User talk:David Eppstein/2014b

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. 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)
 * ✅. 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 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 :

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 yi = xi, then the estimator mxi + b = 1xi + 0 = xi = yi and thus the tau correlation between the estimator mxi + b and the original value yi 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)


 * I have made a comment about the correlation coefficient being zero on the article talk page. But I would comment that the edit summary cited above ("so read the reference given in the same sentence and fix it, don't falsely state that there is no reference") is far from optimal.  Firstly, the reference in the same sentence does not support the assertion made: indeed, Kendall's tau is not mentioned on either of the pages mentioned (I was able to see both), or indeed anywhere else in the book, according to the index, so the tag is justified.  Secondly, to characterise a fact tag as a false statement is overly aggressive given that this is a clear good-faith attempt to resolve a genuine issue.  Thirdly, the burden of providing adequate citations to support the text is on the writer, not on the subsequent reader.  Deltahedron (talk) 20:05, 27 April 2014 (UTC)
 * Book? We are talking about Sen's paper. From pp. 1380–1381, where $$N$$ is the number of nonzero differences among the pairs of $$t_i$$ values: "For any real $$b$$, define $$Z_i(b)=Y_i-bt_i, i=1,\cdots, n$$. We then consider the following statistic basically related to Kendall's [6] tau between $$t_i$$ and $$Z_i(b), i=1,\cdots, n$$.
 * $$U_n(b)=\left\{N\binom{n}{2}\right\}^{-\frac{1}{2}}\sum_{1\le i<j\le n}c(t_j-t_i)c(Z_j(b)-Z_i(b)).$$ (2.2)
 * Thus $$\left\{N\binom{n}{2}\right\}^{\frac{1}{2}} U_n(b)$$ is the difference-sign score that would appear in the numerator of the tau coefficient of correlation between the $$t_i$$ and the $$(Y_i-bt_i)$$ for some fixed $$b$$ ... one way of estimating $$\beta$$ is to make $$U_n(b)$$ (by a proper choice of the estimator $$b$$) as small as possible. Since, $$U_n(b)$$ is non-increasing in $$b$$, there will be an half-open interval (in $$b$$) for which $$U_n(b)$$ will be equal to zero. The midpoint of this interval suggests itself as a natural estimate of $$\beta$$."


 * I.e. he is choosing the median (the midpoint of the zero interval) in order to make $$U_n$$ (a multiple of the numerator of the tau correlation and hence the tau correlation itself) as close to zero as possible. —David Eppstein (talk) 20:11, 27 April 2014 (UTC)
 * The "book" in question is the one you mentioned in your edit summary: "the reference given in the same sentence" is the book "Rousseeuw & Leroy (2003) pp. 67, 164". Deltahedron (talk) 20:22, 27 April 2014 (UTC)
 * No, that's the previous sentence. The reference on the sentence we're actually talking about is "As Sen observed". The name-check to Sen is a reference. —David Eppstein (talk) 20:28, 27 April 2014 (UTC)
 * Then you needed to explain that in the edit summary, which managed to confuse, and waste the time of, two readers. The single word "Sen" is not a reference.  "Sen (1968)" or "Sen (op cit.)" or even "Sen's paper" is a reference.  "Sen" is a person.  Deltahedron (talk) 20:41, 27 April 2014 (UTC)
 * Well, as long as we're being condescending, you could work on your reading skills. What did you think his name was doing as part of that sentence? And why did you think the placement of the footnote at the end of the previous sentence meant it was the only thing that could be the reference in question? As for how to cite: my understanding is that in Harvard style one uses Sen (1968) for the first use of a term and then can abbreviate it in later cases where it would be obvious to a competent reader. Much as one only wikilinks the first use of a term that has a separate article and then avoids repeatedly linking again, because the overlinking becomes more annoying than helpful. —David Eppstein (talk) 20:48, 27 April 2014 (UTC)
 * I don't know what was his name doing in the sentence in question, but the sentence was obviously wrong - it's not an estimated value but its residual being used in this correlation. Now I have fixed it using Deltahedron's sources. Please don't address reading skills of other people, it's not in the line of a university professor, and you are not the only one coming from the academia here. Olaf (talk) 20:56, 27 April 2014 (UTC)


 * The comment "you could work on your reading skills" is the sort of language that tells that I need not attempt to pursue the conversation any further.  Deltahedron (talk) 20:59, 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? — Preceding unsigned comment added by 5.102.200.57 (talk) 19:48, 27 April 2014 (UTC)
 * I think you were right the first time. Let's change the caption as you previously suggested and leave the figure in place. —David Eppstein (talk) 20:11, 27 April 2014 (UTC)


