Wikipedia talk:WikiProject Mathematics/Archive/2012/Dec

Order of magnitude lists
I question the necessity, validity, and encyclopedic fitness of the numerous articles listing items within orders of magnitude of measurements, such as 1 E+5 m² or 100 nanometres. To me at least, they seem like syntheses of arbitrary information, and some of the article names (e.g. all the area ones) make no sense as such. Is there a compelling reason to have them as standalone encyclopedia articles? —Frungi (talk) 05:03, 30 November 2012 (UTC)


 * you might want to take a look at the old deletion discussion here: http://en.wikipedia.org/wiki/Wikipedia:Articles_for_deletion/1_E0_m. --JBL (talk) 05:45, 30 November 2012 (UTC)
 * Ah, thanks for that. Well, I could definitely see this sort of stuff being in the supplemental section or something of an encyclopedia. So how about renaming those "1 E+# m²" pages, and whatever similarly named groups there might be? —Frungi (talk) 06:02, 30 November 2012 (UTC)
 * Frungi already knows this, but for others new to the discussion: there was a related RFC here that ended up redirecting 1 E+4 m² to hectare. But that's not as feasible for some of the other articles of this type, because they don't all correspond to names of other units. —David Eppstein (talk) 06:22, 30 November 2012 (UTC)
 * I didn’t link to that? Wow, sorry. I’d meant to. Thanks. —Frungi (talk) 17:25, 30 November 2012 (UTC)
 * There are a lot of pairs of articles like Centimetre (article) and 1 centimetre (list). Not only is the naming convention confusing, with no indication that the latter is a list, but none of the lists are very long. Why not merge the lists into the articles? RockMagnetist (talk) 16:32, 30 November 2012 (UTC)
 * Or what about subpages? E.g., Orders of magnitude (length)/1 centimetre, or Orders of magnitude (volume)/1 E+6 m³. The scientific notation names would make sense in that context, and wouldn’t require explanation in the articles (as I feel they currently do). —Frungi (talk) 17:25, 30 November 2012 (UTC)
 * Subpages are not allowed in article space. RockMagnetist (talk) 17:28, 30 November 2012 (UTC)
 * Oh. Well, they definitely need to be renamed (I think so anyway—does anyone think that 1 E+6 m³ is an appropriate article name?), but I’m not sure what naming scheme would be best. “List of items of area 1 E+6 m³”? —Frungi (talk) 17:36, 30 November 2012 (UTC)
 * That would be an improvement. --JBL (talk) 21:24, 30 November 2012 (UTC)
 * Since a lot of articles are involved, any name change should probably go through Requested moves and WikiProject Measurement should be notified. RockMagnetist (talk) 21:44, 30 November 2012 (UTC)

These articles also have homemade previous/next links that work well in a small article but not in longer ones. They probably break some style rule. Succession boxes would be better. RockMagnetist (talk) 23:28, 30 November 2012 (UTC)
 * All right, I’ve posted to WikiProject Measurement about this thread, since that seems to be the appropriate place for this discussion. Sorry for my confusion. —Frungi (talk) 07:38, 1 December 2012 (UTC)

Lists and outlines
Some time last year, there was a substantial debate about the relative merits of "lists" and "outlines"; see, for example, Wikipedia_talk:WikiProject_Mathematics/Archive/2011/Sep. I thought we reached a consensus that various mathematical lists should be kept. I've just reverted edits to List of complex analysis topics and Outline of complex analysis; it might be worth keeping an eye on these and similar pages. Jowa fan (talk) 12:56, 2 December 2012 (UTC)


 * There is also
 * Wikipedia_talk:WikiProject_Mathematics/Archive_38
 * Wikipedia_talk:WikiProject_Mathematics/Archive_45
 * Wikipedia_talk:WikiProject_Mathematics/Archive_54
 * Wikipedia_talk:WikiProject_Mathematics/Archive_63
 * I agree that, unless there is a demonstrable change form the previous consensus, the lists should stay at their present titles. &mdash; Carl (CBM · talk) 13:14, 2 December 2012 (UTC)

Articles for deletion/Gyula J. Obádovics
The AfD Articles for deletion/Gyula J. Obádovics about Gyula J. Obádovics could use some input from members of the project. Sławomir Biały (talk) 13:42, 8 December 2012 (UTC)

Should solutions to logic puzzles be hidden ?
has hidden the Solution sections in the logic puzzle articles four glasses puzzle, bridge and torch problem, wine/water mixing problem and Ages of Three Children puzzle. In an edit summary he says he has done this "to stop any reader from inadvertently looking at the solution". I disagree with hiding article sections like this because I think it impedes the clarity and readability of the article. Do you have an opinion ? I have started a discussion thread at Talk:Four glasses puzzle. Gandalf61 (talk) 08:42, 9 December 2012 (UTC)


