Wikipedia talk:WikiProject Mathematics/Archive/2011/Jul

MathJax

I'd like to mention MathJax and it's implementation. I was introduced to it by Salix Alba via the maths reference desk. Has anyone used it before? It's absolutely amazing. You can use in-line LaTeX and it sorts out all the font size problems, the base line heigh problems; everything. It looks really slick. At the moment we need to include some code in our vector.js files and then change our preference so that all maths code in displayed in LaTeX. But after that MathJax does the rest. I've included a couple of screen shots. The first one is without MathJax and with default IP preferences and settings. The second one is with MathJax added to my vector.js and with "always display LaTeX" preference. I'm sure you'll agree that the difference is quite astounding.

Without MathJax; standard default IP settings

With MathJax; one small preference change

I was hoping that we might discuss it, and it's future use. How many people have used it? Would we recommend using it as default in future, i.e. getting the developers involved? Any other comments would be welcome. — Fly by Night (talk) 22:58, 24 June 2011 (UTC)

Are there any particular Wikipedia articles in which this is used? If so, we could see some examples of how it's done. I haven't the foggiest idea what vector.js files are. Must one set one's preferences appropriately in order for this to work? If so, every reader who looks at an article in which this software is used without their preferences suitably set will see something different from what is intended. If the use of this software is to be widespread, then some examples and guidelines on its use should be at Wikipedia:Manual of Style (mathematics) and at Help:Displaying a formula. Michael Hardy (talk) 00:07, 25 June 2011 (UTC)

I think the only requirement on a Wikipedia article is that it uses <math> formatting instead of HTML formatting, but indeed one must set one's own preferences to see this. I would very much like to see mathjax become standard for Wikipedia math formatting, so that no special user-preference tweaking is required; it works well on the other sites I've used that use it (e.g. mathoverflow and mathscinet) and looks a lot better a lot more consistently than the alternatives. —David Eppstein (talk) 00:34, 25 June 2011 (UTC)

If what David Eppstein suggests can be done, it will solve a problem that's been plaguing this, the most active of all WikiProjects, since about the beginning of 2003 (that being when we got TeX, IIRC). Michael Hardy (talk) 03:18, 25 June 2011 (UTC)

It can be done. That was my very reason for coming here. Hopefully the developers will write it in as the default maths mode. But at the moment not many people use the MathJax set-up and it's still in testing. We need to get the maths Wiki project behind it before it's even conceivable that the developers will do anything about it. There's no need to write the whole page in maths mode. The beauty of MathJax is that it can handle HTML and LaTeX side by side; in fact that's the reason for it's introduction onto Wikipedia. All it does is change the way the browser sees the maths output. Why not follow the instructions in my bulleted post below and give it a go. — Fly by Night (talk) 03:37, 25 June 2011 (UTC)

Michael, I have posted an example above. The use of MathJax is a preference setting. You add two lines of code you your vector.js page, and then change your preferences so that all maths code appears as LaTeX output. The vector.js page (assuming your using the vector skin) is some extra code that you add that changed the way your browser displays Wikipedia; the .js suffix means Java Script. Then you will see all pages in the new way. But it only works for those users that have performed those two steps. I mentioned it here because the first step is to get the maths Wiki project to endorse it. Take a look at User:Nageh/mathJax for a better explanation. — Fly by Night (talk) 01:03, 25 June 2011 (UTC)

• To use MathJax (I borrowed this from Salix); you need to add

mathJax={}; mathJax.fontDir="http://cdn.mathjax.org/mathjax/latest/fonts";
importScript('User:Nageh/mathJax.js');

to your Special:MyPage/vector.js. Then switch the option for Math to "Leave it as TeX" in your Preferences - Appearance tab. That's assuming you use the vector skin. If you use another skin then replace vector with the name of the skin. — Fly by Night (talk) 01:09, 25 June 2011 (UTC)

I think it's working! I didn't have a Special:MyPage/vector.js file; I created it by adding that bit of code. Now all we have to do is implement David Eppstein's suggestion above and all the problems of the Universe are solved. Michael Hardy (talk) 03:31, 25 June 2011 (UTC)

Excellent! Another feature I really like is if you enter a backslash command incorrectly, it compiles all the code except that command and then highlights the incorrect command in red; instead of giving a screen full of red error message. My LaTeX editor can't even do that! To see the difference it makes, log out and view the page as an IP. — Fly by Night (talk) 03:41, 25 June 2011 (UTC)

While its still a bit early to get this set as default for all users it might be an idea to see if this could be set as a Wikipedia:Gadget making it easier to people to install it and increase the user base. A MathJax userbox might also help its uptake.--Salix (talk): 07:48, 25 June 2011 (UTC)

I use MathJax mainly because it is scalable; I don't like the small size of the default TeX rendering. And if any of you use Firefox and have STIX fonts installed, you may want to choose MathML as the renderer, for it is faster and better looking.--Netheril96 (talk) 08:33, 25 June 2011 (UTC)

MathJax has been brought up before here, see Wikipedia talk:WikiProject Mathematics/Archive 68, among others.--RDBury (talk) 11:43, 25 June 2011 (UTC)

Serious software bug!

${\begin{aligned}2+3&=5\\[8pt]3\times 3&=6\end{aligned}}$

Spacing by the use of \\[8pt] and the like within the align environment in TeX, and within arrays and matrices set in TeX, occurs in MANY Wikipedia articles. If you see what I'm seeing on the screen in front of me, it's not working here, and even worse—far, far worse—the reader actually sees "[8pt]" at the beginning of the following line, and will wonder what it means in the mathematical notation. Michael Hardy (talk) 16:54, 25 June 2011 (UTC)

(I observed this when I looked at the article titled meridian arc.) Michael Hardy (talk) 16:55, 25 June 2011 (UTC)

I am aware of this. It's a current limitation, not a bug. You will find a few things not (yet) implemented, which is because MathJax does not rely on a full-featured TeX back-end. This is one of the reasons why the extension is still for testing and not production usage. FYI, I am already working on a (temporary) work-around for this issue. Future bug reports should go to the extension's discussion page. Thanks for testing! Nageh (talk) 17:03, 25 June 2011 (UTC)