 * David - Now you've confused me. I agreed with your first revert and don't know why you changed back. As I see it, the graph is no longer the permutation graph of the written permutation (vertex 5 should have degree 3 since it is involved in three inversions). Bill Cherowitzo (talk) 04:13, 28 April 2014 (UTC)
 * I might have confused myself, trying to think about the permutation in terms of how it acts on things rather than as just a sequence of numbers. But you only need the sequence of numbers interpretation for these graphs. The figure was definitely intended to be read top down: the top row is $$i$$ and the bottom row is $$\sigma(i)$$. —David Eppstein (talk) 04:39, 28 April 2014 (UTC)
 * And I'm confused as well. I suggested (Edited)(4,5,2,1,3) and I still think it is the correct notation for the bottom half of the figure. If we read elements as going from top to bottom then (Edited)f(1)=4,f(2)=5,f(3)=2,f(4)=1 and f(5)=3 which corresponds to (4,5,2,1,3) in single row notation. Earlier, I thought perhaps the top half of the figure (the actual permutation graph) was not invariant under such a reversal, but I checked again and this doesn't seem to be the case (perhaps a general property). Specifically, when the bottom half of the figure is read from top to bottom I see the element 5 is involved in only 2 inversions and not 3 as Bill suggests, that is in the lower figure only 1 and 2 are inversion with respect to 5.
 * ...also, the numbers on the bottom row are emphatically not $$\sigma(i)$$. $$\sigma(i)$$ is the *position* to which the corresponding element goes, the bottom row is the actual element that ends up there. That is if $$\sigma(x)=y$$ then the bottom row of numbers in the figure at position y corresponds to x not $$\sigma(x)$$. — Preceding unsigned comment added by 188.120.155.109 (talk) 12:38, 29 April 2014 (UTC)
 * I was referring to the incorrect 45213 permutation. I know of absolutely no source in which $$\sigma(i)$$ refers to the "position" of i after the permutation, although I have seen this statement elsewhere on WP. As a permutation is a function, this interpretation would go counter to every convention of functional notation that I am aware of. Bill Cherowitzo (talk) 17:15, 29 April 2014 (UTC)
 * I edited above as I got things mixed up despite my best efforts. I still contend that f(1)=4,f(2)=5,f(3)=2,f(4)=1 and f(5)=3 corresponds to (4,5,2,1,3) and that this is consistent with Permutation, and at least a couple of abstract algebra I've recently spent time with. Let's put aside my use of the term "position" if that only muddles the issue.
 * "f(1)=4,f(2)=5,f(3)=2,f(4)=1 and f(5)=3 corresponds to (4,5,2,1,3)" is correct, but has nothing to do with the permutation depicted in the article. What is there is just a simple 2-line permutation notation (the straight lines are put in to help count the inversions), and in its one-line form it is just the second line, written as is. I do not think that we should be cluttering David's talk page with this. If you want to continue this "discussion", use my talk page. I am curious as to what on the permutation page is leading you to this bizarre interpretation. Bill Cherowitzo (talk) 19:04, 29 April 2014 (UTC)

Fine, moved to your talk page. Ultimately the "bizzare" interpretation is that there are different ways to visualize the same math and my intuition differs from yours. Larkin2 (talk) 19:14, 29 April 2014 (UTC)

Proof via König's theorem section on Dilworth's theorem page
Hi David,

I just had a question regarding this statement " Let A be the set of elements of S that do not correspond to any vertex in C; then A has at least n - m elements (possibly more if C contains vertices corresponding to the same element on both sides of the bipartition)".

I believe that C can never have any duplicate elements otherwise this can't be a vertex cover on a comparability graph! According to Konig's theorem: every matched edge has exactly one of its endpoints in C. Assume we had 2 vertices in C that correspond to the same element X on both side of bipartition, let's call the vertex on the left side X L  and the one on the right side X R . Then there exists some element Y L  that's matched to X R  and also there exists some element Z R  such that X L  is matched to. Now there must be an edge from Y L  to Z R  in the comparability graph! So if we ever include both X R  and X L  in C then C will not be a vertex cover since there is an uncovered edge Y L  to Z R .

