationals. (The fact that an enumeration exists, i.e. that these irrationals are countable, is not sufficiently notable by itself, as it is a simple consequence of the fact that the algebraic numbers more generally are countable.) In order to avoid being original research, you need to find sources that explicitly describe that specific enumeration. I don't see any such sources in your current draft. —David Eppstein (talk) 23:14, 3 January 2014 (UTC)

Look, your reply is like writing “The topic of the article Exact trigonometric constants is to provide a specific enumeration for the sin, cos and tan values with rational degree arguments which are exactly specifiable with √-expressions.” Does any of the there at the end simply listed books contain exactly such a list in 3° steps? Or which source contains a clarification diagram for the chaotic course of Ω like presented in Arithmetic functions? Or which source contains exactly these magnification areas with these colors in Nova fractal? Answer to all 3: Apparently no in the Wikipedia mentioned source, but it's ok because also  further explanations derived from the sources contents  are here possible and, when made with high quality, welcome, according to WP:CALC and Wikipedia:What SYNTH is not#SYNTH is not explanation. Of course you can order finitely specifiable periodic cont. fractions pursuant to the method exactly described in the draft. This "of course" makes it clearly to an explanation like in these 3 examples. (Are there maybe special difficulties in the peoples mentality to accept such, because too many children over generations already have and had to calculate simply through quadratic formulas, so that a too rigid school teaching mentality developed together with a fear of any change in a so basic matter as it could impact math teaching methods in too many schools too much?) --MathLine (talk) 01:59, 4 January 2014 (UTC)

Ok, so apparently your chosen title and your current writeup have failed to communicate to me what you actually intend as the topic of the article. Perhaps that indicates a problem with your writing. —David Eppstein (talk) 02:13, 4 January 2014 (UTC)

I have perhaps indeed a problem with my writing. Thank you for the hint. But one question about this draft remains for me right now:

If none of the listed books at the end of Exact trigonometric constants explicitly describes such a listing in 3° steps, no mentioned source describes such a Ω course diagram in Arithmetic functions, and no source contains exactly these magnification areas with these colors in Nova fractal, so that all these 3 content pieces are accepted as WP:CALC and Wikipedia:What SYNTH is not#SYNTH is not explanation, why is this draft then different, why is it not likewise recognizable as further explanation and clarification of quadratic irrationals directly derived from the now even in this draft added source (which is also a source for Periodic continued fraction), also according to WP:CALC and Wikipedia:What SYNTH is not#SYNTH is not explanation? --MathLine (talk) 04:59, 4 January 2014 (UTC)

Well, it's the difference between a set and a sequence, right? We could have a list of quadratic irrational numbers, including the notable ones such as the golden ratio, the square root of 2, and the plastic number, not include the other ones, choose an arbitrary ordering (say, alphabetical by article title), write it in a way that doesn't emphasize the ordering as being important, and I doubt it would be a problem. (In fact there's sort of a mini-list of this sort in the template {{irrational numbers}}). But in your case the ordering of the list members seems to be significant information. Where does that information come from? —David Eppstein (talk) 07:57, 4 January 2014 (UTC)

You already find a list of irrationals in List of numbers#Irrational and suspected irrational numbers. The most there are quadratic irrational. That information—indeed about a sequence of ordered periodic continued fractions—comes directly from this article and keeping such a sequencing thought away from Periodic continued fraction is like keeping also the content pieces in these other 3 math examples away and the reader could likewise ask "Why not mention here this further view into it?" Doesn't deserve the topic algebraic irrationals more explicative listing and further sequencing than only this List of numbers#Irrational and suspected irrational numbers—according to WP:CALC and Wikipedia:What SYNTH is not#SYNTH is not explanation? —MathLine (talk) 01:07, 5 January 2014 (UTC)

Babylonian square root of 2 edit

I understand your change to my edit of the caption at square root of 2, but I have to question it. Interpreting the 30 glyph as 1/2 is elegant and produces the familiar 0.707…, but the image labels the side as 30 and I think the caption should describe the image. The move from 30 to 1/2 while legitimate, is not obvious to the likely audience of this article. We could add more explanation in the caption, but it is already long. A third option might be an article about the tablet itself, with details on the various calculations, including how to get from 1 24 51 10 to 42 25 35, if that would not be considered WP:OR. That article could be referenced in the caption here and other places the tablet image appears. What do you think?--agr (talk) 20:42, 8 January 2014 (UTC)

The point is that in the Babylonian number system there is no difference between 30 and 1/2. They are the same number. So when we convert these numbers to decimal we have to make a choice and we should choose the simplest option possible. 1/2 is simpler than 30, so it is a better translation. —David Eppstein (talk) 00:10, 9 January 2014 (UTC)

Yes, but the picture says 30, and the caption is there to describe the picture. We can't expect readers to know that "in the Babylonian number system there is no difference between 30 and 1/2" or why that is true.--agr (talk) 01:21, 9 January 2014 (UTC)

Shaleen Malhotra

Hello! The subject article was recently deleted by you as "Expired PROD, concern was: No third party sources that show WP:NACTOR and WP:ANYBIO". I don't know how the article did not get transcluded on Wikipedia:WikiProject India/Article alerts. But the subject actor seems to pass our notability guidelines. He was participant in one of the season of the reality show MTV Roadies and then also hosted some seasons. He later on has been playing the title role in the show Arjun that's currently on air since August 2012. (Ref for all). Can you please undelete it? Had the article been transcluded on the alert page, i would have deproded it. §§Dharmadhyaksha§§ {T/C} 06:22, 9 January 2014 (UTC)

