Wikipedia talk:WikiProject Mathematics/Archive/2014/Nov

Please help review a submission at AFC
Please review Draft:Lie bialgebroids -- Roger (Dodger67) (talk) 14:48, 31 October 2014 (UTC)
 * The title was inappropriately plural. I changed it to the singular.  I also did some punctuation editing and the like.  So far only one other article links to it. Michael Hardy (talk) 15:57, 1 November 2014 (UTC)

Arrowhead matrix
A COI edit stopped by a filter is discussed at Help desk. Review by an editor with matrix knowledge is needed. PrimeHunter (talk) 00:03, 4 November 2014 (UTC)

Ivar Stakgold
I expanded the new biography Ivar Stakgold greatly (previously a {bridge-game-stub}). As academic applied mathematician he earned a 70th birthday volume in his honor, c1996. WP:CAT {20th-century mathematicians} altho he is living, emeritus. {maths rating} on the Talk page.

I used as sources Library of Congress online catalog records and enhancements and the Mathematics Genealogy Project, with some references that are fullish but free form. Planning to leave a notice here, I provided fullish edit summaries and some comments (especially at Ivar Stakgold). I hope they help.

--P64 (talk) 20:00, 4 November 2014 (UTC)
 * fullish. adj. Meaning, rather full. Pronunc., full-ish or foolish. -P64

MathML rendering available
An announcement at the wikitech-l mailing list says that logged-in users now have an option to enable MathML rendering at Special:Preferences. I think it's saying that Internet Explorer would fallback to SVG. Also, there are a couple of editing tricks (create an anchor and display inline/block). Johnuniq (talk) 02:21, 24 October 2014 (UTC)
 * I'm impressed; the big formula in squared triangular number (the one in the proofs section) looks pretty good with this option, and the formulas in the reference titles are correctly sized. (I'm less impressed that you broke my previous preference setting for MathJax, but never mind.) One issue I noticed, though: we have a bunch of formulas in which editors have included \scriptstyle in order to try to get the formula size produced by the old bitmap renderer closer to the text size. Doing that with the MathML option is a bad idea; it actually comes out subscript-sized (just what you asked for but way too small). So I think the best option for these is to remove the \scriptstyle command, but in some cases \textstyle may be needed instead (e.g. look at the references of squared triangular number — I've used textstyle there because otherwise the formulas in the titles come out way too big). Another issue: the baseline of the formulas doesn't match the baseline of the text. That's annoying enough to me that for now I think I'll stick with MathJax. (This is all on Chrome for OS X btw; presumably these rendering issues will differ for different platforms.) —David Eppstein (talk) 02:54, 24 October 2014 (UTC)


 * I really like this so far. Formula looks a lot better, for instance.Brirush (talk) 03:06, 24 October 2014 (UTC)


 * I've reopened which addresses baseline issues.
 * For what its worth only Firefox has decent MathML support and Chrome will fallback to SVG. --Salix alba (talk): 06:43, 24 October 2014 (UTC)


 * The jury is still out for me on this one. The \scriptstyle command, seemingly ignored by MathJax, does result in an unacceptable rendering with MathML. I've removed them from one article (Square root), but this was a lot of work ... could someone write a bot to do this? Also, the baseline problem does need to be dealt with. In said article there was an instance of two radicals appearing at different heights wrt the baseline on the same line of text. I used \phantom as a kludge to get the heights right, but then the radical sign extends too far (in order to cover the phantom letter) ... I left it that way as the lesser of two evils. Editors will be spending far too much time on these appearance issues unless something is done relatively quickly. Bill Cherowitzo (talk) 19:01, 24 October 2014 (UTC)


 * Better, but not good enough (Chrome on Windows). The math is displayed in a (too) bold typeface - and there is, as mentioned, the baseline problem. This is still unacceptable for inline LaTeX. YohanN7 (talk) 01:55, 27 October 2014 (UTC)


 * As noted above. Only Firefox (and other Gecko engine based browsers) has proper support for MathML. For other browsers (including Chrome) this setting will just fall back to SVG rendering (which is suboptimal).TR 09:39, 27 October 2014 (UTC)


 * I'm fairly optimistic that things will get better quickly on this. Physikerwelt, Frédéric Wang and other have done great work getting basic system going. This has been tricky as it involves large changes in the code which are hard to get through code review. Now thats out of the way the smaller tweeks to the system should be easier to do. There has been quite a bit of traffic on the baseline bug including input from the main MathJax person. I've started a new bug about the font size it would be helpful if people could add to that as its quite a browser dependant issue.