 * This falls under Spoiler. Spoilers are not to be hidden or removed merely because they are spoilers. He should be reverted and told to stop. JRSpriggs (talk) 09:46, 9 December 2012 (UTC)


 * This does NOT fall under Spoiler which currently states "A spoiler is a piece of information in an article about a narrative work (such as a book, feature film, television show or video game) that reveals plot events or twists, and thus may "spoil" the experience for any reader who learns details of the plot in this way rather than in the work itself." In time this may change, but at the moment it does not hold anything relevant to this discussion. Paul venter (talk) 18:51, 9 December 2012 (UTC)


 * I think that the same justifications for WP:SPOILER apply here. The purpose of our articles is to give people information, not to make it more difficult to obtain. If someone reads about the Monty Hall problem or a logic puzzle, they should expect to see an answer - that is what the encyclopedia is here for. If they want a list of problems to try to solve, they should get a problem book or a list of previous problems from a contest. In particular, if they read a section with the title "solution", they should expect to see the solution there without having to click to see it. &mdash; Carl (CBM · talk) 19:09, 9 December 2012 (UTC)
 * I agree. —David Eppstein (talk) 19:15, 9 December 2012 (UTC)


 * As do I. And even if WP:SPOILER doesn't literally cover this, I think the spirit of it should be applied - I don't see a fundamental difference. Dougweller (talk) 19:36, 9 December 2012 (UTC)


 * I agree. Solutions should not be hidden.  Wikipedia is an encyclopedia, not a puzzle book.   Sławomir Biały  (talk) 19:44, 9 December 2012 (UTC)


 * In that case get a consensus to change WP:SPOILER to include logic problems and then there will be no confusion - but one still has to wonder why there is a "hide/show" feature on WP if it goes against everything an encyclopaedia stands for..... Paul venter (talk) 07:14, 10 December 2012 (UTC)


 * Show/hide boxes are good for hiding text that the reader may ignore at a first reading, like brief derivations/proofs etc. There is no point to hiding solutions, it's not about testing the reader. Maschen (talk) 08:12, 10 December 2012 (UTC)
 * If you read this you'll see that the hide template is used for a lot more than you may think. Is there some source for your opinion on the proper use of the template or did you just invent that? Paul venter (talk) 14:05, 10 December 2012 (UTC)
 * They're also mostly used in talk space. I've almost never seen them in article space, apart from navboxes. Anyway no, Paul, in addition to the spirit of WP:SPOILER, which applies here, we're not censored. I'll see that WP:SPOILER is explicit on this. -- Cycl o pia talk  08:37, 10 December 2012 (UTC)
 * I'm not keen on the use of hide anywhere as it assumes one is using Javascript, anyway what's the point of downloading loads of stuff that people don't look at? I sure there must be a better way of dealing with all those hides that people want to stick in navboxes. 10:00, 10 December 2012 (UTC)
 * ... by Dmcq.
 * Where on earth does 'censorship' come from? This has nothing to do with morality or ethics, it is simply a way of stopping someone from accidentally seeing the solution - a barrier which is removed by a simple click (clicking is what WP editors and readers do for most of their lives, so that it is not rocket science!) Paul venter (talk) 14:05, 10 December 2012 (UTC)


 * It's not about censorship, just that there is no reason to hide anything. It doesn't gain anything, the reader will see the solution anyway if they click open. Maschen (talk) 14:14, 10 December 2012 (UTC)
 * We can discuss the correct alphabet soup six ways to Sunday. For instance, I think the most relevant extant guideline is WP:DISCLAIMER, rather than WP:SPOILER or WP:CENSORED.  But I think the bottom line is that having content hidden violates the spirit of these guidelines taken as a whole, and no compelling reason exists for doing such a thing in an encyclopedia.   Sławomir Biały  (talk) 15:28, 10 December 2012 (UTC)
 * Talking about the "spirit of these guidelines" implies that you are privy to some insider knowledge not explicitly expressed where ordinary mortals can read them. So for the sake of clarity let's stick to the written word and not conjure up hidden meanings. Paul venter (talk) 18:30, 10 December 2012 (UTC)
 * I don't feel strongly one way or another about this, but the tendency (of many users) to rely excessively on the invocation of sacred texts when common sense will do is always frustrating. Quite possibly, Wikipedia does not have a guideline that actually addresses the question of whether the solutions to logic puzzles should be hidden.  In this case, the right thing to do is not to spend endless posts arguing about precisely which guidelines do or do not apply and how; it's clear from the discussion above that there's a consensus among math editors on this question, and that it's that these solutions should not be hidden.  This is true regardless of whether WP:SPOILERS is the "right" guideline or just an analogy.  --JBL (talk) 18:40, 10 December 2012 (UTC)
 * I think the spirit of these guidelines is quite obvious to most ordinary mortals, there’s no hidden meaning. If I may drop in yet another ingredient to the alphabet soup, asking to “stick to the written word” sounds very much like WP:LAWYERING.—Emil J. 18:58, 10 December 2012 (UTC)
 * Contrary to Paul venter's statement near the beginning of this discussion, WP:SPOILER does mention logic puzzles explicitly: see Other types of spoilers. RockMagnetist (talk) 19:00, 10 December 2012 (UTC)
 * Well, that section has been added there six hours ago.—Emil J. 19:12, 10 December 2012 (UTC)
 * So it was. That weakens the argument for sticking to the written word of a policy! RockMagnetist (talk) 19:43, 10 December 2012 (UTC)