 Done. —David Eppstein (talk) 06:30, 9 January 2014 (UTC)

That was very quick. Thanks! I will work on cleaning and referencing the article now. The image in it is a copyvio! §§Dharmadhyaksha§§ {T/C} 06:47, 9 January 2014 (UTC)

Christopher Karas

Hello, David. Could you have a look and tell us if sufficiently improved to overcome Wikipedia:Articles for deletion/Christopher Karas? (I don't think so. I need an uninvolved admin.) The suspense is terrible. Dlohcierekim 06:42, 9 January 2014 (UTC)

Oh, the hard working recreator has moved it to AfC Dlohcierekim 06:43, 9 January 2014 (UTC)

My guess is not. It doesn't seem to pass WP:BIO1E (the protest may be notable but that doesn't make him notable) and hasn't had time to demonstrate the enduring notability needed for WP:NOTNEWS. —David Eppstein (talk) 06:45, 9 January 2014 (UTC)

Relation between concept lattice and Dedekind–MacNeille completion

On 23 May 2011, you added an explanation about the relation between the concept lattice and the Dedekind–MacNeille completion to the articles on the Dedekind-MacNeille completion (http://en.wikipedia.org/enwiki/w/index.php?title=Dedekind–MacNeille_completion&diff=430554321&oldid=430549927) and the Formal concept analysis (http://en.wikipedia.org/enwiki/w/index.php?title=Formal_concept_analysis&diff=430553853&oldid=422121786). The statement made in the explanation is quite interesting, but not completely true. (The completion will contain each single object (and each single attribute), but the concept lattice only contains a concept for an object, if its attributes differ from all other objects. In other words, in the concept lattice, similar objects and similar attributes are merged together into a single concept, but the Dedekind–MacNeille completion won't merge anything.) A reasonable fix seems to be using x≤y ∧ x≠y instead of x≤y for defining the cuts, which would give a new construction related to both the concept lattice and the Dedekind–MacNeille completion. But without a reference to a primary source, it would be original research and hence unsuitable for wikipedia.

Do you still remember the original source where this explanation came from? Jakito (talk) 00:35, 13 January 2014 (UTC)

I don't remember what source I used for this (if I used a source) but essentially the same statement appears in Reuter (1989), "Removing critical pairs", Order 6: 107–118: He states that the concept lattice derived from (P,P,≤) where P is a partial order is the same as the Dedekind–MacNeille completion of P. —David Eppstein (talk) 04:46, 13 January 2014 (UTC)

The statement I'm interested in is rather: "It [=the concept lattice] may be viewed as the Dedekind–MacNeille completion of a partially ordered set of height two in which the elements of the partial order are the objects and attributes of M and in which two elements x and y satisfy x ≤ y exactly when x is an object that has attribute y." May I interpret your answer in the sense that this statement is an (over)simplified version of some basic theorem on concept lattices like: "A complete lattice L is isomorphic to B(G,M,I) if and only if there are mappings γ:G↦L and μ:M↦L such that γ(G) is supremum-dense in L, μ(M) is infimum-dense in L and gIm is equivalent to γ(g)≤μ(m) for all g∈G and all m∈M. Jakito (talk) 09:23, 13 January 2014 (UTC)

Constant function edits

With regards to your recent edit to the page: Constant function. Thank-you for not deleting the introduction or section 1. This is my primary consideration (and my primary contribution and the reason I edited the page (see Talk:Constant_function)). As illustrated by the citations carefully researched, it is the definition most central to this topic (and I believe the reason that most users enter the page). So hopefully it will remain, but my experience with the patrol of these pages is that this level of explanation is automatically deleted as "not mathematical".

---

Everything below is just conversation. I absolutely welcome any improvements in the continuity, readability and usability of wikipedia math pages to the user. I teach engineering mathematics (40 years), so these are not my forte and it really is fascinating to see how different people think about mathematics.

Also, I only added section 2 in the hope that the intro and section 1 would remain. However - if you have time- I would ask just in general...

(a) Section 2 "generalization" is(was) not unsourced. It was in the original article without source (albeit with different letters). It is a single sentence taken directly from: http://planetmath.org/ConstantFunction (in the external links) and constitutes the generalized set theory definition of the explanation given in the introduction. To me, an explanation is not a definition (and again I was concerned that without a formal mathematical definition both the introduction and section 1 would simply be deleted). Constant functions are not limited to real-valued functions of a real variable R->R).

(b) In what way do you think the 3 examples with simple graphics illustrating that the generalization of the term constant function defined between spaces other than the real numbers R is "unhelpful"? What does "unhelpful" mean here? Do you think other examples or more explanation would be better? I do not like leaving the reader jumping from basic algebra to abstract algebra in a single blow.

Example 1 and in consistency with the material (not my contribution) in e.g. the main link at the top of this article function (mathematics) showed that the domain and image of a constant function need not be analytic spaces. It is a particularly important definition of a constant function in computation and programming (where e.g. all values of an array are initially set to 0).

Example 2 was an example showing that the domain could be R^2 and this is the example of a constant function in Calculus II. Kiddies do not understand that a horizontal line in the plane extends naturally to a horizontal plane in 3d. (I had hoped that someone might add a bit on the fact that the concept of zero (partial) derivative extends here.)

Example 3 showed that the domain and range can be polar coordinates and not just rectangular coordinates. Here again I had hoped that someone might extend this discussion as kiddies tend not to understand that the constant polar function is a circle and not a line. (This function has so many applications and extensions, but I am not competent here.)