 * For the \scriptstyle in square root, I could not quite see why it was used in the first place. The best way to do derivative inline might be to use \tfrac  $$\tfrac{dy}{dx}=3x^2$$ or    $${\scriptstyle \frac{dy}{dx}}=3x^2$$ with the \scriptstyle in { } so the whole equation is not rendered small. I'm generally against specific hacks to make the equation look nice as there are so many different ways to view equations and a hack might work in one method and not another.--Salix alba (talk): 10:25, 27 October 2014 (UTC)


 * Thanks for that example. It both shows an appropriate use of \scriptstyle and implies why a bot would not be such a good idea. I agree with your position on specific hacks. I was experimenting in square root and don't usually engage in such behavior. Bill Cherowitzo (talk) 19:40, 27 October 2014 (UTC)


 * Looks good in Firefox, albeit slightly too small on Windows. That is because the size for the (defualt serif) font is not adjusted to fit the page's sans-serif font. Firefox' internal fontstack for MathML is . I happen to have STIX fonts installed, but Cambria (which 99% of Windows users will see) is equally small. So if possible (that is, if Firefox supports it), you may need some CSS to increase the size.   11:54, 27 October 2014 (UTC)

I've just noticed a bug when an equation contains a percent. $$P = 10\%$$ now cause a bug $$P = 10\%$$ it should be $$P = 10\%$$ giving $$P = 10\%$$. I think the old texvc system managed to parse this OK. I'm doing a scan to find all the pages where this occurs.--Salix alba (talk): 20:35, 27 October 2014 (UTC)
 * That would cause an error in LaTeX, too, so I think the bug is in the formula rather than in the MathML implementation. —David Eppstein (talk) 20:57, 27 October 2014 (UTC)
 * Yes the latex formula need to be fixed. I've compiled a list User:Salix alba/percent bug of the 250 or so articles which may contain the bug. I've corrected some of them but there is still about half to do. The list is generated from the September dump so there will be other articles with the bug.--Salix alba (talk): 23:37, 27 October 2014 (UTC)

The bug for darkness of the font is. It is currently wontfix as its device dependant.--Salix alba (talk): 08:23, 28 October 2014 (UTC)


 * I've now hopefully fixed all the cases of percentages causing problems. Strangely the presence of an unescaped percentage did not always cause the red error message, sometimes is just didn't display the percent, which is harder to spot. There are a couple of other rendering bugs I've noticed.


 * The  command causes a couple of problems. With png rendering it needs   to force spaces between words and spaces are ignored so $$\textrm{A\,B C}$$ is rendered as "A BC". In MathJax $$\textrm{A\,B C}$$ is rendered as "A\,B C". The solution is to change to the   command which preserves spaces.


 * Setting the vertical-align style B (B) renders the equation invisible when using the mathml or SVG fallback in chrome. I think this is a bug in the system rather than with the syntax, although all the instances I've found seem to be workarounds for the baseline problem.--Salix alba (talk): 09:33, 29 October 2014 (UTC)


 * MathML accepts characters such as π. I noticed this when translating from HTML to LaTeX (missing the π) and then later switched to PNG rendering. I don't know if this should be considered a feature or a bug. See for yourself below.
 * $$π$$
 * YohanN7 (talk) 11:08, 29 October 2014 (UTC)


 * Info: You can report bugs and give suggestions at mw:Extension:Math/Roadmap. Best wishes, --Quartl (talk) 07:34, 5 November 2014 (UTC)

This doesn't work
I set my preferences for MathML and then I could no longer see anything coded in TeX. All I see is "[Math Processing Error]". This persists even after I've changed my preferences back to what they were. Michael Hardy (talk) 06:16, 5 November 2014 (UTC)
 * You are still loading Nageh's obsolete MathJax script from your vector.js. Remove it and MathML should work.  06:59, 5 November 2014 (UTC)

A new feature
https://lists.wikimedia.org/pipermail/wikitech-l/2014-October/079144.html For editors, there are also two new optional features:

1) You can set the "id" attribute to create math tags that can be referenced. For example, the following math tag