I've made an edit to the page. Please let me know what you think. Adel Ali (talk) 09:33, 28 April 2014 (UTC)
 * I believe also that C can't have duplicate elements, but as a consequence of the proof (otherwise we wouldn't have equality at the end). Stating it in the middle of the proof requires an extra argument and makes me worry about potentially circular reasoning, and isn't really necessary (at least that many elements is good enough). Also, in your argument for why there can be no duplicates, why do you assume that X is matched to anything? —David Eppstein (talk) 17:29, 28 April 2014 (UTC)
 * Well you may have a point here but I fear that this is a bit misleading (at least this was the case for me when I was learning about Dilworth's theorem for the first time). And regarding your question, since X is in the minimum vertex cover, it must be matched to something in the maximal matching, otherwise the vertex cover is not minimal. Adel Ali (talk) 20:07, 28 April 2014 (UTC)

A beer for you!

 * Thanks! *raises glass* —David Eppstein (talk) 07:17, 1 May 2014 (UTC)

Karen Henwood
It was an odd case, I was very iffy about it-but as all I could find was one page that had her name not including ones that linked to references (which you are not apparently allowed to link to) and the fact it had that tag on it. Also I have seen some doctors/phd people get tagged for deletion who have written stuff. I was very unsure to tag her or not-but I think in a way it might of helped her article get more cleaned up now ha ha. But yeah thanks for clearing anything up.

Wgolf (talk) 18:52, 1 May 2014 (UTC)

Disambiguation link notification for May 5
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Control points article
Hi… Could you join the discussion on the  control point talk page ? I'm a bit confused about the usage of the term and wonder if it's not more general than computer graphics/design. Thanks! --Jhfrontz (talk) 22:27, 5 May 2014 (UTC)

Song of the South
The introduction to this article has a tone that seems steeped in bad reporting. I'm not trying to whitewash anything, I just think all the facts should be there, and with less hysteria. The idea that the film is *widely held* to be racist is unapparent when one looks at all the things written about it, not including the hundreds of comments online by people who have actually seen it. I won't bother touching the intro again, but I would like to see more fact and less presupposition. Dutchmonkey9000 (talk) 18:07, 7 May 2014 (UTC)
 * It's not hysteria to report that it's widely perceived to be racist. It's neutral unbiased reporting of the sources. Removing that fact is whitewashing and Wikipedia has come under harsh criticism for past iterations of the same whitewashing; see e.g. http://nielsenhayden.com/makinglight/archives/015385.html and the comments therein. In particular, Wikipedia's neutrality does not mean removal of opinions from Wikipedia article, it means reporting what the significant opinions on a subject are and who holds them. —David Eppstein (talk) 19:04, 7 May 2014 (UTC)

May 2014
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 * year=2011}isbn=9781133708964|page=48|url=http://books.google.com/books?id=sZYJAAAAQBAJ&amp;pg=PT63} . and digital clocks.  Leading zeros are also generated by many older

Norman J Wildberger Article Issue
The article Norman J Wildberger has been proposed for deletion&#32; because of the following concern:
 * Having a Youtube channel does not make you notable, and looking at it the Youtube channel is hardly popular or famous, by just the viewcount. No other evidence of or claim to notability.

But you guys are doing something ethically wrong. You cannot redirect Norman J Wildberger to rational trigonometry page!!!! Rational Trigonometry is an area in mathematics. You cannot replace a person's name with an area in mathematics. I do strongly believe that Norman J Wildberger deserve to be in wikipedia. He is famous trough his Youtube channels of  Mathematics. I don't have any connection with him but I know him though internet. This clearly say that he is a notable personality. Your wikipedia editing is guided by professional jealousy !! I seriously doubt about that ! If you are a good wikipedia editor, then try to add more references and content to that page, that will be really appreciated. — Preceding unsigned comment added by Sijothankam (talk • contribs) 13:21, 10 May 2014 (UTC)

Proposed deletion of Norman J Wildberger


The article Norman J Wildberger has been proposed for deletion&#32; because of the following concern:
 * Having a Youtube channel does not make you notable, and looking at it the Youtube channel is hardly popular or famous, by just the viewcount. No other evidence of or claim to notability.

You cannot redirect the page of a Mathematician to a page about the Rational Trigonometry. How will you measure the popularity of a Mathematician ? I personally do not know him, But I know him though internet. For me that is the definition of famous. You are doing ing immoral things, you cannot redirect an article to a mathematics section. Above all you cannot immediately delete an article without allowing the time to add proper references.
 * I can do all of those things. And we don't keep articles here for people who are internet famous unless they also meet our notability standards. —David Eppstein (talk) 15:48, 10 May 2014 (UTC)

Gödel's incompleteness theorems
Hi!