---

(c) Section 3 is completely unsourced and undocumented (not my contribution). It actually is about constant mappings and not constant functions. Why doesn't anybody care about that?

(d) Finally, I might ask why it was necessary by the previous editor to remove the See also link I had added to Linear function (calculus) (which BTW is mainly my contribution although improperly classified as calculus) since many consider a constant function to be a special case of a linear function (as defined in standard algebra).

---

Let me try to remember to sign this. (Always forgetting.) Lfahlberg (talk) 08:47, 14 January 2014 (UTC) Thanks for your time. Edited: Lfahlberg (talk) 10:52, 14 January 2014 (UTC)

«Linear function» is mainly Lfahlberg’s contribution? The cumulative diff lies here… enough said. Incnis Mrsi (talk) 10:55, 15 January 2014 (UTC)

Mark Overmars article

I have left you a response. Talk:Mark_Overmars#Article_Deletion — Preceding unsigned comment added by BlitzGreg (talk • contribs) 19:14, 16 January 2014 (UTC)

I have clarified my response now Talk:Mark_Overmars#Article_Deletion. BlitzGreg (talk) 19:46, 16 January 2014 (UTC)

Breweries prods

Hi David: Thank you for taking the prod off the List of breweries in California page. I don't know why the user who is prodding these lists all over the county is doing that, but they have plans to do it to the entire country![1] I really don't get some of the people who don't like the "lists of" parts of Wikipedia. The lists are very helpful in organizing data and assisting editors working on the topic. Also for California which is the largest producer of beer by volume in the U.S. I think the entire concept of Breweries in California is very relevant. In Humboldt County, the breweries are among our largest exporters of manufactured goods and some of our larger private-sector employers. They may not seem very important to the prodding editor - but they are of great importance to us, even those like myself who do not drink alcohol. I enjoy editing the Brewery pages in Humboldt because I figure I have the least WP:COI of any local wikieditor; I've not even been to three of them! Thanks again for removing the prod! Ellin Beltz (talk) 20:40, 16 January 2014 (UTC)

You're welcome. I also unprodded and improved the sourcing of two individual breweries that seem clearly notable to me: Triple Rock Brewery and Alehouse (one of the oldest in the microbrewery movement) and Mad River Brewing Company (known for its green production methods). But probably there are more of those that the same user prodded that should also be fixed up. —David Eppstein (talk) 21:16, 16 January 2014 (UTC)

Name of Pi

I edited the Name section of "Pi" because it contained a fundamental inaccuracy, which your reversion restored: "pi" is not a Latin word. Fortunately, User:Imaginatorium has re-corrected that inaccuracy, though without restoring my (arguably excessive) elaboration, and I have thanked him for it. --Thnidu (talk) 08:52, 17 January 2014 (UTC)

Yes, what's amazing is how long this claim has been there -- back in 2011 it appeared as "The Latin name of the Greek letter π is pi." which might be true, but is somewhat irrelevant. Imaginatorium (talk) 09:06, 17 January 2014 (UTC)

Ariana Ayam

FYI, Ariana Ayam was deleted and a new - or perhaps the same - article is now occupying that title. davidwr/(talk)/(contribs) 04:00, 19 January 2014 (UTC)

Ok, thanks for the heads-up. It looks like the prod lasted the proper seven days before the deletion, and recreation after a prod is completely permissible, so I don't think anything more needs to be done at this point. —David Eppstein (talk) 05:51, 19 January 2014 (UTC)

The only thing I can think of that might need doing is if it was a copy-and-paste of an off-wiki copy of the deleted article, in which case a WP:HISTMERGE may be needed if there was more than one significant editor and a more complete verison of {{old prod}} or {{old prod full}} should replace the template that is on the talk page now. Also, if the reasons for the PROD are still a concern, AFD should be considered. If it's NOT a copy-and-paste then the previous recommendations aren't relevant. davidwr/(talk)/(contribs) 02:33, 20 January 2014 (UTC)

The old version was neither the same text nor more complete, but I restored it anyway. —David Eppstein (talk) 02:37, 20 January 2014 (UTC)

People with Erdos number

I wonder why have you removed my addition of Wlodek Holsztynski?

He is listed here:

https://files.oakland.edu/users/grossman/enp/Erdos1.html

Web of Knowledge lists him with:

Siemion Fajtlowicz

I have no access to Math Reviews from home but it is inconceivable that:

ON POWERS OF BASES IN SOME COMPACT ALGEBRAS

By: FAJTLOWI.S (FAJTLOWI.S); HOLSZTYN.W (HOLSZTYN.W); MYCIELSK.J (MYCIELSK.J); WEGLORZ, B (WEGLORZ, B) COLLOQUIUM MATHEMATICUM Volume: 19 Issue: 1 Pages: 41-& Published: 1968 View Journal Information

Pls kindly notice that in 1968, abbreviated names were used but you can see it here:

http://journals.impan.gov.pl/cgi-bin/shvold?cm19

and more here:

by google with:

ON POWERS OF BASES IN SOME COMPACT ALGEBRAS — Preceding unsigned comment added by Eto5166 (talk • contribs) 01:26, 24 January 2014 (UTC)

Because the Wikipedia list only includes people who have articles about them on Wikipedia. Holsztynski does indeed have a small Erdős number but he has no Wikipedia article (and it was not obvious to me that he should have one; see WP:PROF for criteria under which an article could be justified). For instance, an h-index of 12 (from here, not counting the patents) seems too small to justify WP:PROF#C1 for someone who has been publishing for 50 years. —David Eppstein (talk) 01:31, 24 January 2014 (UTC)

I see your point but pure mathematicians usually do not have large number of publications or high indexes. For example, Frederick Bagemihl (used for ILLUSTRATION only!) has Wikipedia entry and H=5 by 'Web of Science' (by Thompson Reuters). Holsztynski has H=8.