At q-Gaussian I find this:

$x\in \left[\pm {1 \over {\sqrt {\beta (1-q)}}}\right]$

Using mathJax, the way it appears in the article sets the material within the brackets visibly closer to the bottom of the brackets than to the top. Michael Hardy (talk) 17:36, 25 June 2011 (UTC)

It's even worse without MathJax. Try logging out and looking at the same formula as an IP without MathJax. The square root sign sticks out of the bottom of the brackets. See Here — Fly by Night (talk) 18:16, 25 June 2011 (UTC)

This one is of course a minor issue. Then one I labeled "serious software bug" is a major issue; it makes it unthinkable to force mathJax on everyone. Michael Hardy (talk) 04:14, 26 June 2011 (UTC)

That's why it's currently in testing, and hasn't been forced on anyone. Nageh said that it's a not a bug, but a limitation, and that he's working to get around it. Besides that, I wouldn't think that many people use that command you gave. I never seen it or used it, and I've been using LaTeX for the best part of 10 years. I think you might be in the minority of users that uses that type of command. In which case, even in its present state, it would work perfectly for the majority of users. — Fly by Night (talk) 13:53, 26 June 2011 (UTC)

Even those who don't use that code still want to read articles that do use it! I've seen many instances of others using it, and even if only one user is putting it into articles, the number of readers of those many articles may be large. Michael Hardy (talk) 19:34, 30 June 2011 (UTC)

… and Nageh has said that he's working on a fix. So don't worry, relax, all will be well in no time. — Fly by Night (talk) 00:51, 1 July 2011 (UTC)

• There is a feedback page at User_talk:Nageh/mathJax. It might be an idea to list any problems there as a more permanent reference. This discussion will be archived in a few days.

Lévy flight

The article titled Lévy flight is currently nonsensical. Work on it if you can. Michael Hardy (talk) 01:00, 1 July 2011 (UTC)

'Learning resources' sections

Following on from that complain yet again that Wikipedia doesn't teach, I was wondering what people felt about having a standard 'Learning resources' section in the externals of articles where there were reasonable books or web sites to learn from? This would be as distinct from externals which are aimed at finding more about the subject. Lots of universities for instance put course notes onto the web so even fairly complex subjects could be covered this way and it could advertise Wikiversity so it might be improved. 10:50, 28 June 2011 (UTC)

One of the standard appendices/footers to Wikipedia articles is a Further reading section, which is described at MOS:APPENDIX as "an optional bulleted list, usually alphabetized, of a reasonable number of editor-recommended publications that would help interested readers learn more about the article subject". Seems to be very similar to your proposal. Gandalf61 (talk) 12:22, 28 June 2011 (UTC)

Unfortunately that implies reading beyond what is in the article rather than introducing into the same as the article, exactly what I was saying is a problem about the requirements for the externals section. Dmcq (talk) 17:41, 28 June 2011 (UTC)

I think "more about the article" can refer to more background/pedagogical material, as well. RobHar (talk) 20:56, 28 June 2011 (UTC)

It could, but it doesn't straightforwardly imply that. It says more. They very often don't want more. They just want to learn a bit of what is there in front of them in a more digestible way. Dmcq (talk) 21:01, 28 June 2011 (UTC)

I agree it only could or rather it works by reading the exterrnal links guideline "in the right way". However this reading might not be shared by many self proclaimed guardians of the guideline and often lead to conflict. Polemically speaking, you might say, it works because authors constantly ignore it. The guideline if taken all to literally is rather restrictrive and often blocking useful links to readers. It is essentially written with the focus on avoiding spam (at all cost) rather than providing useful links.--Kmhkmh (talk) 08:44, 1 July 2011 (UTC)

Frappadingue du Valseur - hoax?

I'm sceptical about this French woman mathematician - see talk page. Could someone with access to any of the 3 printed sources verify that she existed?

Refs given are:

• Lynn M. Osen (1976) Women in Mathematics (MIT Press) ISBN 0262650096
• John G. Ratcliffe (2006) Foundations of hyperbolic manifolds, Graduate texts in mathematics 149 (Springer-Verlag) ISBN 0387331972
• Centennial College of Applied Arts and Technology (1992) Cahiers de la femme 13 (York University: Toronto, Ont.)

Thanks. PamD (talk) 09:10, 30 June 2011 (UTC)

I don't, but I vote for speediable blatant hoax anyway. Frappadingue is not a first name, it's French slang for nuts. Du Valseur (nobilitated form of "Waltzer") is not documented as a surname, either. Instead, there is this:

"Lageat in Robert des Halles: elle était trop frappadingue du valseur (she was too keen on wiggling her bottom)" Fair of speech: the uses of euphemism

Also Wallonia is just where you would expect someone of that surname to come from for phonetic reasons. And of course "Theoreme des Valseuses" (Theorem of the female Waltzers) makes no sense at all given that a male person is supposed to have been involved. As hoaxes go, this one is much more cheeky than funny. Hans Adler 10:22, 30 June 2011 (UTC)

"Women in Mathematics" is available to be searched on Google Books, no hits. I think the cumulative evidence is enough for a blatant-hoax speedy, and I have zapped it. Thanks to all. JohnCD (talk) 10:52, 30 June 2011 (UTC)

• I think you'll find that "Valseuses" is more accurately translated as "testicles" or "bollocks", rather than "Waltzers" -- compare our article on the 1974 film of that name with Gerard Depardieu. (Title bowdlerised for the American market). Frappadingue on the other hand means nuts in the sense of "crazy" [1], so "frappadingue du valseur" means bollock-crazy. Jheald (talk) 11:36, 30 June 2011 (UTC)
  • Several reliable sources (from serious literary criticism) actually seem to agree that "frappadingue du valseur" has the translation that I have given above, at least in the context in which it first appeared. See also this for the basic meaning, the female plural slang meaning and the male singular informal meaning. Hans Adler 12:24, 30 June 2011 (UTC)
    • In French slang, "les valseuses" (a plural feminine noun) means "testicles", but "le valseur" means "the ass". "Frappadingue" is made of "frapper" (to strike) and "dingue" (silly). So, it's a hoax. --El Caro (talk) 18:42, 1 July 2011 (UTC)