I saw you reverted an ip-editor on the talk page. You might want to check out the article too. I noticed a couple of edits by the same ip. I have made a couple of small edits since he did his.

Best, YohanN7 (talk) 20:43, 11 May 2014 (UTC)
 * Thanks for the heads up. I just undid them. —David Eppstein (talk) 21:14, 11 May 2014 (UTC)

Lebesgue point
Oops, my mistake: ever so sorry! You're quite right. Please accept my apologies. --Tristessa (talk) 01:24, 12 May 2014 (UTC)
 * No problem. —David Eppstein (talk) 01:26, 12 May 2014 (UTC)

Please avoid the personal attacks in edit summaries
Improving the encyclopedia is not pedantry. This is uncalled for. -- JHunterJ (talk) 17:42, 15 May 2014 (UTC)
 * Yes, but repeatedly removing relevant and easily-sourced information for the sole reason that it was added to one part of the encyclopedia without having already been added to a different part of the encyclopedia is pedantry. —David Eppstein (talk) 17:56, 15 May 2014 (UTC)
 * "Yes, but" is not the appropriate response to a notification of a personal attack. Focus on the edits, not the editors. Repeatedly removing entries from a Wikipedia disambiguation page for which there was then no Wikipedia ambiguity is not pedantry. -- JHunterJ (talk) 17:59, 15 May 2014 (UTC)
 * By the way, as long as we're being pedantic, I don't think WP:DABMENTION was the correct guideline to apply. It's about topics that don't have their own article but are mentioned as part of other topics. LvG clearly does has his own article; it's the nickname that wasn't mentioned, but the topic was the person not the nickname. I agree that the entry should not have been included without being mentioned in its parent article (and reiterate that a very quick Google search would have easily found sourcing for its inclusion there) but the proper link was WP:DABINITIALS. And I also agree with your removal of LVGZ; when adding all the other recent entries I considered but rejected that one for the same reason you state. —David Eppstein (talk) 18:06, 15 May 2014 (UTC)

Average-case complexity
Thank for reviewing my changes. The definitions in the article certainly need to be clarified much further, it's not even clear what is being defined in some passages. For now I tried a minimal change, which I still believe to be correct, more precisely I mean 'there is a polynomial p and an epsilon>0 such that for every n,t ...'. See the article referenced, Impagliazzo, Def 3.1. (it's still a bit informal, there's probably better references). The definition present now reads to me like 'for all n, for all t, for all epsilon>0 and for all? polynomials p' which is completely bogus. But even if we fix the polynomial, then epsilon should be existentially quantified, otherwise fixing n and t>1 the statement says that even for arbitrarily large epsilon, which makes the right-hand-side arbitrarily small, the inequality holds. So this asserts Pr[...]=0. Tokenzero (talk) 23:10, 19 May 2014 (UTC)
 * Ok, I see from Impagliazzo's paper that you're correct about the universal vs existential quantification of epsilon. Can you find a better way of writing the existential than "for some", though? —David Eppstein (talk) 23:38, 19 May 2014 (UTC)

Request for comment
Hello there, a proposal regarding pre-adminship review has been raised at Village pump by. Your comments here is very much appreciated. Many thanks. Jim Carter through MediaWiki message delivery (talk) 06:46, 28 May 2014 (UTC)

Could you lend a hand at Jean Berko Gleason?
Your cool head (to counter my hot one) would be of great help at Template:Did you know nominations/Jean Berko Gleason. EEng (talk) 19:53, 30 May 2014 (UTC)
 * P.S. Perhaps you will enjoy Widener Library. EEng (talk) 07:48, 31 May 2014 (UTC)
 * As a place or as an article? My favorite library to have visited is the one in Trinity College Dublin. —David Eppstein (talk) 15:38, 31 May 2014 (UTC)
 * I was just in Dublin in March, and you're right -- the Trinity library is stunning. But they're not in competition -- the Trinity library is the Sistine Chapel, while Widener is the Florence Duomo. They excel on different axes. But as a research base I don't think anything can beat Widener.
 * From Dublin I went to Bletchley Park -- it was so great I stayed overnight and spent a second day. They've built a completely authentic bombe and it's absolutely fascinating. One of the "girls" who ran the bombes was there the first day. I try to imagine what the mixture of feelings would be in someone who saved lives every day of the war, and literally helped win the war, yet couldn't say a thing about it to anyone for decades.
 * If you're willing, please keep an eye on -- as well. Note this is not the main DYK nom where you already commented, but another page where a kind of just-us-girls huddle is taking place. EEng (talk) 22:34, 31 May 2014 (UTC)