Leon Bankoff (in Wikipedia) has H=1. In fact, I have just spoted: Average Citations per Item [?] : 0.05 and it may be a real record for any mathematician listed in Wikipedia...

Holsztynki moved to the industry but his theorem (Holsztynski Theorem) is till cited. His "Geometric_Arithmetic_Parallel_Processor" was breakthrough in parallel computing. It is hard to even imagine what impact it has on the high performance computing.

I am busy but will try to draft a simple article on Holsztynski.

In fact, I would like to thank you for mobilizing me to write about him.

This is what I have found today:

The majority of this work was funded by the DOD, which was motivated by the unique military need for performing pattern recognition (for targeting) on multiple high speed video data streams, within minimum military platform physical constraints (i.e., size, weight and power). These requirements resulted in the revolutionary development of the Geometric Arithmetic Parallel Processor (GAPP), a fine-grained, massively parallel, two dimensional mesh

computer architecture that is uniquely efficient for two dimensional, video processing

applications.

...

Lockheed Martin, with government sponsorship, has invested over $100 Million to

develop, apply and refine the GAPP architecture for solving complex, video rate image applications.

and I intent to contact the company who has the technology now to help him. One of the greatest contributors to computer technology completely unknown...

— Preceding unsigned comment added by Eto5166 (talk • contribs) 13:39, 25 January 2014 (UTC) 

Note that by mentioning the h-index I wasn't saying that would be the only way an article could be justified; only that it is the most common way to justify articles on academics but that this form of justification will not work for Holsztynski. So you will need to find some other way of making notability clear, perhaps via WP:GNG. —David Eppstein (talk) 16:59, 25 January 2014 (UTC)

I will look at it but in few days since it is the end of month and may things to close... This poor use interface is not helping... — Preceding unsigned comment added by Eto5166 (talk • contribs) 10:26, 30 January 2014 (UTC)

A barnstar for you!

	The Original Barnstar
	Really nice pics Franz Scheerer (Olbers) (talk) 18:24, 24 January 2014 (UTC)

Thanks! —David Eppstein (talk) 18:51, 24 January 2014 (UTC)

Golden ratio in art

David, if there is documented evidence of artists using the golden ratio in their works, we should document that with some refs. Or we should document some who "purport" it. As fas as I know, there's not much evidence of artists actually doing so, and if there is it's probabaly late 20th century. What you have found? Dicklyon (talk) 06:36, 29 January 2014 (UTC)

Oh, I meant the 20th century ones, mostly. I don't think there's much dispute over Le Corbusier, for instance. or Salvador Dalí. I thought the added adverb was too strong, implying that no artist really used the golden ratio, an obvious falsehood. Incidently, mathematics and art is a wealth of dubious credulousness, much worse than golden ratio. —David Eppstein (talk) 08:18, 29 January 2014 (UTC)

Thanks

Dear David: Thanks for fixing up my misplaced edit. That will teach me to edit in the middle of the night.... —Anne Delong (talk) 07:54, 31 January 2014 (UTC)

Wikipedia talk:Articles for creation/Jordan code

Your opinion there would be helpful. DGG ( talk ) 01:22, 3 February 2014 (UTC)

Elementary polytopes and set theory

Hi David, you reverted my recent edit to the polytope article on the grounds that polytope theory is not "part of" set theory. While abstract polytopes certainly come close, that was not my import. The point is that set-based formulations of geometry, such as treating any arbitrary geometric extent as a point set, are not part of elementary geometry, which deals with the consequences of Euclid's axiomatic treatment in his Elements. Somebody had added a note, and somebody else had added a note to a set-based idea in that note, which made it inappropriate to place in a paragraph which begins, "In elementary geometry...." I feel that the distinction between the approaches needs to be made explicit at the point the note is inserted. You have simply reverted ny effort without attempting to rectify the problem I attempted to rectify. Do you have a better idea? — Cheers, Steelpillow (Talk) 11:59, 13 February 2014 (UTC)

The point is that set theory is an area of research mathematics that has nothing to do with Euclidean geometry. It is about infinite sets of different cardinalities and their combinatorial properties. So calling the less-elementary parts of polytope theory "set theory" is completely mistaken. —David Eppstein (talk) 14:59, 13 February 2014 (UTC)

I am intrigued that you feel a need rephrase my comment above that "The point is that set-based formulations of geometry, such as treating any arbitrary geometric extent as a point set, are not part of elementary geometry, which deals with the consequences of Euclid's axiomatic treatment in his Elements." - seemingly as if I had not made it. Am I missing a subtle difference between our two meanings? Also, can you confirm whether [this edit] linking to a set-related topic is appropriate to the lead of an article on polytopes, if only in a note? It was this edit which prompted my revision which you found unacceptable. — Cheers, Steelpillow (Talk) 15:25, 13 February 2014 (UTC)

One might emphasise also that some non-elementary treatments, such as abstract polytopes are set-theoretic constructs, while many other models, especially of convex polytopes, invoke set=based models as I explained. So the fact that a treatment is not Euclidean does not debar it wholly from an article on polytopes, but merely from those parts dealing with elementary treatment. — Cheers, Steelpillow (Talk) 15:30, 13 February 2014 (UTC)