E=mc^2

can be referenced by the wikitext

mass energy equivalence

This is true regardless of the rendering mode used. Michael Hardy (talk) 15:18, 5 November 2014 (UTC)


 * What is the second feature? -- Taku (talk) 16:54, 5 November 2014 (UTC)
 * It's explained in more detail in the link, but it's a way of doing \textstyle or \displaystyle in the html part of the encoding rather than in the latex part. —David Eppstein (talk) 18:22, 5 November 2014 (UTC)

Wikipedia talk:Articles for creation/Saddlepoint approximation
Hello mathematicians. This old AfC submission will soon be deleted as a stale draft. Is this a notable topic, and should the page be kept and improved instead? &mdash;Anne Delong (talk) 12:44, 6 November 2014 (UTC)


 * It's definitely a notable topic (although pretty far from my own areas of expertise). I'm a little puzzled by the decline reason, as the AfC draft cites two books on the subject of the article by reputable academic publishers.  It's not a great article at the moment, but pushing it out into the main space may be a way to solicit improvement by normal editing.  What do others think?   Sławomir Biały  (talk) 12:49, 6 November 2014 (UTC)


 * The style needs work, but besides that I think the article is fine. The topic is notable, and the citations are adequate per WP:SCICITE.  Ozob (talk) 14:30, 6 November 2014 (UTC)


 * I agree that this topic is notable and lack of inline citations shouldn't prevent a transition to mainspace. But we already have an article on Method of steepest descent, of which the saddle-point approximation is a synonym. Hence a merge may be best. --Mark viking (talk) 16:31, 6 November 2014 (UTC)


 * (sigh) Thanks,, Ozob and Mark viking; I wish I could do this merge but I don't have the knowledge. If someone here will move the text, I will be happy to handle the attribution stuff.  &mdash;Anne Delong (talk) 19:10, 6 November 2014 (UTC)


 * I think it is unlikely you will find volunteers on a short notice, but how about just approving the article and tag it with " suggested merge"? YohanN7 (talk) 19:20, 6 November 2014 (UTC)


 * I am not sure whether "saddle-point approximation" is a synonym of "method of steepest descent" or not, but I see that this article "Saddlepoint approximation" describes only the real-valued case. No contour integrals on the complex plane, no complex numbers at all. This makes it less general, and accordingly simpler, more accessible. It is also written in the probabilistic language (still more accessibility for some audience). And it is shown that this special case is indeed useful for some applications. If merge them, then probably the merged article should be nearly the "direct sum" of the two articles. That is, two separate sections, with some common lead. Or not to merge them? Boris Tsirelson (talk) 20:21, 6 November 2014 (UTC)
 * But wait; maybe it should rather be merged with Laplace's method? Indeed, Laplace's method and Wikipedia talk:Articles for creation/Saddlepoint approximation could be a single list. Boris Tsirelson (talk) 20:25, 6 November 2014 (UTC)

Fréchet space
I post this here because I suspect the page has few watchers. I find the article very nice, it is crisp and clear. The page rating should be changed, but there is not a single inline citation. I can (and will) add a couple, but my access to functional analysis literature is limited (to John B Conway's A course in Functional Analysis). Some help appreciated. YohanN7 (talk) 16:04, 6 November 2014 (UTC)
 * Maybe try to contact User:Robert McGuigan=User:RMcGuigan, the originator of "LF-space" in 2005, last seen in May 2014. Boris Tsirelson (talk) 21:17, 6 November 2014 (UTC)

Symmetry: Splitting off geometry section
On Talk:Symmetry, I have proposed a major revision to symmetry which would remove the geometry portion and replace it with low-difficulty description and link to the new page, as well as simplifying the physics portion by moving relevant material to the pre-existing article symmetry (physics). I have a sample draft available at User:Brirush/sandbox, and I would be interested in hearing feedback before taking any action.Brirush (talk) 18:52, 9 November 2014 (UTC)
 * A remark: scale symmetry is not isometric. Otherwise, yes, looks good. Boris Tsirelson (talk) 19:20, 9 November 2014 (UTC)
 * Good catch! I removed the offending line.Brirush (talk) 20:09, 9 November 2014 (UTC)

Redirect for "Numbers"
There is a discussion at Redirects for discussion/Log/2014 November 4 for deciding if should remain a redirect to Number or should be redirected to Number (disambiguation). Further opinions are needed to reach a consensus. D.Lazard (talk) 16:53, 12 November 2014 (UTC)