 * I'll add my voice to the consensus here to not hide solutions. Paul August &#9742; 20:37, 10 December 2012 (UTC)

This could (and looks like it will) prevail on and on forever... The changes have been reverted, and there is an unlimited consensus not to hide the solutions. So I closed the discussion now, else we're all just wasting time... Maschen (talk) 20:47, 10 December 2012 (UTC)

List of translations into set theory
See a discussion at Talk:Constructible universe. Should we have an article containing a list of formulas in the language of set theory which are equivalent to simple formulas (like "&alpha;+&beta;=&gamma;") used throughout mathematics? JRSpriggs (talk) 11:56, 9 December 2012 (UTC)
 * Has such a list been discussed as a group or set by independent reliable sources? If so, then we could write an article about it — please cite the sources.  Otherwise it would consititute original research.  Deltahedron (talk) 16:57, 9 December 2012 (UTC)
 * I do not understand the point: What is the relation between the question and the link?
 * About the translation of formulas in some constructive language (I believe that it is such a translation that underlies the question), this is the same thing as coding an algorithm in some programming language (here in a language that is less readable than assembly languages). IMO, the rules for source code in MOS:MATH should apply here: such translations are (or should be) more or less mechanical and do not have any encyclopedic content. D.Lazard (talk) 18:45, 9 December 2012 (UTC)
 * Regarding the relationship between the link and the question: Alan U. Kennington seemed to want to add to Constructible universe a statement of the formula of set theory which well-orders L. As I thought about how one might try to do that, I realized that one would have include set theoretic definitions of addition of ordinals and other common operations. Then I thought that it would be easier to justify the effort of doing that if it were done as part of a new article containing a list of such expressions. Hence my question.
 * However, I am not at present aware of any sources which could be used for such a list. So as you say, this would probably be barred as OR. I hope that by asking the question here I may find someone who knows of such a source. JRSpriggs (talk) 04:55, 10 December 2012 (UTC)
 * I looked at Metamath's list of definitions, mmdefinitions, but that seems to lack adequate explanations for what the defined terms mean. JRSpriggs (talk) 05:32, 10 December 2012 (UTC)

Russell's Paradox
I don't want to edit the article myself, but is this statement incorrect?:

http://en.wikipedia.org/wiki/Russell%27s_paradox

'If the librarian doesn't include it in its own listing, it is still a true catalog of those catalogs that do include themselves.'

This makes more sense:

http://wiki.ironchariots.org/index.php?title=Russell%27s_paradox

Now consider two master catalogs to be held at the city's Central Library:


 * 1) the first lists all catalogs that contain themselves;
 * 2) the second lists all catalogs that don't contain themselves.

Clearly the first catalog can list itself; that's no problem. But should the second catalog not list itself? Either way one answers this question leads to a contradiction:


 * If the second catalog lists itself, then it clearly doesn't belong in the list of catalogs that don't list themselves.


 * But if the second catalog doesn't list itself, then it does belong in the list of all catalogs that don't list themselves.

preceeding unsigned comment by IP: 188.31.8.184.


 * What's your point? Isn't that the essence of Russell's paradox?
 * To break the first statement down (re-wording):
 * "If the second catalog lists itself, then it doesn't belong in the list of catalogs that don't list themselves."
 * ="If the second catalog lists itself, then it is not an element of the set of catalogs that don't list themselves."
 * ="If the second catalog lists itself, then it is an element of the set of catalogs that do list themselves."
 * ="If the second catalog lists itself, then it does belong in the list of catalogs that do list themselves."
 * and simultaneously
 * "But if the second catalog doesn't list itself, then it does belong in the list of all catalogs that don't list themselves."
 * ="But if the second catalog doesn't list itself, then it doesn't belong in the list of all catalogs that do list themselves."
 * i.e. the second catalogue does and does not belong the list of catalogs that do list themselves... which is a contradiction. Maschen (talk) 20:25, 10 December 2012 (UTC)