Repeating your mistake in a second comment does not make it any less a mistake. This is not set theory. It may be advanced mathematics, and may model polytopes as sets of points just as modern algebra models arithmetic values as sets of elements of a ring or field, but this is inescapable in any branch of mathematics and conveys no distinction from the elementary theory. More to the point, none of those things is what is conveyed by calling something set theory. Calling something "set theory" to me means I am likely to see something involving infinitary combinatorics or descriptive set theory or the like, none of which has much relevance to polytopes. Or, to put it another way: "elementary geometry" uses exactly as much set theory as any other kind of geometry, it's just hidden under the covers a little more thoroughly. —David Eppstein (talk) 06:28, 14 February 2014 (UTC)

OK, so I take it that you view the previous editor's work - here is the diff - as acceptable because the use of "bounded set" is within the purview of Euclid's axioms? My own view is that, while the two approaches are consistent, the use of point sets is not definitive in this context and is therefore out of place in a definition inserted into a paragraph discussing the elementary case. That is to say, the logical development based on axiomatic treatment does not run. "this point set is unbounded, so we say that the region extends indefinitely," but rather, "this region extends indefinitely, so we say that the point set within it is unbounded." Set theory is not so much hidden under the covers as painted over them. I am aware that this is contentious to some philosophers of mathematics - there is a view that everything is set theory but this is far from universal, there is also a view that while set theory can be applied to most things, it is not always foundational to them. This is perhaps most visible in axiomatic projective geometry, where "points", "lines" and "planes" may remain wholly abstract primitives and say defining a line segment as a dense point set becomes untenable. — Cheers, Steelpillow (Talk) 11:03, 14 February 2014 (UTC)

Request to userfy the page

Hello, I'm a student and I have a problem. About one month ago, I created page named Pacific Premier Bancorp and The Cato Corporation, but they had been deleted because the companies do not assert notability. But these companies are my homework and my teacher requires me to create them. I know you are very busy as an admin, but would you please userfy the pages? I'll improve the quality of the pages and I can also learn from it. Thank you!ReganChai([User:ReganChai|ReganChai]]) 09:45, 16 February 2014(UTC)

 Done. They're now at User:ReganChai/Pacific Premier Bancorp and User:ReganChai/The Cato Corporation. —David Eppstein (talk) 17:47, 16 February 2014 (UTC)

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Question about ring theory

Hello Mr. Eppstein,

I am a Wikipedia user from the german Wikipedia, and I translated your article Kawasaki's theorem, and you are the only mathematician on the English Wikipedia I know. Today an IP address reverted one of my few edits on en-wp, but I did not agree with the revert. Therefore, I wanted to ask if I missed something. --Mathmensch (talk) 17:11, 17 February 2014 (UTC)

I see my mistake now. --Mathmensch (talk) 17:14, 17 February 2014 (UTC)

Ok, I was just about to explain it. I agree with the IP. —David Eppstein (talk) 17:16, 17 February 2014 (UTC)

I reverted the article so that the mistake is corrected. --Mathmensch (talk) 17:36, 17 February 2014 (UTC)

Math-Bridge

hi! I’m in a hurry, but just a few words re: your revert.

I’ve seen the RfD from 2011, but 1. the arguments are no longer valid 2. consensus was to merge but it is not merged now (IDK whether it has been ever).

please reconsider your revert. KTHXBYE Torzsmokus (talk) 16:09, 21 February 2014 (UTC)

So what is your argument that this project has newly become notable? I don't find "the arguments are no longer valid" to be convincing — what has changed to cause them to become invalid? —David Eppstein (talk) 16:54, 21 February 2014 (UTC)

Stacy Blackman

Wanted to get feedback on how to improve the deleted Stacy Blackman article. I though the changes I made, which I posted on my talk page addressed your concerns regarding bad sources. What could I do to improve it? Thanks —Artfog (talk) 20:20, 28 February 2014 (UTC)

I'm not sure this is even the right question. The question should be: is this subject notable enough to appear in Wikipedia. Instead you seem to be asking: how do I make the Wikipedia article portray the appearance of notability. —David Eppstein (talk) 20:40, 28 February 2014 (UTC)

I thought the subject fits the criteria Wikipedia:Notability_(people), since she is both the subject of multiple articles and "has made a widely recognized contribution that is part of the enduring historical record in his or her specific field.". I don't see why it doesn't fit the notability criteria. —Artfog (talk) 20:53, 28 February 2014 (UTC)

Many of the comments at Wikipedia:Articles for deletion/Stacy Blackman disagree, and give reasons why the editors who wrote them think she doesn't fit the criteria. —David Eppstein (talk) 02:14, 1 March 2014 (UTC)

March 9 edit-a-thon at MOCA in downtown LA

LA Meetup: March 9 edit-a-thon at MOCA

Dear fellow Wikipedian, You have been invited to a meetup and edit-a-thon at the Museum of Contemporary Art in downtown Los Angeles on Sunday, March 9, 2014 from 11 am to 6 pm! This event is in collaboration with MOCA and the arts collective East of Borneo and aims to improve coverage of LA art since the 1980s. (Even if contemporary art isn't your thing, you're welcome to join too!) Please RSVP here if you're interested. I hope to see you there! User:Calliopejen1 (talk) To opt out of future mailings about LA meetups, please remove your name from this list.