Max-min inequality

This article is a very stubby stub but the inequality seems notable if somewhat trivial. The name is questionable though since the term has other meanings. The most common meaning (in my search at least) is the theorem in elementary calculus that puts bounds on an integral in terms of the length of interval and the maximum and minimum values. Is the theorem in the article known by another name that can be used as a target for a move?--RDBury (talk) 15:48, 4 July 2011 (UTC)

The sets W and Z do not have to be subsets of real vector spaces, any nonempty sets will do so long as f is defined on W×Z and has values in a complete lattice. JRSpriggs (talk) 00:36, 5 July 2011 (UTC)

The number system article is shrinking

I've noticed number system getting quite a lot shorter recently; compare this old version from 2008. I haven't reverted the recent section blankings because the article wasn't in a good state even before those edits. Do people see it as worth rescuing? — Preceding unsigned comment added by Jowa fan (talk • contribs) 13:56, 5 July 2011 (UTC)

I went ahead and restored two sections that were blanked by an anonymous user with no comment. The sections did have issues but it's possible they can be improved. The article could use some work or maybe merged with another article.--RDBury (talk) 15:39, 5 July 2011 (UTC)

I also restored a bunch of material lost at the end of 2008. A misguided anon deleted some vandalism without restoring the material the vandal deleted. The article is a bit textbooky now but at least it's no longer a stub. It should probably be reviewed to make sure more recent edits aren't duplicating the stuff that was lost.--RDBury (talk) 15:53, 5 July 2011 (UTC)

number 1

The usage of 1 (edit | talk | history | protect | delete | links | watch | logs | views) is under discussion, see Talk:1, to see if small numbers should be numbers or years.

65.93.15.213 (talk) 04:29, 6 July 2011 (UTC)

decimal points, full stops, and commas

WP:MOSMATH doesn't seem to say anything about things like this. I think in much of Europe it is customary to use a comma as a decimal point and a period (or "full stop") in the way most English-speaking people in the present day are taught to use commas in numerals. I think the system used in much of continental Europe has been taught in England within the memory of persons still living today.

Should WP:MOSMATH say something about this? Michael Hardy (talk) 21:26, 25 June 2011 (UTC)

The use of period for a decimal point has been standard in England for at least a century. See, for example, page scans of the 1911 Encyclopedia Britanica which are available on WikiSource. I don't think the issue would come up except for people copying and pasting tables from foreign language sources or using machine translation without proof reading. To me it's not an issue for MOSMATH anyway since most math articles don't have many big numbers; you're more likely to get them in geography articles.--RDBury (talk) 22:43, 25 June 2011 (UTC)

Actually, it's already in the general MOS, see WP:MOS#Large numbers and WP:MOS#Decimal separator.--RDBury (talk) 12:09, 26 June 2011 (UTC)

On my talk page, User:Peter Mercator has said that the convention alleged above to have been standard in England for at least a century is "laziness", and the opposite convention has been traditionally taught in English schools. In particular, he says that the usage that is no longer standard in English preserves the distinction between decimal points and full stops. I responded that it fails to preserve the distinction between mid-level dots as decimal points and mid-level dots to indicate multiplication. Michael Hardy (talk) 23:51, 26 June 2011 (UTC)

In fact the traditional British usage did distinguish: it used mid-level dots as decimal points, and periods for multiplication. 63.107.91.99 (talk) 16:42, 6 July 2011 (UTC)

The raised decimal point is mentioned in Interpunct. In tex it is supported by the 'decimal' package, wherein we read "The decimal point (decimal separator) is variously implemented as a comma (European), a full point (North American), or as a raised full point (English)." This variation is present amongst the text books in my library. So the dispute, if there is one, is between American and British usage. Peter Mercator (talk) 11:46, 27 June 2011 (UTC)

WP:MOS#Decimal separator says "Use a period character between the integral and the fractional parts of a decimal number, not a comma or a raised dot". That seems clear and unambiguous to me. If you want to lobby for a change to the MOS guideline, you could start a discussion at Wikipedia talk:Manual of Style. Gandalf61 (talk) 12:01, 27 June 2011 (UTC)

Even in British English, the raised dot is seldom used, so this isn't a British versus American usage issue. As long as we're quoting the documentation from the LaTeX "decimal" package, let's be sure not to quote it out of context [2]:

In Great Britain until about 1970 or so the decimal separator was typically implemented as a raised dot (middle dot)... While the raised dot does make occasional appearances in British newspapers, it is, unfortunately, seldom seen nowadays even in British scientific journals.

I think a "revival" of the middot would be quite inappropriate given the overwhelming predominance of the period to denote the decimal point in modern English typography. Sławomir Biały (talk) 12:25, 27 June 2011 (UTC)

Italicizing Greek letters in mathematical notation

I was surprised to find at Wikipedia:MOSMATH#Greek_letters that

Greek letters are not commonly italicized, so that one writes, for example, λ + y = π r²,

But look at what happens in TeX:

$\lambda +y=\pi r^{2}\,$

I had thought the over-arching rule was that things italicized in TeX are to be italicized in non-TeX mathematical notation. Thus:

$\alpha \beta \gamma \delta \varepsilon ,\dots ,\mathrm {A} \mathrm {B} \Gamma \Delta \mathrm {E} \,$

TeX italicizes lower-case Greek letters, but not capital Greek letters.