June 2014
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 * minors]], but the exact characterization of this form remains unknown. Every graph with an graph embedding|embedding  in the projective plane has a planar cover coming from the orientable double cover of the

Comment
Hello David,

I am Patrice, the author of the article about the golden ratio in ancient Greek architecture. You deleted the result of this research mentioned in the Wikipedia article on the Golden ratio for giving undue weight to the point of view examined in this research. Did you read my article in the Cambridge Archaeological Journal? I would sincerely love to discuss it with you. You can respond here, or to my personal e-mail address: foutakis@orange.fr

Thanks, Patrice 82.123.166.180 (talk) 10:15, 2 June 2014 (UTC)
 * If you're the author of the journal article, then you should certainly not be the one to push for its inclusion in Wikipedia. See WP:COI. —David Eppstein (talk) 13:57, 2 June 2014 (UTC)

Edge-transitive graphs
Hi David,

I just stumbled across an edit of yours to this article from a couple of years back, stating that "Every edge-transitive graph must be bipartite and either semi-symmetric or biregular." This is false, and I'm trying to work out what you meant to say. Was it something like "Every semi-symmetric graph must be biregular"?

Thanks, Robin S (talk) 15:31, 5 June 2014 (UTC)
 * As you say it is obviously false that every edge-transitive graph is bipartite. I suspect it was that every edge-transitive graph must either be vertex-transitive or semi-symmetric and biregular. —David Eppstein (talk) 16:16, 5 June 2014 (UTC)

Useless reference
Gosh, your glass really is half-empty isn't it? "More useful" would have been less effort to type than "less useless" and more polite. Deltahedron (talk) 21:40, 5 June 2014 (UTC)
 * My first reaction was to just revert your change as WP:REFSPAM. That would also have been less effort. —David Eppstein (talk) 21:43, 5 June 2014 (UTC)
 * Not to mention being incorrect, since the reference was, as you acknowledged by your choice of action, a legitimate good-faith addition intended to verify article content and help build the encyclopedia. Deltahedron (talk) 21:46, 5 June 2014 (UTC)
 * Well, yes, but I don't have a high opinion of the usefulness of book references without page numbers. In your case I'm sure it's not true but too many of them were probably added because they looked like they might be on the right subject rather than because they actually source anything specific in the article. —David Eppstein (talk) 00:26, 6 June 2014 (UTC)
 * Thanks for the acknowledgement, but as you may have noticed, I don't have a high opinion of edit summaries with sarcastic comments in them. In your case I'm equally sure it's not true, but too many of them were probably made deliberately to annoy other users.  I suppose we all have our likes and dislikes.  Deltahedron (talk) 06:41, 6 June 2014 (UTC)
 * There was no sarcasm intended, neither in my original edit summary nor in the comments above — just an expression of my opinions. —David Eppstein (talk) 06:45, 6 June 2014 (UTC)
 * Sigh. I'm sure that it was an expression of your opinion.  I'm equally sure that it was at best unthinkingly sarcastic and at worst intended to be mildly irritating to me as the person who added the reference you thought so useless.  At some point before this in the discussion I would have hoped for an expression of regret, however mild, that you had been, however inadvertently, less than perfectly civil.  Still, that obviously isn't going to happen, and since I'm pretty sure that you knew, and know, exactly what effect your words would have, and are pursuing the discussion for reasons other than a desire to resolve the situation, I'll drop the matter.  Deltahedron (talk) 16:54, 6 June 2014 (UTC)

A clear mistake in article: Firoozbakht's conjecture
Hi. I just wrote a comment in Firoozbakht's conjecture talk's page. Would you kindly consider it? Thanks. JohnAu2000 (talk) 11:09, 6 June 2014 (UTC)

Strongly connected component and cliques
Hi, could you please clarify what was inaccurate in my edit? I've seen people often get confused between these two and hence I'd added the statement:

Strongly connected components is a weaker concept of Clique (graph theory) where it is required that each pair of vertices have an edge as opposed to only be reachable. — Preceding unsigned comment added by Sytelus (talk • contribs) 07:33, 8 June 2014 (UTC)
 * Strongly connected components are a concept in directed graphs. Cliques are a concept in undirected graphs. Both are a type of clustering in graphs, but in my view they are not very closely related to each other except that both are types of clustering, among many other types of clustering. —David Eppstein (talk) 17:24, 8 June 2014 (UTC)

Singular point and node
I have seen your edit in Singular point of an algebraic variety: "In classical algebraic geometry, singular points were also called nodes". As far as I know, not all singular points were called node, but only the singular points where the Hessian matrix is non singular (this means that the singular point has multiplicity 2 and the tangent cone is not singular outside its vertex). Maybe "node" has been used for other singularities, but certainly not for singular points that belong to a curve of singular points.

I agree to mention "node" in this article, but it must be said that "node" denotes a specific class of singular points.

Therefore, I'll revert your edit. D.Lazard (talk) 21:22, 9 June 2014 (UTC)
 * Ok, but please at least mention nodes in the article — previously they weren't there at all, and I redirected Node (algebraic geometry) there because it needed to be somewhere. —David Eppstein (talk) 22:10, 9 June 2014 (UTC)

Alleged adverbs
Most of the spam is composed of adjectives, not adverbs. I am not sure what you think is ungrammatical. — Preceding unsigned comment added by 109.150.179.157 (talk) 18:20, 13 June 2014 (UTC)
 * Spam is something different from promotion. And promotion is something different than using adverbs or adjectives accurately. And when you delete "red" from "a red umbrella" you have to change the "a" to "an". —David Eppstein (talk) 19:57, 13 June 2014 (UTC)

Edit summaries
Please think about your use of edit summaries. We have already spent time unpicking one which I found ill-judged. Just now you wrote "they are not made of cardboard" in a revert of an edit about the use of the word "boxes" versus "polyominoes". Since I did not suggest that they (whatever "they" might refer to) were, the point is lost on me. I assume this is an elliptical way of saying that you think "boxes" is too literal a term, but I cannot be sure, and the summary fails to convey your meaning. If you have a complex thought to express, please use the article talk page rather than making an overly compressed edit summary which serves only to confuse other editors. Deltahedron (talk) 08:06, 14 June 2014 (UTC)
 * No similes. No sarcasm. No attempts at humor. Only a plain literal description of what I have changed; anything else is too upsetting for you. Probably best if I just copy and paste the actual changes from the article text to the change log. It's very important that the text in the change long be as clean and dry as the text in the actual article. Got it. —David Eppstein (talk) 16:50, 14 June 2014 (UTC)
 * That would be this sarcasm thing again, right? Is it really too much trouble for you to think "hey, here's a fellow mathematician I'm not getting on with, let's try to have a serious discussion and resolve our differences"?  Or is "what's the cheapest bit of sarcasm I can get away with" just too attractive?   Deltahedron (talk) 16:54, 14 June 2014 (UTC)
 * Our differences seem to have nothing to do with the mathematics (or when they do they're easily worked around by discussion), they seem to be more that you're looking for insults in everything you read from me and finding them even when (as most times) nothing of the sort was intended. How about you try to be less prickly? It is getting very irritating having you come to my talk page and whine every time you think I phrase something in a way that even slightly hints at the fact that I'm a human and not a robot. —David Eppstein (talk) 17:00, 14 June 2014 (UTC)
 * So "most times" you don't intend to insult me. That's something.  Deltahedron (talk) 17:09, 14 June 2014 (UTC)
 * That would be this sarcasm thing again, right? What DE said was that here, as most times, nothing even of the sort of an insult, i.e. nothing meant in any way to be troubling or vexing, was meant. That leaves room for the occasional time when DE might show annoyance, as all editors not destined for sainthood sometimes do. That you apparently felt you needed to deny having said that Young diagrams are made of cardboard suggest that a more flexible approach to interpretation might help you feel less put upon. EEng (talk) 17:24, 14 June 2014 (UTC)
 * Thank you for interpreting David Eppstein's words for me. I venture to suggest that the more discussion, the more explanation and the more interpreters these words need, the more support there is for my original, rather mild, suggestion that they are overly compressed.  While you're in an explaining mood, perhaps you could interpret this, and explain exactly how the phrase "they are not made of cardboard" explains this edit?
 * However, all this could be avoided if David Eppstein could bring himself to say something like "I see that my joke at XXX didn't quite work / I didn't word my edit summary very carefully / I posted in a hurry -- sorry you were upset".   Deltahedron (talk) 18:13, 14 June 2014 (UTC)

It may seem that I'm taking sides, as DE and I have collaborated now and then, but I want you to know I am quite sincere when I say this: the words don't need explaining, but rather one recipient seems to need them explained to him (or her). Length constraints mean edit summaries are necessarily telegraphic, and one must interpret them with that in mind.