Apologies for the time-wasting, and thanks for the breakdown above -

I had misread part of the Wikipedia article (I actually thought that there had been a misprint):

http://en.wikipedia.org/wiki/Russell%27s_paradox

For that reason (having mis-read the Wikipedia article), to my eyes it mis-matched the ironchariots.org explanation (which I thought to be the clearer of the two explanations):

http://wiki.ironchariots.org/index.php?title=Russell%27s_paradox — Preceding unsigned comment added by 188.31.8.184 (talk) 22:44, 10 December 2012 (UTC)

&amp;nbsp; and mysterious "latex to html" user
I've recently noticed that has been going around and converting latex to html in a lot of math articles, and in most cases also modifying the existing html. I'm sort of neutral to this in general, but the main problem is that the edits seem to convert non-breaking spaces &amp;nbsp; into ordinary spaces. This can cause browsers to insert newlines into the middle of formulas. I was surprised at how many articles this user has done this to over the span of several months, and only just now have I notified him/her. I only now became aware of the problem when I saw that this edit from September broke the formatting in the section Hilbert space#Bounded operators, although it is to be hoped that this degree of breakage is the exception rather than the rule. Anyway, I don't know if it's worth fixing the &amp;nbsp; problem retroactively, as that would likely be very time consuming for all but the most stalwart wikignome, but I thought I should at least notify the project. Sławomir Biały (talk) 00:14, 10 December 2012 (UTC)
 * In the long run I think the goal should be to make MathJax into the default view for everybody and then convert everything from html to latex again. But the long run is not here yet, sadly. In the short run I think we should use a consistent style within each article, whether it be latex everywhere, html everywhere, or latex for the displayed formulas and html for the inline ones. That means that, once we have a single inline latex formula, as Hilbert space does towards the end of its Definition section, the rest of the article should use latex as well. I do agree that using &amp;nbsp; to prevent bad linebreaks is a necessary part of proper formatting in html formulas, but my guess is that since the anonymous editor seems to be acting in good faith to improve the appearance of these formulas, he or she will take your admonishment seriously. —David Eppstein (talk) 05:13, 10 December 2012 (UTC)


 * You could also point out that the use of non-breaking spaces is recommended in the Manual of Style (WP:NBSP). RockMagnetist (talk) 20:44, 10 December 2012 (UTC)

strings of nbsp's jammed into formulas make things hard to read, at least in my opinion. I prefer ((nowrap begin)) ... ((nowrap end)) where ( and ) should be replaced by { and } -- Virginia-American (talk) 10:40, 14 December 2012 (UTC)


 * The math code is currently




 * I presume the "texhtml" and "texhtml-big" classes use, then do we still have to use nbsp? By the way, 165% for bigmath is way too big, 135% would be more appropriate. (Actually, the display style font is supposed to be the same size as for the text style font, except for large operators.) &mdash; TentaclesTalk or ✉ mailto:Tentacles 22:25, 18 April 2016 (UTC)

Unreferenced (incomplete) statement on Halin graphs?
Hello,

I was reading Halin graph and I noted that it said: Because every tree contains two leaves that share the same parent, every Halin graph contains a triangle. In particular, it is not possible for a Halin graph to be a triangle-free graph nor a bipartite graph.

Is this correct, aren't there many trees with no two leaves sharing the same parent? And don't you need a root in your tree to speak of parents (according to Tree (graph theory) ?). Finally, unlike other claims in that list, this one is unreferenced.

I noticed that the Talk page for that article is still empty, and since I am not exactly an expert on this, I decided to bring this up here.

Thanks, Evilbu (talk) 08:06, 14 December 2012 (UTC)


 * The assertion is incorrect for general trees, but correct for the trees that define Halin graphs (no vertex of degree 2). I have corrected the article. D.Lazard (talk) 08:55, 14 December 2012 (UTC)
 * Thanks for fixing this. —David Eppstein (talk) 03:48, 15 December 2012 (UTC)

Consistent upright d's
It's deja vu all over again. Somebody has been consistently uprighting all the d's again. Tkuvho (talk) 20:48, 8 December 2012 (UTC)


 * I made them italic (feel free to complain if I missed a few). Yes - in the past I was one who favoured upright differentials (and still do) causing much irritation, but not anymore (on WP). Maschen (talk) 21:13, 8 December 2012 (UTC)
 * Update: just warned the new editor. Maschen (talk) 21:20, 8 December 2012 (UTC)

The case for all upright "d"s in this context would seem to be that it leaves the italic d available for use as a variable. That has a certain (small?) amount of cogency. It appears that physicists do it that way and mathematicians don't. So the italic version is at least conventional, in something like an article about Lebesgue integration. Michael Hardy (talk) 02:34, 9 December 2012 (UTC)