So it should be in non-TeX notation. I propose that this languate in WP:MOSMATH be changed. Thoughts? Michael Hardy (talk) 18:42, 29 June 2011 (UTC)

I agree that a better match to TeX formatting would be an improvement. —David Eppstein (talk) 18:45, 29 June 2011 (UTC)

I don't know that I'd call those letters italic at all. But it's possible that italicising the HTML versions would match the TeX better, which seems to be a valid goal. CRGreathouse (t | c) 19:12, 29 June 2011 (UTC)

It appears that the {{math}} template doesn't italicize by default: α β γ δ α β γ δ Α Β Γ Δ Α Β Γ Δ Justin W Smith ^talk/_stalk 19:28, 29 June 2011 (UTC)

This seems browser-dependent. They don't look italicized on the browser I'm using at this moment, but they do on most browsers that I use. Michael Hardy (talk) 22:45, 29 June 2011 (UTC)

My understanding was that we italicize variables in our English text to distinguish them from letters which merely form part of ordinary words. Greek letters do not appear naturally in English text so it is unnecessary to italicize them for that reason. JRSpriggs (talk) 04:53, 30 June 2011 (UTC)

In principle that's correct. But it doesn't reflect actual practice. Pulling some books off my shelf at random, I find that the statement Greek letters are not commonly italicized appears to be completely false. There are plenty of examples of upper case Greek letters that aren't italicised, but it seems that the lower case letters are always in italics; I haven't yet found a single counterexample. This predates the invention of TeX; for instance, I have a fourth edition of Whittaker and Watson, published 1927 (reprinted 1962) with Greek letters in italics. Jowa fan (talk) 05:11, 30 June 2011 (UTC)

Correct me if I'm wrong about this, but my understanding is that normally Greek doesn't make a distinction between italic and non-italic. In other words Greek is "semi-italic" and to someone used to seeing upright characters most of the time they seem slanted when that's just the way they're formed normally. Having different forms is a artifact of applying conventions for Roman letters to a different alphabet. So making Greek italic is somewhat redundant. In any case I do think it's reasonable to follow an established convention rather than going by what is displayed on a particular browser. A search on Google turned up [3] which says use italic for variables but not Greek variables.--RDBury (talk) 05:49, 30 June 2011 (UTC)

PS, I Just remembered where I read this, check near the bottom of the thread.--RDBury (talk) 05:56, 30 June 2011 (UTC)

Ah, I didn't know that. So "italics" is the wrong name for what I found in my books; but it's still the case that the lower case Greek letters weren't upright. If symbols such as α, β, γ, δ can appear either upright or slanted depending on which browser is used (and possibly on which font, or which Wikipedia skin), then we seem to have an insoluble problem. Interestingly, the source [4] prescribes italic for non-Greek variables and upright for upper case Greek variables, but is silent on the question of lower case Greek letters. Jowa fan (talk) 06:41, 30 June 2011 (UTC)

We're not writing Greek. We're writing mathematics. Whatever is most common in mathematics should be used. What the Greeks do is irrelevant. The browser problem is solved by us using Tex or {{math}} when an appropriate font will be requested. If they don't actually have a suitable font that's their problem. Dmcq (talk) 07:45, 30 June 2011 (UTC)

There is a standard concerning the use-mention distinction which calls for using italics to indicate that a word is being mentioned not used: Wikipedia:Italics#Words_as_words. I think this particular distinction should be made clear in the math articles. I do not believe this particular guideline is known, understood, nor employed in the math department. I think you should look into it, as it is an important metalogical distinction that make articles more clear. The use and mention of expressions is not made distinctly clear and someone should go through the entire collection of articles and explicate it. Any changes to the math mos should be consistent with this guideline. Greg Bard (talk) 03:15, 2 July 2011 (UTC)

To Gregbard: I prefer to use quotation marks when I mention a word rather than italics. JRSpriggs (talk) 07:49, 2 July 2011 (UTC)

Well at least you are paying attention to the distinction and know what it means. Wikipedia MOS holds that italics should be used not quotes. Perhaps you could propose to change that (I have no preference). In the meanwhile, we should be acting consistent with the MOS. Be well, Greg Bard (talk) 17:23, 6 July 2011 (UTC)

I've done some edits on the style manual

It appeared to me that the style manual could be made more consistent with the spirit of the discussion above by deleting what was the first sentence in that section, and deleting the word "However" from the beginning of the second sentence. Accordingly I have done that. Michael Hardy (talk) 21:40, 1 July 2011 (UTC)

Request for feedback: hopfian object and singular submodule

Hello. To cover two redlinks (one for hopfian module, one for nonsingular ring) I created two articles: Hopfian object and singular submodule. Please read over and (hopefully) remove the unreviewed article tag, and/or leave feedback in discussion. Thank you, and anyone let me know if they need help on an abstract algebra article! Rschwieb (talk) 15:44, 5 July 2011 (UTC)

UPDATE: Please add dense submodule to my previous request to review articles and remove the unreviewed tag... Thanks! Rschwieb (talk) 19:42, 6 July 2011 (UTC)

On the issue of "Why is it so difficult to learn mathematics from Wikipedia articles?"

“ Wikipedia is an encyclopedia, not a textbook. Wikipedia articles are not supposed to be pedagogic treatments of their topics. Readers who are interested in learning a subject should consult a textbook listed in the article's references. If the article does not have references, ask for some on the article's talk page or at Wikipedia:Reference desk/Mathematics. Wikipedia's sister projects Wikibooks which hosts textbooks, and Wikiversity which hosts collaborative learning projects, may be additional resources to consider. ”

The fact that this is case makes me question the utility of encyclopedias in general. What does an encyclopedia do that a textbook covering every academic subject could not? A lot of the higher mathematics articles would seem to be much ado about nothing, if it were not for its utility for those who are simply reviewing for higher level math exams. An encyclopedia that reads like a glossary in prose-form is not very effective as tool for learning; so it has a very narrow purpose, in my opinion.

The habit seems to be, "Never try to combine encyclopedias and textbooks." That might be reasonable advice prior to the internet, as such a volume set would be much larger than an encyclopedia. However, now that we do not have that physical constraint, I cannot not see how we are better off by limiting Wikipedia to an "encyclopedia".siNkarma86—Expert Sectioneer of Wikipedia
^{86' ' = 19+9+14 + karma = 19+9+14 + talk} 03:02, 28 June 2011 (UTC)

A couple of things. One is that didactic exposition makes the articles less useful for readers who come to look things up. It is expected that an encyclopedia is first and foremost a reference work, a place to look things up.