Dedekind–MacNeille completion

Re revert: it kind of makes the plural in "some other related concepts" misleading, though. I think that the two concepts can hardly be confused for one another, and even if so, the relation between them should be discussed by proper prose, not by a bullet-point-like hatnote. Keφr 17:00, 8 March 2014 (UTC)

I think the relation should be discussed both by prose and by a hatnote. Specifically, the Dedekind completion of the rationals to the real numbers is a particular instance of the Dedekind-MacNeille completion of partial orders (in this case the total order of the rationals). —David Eppstein (talk) 17:30, 8 March 2014 (UTC)

I tend to agree with David Eppstein. However, discussions like this would be better held at the article talk page. I have Dedekind–MacNeille completion on my watchlist, but only saw the discussion here by coincidence. Deltahedron (talk) 17:57, 8 March 2014 (UTC)

March 2014

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• Second Series | year=1912 | journal=[[Annals of Mathematics]] | volume=14 | issue=1 | pages=86–94}}.</ref> every Eulerian subgraph of a given graph can be decomposed into [[Cycle (graph theory)|

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Eugene Plotkin (mathematician) -Removal of BLP PROD

Hi David. I noticed you took down the BLP Prod I had placed on Eugene Plotkin (mathematician). In your explanation you assert that it is only for articles with no sources whatsoever. However my understanding is that it applies to articles with no RS sources whatsoever. That's an important distinction. And in fact the wording on the BLP Template is that all articles must have at least one reliable source. In my opinion none of the sources cited, including the external links, pass RS. If I am reading the guidelines wrong, or you think one of the sources actually passes RS, I am open to correction or at least discussion. No claim to infallibility here. But if I am not wrong, then we have a problem. For the record I did a Google search that produced a lot of hits, but failed to yield anything that IMO meets RS. Most were related to other people with the same name, one of whom is under investigation by the SEC. Also for the record I didn't spend hours digging around the internet. But I did look. Anyways maybe there has been a miscommunication or maybe I missed something, but as of right now I very respectfully disagree with your removal of the PROD. Best regards -Ad Orientem (talk) 06:23, 10 March 2014 (UTC)

The sources already in the article include {{mathgenealogy}} and a faculty profile from the university at which the subject works. These don't attest to notability but are good for basic factual data such as the subject's education and employment. And the publications listed are primary but are at least reliable for the fact that the subject has published them. As such, the article is not unsourced. —David Eppstein (talk) 06:24, 10 March 2014 (UTC)

I think the argument for RS on any of the sources is a stretch. But I am going to defer to your judgment because I am convinced that the subject is highly notable and there is no doubt he exists. Also it seems likely that this is a case where the really good sources are probably not going to be in English. Clearly someone didn't just make this all up. Anyways moving on, and thanks for the discussion... -Ad Orientem (talk) 06:40, 10 March 2014 (UTC)

Indexed language: "citation needed"

Hi ‎David Eppstein, to answer your question from the edit summary: No, it isn't too much to ask of people tagging articles for citation needed that they at least skim the reference that looks like it might cover the sentence in question to see whether it really does. - My problem was (and is), that I don't have access to the article Aho 1968 (I admit I should have noted that in the cn reason); otherwise I would have checked it myself. Anyway, thanks for checking and answering the cn. Sorry for the inconvenience. - Jochen Burghardt (talk) 19:03, 17 March 2014 (UTC)

Fair enough. In this case if you followed the doi link you should at least have been able to read the abstract for the paper, which turns out to contain the statement in question. —David Eppstein (talk) 19:52, 17 March 2014 (UTC)

Deletion question

Hi. I found this page User:Anonymous ddoser, and I'm not sure how to tag it for deletion. Can you take a look? Thanks. Rosario Berganza 20:56, 19 March 2014 (UTC)

It expresses a political view, but doesn't seem to me to be offensive or off-topic enough for speedy deletion. If you want it deleted, I think the appropriate process is via Wikipedia:Miscellany for deletion. —David Eppstein (talk) 21:58, 19 March 2014 (UTC)

It's a copy-and-paste of the article Bankruptcy. Rosario Berganza 01:22, 20 March 2014 (UTC)

Yes, with a political statement tacked on at the end. And? —David Eppstein (talk) 01:41, 20 March 2014 (UTC)

You could be less of a dick about it. 01:43, 20 March 2014 (UTC) — Preceding unsigned comment added by Rosario Berganza (talk • contribs)

Well, I don't understand why you think it's important that it be deleted, rather than letting whoever it is have their little rebellious fun. —David Eppstein (talk) 01:54, 20 March 2014 (UTC)

I wasn't clear on whether that copy&pasting was ok or not. If it is, you could've just told me nicely that it was ok and that there was no need to tag it for deletion. There was no need to be short with me like that and act like I was annoying you or something. Rosario Berganza 02:02, 20 March 2014 (UTC)

A barnstar for you

		The Original Barnstar
		A barnstar for your impressive rewrite, expansion, and clarification of Cycle basis and Cycle space! Both articles are a nice window into the algebraic topology of graphs. Mark viking (talk) 23:56, 20 March 2014 (UTC)

Thanks! —David Eppstein (talk) 15:57, 21 March 2014 (UTC)

Vi Hart 3RR Rule

You yourself violated the rule. This is a case of the pot calling the kettle black. If you impose a 24-hour ban on me, then you will have to ban yourself also. Jay Gatsby^(talk) 07:23, 31 March 2014 (UTC)

I stopped at the third revert. You did not. The rule is *no more than* three reverts. You had four tonight. And of course I'm not going to impose anything on you; I'm too closely involved. Someone else will have to do it. —David Eppstein (talk) 07:24, 31 March 2014 (UTC)