 * Actually it also matches upright text for functions like "sin"/"exp" etc, and stands out clearer. Maschen (talk) 11:19, 9 December 2012 (UTC)
 * I don't see that this makes any sense at all. "sin" and "exp" are functions: you plug in a number and you get out a number.  This sin(2.5) and epx(2.5) are actual numbers.  But d2.5 is gibberish. Michael Hardy (talk) 06:16, 16 December 2012 (UTC)


 * One has to interpret the statement a little more broadly for it to make sense. In particular, one needs to include "functional" and "operator" in the word "function" here. As a general rule-of-thumb, the distinction between upright and italic is when the symbol is a name or a placeholder, unless convention creates an exception. Thus, $sin x$, but $f(x)$. Exceptions include d (under discussion here), e (the constant), possibly i (the imaginary unit), c (the speed of light) and a few others. — Quondum 07:12, 16 December 2012 (UTC)
 * IMO, the main general distinction is between symbols consisting in a single letter, that are in italic (unless exceptions) and symbols consisting in several letters that are upright (for them I do not know any exception). D.Lazard (talk) 13:46, 16 December 2012 (UTC)


 * Yes conventions and whatever we should use on WP, but "it stands out better" should (hopefully) make sense, which is all I meant. Also for differentials d(2.5) = 0. M&and;Ŝc2ħεИτlk 14:19, 16 December 2012 (UTC)


 * I thought the upright d had become conventional for differentiable manifolds and the italic one was used in analysis, basically upright for differentials and italic for straightforward calculus. Dmcq (talk) 12:01, 9 December 2012 (UTC)


 * My impression is that the exterior derivative (which appears to be used for manifolds and formally has a distinct definition) uses the upright version, and I'd suggest we stick to this in WP. I doubt whether a clear line can be drawn between physicists and mathematicians on this. There was an informal scan of books (on one of these discussion pages) that the use of the upright d was definitely in the minority. — Quondum 13:34, 9 December 2012 (UTC)


 * I am a physicist, so that is probably why I prefer them upright. Sorry that I made a mess, I just tried to make them consistent (my preferred style). Now they are consistently italic, better than inconsistent! Martin Ueding (talk) 14:05, 9 December 2012 (UTC)


 * I think many of us have been through this learning curve, so you're in good company. Sometimes a particular style seems obviously better, but in the end two points seem to emerge: most people can agree on the merit of consistency, and changing a consistent style within an article is frowned upon. There are however several style-related points that are covered by Wikipedia guidelines. For this case, see WP:MOSMATH. — Quondum 17:48, 9 December 2012 (UTC)

Inversive ring geometry
Based on half an hour of internet searches, and scrutiny of the main author's writings, I am led to the conclusion that the name and subject matter of inversive ring geometry is probably entirely WP:OR. I could of course be mistaken. In the case that I'm correct, I'm inexperienced with this matter and I would appreciate guidance on how to follow up something like this. Thank you. Rschwieb (talk) 18:18, 14 December 2012 (UTC)
 * Have you tried asking the editor who wrote the early versions of the article? They are still active on Wikipedia.  Deltahedron (talk) 18:32, 14 December 2012 (UTC)
 * I will, but part of my goal was to get people other than the original author looking at it too. Rschwieb (talk) 21:03, 14 December 2012 (UTC)


 * I should also rephrase my original post here. My reading is that the title might be WP:OR, and that the contents are a WP:SYNTHESIS of ideas appearing in several disparate sources, most of them primary. I'm still trying to convince myself that there really is such a term, or if it's just an extension of ordinary ideas that someone studied. If it is this latter case, then it is probably not notable enough for its own article. Rschwieb (talk) 03:04, 16 December 2012 (UTC)


 * I see your point. The phrase "Inversive ring geometry" does not appear in ZMATH and the article does not appear to be about inversive geometry over a ring, or about geometry over an inversive ring (this concept does exist  but there is as yet no Wikipedia article on the subject).  Is there an independent reliable source that uses this phrase, or alternatively a single source that discusses the topic of this article as a whole under some other name?  Deltahedron (talk) 17:23, 16 December 2012 (UTC)