Another serious issue is that a textbook exposition inevitably involves choices on the part of the author on how to guide the student to an understanding of the material. It is pretty much impossible to do that neutrally. Encyclopedic "just the facts" exposition does not eliminate that problem entirely, but in my judgment at least, it ameliorates it somewhat. --Trovatore (talk) 07:11, 28 June 2011 (UTC)

A third issue is that didactic exposition needs to assume a certain base level of the reader. This is not (always) necessary for an encyclopedic article, which should be able the relate facts too (almost) any level of reader, since the reader does not need to be brought to understand why a statement is true, but only that the statement is true. (The trouble of mathematics articles is finding a way too convey the content of a mathematical statement to a lay audience.)TR 07:46, 28 June 2011 (UTC)

Plus isn't this supposed to be what Wikiversity was about? The materials there aren't wonderful but if we put in a few links perhaps it would encourage some people to try and develop them. Another alternative might be to put some effort into identifying the best resources on the web for teaching various things and put links to them in a special section in relevant articles, not just externals but say something titled 'Learning resources'. The OP talks about combining encyclopaedia and textbook because we're not constrained by size, but one of the basic things one should do on the web is try and cut down each page to the right size for its main purpose. So the learning resources should be on different pages and just linked to. And if they are linked to why do they need to be jumbled in with the encyclopaedia pages? Dmcq (talk) 08:08, 28 June 2011 (UTC)

With regard to utility for those who are simply reviewing for higher level math exams (or indeed for exams in any other subject): it's not only exam candidates who might like to consult a reference such as an encylopedia. The utility of encyclopedias is that they take you to the bare facts more quickly (albeit with less context) than textbooks. They're useful for looking up a fact quickly when you're in the middle of a task (invaluable for graduate students and researchers), and also as jumping-off points if you're motivated to improve your general knowledge (I've lost count of the times I've gone looking for a textbook or online resource—and not only in mathematics—after seeing a passing mention of some fact on Wikipedia). Wikipedia's broad but efficient coverage of much higher mathematics is one of its strong points. I don't see a problem here. Jowa fan (talk) 08:47, 28 June 2011 (UTC)

Have to disagree - I think the maths articles are terrible. You would expect the leads of articles to be plain and comprehensible - instead they are (mostly) impossibly abstract and inaccessible. Okay for maths PhDs, but useless for most else.

This has come up a number of times, but is always waved away for one reason or another.

-- cheers, Michael C. Price ^talk 08:51, 28 June 2011 (UTC)

Fair enough, I'm not saying that all of the mathematics articles are good, just that I don't see a problem with the idea of Wikipedia being an encyclopedia not a textbook. By all means name some specific articles that you think can be improved. Jowa fan (talk) 09:22, 28 June 2011 (UTC)

Naming specific articles misses the point. This seems a general problem. -- cheers, Michael C. Price ^talk 05:36, 30 June 2011 (UTC)

The comment "this seems a general problem" doesn't give any clues as to what might be wrong, let alone how to fix it. If you'd like to pick one article and examine how it can be improved, there's a chance of abstracting some general principles that can then be applied elsewhere. Jowa fan (talk) 09:24, 30 June 2011 (UTC)

Wikipedia has immense breadth, but, like all encyclopedias, lacks depth. To learn math, you need that depth, and you get it from textbooks, exercises, lectures, and answers to your questions. Wikipedia is useful for finding out about topics you didn't know were there, but you shouldn't expect it to bring you to an advanced level that you haven't reached in classrooms or via exercises and study. Most of Wikipedia's mathematics articles do a good job of what they're for, but they seem to incite complaints that they fail to accomplish something other than their purpose. Way back in 2002 when hardly anyone had heard of Wikipedia, I worked on bringing its existence to the attention of the community of mathematicians, and about six years later I was pleased when a mathematician who had not known of my involvement with it made an effort to call its existence to my attention, saying it's a "great resource". And so it is. The complaints that you need to know a topic already in order to understand the Wikipedia article about it are false. But you usually need to have reached a certain level in your understanding of mathematics. I don't see that as a flaw in the articles, but rather as a fact about learning mathematics generally. It's as if you're learning Hungarian, a language you first heard of three weeks ago, and complain bitterly that an audio recording for the instruction of people beginning their third year of study of that language is incomprehensible to you. Michael Hardy (talk) 03:45, 30 June 2011 (UTC)

I wouldn't expect an advanced math article to be fully comprehensible to the novice, but the lede should at least be able to describe the topic in layman's terms, so they have some idea what it's about. Also, many topics have portions which can be made accessible to laymen, and other portions which can't. StuRat (talk) 04:12, 30 June 2011 (UTC)

Concur with StuRat.

@Michael Hardy, your response makes my point. Wikipedia is a great resource for mathematicans - by which I assume you mean experts - but not for anyone else. The articles are too compact (aside from often badly written, which is a general problem across WP, of course) and dense to be accessible to the general public. I see no reason why articles can't be equally accesible to both beginners and experts. Yes, the beginners should expect to get lost in the main body, but the problem is, IMO, that the lede itself is also incomprehensible to them. -- cheers, Michael C. Price ^talk 05:36, 30 June 2011 (UTC)

I think it's a great resource for students as well. Many of the mathematics articles are readily readable by undergraduates and many by high-school students. Michael Hardy (talk) 21:06, 7 July 2011 (UTC)

It's to respond to this sort of point that we have our FAQ at the top of this page. As the first answer says, "Some advanced topics require substantial mathematical background to understand. This is no different from other specialized fields such as law and medical science." Our articles are not targeted at experts, but for some of these topics, it is impossible to write for a reader who does not already have a lot of mathematical experience (not necessarily experience in the article's subject matter). If you have a specific example of an article that is targeted at too high a level, then we can try to address that. But otherwise this discussion isn't going anywhere. Ozob (talk) 10:33, 30 June 2011 (UTC)

I think Wikipedia is more successful in the field of mathematics than in any other field. Michael Hardy (talk) 22:39, 6 July 2011 (UTC)