The cardboard reference says, to me, "boxes conjures an odd image when I read it... I think this other word might be more apt."

To me, in the sequence,
 * Sen (1968) extended this definition... In Sen's definition... As Sen observed...

It's clear all three refs are to Sen (1868), and it's an appropriate way to make those references.

Lest you think I always side with DE, I will point out that (in my opinion, anyway) the plural of polyomino is polyominoes. EEng (talk) 19:22, 14 June 2014 (UTC)


 * Again, thank you for that. I do not doubt the sincerity of your position, merely disagree with it.  For example, you say that "the words don't need explaining" and then that "one recipient needs them explained", whereupon you proceed to explain them.  This seems internally inconsistent.  I am sure you will understand when I say that the message I receive from your intervention is that I am at fault for failing to understand David Eppstein's edit summaries, which "do not need explaining" -- and that my view is that on the contrary, David Eppstein needs to do better to be understood in his telegraphic edit summaries, which are overly compressed and careless of other editors' positions, and that he should respond in a less dismissive manner when taken up on them.  Deltahedron (talk) 20:53, 14 June 2014 (UTC)


 * The message you received from my intervention is indeed the message sent. — Preceding unsigned comment added by EEng (talk • contribs) 21:24, 14 June 2014‎ (UTC)
 * Then it seems we must agree to disagree. Deltahedron (talk) 21:37, 14 June 2014 (UTC)
 * It seems we must. But if at least something tangibly helpful is to come out of this, I think it is that you and DE should make the agreement to disagree a silent one i.e. I don't think it's helpful to keep taking him to task because you would prefer him to word his edit summaries differently. They may or may not be optimal according to some metric, but they're within policy. EEng (talk) 01:44, 15 June 2014 (UTC)
 * In exchange I promise not to complain about Deltahedron's edit summaries (not that I have had anything to complain about them yet). —David Eppstein (talk) 01:48, 15 June 2014 (UTC)
 * No. Edit summaries are supposed to convey useful information (Help:Edit_summary: "this helps others to understand the intention of your edit").  In this case DE reverted an edit of mine with an incomprehensible edit summary about cardboard, possibly intended to be some kind of joke, and no other explanation, and this is not the first edit summary he has made which refers to a previous edit of mine in unhelpful terms.  I commented here accordingly.  I see no reason not to ask for clarification of DE or anyone else when their edit summaries are confused, confusing or otherwise unhelpful.  I am sure that DE now understands why I have found some of his summaries to be unhelpful and it is clear that he does not intend to change his practice: I find that regrettable but do not see the need to discuss that point further.  Deltahedron (talk) 06:45, 15 June 2014 (UTC)
 * Ok, then, instead: I promise to ignore your future complaints about my edit summaries rather than responding to them, which seems only to bait you into more complaints despite any other intentions I might have. —David Eppstein (talk) 06:56, 15 June 2014 (UTC)

DYK nomination of C. Stanley Ogilvy
Hello! Your submission of C. Stanley Ogilvy at the Did You Know nominations page has been reviewed, and some issues with it may need to be clarified. Please review the comment(s) underneath your nomination's entry and respond there as soon as possible. Thank you for contributing to Did You Know! Soman (talk) 20:08, 15 June 2014 (UTC)

Apology
I am sorry for my intemperate outburst of last night; I will be striking through my personal attacks there as well. It was late, and I probably overreacted because your comments had the effect of undoing a good mood I was in at the time. As a way of adding deeds to words, I have also reviewed your DYK nom for book embedding and passed it (I could only access one of the references, but it met the length and history qualifications otherwise).