"Not listed in the mathematics genealogy project"

Re your inane statement in your new Category:Amateur mathematicians that amateurs are not listed in the mathematics genealogy project: Actually, this is a completely separate issue. People who do not have a doctorate in a mathematical discipline are not listed in the mathematics genealogy project. This is correlated with but logically unrelated to the question of whether they are paid to be a mathematician. And your listing of Vi Hart as an amateur is also dubious since she has in fact been paid (by the Khan academy among others) for her mathematical work. —David Eppstein (talk) 07:31, 31 March 2014 (UTC)

I merely copied the text from the List of amateur mathematicians, a list which has existed since 2004. Jay Gatsby^(talk) 07:34, 31 March 2014 (UTC)

Ok, you copied someone else's stupidity rather than writing it yourself. That reflects well on you. —David Eppstein (talk) 07:36, 31 March 2014 (UTC)

I am not going to engage in name calling here. I'm waiting for evidence that Vi Hart is an expert in some field of math. Being an educator/entertainer does not count. Jay Gatsby^(talk) 07:37, 31 March 2014 (UTC)

BTW, she's being paid to make entertaining YouTube videos, and to educate the internet world; not to do any real mathematics. Jay Gatsby^(talk) 07:36, 31 March 2014 (UTC)

You keep saying that anything other than research mathematics is not real mathematics and doesn't count, but I still don't see any justification for such a limited view. Repeating the same thing over and over again without going into more detail won't help persuade anyone else of your side of the issue. —David Eppstein (talk) 07:40, 31 March 2014 (UTC)

I never said "reasearch" mathematics or "professional" mathematics. I said that the person has to be considered an expert in their field, which is the definition of the word "mathematician." Jay Gatsby^(talk) 07:49, 31 March 2014 (UTC)

Removal of deletion tags from the target of an active deletion discussion

Please do not remove Articles for deletion notices from articles or remove other people's comments in Articles for deletion pages, as you did with Category:Amateur mathematicians. Doing so won't stop the discussion from taking place. You are, however, welcome to comment about the proposed deletion on the appropriate page. Thank you. —David Eppstein (talk) 07:46, 31 March 2014 (UTC)

What is the reason for the deletion tags? Because you simply dislike the category? So much for NPOV. Jay Gatsby^(talk) 07:48, 31 March 2014 (UTC)

Go read the CfD. It doesn't matter what the rationale is or whether I agree with it. The rule is: Do not ever remove active deletion discussion notification messages. By doing so you only make it harder for others to find and contribute to the discussion, which will carry on regardless. —David Eppstein (talk) 07:52, 31 March 2014 (UTC)

Wikipedia talk:Manual of Style/Lead section#WP:BOLDTITLE and election articles

I have started a discussion that may interest you at Wikipedia talk:Manual of Style/Lead section#WP:BOLDTITLE and election articles. Anomalocaris (talk) 08:11, 3 April 2014 (UTC)

Grammatical Discussion

Dear David,

These collaborative discussions are thrilling and enlightening.  :) I hope to work with you in the future.

Duxwing (talk) 04:27, 8 April 2014 (UTC)

Buddy Martiin

Hi David, I am a very novice wiki contributor who is diving in head first to learn. I need your help re: Buddy Martin. Buddy is an emmy-award winning sports producer and award-winning newspaper editor and sports columnist (remember those !?!) who has been in the public eye for more than 50 years. I am in the process of collecting together all the credible references and citations to demonstrate this. However, because he is my dad, I know first hand that he is notable for all the reasons mentioned in the previous sentence. Can you please restore the page and give me a bit more time? Since the internet was invented in the middle of his career, some of his credentials are harder to track down online. However, as he is now 76 years old, he has expressed a desire for me to help him with this task. So I am hoping to get it done for him, including wiki approval, by father's day.

Thanks so much, Lori Gregory — Preceding unsigned comment added by Lmartin gregory (talk • contribs) 00:46, 16 April 2014 (UTC)

I don't want to restore it directly to main article space, because (in the state in which it would be restored) it has no references. And you should be aware of WP:COI. But I would be willing to userfy it, moving it to User:Lmartin gregory/Buddy Martin where you could continue to work on it until it meets our standards for sourcing. Would that be acceptable? —David Eppstein (talk) 00:52, 16 April 2014 (UTC)

That would be great, David. Then it will give me time to fix it when I can. Is there a time limit for how long it can be 'userfied'? Thanks so much, L M Gregory 01:21, 16 April 2014 (UTC)lori — Preceding unsigned comment added by Lmartin gregory (talk • contribs)

 Done. I don't know of any time limits. —David Eppstein (talk) 02:13, 16 April 2014 (UTC)

great! thank you so much L M Gregory 16:47, 17 April 2014 (UTC) — Preceding unsigned comment added by Lmartin gregory (talk • contribs)

Thomas Alured Faunce edit

Good catch. I didn't notice that it was unsourced. -Ad Orientem (talk) 03:23, 17 April 2014 (UTC)

Erdos Number Article

This is the URL for the Erdos Number article: http://en.wikipedia.org/wiki/Erd%C5%91s_number. Try pasting it into your browser. You get a "BAD TITLE" error caused by the character used in his name. This should be fixed. The same is true for his biography page. — Preceding unsigned comment added by 66.66.65.201 (talk) 14:41, 17 April 2014 (UTC)

It works for me, regardless of whether I click on the link you gave directly or whether I copy and paste it into my browser. I suspect the appropriate fix is: you install a better browser. —David Eppstein (talk) 15:18, 17 April 2014 (UTC)

On the article "Kodaira dimension"

Dear Mr David Eppstein! Please see the note of the article "Kodaira dimension." My best regards.--Enyokoyama (talk) 14:07, 18 April 2014 (UTC)

I do not know, but assume that new User:Noellapin meant to question [2] whether the name and the notation κ were introduced as opposed to used in that reference. The latter could of course be verified by reading the reference: the former would indeed require further support. Deltahedron (talk) 17:07, 19 April 2014 (UTC)

A real semantic difference?