Gee, who would have ever guessed that this issue would come up AGAIN. Well whatever you do --folks here at WP:MATH -- don't listen or learn anything from this input. If people have trouble understanding math articles SCREW 'EM. Isn't that right? As long as you and your close buddies like it, that's all that matters. Whatever you do, don't accept anything the OP says as valid. Instead, just get on here and rationalize and justify your culture and dismiss. WP:MATH: The worst Wikipedians of them all. Don't give me any grief either. You deserve these REPEATED criticisms. Greg Bard (talk) 21:34, 7 July 2011 (UTC)

Ah Greg, so nice to see you again. CRGreathouse (t | c) 21:48, 7 July 2011 (UTC)

Greg, and others who agree with him: If you point to specific problem articles, I for one am happy to help make them more accessible. Just saying, "there's a general problem; fix it!" isn't very helpful, because there's no particular edit I can make that will fix a general problem. I suspect that many math editors besides myself would be only too happy to make specific articles more readable. -GTBacchus^(talk) 21:57, 7 July 2011 (UTC)

I appreciate this, and I think it is a sincere and wonderful gesture. There are a few wonderful editors in WP:MATH, however even among the most wonderful (CBM, Greathouse, Hardy, and I know I am leaving one or two out) editors they are STILL guilty of unapologetic anti-intellectualism. Explicating the intellectual foundations of mathematics is the solution to this problem. However, there has been steady hostility to that project. I think we need to look to WP:PHYSICS as a good model. They make wikilinks to the foundational concepts in lede of every article. Here, the goal is to avoid that. Invariably the lede of every mathematics article should have wikilinks that are recursively connected to articles like point, line plane, theorem, etcetera and ultimately concept. The hostility seems to be caused by a disdain for anything philosophical. That's not helping.Greg Bard (talk) 22:13, 7 July 2011 (UTC)

"Unapologetic anti-intellectualism"? I thought we were being accused of being snobbish intelligentsia. Perhaps, as GTBacchus suggests, concrete examples would be more helpful. CRGreathouse (t | c) 00:45, 8 July 2011 (UTC)

Well, I would use the terms "prima donnas" and "pedantic." In the case of articles dealing with mathematical logic, I have tried to contribute metalogical distinctions, which have been dismissed as irrelevant under wp:weight and deleted very often with insults toward myself. The entire category:math-logic should be gone through, and in the lede paragraph account for all of the pertinent metalogical distinctions (see metalogic). Furthermore, in order to properly address POV issues, articles should account for all of the prevailing approaches i.e. formalism, intuitionism, constructivism, non-classical, non-standard, etcetera. Accounting for these is the proper way to deal with pov issues, not by ignoring them. Greg Bard (talk) 01:33, 8 July 2011 (UTC)

I'd like to more concretely understand what you're asking for, Greg. Can we start with one article? You can pick one, or if you prefer, I'll pick one. Saying "the entire category:math-logic should be gone through" is great, but we have to start somewhere to even determine whether we're talking about the same thing. How does that sound; why don't you pick an article? -GTBacchus^(talk) 01:46, 8 July 2011 (UTC)

He's done that before, by removing or damaging the mathematical content of the articles, and adding "metalogical" concepts (not distinctions). (I'm not saying that he was vandalizing the articles, just that he didn't understand the mathematics enough to see that he was damaging them.) — Arthur Rubin (talk) 06:07, 8 July 2011 (UTC)

It doesn't sound like you're talking about vandalism. It would be nice, though, if someone complaining about intelligibility of math articles would also present an example, at least for the purposes of discussion. Simply making general complaints isn't very constructive. -GTBacchus^(talk) 06:23, 8 July 2011 (UTC)

No, it's not vandalism. It's a WP:COMPETENCE problem. He's often writing about a different concept with the same name, and frequently he's the only editor who sees a relationship. — Arthur Rubin (talk) 06:55, 8 July 2011 (UTC)

Greg, given the unapologetic rudeness and incivility of your posts here, is really so hard to imagine why other editors react to your suggestions with what you perceive as hostility? I've never even had any interactions with you in article space, but here you are hurling invective at me, along with everybody else in the fictitious monolithic group that you are attacking. That's not a good way to win the hearts and minds of your fellow editors. Sławomir Biały (talk) 16:04, 8 July 2011 (UTC)

Some people don't wish to persuade; they wish to feel that they were right and others were wrong. Anyone who wishes to persuade acts like it, and manages to persuade people. It's not very difficult. -GTBacchus^(talk) 20:02, 8 July 2011 (UTC)

Obsolete number concepts

I recently deprodded Denominate number since it seems to be notable if somewhat obsolete; I found hundreds of references in Google Books. It seems to part of a wider classification of numbers that we don't seem to cover at all, or if we do then please point me to where it is. The classification is something like:

• Number
  • Abstract
  • Concrete
    • Denominate
      • Simple
      • Compound

As a first step I'd like to move the article to Concrete number, expand it and create redirects. I'm not entirely happy with "Concrete number" as the name of the article so reasonable suggestions for a better title will be appreciated. Or if the material might work better as part of another article then I'd be interested in ideas for a target. Our Number article seems to cover abstract numbers only so that doesn't seem like a good fit. Measurement seems to be more of a science article than a math article so probably not a good fit either. Finally, there are a large number of possible sources to use for this and I don't feel like evaluating all of them, so if anyone has a favorite book on elementary arithmetic which covers this, preferably in the public domain, let me know and I'll use it, otherwise I'll just pick one at random.--RDBury (talk) 14:09, 2 July 2011 (UTC)

I'm not sure about the title but certainly there should be something more about the development of the concept of number, for instance in some languages different words are used to count different types of things or for measuring quantities. Dmcq (talk) 15:14, 2 July 2011 (UTC)

p.s. I once developed my own computer language which had dimensional analysis built into the type system so I wouldn't say those sort of numbers are obsolete! Dmcq (talk) 15:18, 2 July 2011 (UTC)

Cf. Frink. CRGreathouse (t | c) 18:19, 8 July 2011 (UTC)

Significant Problem with Math Genealogy template

I recently tried out the MathGenealogy template and noticed it appears to be broken. It's still linked to the AMS site, and according to MGP's website they moved to http://genealogy.math.ndsu.nodak.edu/index.php in January 2003. Has this problem really existed 8 years without anybody noticing?! :( In any case, who knows how to get it to point to the new correct site? Rschwieb (talk) 01:33, 8 July 2011 (UTC)