I look forward to better collaboration with you in the future, should we find ourselves doing so. Daniel Case (talk) 17:24, 17 June 2014 (UTC)

DYK nomination of Book embedding
Hello! Your submission of Book embedding at the Did You Know nominations page has been reviewed, and some issues with it may need to be clarified. Please review the comment(s) underneath your nomination's entry and respond there as soon as possible. Thank you for contributing to Did You Know! Yoninah (talk) 22:30, 17 June 2014 (UTC)

DYK for Book embedding
Cas Liber (talk · contribs) 13:37, 20 June 2014 (UTC)

Prüfer rank
You recently added a citation to a paper of Yamagishi to this article which had remained without references for almost 10 years(!) but I'm concerned about the whole tenor of the article: I think the definition is over-specialised at best. I don't have access to the full text Yamagishi paper, and presumably you do, so your comments at Talk:Prüfer_rank would be appreciated. Deltahedron (talk) 08:41, 22 June 2014 (UTC)

Formula for primes and OEIS A240673
OEIS A240673 is connected with Rahmin Zahedi whose work has already been pushed at this page by, another SPA. Deltahedron (talk) 20:50, 22 June 2014 (UTC)
 * Hmm, maybe time for a sockpuppet investigation? Thanks for the info. —David Eppstein (talk) 20:56, 22 June 2014 (UTC)
 * There's something odd about . In his second edit  his edit summary claims to be using STiki which does not seem likely as he cannot have the rights to it yet.  If the summary is a fake, though, and added manually, it's rather a sophisticated one for a new user.  Something is not right here.  Deltahedron (talk) 21:00, 22 June 2014 (UTC)

Transitive relation
Three words: "a type of". A bunch more words: "Transitivity", the "transitive property", the "law of transitivity" [//toolserver.org/~dispenser/cgi-bin/rdcheck.py?page=Transitive_relation et alia] are labels for a (kind of) relation that is defined in mathematics but is also used in all sorts of discussions not thought of as part of mathematics per se. Adding the three words "a type of" to [//en.wikipedia.org/w/index.php?title=Transitive_relation&diff=prev&oldid=614036440 my version] of Transitive relation would have solved your objection, I think, without discarding the metaphorical baby of a lead section that summarized article content and defined the concept in a way that is accessible and readable for non-mathematicians and non-Wikipedians. Cnilep (talk) 03:46, 23 June 2014 (UTC)
 * A lead sentence must be readable, true, but it must also say what the subject of the article is. "A transitive relation is a mathematical thing", for instance, would be true and readable but not useful, because it fails to distinguish transitive relations from convex polyhedra, polynomials, negative numbers, or large cardinals. Your rewrite has the same problem: the lead needs to say both precisely and readably what the subject of the article is, but you say only that it "is a binary relation between sets.", something that is also true of many other things that are not transitive relations. Also despite its unnecessary vaguenesss it's not even correct: the things that a transitive relation relates do not themselves have to be sets. —David Eppstein (talk) 03:54, 23 June 2014 (UTC)


 * So is the version you restored ("a binary relation R over a set X is transitive if...") incorrect, or just misleadingly vague? Cnilep (talk) 04:53, 23 June 2014 (UTC)
 * A relation over a set (the current version) is a very different thing than a relation between sets (your proposed version). In the first, the things being related are the elements of a single set, which could be any other kind of mathematical object. In what you wrote, the elements being related are themselves sets. —David Eppstein (talk) 04:57, 23 June 2014 (UTC)

Explain the removal of substantial information on the difference in size of cuneiform numerals for 60 and 1
It is a travesty that information is being lost in regards to the difference in size between the Babylonian cuneiform numerals 60 and 1. Why was the removal necessary? The information came from a reputable source, a professor with expertise in Babylonian mathematics at the sixth largest university in the nation. — Preceding unsigned comment added by 64.134.221.9 (talk) 07:21, 25 June 2014 (UTC)
 * Presumably you mean this edit? The source from that edit might potentially be acceptable as a reliable source, under the "recognized expert" clause of WP:SPS, but it says nothing about size of cuneiform symbols. One might *infer* something from the figure showing two symbols of different sizes, but that would be original research, and how would you reconcile that with e.g. the later image of Plimpton 322 which to my eye shows no size variation? —David Eppstein (talk) 07:36, 25 June 2014 (UTC)

Why do you(= mess up) edit mathematics articles of Wikipedia!?
You are a computer science professor, OK let we suppose it is so. But as we tracked your edits, you don't know anything about mathematics, why do you(= mess up) edit mathematics articles of Wikipedia??? How many pscycs like you are editing Wikipedia? ...Real tragedy.Prominent361 (talk) 20:08, 26 June 2014 (UTC)
 * Some context, please? This is your first edit as a logged-in Wikipedia user so I can't tell what bad edit of yours I undid. —David Eppstein (talk) 22:00, 26 June 2014 (UTC)