 * You can take a look at the author's responses on his talkpage which have been a little illuminating. The responses so far seem to indicate he invented the title. I am still asking questions about the notability of the content. I think that two or three of the references are texts (meaning that they are potentially secondary resources), and the rest seem to be century-old primary sources. The Yalgom and Benz references are all either foreign language or translated from foreign language, and I haven't been able to tell if they are truly secondary or not. It kind of sounds like they just chased down extensions of a few well-known ideas. In that case it would make more sense if this content existed as a short section under more notable sections, rather than having a page of its own with an invented title. Rschwieb (talk) 14:25, 17 December 2012 (UTC)
 * In fact, this seems to be a part of a larger pattern of contributions by User:Rgdboer that happened from 2004-2006. I've found more than a handful of similar articles written during that time. The pattern is that he holds the lion's share of edits in these articles, which often seem to give undue importance to some obscure historical topics. (I am not saying the contents should disappear completely, I just think their location and presentation needs to be reevaluated. For example, do we really need an article on 2_%C3%97_2_real_matrices?) There might be some serious inclusion issues. At worst I would guess some of the contents belong in different articles, and at best I think someone needs to seriously evaluate the references given. I have already removed a few self-citations by the editor, especially because they were just links to biography webpages. Part of the pattern can perhaps be excused as an editor acclimating to the editing process here. Rschwieb (talk) 18:46, 17 December 2012 (UTC)
 * The author says that the article "blends inversive geometry with ring (mathematics) or ring theory", but that does not seem to be the case. The article begins "Not to be confused with Inversive geometry" and indeed inversive geometry is not based on "the concepts of projective line, homogeneous coordinates, projective transformations, and cross-ratio".  The article in question appears to be an extension of projective algebraic geometry to non-commutative rings, and as such might be an elementary form of Noncommutative geometry.  However, what is needed is a reliable source that presents this material as a whole, or at least, which states the nature of the subject and its relationship to the other topics already mentioned.  We traditionally have a fairly liberal attitude to essays presenting mathematical topics, but they do need to have a sound basis in the literature.  Deltahedron (talk) 19:06, 17 December 2012 (UTC)

You've definitely captured and/or confirmed my feelings on this matter. After allowing more time for him to respond, I'll ask about a course of action here again. No matter the resolution, the next article that seems to need the same examination is motor variable. I appreciate your attention so far, and hope you can spare a moment to take a look at that one too. Rschwieb (talk) 14:16, 18 December 2012 (UTC)
 * ... which should be merged into split-complex number; it is simply another (and archaic) name for this, and should not have its own article. — Quondum 14:28, 18 December 2012 (UTC)
 * I'm not sure where it should go to, actually. So we all get "function of a real (or complex) variable". His original intent seems to have been to make pages for such functions for quaternion and split-quaternion functions, however he arrived at the unfortunate choice of "motor variable" and "quaternion variable". ("Real variable" redirects to "function of a real variable" and "complex variable" redirects to "complex analysis"). Maybe they can be combined into a single article on "functions of hypercomplex variables"?Rschwieb (talk) 21:22, 18 December 2012 (UTC)
 * Ignoring the naming problem for now, in principle, I think merging into each of the hypercomplex number articles (real number, complex number, split-complex number, quaternion, bicomplex number etc.) is more appropriate than an overlap article such as "functions of hypercomplex variables", which would in any event possibly be WP:SYNTH. Once a section gets too involved, it gets split off as a "subarticle", but should not be started as a stub or start-class article until then. IMO, anyway. — Quondum 06:29, 19 December 2012 (UTC)
 * Well, as amusing as I find the insinuation I'm committing precisely the same mistake I am trying to clean up, let me give a reason why I recommended that. There appear to be lots of secondary resources for hypercomplex function analysis. Try "hypercomplex variable" and "hypercomplex analysis" in googlebooks. Doing the same in googlescholar also shows fresh research in the past four years with the same keywords.
 * I have noticed now that "hypercomplex analysis" redirects to "Clifford analysis" which also gets plenty of hits. The problem is that Clifford analysis seems to be an abstruse physics topic rather than an analogue of complex analysis. To parallel the linkage we have now for reals and complexes, wouldn't it make sense to make "hyperbolic analysis" its own page, if the secondary resources bear out the coherence and notability? (With pointers to Clifford analysis, where appropriate.) Rschwieb
 * As an aside, Rgdboer has told me that "motor variable" was actually the word Clifford used, however I disagree with him on deciding to use that. He recently added that the term is used in the article "for euphony and tradition" which are not very encyclopedic reasons, in this case. It would be better to choose the more recognizable and widespread term, rather than a single (albeit the first) author. Rschwieb (talk) 14:26, 19 December 2012 (UTC)
 * My theory that "hypercomplex analysis" is the right term will collapse here if it is only ever used for Clifford analysis... I've been browsing the books and it looks a little that way. I hope others reading might have a gauge on it. Rschwieb (talk) 14:33, 19 December 2012 (UTC)
 * I guess I should withdraw my comment if the notability of general hypercomplex numbers (and in particular related topics e.g. functions over them) are referred to in secondary sources. Perhaps I shoot from the hip a bit too quickly. I do tend to concur that the title "motor variable" could be changed; it is current usage that should determine titles, not historical usage. If the article does not change but is renamed, the title should include the phrase "split-complex". I can't yet comment on "hypercomplex analysis" though. — Quondum 18:47, 19 December 2012 (UTC)