It seems that both http://genealogy.math.ndsu.nodak.edu/index.php and http://www.genealogy.ams.org/index.php give the same page. The url in {{MathGenealogy}} was changed in this edit on 5 march this year. --Salix (talk): 06:38, 8 July 2011 (UTC)

Ah genealogy.ams.org is a mirror of genealogy.math.ndsu.nodak.edu. I've changed the template to point to the main site.--Salix (talk): 07:00, 8 July 2011 (UTC)

I don't know how other people experienced it, but whenever I clicked the templates appearing on mathematician pages, it said it couldn't open the webpage. Everything works perfectly for me now, so thanks! :) Rschwieb (talk) 12:18, 8 July 2011 (UTC)

Formal sciences

The Formal sciences article contains the following anti-mathematics paragraph:

"In the mid-twentieth century, mathematically-based studies such as operations research and systems engineering were developed. The rise of the computer gave a great impetus to these sciences and to theoretical computer science and information theory, allowing the study of complex systems beyond the range of traditional mathematical techniques. Theoretical computer science, however, is at least as old as the work of Turing, and could be argued to go back as far as Babbage, or even Leibniz. The rise of these disciplines made it clear that mathematics was only one of a range of formal or mathematical sciences."

It basically says that because these areas aren't "traditional" (whatever that is supposed to mean) that they are not mathematics. To me "formal sciences" is synonymous with mathematics, and saying theoretical computer science is not mathematics is absurd. There's more to math than algebra, geometry and calculus. Mathematics is more than what appears on a school curriculum. Mistory (talk) 23:17, 3 July 2011 (UTC)

The key word here is discipline. To me its saying that OR and Computer Science have developed in there own disciplines/cultures, which differ from the culture of mathematics. They differ in what they consider interesting problems and in methodology. Yes you could consider them as version of applied mathematics but that misses the cultural aspects.--Salix (talk): 23:41, 3 July 2011 (UTC)

OR is a mathematical science. But as Salix says, or implies, it's not realy part of applied mathematics. — Fly by Night (talk) 23:47, 3 July 2011 (UTC)

The entire article is unsourced except for a single quote and there are several comments on the talk page questioning the validity of material, though perhaps these have since been addressed. I think there is a case that logic is not part of mathematics but I agree that most of the areas listed as being formal sciences are really different areas of applied mathematics. This is math project though so the people here, including myself, might be a bit over-inclusive about what math is. Apparently the original title of the article was "Formal science" but that didn't wash, the comment was there's no such thing as a "Humanity" so there doesn't have to be any such thing as "Formal science". Not sure of that reasoning is valid. As it stands the article does not meet notability criteria. If someone can establish notability then reliability can be addressed. The article is marked High priority in the Systems project so apparently someone there thinks it's notable; it would have been nice if they added some evidence to article.--RDBury (talk) 00:06, 4 July 2011 (UTC)

Mathematics has broadened its scope because of the rise of mathematical sciences outsides of mathematical physics.

(Mathematics is the science of necessary truths. Logic is the science of inference, including fallacious reasoning, heuristics, and probable inference. Mathematical logic is at the intersection of mathematics and logic. Charles Sanders Peirce)  Kiefer.Wolfowitz 23:57, 7 July 2011 (UTC)

That's not really an accurate description of mathematical logic, as the term is presently used. Mathematical logic is a collection of branches of mathematics; the usual list is set theory, recursion theory, model theory, and proof theory. My feeling is that category theory and universal algebra could easily be added, as they have a similar feel, but usually they are not, for some reason.

Of these, only proof theory (which is the runt child of the litter) is very naturally described as part of "the science of inference". The others all have things to say about inference, but it is not their main preoccupation. --Trovatore (talk) 00:06, 8 July 2011 (UTC)

Peirce had basic competence in the logic of definition, and so was not collecting marbles.  Kiefer.Wolfowitz 00:24, 8 July 2011 (UTC)

Were you quoting Peirce? That was hardly obvious. Anyway, Peirce made an undeniable contribution, but matters have moved on a bit since then. There is a commonality among the four branches I enumerated (which I think is also shared with the other two) but it is difficult to express clearly; I at least have never managed to quite put my finger on it. It is in any case certainly not about being the "science of inference". --Trovatore (talk) 00:27, 8 July 2011 (UTC)

The definition of mathematics is due to B. & C.S. Peirce, and the rest was paraphrase. I don't believe that Peirce saw fit to revise his definition.

CS Peirce made fundamental contributions to nearly all of the above areas of mathematical logic: I believe that Putnam may be trusted for the judgment on set theory, and Hintikka on model theory, and Birkhoff on universal algebra, Tarski on relations, Hotelling/Stigler on statistics, Burks on computing, etc.  Kiefer.Wolfowitz 03:12, 8 July 2011 (UTC)

At the time of Peirce's death there wasn't a whole lot of set theory yet. The basic stuff about transfinite ordinals and cardinals, due to Cantor, and really not much more. In the Twenties and around there, set theory fooled around with stuff about competing axiomatizations for a while, but it didn't really take off as a discipline until Goedel's work on L. During Peirce's lifetime it might well have been possible to see set theory as a branch of "the science of inference", but today it is really not.

Putnam is another matter, of course, but you haven't indicated what assertion of his you're relying on.

Of course, when it became clear that set theory was not "logic" in the strict sense of the word, in an alternative history, people might have stopped calling it "mathematical logic". Maybe they should have. But they didn't. In an encyclopedia, we don't do language reform, so we're stuck with the fact that "mathematical logic" is not purely logic. --Trovatore (talk) 04:28, 8 July 2011 (UTC)

Trovatore, please read Putnam's long introduction to Peirce's lectures, particularly.