Inductive probability
Can someone check if the article Inductive probability makes any sense? —Ruud 09:43, 13 November 2014 (UTC)


 * The article doesn't make much sense to me, in that it seems to be a big synthesis of Bayesian inference, mutual information, algorithmic complexity, and other concepts into some original research. It seems related to Solomonoff's theory of inductive inference, another problematic article. There does exists a notion of inductive logic and inductive probability in philosophy; the Stanford Encyclopedia of Philosophy article has a nice summary of the different approaches tried and we have a a start of an article on it in Inductive reasoning. --Mark viking (talk) 10:29, 13 November 2014 (UTC)


 * It seems reasonable, but it is too long and repetitive. And reads like a textbook. JRSpriggs (talk) 10:32, 13 November 2014 (UTC)


 * This quotation from the user's talkpage does not inspire a lot of confidence:


 * "Also I have done the maths as text, which works alright because the maths is not difficult. However I dont have references (other than to other wiki pages). Honestly I find it difficult to read scholarly articles. I am not an academic. So maybe my page is not useful to anyone else. Thats OK."


 * Maybe some more careful checking is warranted. Rschwieb (talk) 14:59, 13 November 2014 (UTC)

Draft:Reckless Xi function
Dear mathematicians - is there anything in this old draft that should be kept? &mdash;Anne Delong (talk) 23:57, 13 November 2014 (UTC)


 * Nope. At best, it's self-named original research.  The OEIS entry referenced in the article is written by someone claiming to be "Frederick Reckless", but there is no evidence that such a person actually exists.  It seems likely that this is a hoax.  Oh, and someone should probably ping User:CRGreathouse to look into the OEIS entry.  Sławomir Biały  (talk) 00:35, 14 November 2014 (UTC)


 * Thanks for the heads-up. It looks like OR to me, more than a hoax -- the math checks out, as best I can tell, though of course it doesn't meet the notability guidelines.
 * Modulo the (nontrivial) issue of attribution, the OEIS sequence looks fine to me.
 * CRGreathouse (t | c) 05:35, 14 November 2014 (UTC)

Alexander Grothendieck
I'd like to let you know about the nomination of the article Alexander Grothendieck for ITN at In the news/Candidates. It isn't posted yet due to concerns on article quality, mostly referencing. Cenarium (talk) 14:36, 15 November 2014 (UTC)


 * There has been some grumbling at Talk:Alexander Grothendieck that the mathematical works of Grothendieck should be made understandable to someone who doesn't know anything. Perhaps editors here more familiar with his works than I would care to weigh in on the futility of that request.   Sławomir Biały  (talk) 20:45, 15 November 2014 (UTC)


 * An anecdote: many years ago I gave a talk "The Grothendieck constant in physical laboratory" in France, and the audience was very disturbed and angry. I did not understand, why, and asked a friend. The answer was that I took a tiny result of Grothendieck, not worth to be mentioned, which was an insult for his admirers... Boris Tsirelson (talk) 21:51, 15 November 2014 (UTC)


 * It is getting rather exasperating dealing with User:Medeis, who citing his own ability to express elementary biological facts in a way that any educated lay person can understand, seems to believe that all concepts can therefore be expressed by some sort of sound-bite. Moreover, he refers to WP:JARGON and WP:MTAA without (apparently) having read or understood either.  Please see his rather baffling assertions concerning accessibility at Talk:Alexander Grothendieck and Candidates.  Sławomir Biały  (talk) 01:43, 16 November 2014 (UTC)
 * It is now on the main page, under recent deaths with no blurb. Could the one liner in Deaths in 2014 be improved to say more than just one a field medal? --Salix alba (talk): 09:07, 16 November 2014 (UTC)


 * Richard Feynman said (something like) "I can't teach you how to understand quantum theory, because I don't understand it." The problem is that quantum theory requires some difficult math and violates a lot of our common sense. Grothendieck's work requires much more difficult math (at least at the start). Because it's not about reality, it doesn't violate much common sense, but it's very hard to motivate to the non-mathematician.
 * My point is that making Grothendieck's work accesssible would be a feat, perhaps worthy of a prize itself. So we can use this occasion to improve the articles on Grothendieck, including citations, but making them truly accessible in a few days seems too ambitious. Mgnbar (talk) 14:59, 16 November 2014 (UTC)
 * I fully agree. The basic starting point of his whole work in algebraic geometry is the introduction of the notion of scheme. This definition involves commutative algebra, topology, sheaf theory and category theory, and, for being well understood, requires to understand an analogy with manifolds. And this is the first hundred pages of a work of thousands of pages! D.Lazard (talk) 15:43, 16 November 2014 (UTC)