In this edit what are the two distinct meanings in English as English is used and understood? The editor who uses the pseudonym "JamesBWatson" (talk) 20:41, 18 April 2014 (UTC)

The answer will probably involve the difference between British and American English in the use of "which" in restrictive clauses. Deltahedron (talk) 20:54, 18 April 2014 (UTC)

Maybe, but I have no idea whether this distinction is supposed to be American or English. The difference is that one uses "which" descriptively and "that" restrictively: "clouds, which are in the sky, ..." describes all clouds. But "horses that are in the barn" describes a subset of horses, the ones that are not somewhere else. —David Eppstein (talk) 21:06, 18 April 2014 (UTC)

PS The Chicago Manual of Style agrees, as does the BBC. So I doubt this is a trans-Atlantic style difference. —David Eppstein (talk) 21:10, 18 April 2014 (UTC)

Then you would be wrong: Note that in British English, the word which is often used interchangeably with the restrictive that ... This common British construction is not strictly incorrect in American English, but it is generally avoided, especially in formal writing. Oxford Dictionaries. Deltahedron (talk) 21:32, 18 April 2014 (UTC)

Maybe it's the BBC that you think is wrong? In the link I gave above, they say it's often interchangeable but then they go on to express exactly the same distinction I did. The examples where it's interchangeable are other usages than these. —David Eppstein (talk) 22:39, 18 April 2014 (UTC)

I am sure you are correctly expressing the rules you learned in school and which are general in American English. I am equally sure that in British English the rules are different on this point. So I am sure that you are wrong to doubt that there is a transatlantic difference on this point. Or maybe it's the Oxford Dictionary you think is wrong? Anyway, as far as writing articles is concerned, WP:ENGVAR applies. Deltahedron (talk) 06:46, 19 April 2014 (UTC)

You still haven't read the BBC link I pointed you to, have you? —David Eppstein (talk) 07:03, 19 April 2014 (UTC)

I read it the first time round. It is advice to those learning English. In what way could it override the statements of fact I showed you about there being differences between British and American English on this particular point of style? Perhaps in urn you would like to consider the Oxford Dictionaries link? Deltahedron (talk) 11:26, 19 April 2014 (UTC)

Conway's Game of Life example

Hi David,

I am just writing to you with a quick query. I added a simple example of a functioning Game of Life simulator to the Wiki Page for Conway's Game of Life, and while I have no issue with you doing so, I am just wondering your reasons for removing the link.

I thought that adding a quick and simple demonstration of the game would be of benefit to the page. Additionally I was very careful that the page I linked to was in no way advertising myself or anything else.

Kind regards,

Chris

There's a comment at the top of the list of life programs in that article explaining the criteria for inclusion. The basic issue is that at this point there are probably millions of Life programs and we can't list them all, so we have to be highly selective rather than just taking everything that someone takes the trouble to link. —David Eppstein (talk) 15:48, 23 April 2014 (UTC)

Hi David, I appreciate your prompt response. I completely understand and agree with your reasoning, although I would have to question the last link currently on the page ("Cellular Automata FAQ – Conway's Game of Life"). Most of the simulators this page subsequently links to either no longer exist, with one site having even been flagged by Google as containing malware! I totally understand that you cannot possibly list all possible simulators but I don't think any of the existing links provide reasonable access to a functioning simulator, which would be invaluable for users to get a complete understanding of the game. I'm not suggesting my link by any means, but I feel a review of some of the links present would be beneficial. Many thanks again, Chris. — Preceding unsigned comment added by ChrisLongridge (talk • contribs) 16:18, 23 April 2014 (UTC)

Theil–Sen estimator

On [3]:

If the Kendall's tau correlation between the original value and its estimator were approximately zero, then it wouldn't be an estimator at all, because its results looked like independent from the estimated variable. Even on the figure in the Wikipedia article one can see the correlation is rather 1 than 0. It's also easy to show a counterexample: if y_i = x_i, then the estimator mx_i + b = 1x_i + 0 = x_i = y_i and thus the tau correlation between the estimator mx_i + b and the original value y_i is equal to one. I believe it's just an error in the Wikipedia article, but I have no sources to back this statement, so I tried to insert {{fact}} and possibly remove it. Could you quote the exact passage from the Sen's work or "Rousseeuw & Leroy (2003) pp. 67, 164" used as a reference in the article? Google books show only page 67, where there is nothing about the tau coefficient. Best regards, Olaf (talk) 19:23, 27 April 2014 (UTC)

Figure on Permutation Graph page

Your revert points out that the permutation figure at Permutation Graph is meant to be read as going from bottom row to up. I do take your point that the caption matches the figure, but isn't the figure itself problematic? Cauchy's two-row notation goes the other way (at least that's the convention detailed in Permutation and the row annotated as [1 2 3 4 5 ..] is customarily taken as the original ordering while the other row gives it's image under the permutation.

Should a revised figure be used?