Foundations of geometry
Foundations of geometry is a new article. It but it has potential IMO. So have fun with it. Michael Hardy (talk) 18:55, 19 December 2012 (UTC)
 * is a stub; and
 * lacks references; and
 * may have other issues;

Hawking birthday TFA
Is anyone available to review Talk:Stephen Hawking to prepare the article for a possible mainpage appearance on his birthday? Thanks in advance, Sandy Georgia (Talk) 22:54, 19 December 2012 (UTC)

Deletion of Determination of the day of the week?
See Articles for deletion/Determination of the day of the week.

Don't just say Keep or Delete; explain your rationale. Michael Hardy (talk) 18:15, 19 December 2012 (UTC)

I'm observing with interest to see whether any of you get around to. Uncle G (talk) 14:33, 20 December 2012 (UTC)

Article Count vs total Assessment numbers
I was pleased to find that there are more than 2800 articles in the project, which is mentioned here on the project page. I was also pleased to find that there are fewer than 200 articles in need of assessment, which is found here on the project page.

However, the total number of articles in the assessment table (~10,500) is much less than the number of articles (>28,000). Clearly there are many articles not in being assessed - some of them are important, and even some good, such as Implicit function theorem. This is a major issue. Does anyone know the reason, or a way that I could help?

Thanks, Brent Perreault (talk) 15:06, 20 December 2012 (UTC)


 * The best way to help is to assess math articles you edit that are not yet assessed. There are three reasons that we do not have assessments on every article on the List of mathematics articles:
 * The list is intentionally very broad, but talk page tagging should not be quite that broad. Some articles on the list are only tangentially related to mathematics, such as Euro club index. Only a human can decide whether an article is sufficiently in our scope to warrant including it in the table of article statistics.
 * We would like editors to fill in the assessment information (quality, priority, field) when they add the talk page tag. Since we already have a list of mathematics articles, there's no benefit in having a duplicate of that list; the article tag is just for ratings info. If we added "unassessed" tags to thousands of articles, it would not give us any information that we don't already have. The 200 articles you mentioned require human attention to go back and add ratings information - that can be done in a few sessions of work, but 10,000 articles cannot.
 * It takes human effort to add the ratings information, and this is a limited resource.
 * Please do add the rating tag maths rating to any math article that doesn't already have it, along with the assessment information. There are some tools on my user page that can help you list articles by category that do not have math ratings. &mdash; Carl (CBM · talk) 15:17, 20 December 2012 (UTC)
 * Is there a collection somewhere (like in Pages needing attention/Mathematics/Lists) of articles that are known to the bots as being mathematics articles but that do not have a maths rating banner? That would give the people who want to add these sort of ratings somewhere to start. It would be easy to set up a bot to add empty banners to them all but I think that's probably a bad idea because of the reasons you list. —David Eppstein (talk) 19:39, 20 December 2012 (UTC)
 * Since there are thousands of them, I believe that a category-by-category list is more useful, because most editors will be more comfortable in some areas than others. If you use this tool it will let you navigate the category tree and see which articles in each category are not tagged. The list is dynamically generated on the toolserver, so it is automatically updated. &mdash; Carl (CBM · talk) 19:43, 20 December 2012 (UTC)

Teorema del mono infinito
I note that es:teorema de los infinitos monos has been moved to es:teorema del mono infinito, with an edit summary Traducción correcta.

I suspect that the person who moved it is being overly literal. In English we don't say theorem of infinitely many monkeys because it's just a bit labored. But my intuition (unreliable, as I don't speak Spanish very well) is that it's hard to avoid reading teorema del mono infinito as being about a single, infinite monkey rather than infinitely many monkeys. (Granted, a single monkey that's infinite in the sense of being infinitely long-lived and willing to type forever gets you the same result, but this is not the usual metaphor.)

My Spanish is not good enough to engage the issue on es.wiki, but perhaps someone here who does speak Spanish would be interested in doing so? --Trovatore (talk) 19:33, 20 December 2012 (UTC)

html to latex changes
I've reverted recent changes to Kruskal–Katona theorem‎ that replaced some (but not all) inline html formulas with latex, but they were restored with a request to quote a specific policy. My recollection is that in the past such changes were discouraged and reverted. Is there a policy or guideline that governs this situation? I was not able to find anything at WP:Math, for example. Arcfrk (talk) 00:04, 21 December 2012 (UTC)
 * Everyone has their own opinion about which of LaTeX or HTML is better, and Math lists some pros and cons for each. In other contexts such as citations, policy recommends getting consensus before changing a prevailing style, and I think this commonsense principle applies here. It is not mentioned in WP:MATH, but it probably should be. RockMagnetist (talk) 00:55, 21 December 2012 (UTC)
 * However, MOS:MATH says "Having LaTeX-based formulae in-line which render as PNG under the default user settings, as above, is generally discouraged, for the following reasons." Nevertheless, in this case, the changes have been done for badly formatted html formulas, containing a "-" with a space before if but without one after. Thus I suggest to revert to corrected html formulas. D.Lazard (talk) 02:03, 21 December 2012 (UTC)