Formula overload in Artin transfer
I can't view Artin transfer (group theory) (primarily edited by ) when logged in — it's ok logged out or probably with different math rendering preferences — because it's huge and packed with formulas that cause the Wikipedia servers to choke. Instead I get the error message "Sorry, the servers are overloaded at the moment. Too many users are trying to view this page. Please wait a while before you try to access this page again. Timeout waiting for the lock".

I was looking at it to see what should be done about the proposed merge between this and Transfer (group theory), which appears to be on the same topic in much more high-level terms. The "Transfer" article is not much more than a stub, but I think the other one goes too far to the other extreme, so some trimming and attention to WP:TECHNICAL is in order. Maybe some group theory expert here would like to take this on? —David Eppstein (talk) 07:07, 16 November 2014 (UTC)


 * I have no problem viewing the page; perhaps it depends on the math rendering system used. But holy smokes, that is a lot math formulas, badly formatted and mostly unexplained. Beyond the lead, it reads more like a terse journal article than an encyclopedia article. It also seems to lean pretty heavily on D.C. Mayer's publications, but I don't know enough of this field to determine whether this is a COI issue. --Mark viking (talk) 07:44, 16 November 2014 (UTC)
 * Perhaps we should just redirect Artin transfer (group theory) to Transfer (group theory), and let others debate what should be in it other than Mayer's paper. — Arthur Rubin  (talk) 06:58, 17 November 2014 (UTC)
 * I tried PNG, MathML and MathJax (all with Firefox on Windows). MathJax, of course, takes forever. (The article, b t w, illustrates why the use of inline LaTeX should carry a lifetime sentence, or at the very least, a sentence of a few years behind bars ) YohanN7 (talk) 15:59, 16 November 2014 (UTC)
 * Yup, MathJax can't handle this, strange though that the server pukes. YohanN7 (talk) 16:04, 16 November 2014 (UTC)


 * The practice of creating detailed articles in the field of your own research and then subsequently sneaking in references to your own very recent publications (see also Principalization (algebra)) should at least be looked at closely, the more so because it is not a very blatant WP:COI in this case. YohanN7 (talk) 17:03, 16 November 2014 (UTC)

Diophantus spam
User talk:Morcohen2 insists on adding material on Diophantus that's not properly sourced. He did it twice from his account and once from IP in the past 24 hours. Tkuvho (talk) 13:17, 18 November 2014 (UTC)
 * User talk:Morlvi seems to be a sockpuppet based on edit history. Tkuvho (talk) 13:21, 18 November 2014 (UTC)
 * Apart from the issue of sourcing, the added content states a matter of opinion (that the title "father of algebra" ought to belong to Diophantus instead of al-Khwārizmī). A comparison might indeed be appropriate, but we cannot advance unattributed opinions.   Sławomir Biały  (talk) 13:25, 18 November 2014 (UTC)
 * We now have some further insights by the same editor here: https://en.wikipedia.org/w/index.php?title=History_of_algebra&diff=prev&oldid=634376716 Tkuvho (talk) 14:06, 18 November 2014 (UTC)
 * Since the editor is very new, I'm not sure that the use of multiple accounts is malicious. I've asked him on his talk page to create user pages which identify the accounts as alternates.  Ozob (talk) 15:20, 18 November 2014 (UTC)

more upright d's
Please help with this https://en.wikipedia.org/w/index.php?title=Leibniz%27s_notation&oldid=634556411&diff=prev and there is a similar development taking place at derivative. Tkuvho (talk) 18:46, 19 November 2014 (UTC)