Fractions
Why are fractions hard to most people? — Preceding unsigned comment added by 72.0.148.82 (talk) 19:18, 21 December 2012 (UTC)
 * That question is better suited to the Reference desk. RockMagnetist (talk) 19:40, 21 December 2012 (UTC)
 * Indeed. This page is for discussions of editing and organizing Wikipedia's mathematics articles. Michael Hardy (talk) 04:38, 23 December 2012 (UTC)

Article listed for deletion
Warning that you'd be coming has been given. You have your choice of logic and philosophy textbooks by professors to cite. Feel free to mention the examples from Aquinas, Aristotle, and Locke if you want to get into the philosophy in addition to the logic. &#9786; Uncle G (talk) 01:19, 23 December 2012 (UTC)


 * Articles for deletion/Gyula J. Obádovics could use additional input. Tkuvho (talk) 09:53, 25 December 2012 (UTC)

Missing eponym in Blancmange curve
In Blancmange curve, there is a mention of the "Takagi–Landsberg curve" (a generalization that includes the blancmange curve). The same name does appear in a few publications such as this one, but I haven't found out who Landsberg is/was or what connection he/she has with the curve. Any suggestions? —David Eppstein (talk) 02:22, 26 December 2012 (UTC)
 * Never mind, I found it from a reference in one of Mandelbrot's books. It's Georg Landsberg — new article created. —David Eppstein (talk) 06:44, 26 December 2012 (UTC)

Images by User:Aughost
Can some other editors look at the contributions of. They recently consist of adding images to articles which have numerous problems; they are usually too large, generally too complex so need overlong captions (which are also unclear), and often only marginally related to the article. Some can be fixed with better sizing, comments and placement but others should be removed. But some of my attempts to remedy this have been undone,, , and as it's across multiple articles I thought It's best discussed somewhere centrally.-- JohnBlackburne wordsdeeds 17:53, 28 December 2012 (UTC)


 * Yes, [this editor's Contribs page] shows evidence of warring on several pages including stellation, Regular polyhedron, Golden ratio and probably more. You have posted on their talk page, I have added my own comment there, so if that doesn't work I guess an Admin will need to get dragged in. &mdash; Cheers, Steelpillow (Talk) 20:17, 28 December 2012 (UTC)
 * In connection with this editor (or someone indistinguishable from him) please see also Commons:Commons:Categories for discussion/2012/12/Category:Pythagorean tiling. —David Eppstein (talk) 21:08, 28 December 2012 (UTC)


 * I had a look at and there are a few which are okay but in general they seem unnecessarily complex and messy. I guess Baelde must be the same as Aughost - don't know why they use two different names. If they are actually warring to shove the images in that's bad and a great pity. I hope there is the possibility for helping the person perhaps make things simpler and try and look at things from other peoples' point of view. Dmcq (talk) 01:33, 29 December 2012 (UTC)

Possible useful information
This alleges to be novel and useful. If it truly is novel, then Wikipedia is the wrong place for it, as per Original Research; however, I only have a passing familiarity with the subject at hand, and so can't really judge if this is actually novel, or just a restatement of something we already have, or possibly a restatement of something we don't have but should. There's also the question of, if it is novel, is it actually useful? (I frankly doubt it, but as I said, I'm not fit to judge this). Thoughts? DS (talk) 14:39, 31 December 2012 (UTC)
 * This might be novel as announced but wiki coverage would have to wait until Italia, Peter actually publishes his discoveries in a reliable venue. Unpublished manuscripts cannot be covered in wiki.  Tkuvho (talk) 14:46, 31 December 2012 (UTC)
 * It doesn't seem to be a restatement of some already well-known procedure for numerical integration. Indeed, one would expect it not to be, since this method relies on being able to differentiate the function which is generally much less numerically robust than integration.  It's doubtful that one can prove any good error estimates using the proposed method.   Sławomir Biały  (talk) 15:02, 31 December 2012 (UTC)

RfC at WikiProject Numbers
There is currently a Request for Comment here, which is discussing how much non-mathematical material belongs in articles about numbers. Please contribute your ideas. --  YPN YPN   ✡  16:32, 31 December 2012 (UTC)