Draft:360360
Is this a collection of trivia or does it deserve a place on WP? Roger (Dodger67) (talk) 20:43, 18 November 2014 (UTC)
 * Lean toward exclusion; all the interesting facts are already in the "360360" entry in . — Arthur Rubin  (talk) 21:51, 18 November 2014 (UTC)
 * Of the facts presented about 360360, I can't detect a single noteworthy or interesting one, except perhaps that it is highly composite (?). Also the tone is unencyclopedic ("infamous") and unclear (is it highly composite?). Mgnbar (talk) 03:09, 19 November 2014 (UTC)
 * I disagree that there is nothing interesting about this number, but I don't think there's enough. I think being the lcm of the first few positive integers is interesting. But when I searched this number on OEIS, the only interesting properties of this number that I found all seemed to be minor variants of this, and that WP:NUMBER requires at least three independent interesting properties. —David Eppstein (talk) 03:53, 19 November 2014 (UTC)
 * Hi all, if you do decide that it's a notable topic, would you mind pinging me so I can fix/approve the page? Otherwise I'll just link to this discussion as a reason not to approve the article. Cheers, Primefac (talk) 20:01, 19 November 2014 (UTC)

Category:Zero and Category:One
The naming of Category:Zero and Category:One is under discussion, see Categories_for_discussion/Log/2014_November_19] -- 67.70.35.44 (talk) 07:34, 20 November 2014 (UTC)

Singles and plurals and distribution families
An issue has come up at Student's t-distribution, where a user doesn't like the existing phrasing, "In probability and statistics, Student's t-distribution (or simply the t-distribution) is a family of continuous probability distributions that arise when... " -- complaining that the subject-verb agreement is wrong.

He's made three alternative proposals so far, most recently diff, none of which seem to me to work.

Apparently he finds the existing version "awkward and bizarre" (as he put it in a lengthy discussion on my talkpage). It seems fairly regular mathematical usage to me. But, rather than the two of us just go backwards and forwards, it does seem to me that we could use some external input here. So, although it seems rather a trivial thing to bring here, I would be grateful for some wider community input. Thanks, Jheald (talk) 23:32, 20 November 2014 (UTC)

Quotient by an equivalence relation
Quotient by an equivalence relation is an article that can be immensely improved. Remind me to look at it some time over this weekend. (And look at it yourself!) Michael Hardy (talk) 04:54, 22 November 2014 (UTC)
 * The concept of "quotient by an equivalence relation" is defined and studied in Equivalence class, which is a redirect from quotient set and quotient space. This generalization to category theory and scheme theory must have another title such as quotient (category theory). D.Lazard (talk) 09:53, 22 November 2014 (UTC)


 * I must admit there might be a better title. There "is" a generalization of a quotient in equivalence classes to category theory and that is called a coequalizer. The article in question is about a special case, which is important and deserves its own article (whence one). Unfortunately, the most common term is just "quotient" (by f). -- Taku (talk) 13:23, 22 November 2014 (UTC)

Match-3 games are NP-hard
There's been a few studies (such as the one above) on the issue, might be something to update various match 3 game articles with, to add a mathematical/educational context -- 67.70.35.44 (talk) 10:33, 24 November 2014 (UTC)

Talk:Ellipse
Although I am for the moment assuming good faith, I'm having a harder and harder time believing that I'm not being messed with by the OP there. Does anyone have any suggestions on how to respond to future replies, if any appear?--Jasper Deng (talk) 02:06, 25 November 2014 (UTC)
 * Why do you need to explain to this person that they are wrong? The talk page is not a classroom nor a discussion forum. --JBL (talk) 02:10, 25 November 2014 (UTC)
 * Exactly my thoughts. At least he isn't inserting that nonsense into articles. I completely agree that it's quickly getting contrary to WP:NOTAFORUM.--Jasper Deng (talk) 02:11, 25 November 2014 (UTC)
 * I've collapsed it; I doubt any further replies would help solve whatever problem the OP has, and it has nothing to do with improving the article.-- JohnBlackburne wordsdeeds 03:14, 25 November 2014 (UTC)

Breaking up topos
I have started a discussion on whether it makes sense to separate the article topos into two articles: one on math, the other on logic. The feedbacks are very welcome. -- Taku (talk) 05:14, 28 November 2014 (UTC)

Good article nomination: Addition
I have nominated addition as a good article. It is well-sourced, covers all major topics, etc. Due to the simple nature of the subject, it should not take someone with an advanced background to review it (I believe it mentions Dedekind cuts, but that's about as bad as it gets). Link:Good_article_nominations Brirush (talk) 00:03, 30 November 2014 (UTC)

Homothety
Should homothetic transformation and homothetic center really be two different articles? Michael Hardy (talk) 23:27, 30 November 2014 (UTC)