• Reasoning and the Logic of Things (RLT) (The 1898 Lectures in Cambridge, MA)

• Peirce, C. S., Reasoning and the Logic of Things, The Cambridge Conference Lectures of 1898, Kenneth Laine Ketner, ed., intro., and Hilary Putnam, intro., commentary, Harvard, 1992, 312 pages, hardcover (ISBN 978-0674749665, ISBN 0674749669), softcover (ISBN 978-0-674-74967-2, ISBN 0-674-74967-7) HUP catalog page. Text of the lectures that William James invited Peirce to give in Cambridge, MA. (Extracts variously from drafts and from delivered lectures were earlier published in CP 1.616-677, 6.1-5, 185-213, 214-221, 222-237, 7.468-517.)

Editorial Procedures, xi-xii Abbreviations, xiii-xiv Introduction: The Consequences of Mathematics, 1-54   (Kenneth Laine Ketner and Hilary Putman) Comment on the Lectures, 55-102   (Hilary Putman) Lecture One: Philosophy and the Conduct of Life, 105-122 Lecture Two: Types of Reasoning, 123-142 [Exordium for Lecture Three], 143-145

Lecture Three: The Logic of Relatives, 146-164 Lecture Four: First Rule of Logic, 165-180 Lecture Five: Training in Reasoning, 181-196 Lecture Six: Causation and Force, 197-217 Lecture Seven: Habit, 218-241 Lecture Eight: The Logic of Continuity, 242-270 Notes, 272-288 Index, 289-297

Peirce's relation to Cantor is worth studying. Some comments are made in the article on Peirce, in the logic section. Sincerely,  Kiefer.Wolfowitz 04:47, 8 July 2011 (UTC)

Addressing the problem originally raised, I rewrote the offending paragraphs, leaving these in my wake:

As a number of other disciplines of formal science rely heavily on mathematics, they did not exist until mathematics had developed into a relatively advanced level. Pierre de Fermat and Blaise Pascal (1654), and Christiaan Huygens (1657) started the earliest study of probability theory. In the early 1800s, Gauss and Laplace developed the mathematical theory of statistics, which also explained the use of statistics in insurance and governmental accounting. Mathematical statistics was recognized as a mathematical discipline in the early 20th century.

In the mid-twentieth century, mathematics was broadened and enriched by the rise of new mathematical sciences and engineering disciplines such as operations research and systems engineering. These sciences benefited from basic research in electrical engineering and then by the development of electrical computing, which also stimulated information theory, numerical analysis (scientific computing), and theoretical computer science. Theoretical computer science also benefits from the discipline of mathematical logic, which included the theory of computation.

Informally,  Kiefer.Wolfowitz 00:13, 8 July 2011 (UTC)

Thankyou for the rewrite Kiefer Wolfowitz. Makes more sense than restricting math to some finite set of specialties carved in stone and saying anything new is a separate subject, even if some disciplines are more culturally and departmentally separate than others. Mistory (talk) 23:52, 9 July 2011 (UTC)

Penrose graphical notation

Someone at Penrose graphical notation is talking about changing the title. I think firstly they are thinking about a generalizion of it to category theory or algebra. Secondly I think just looking at dates of books is OR about their allegation Penrose didn't devise it. However having had a quick look around I can't find earlier references than his Road to reality in 2005. I know it dates to before 1970 and my guess is he devised it around 1955 but can't find anything to back that up. Anyone have something a bit more substantial? Dmcq (talk) 11:50, 9 July 2011 (UTC)

It's described in detail in the appendix to volume 1 of Penrose and Rindler. He cites a paper of his from 1971 where he introduces the notation, but I haven't looked at that. Sławomir Biały (talk) 12:03, 9 July 2011 (UTC)

For our purposes it makes no difference who created it; if it is the name most commonly used in the literature, justly or not, then that is the name that should be used as the article title. In this case it's a bit tricky because even though the subject is notable, the name of the article is apparently not. So if there is a more commonly used term to describe the subject then the name of the article should be changed. If there is no commonly used name then I'd say go with the name the Penrose himself used: "Diagrammatic tensor notation" (Fig. 12.17 in RtR).--RDBury (talk) 13:32, 9 July 2011 (UTC)

I would heartily support that change. What I'm arguing against is the claim that Penrose appropriated some notation from quantum algebra and applied it to the very special case of tensors for the general and special linear groups. Rather it was the other way around. Sławomir Biały (talk) 13:59, 9 July 2011 (UTC)

τ-Day

Some of you many have heard that yesterday was the so-called τ-day, see This BBC story. Every since Michael Hartl wrote his τ-manifesto on March 14, people have been adding τ to quite a few article. Recall that τ = 2π. What's the situation here? In the article turn (geometry), τ is mentioned even before π. — Fly by Night (talk) 08:40, 29 June 2011 (UTC)

I've fixed (i.e. reverted) the recent addition to turn (geometry) - the tau notation was already mentioned further down in the lead, so it didn't need to be jammed into the first sentence too. Having said that, the tau notation has gained a certain amount of coverage in a range of sources. We may think it is a daft idea, possibly even fringey, but it is difficult to argue that it is not notable. Mentions in our articles on tau, pi and Michael Hartl (if that survives current AfD) seem to be appropriate. Gandalf61 (talk) 08:59, 29 June 2011 (UTC)

It's not daft, it's just non-standard. I don't use it for the same reason I don't write xf when I mean f(x). τ and xf may make a lot more sense, but most people will have no idea what you're talking about. Ozob (talk) 10:36, 29 June 2011 (UTC)

I'm not sure τ does make sense. Okay, it makes the radian measure easier but that's it. The area of a circle would be ${\frac {1}{2}}\tau r^{2}$. It's the same for volumes and surface areas of hyperspheres: there is no simplification. I'm not sure it's the same as xf either. That is a notational change, while τ is just multiplying by 2. Why not use $\alpha =e^{1}\pi$? — Fly by Night (talk) 10:55, 29 June 2011 (UTC)

Good idea. That would make the entropy of the normal distribution easier to express.  :-D Sławomir Biały (talk) 12:00, 29 June 2011 (UTC)

The tau day manifesto discusses ${\frac {1}{2}}\tau r^{2}$ at some length (short answer: it expresses that area is the antiderivative of circumference with respect to radius). But this is somewhat irrelevant to wikipedia, since our job, for the most part, should be to follow rather than lead. Kingdon (talk) 02:05, 1 July 2011 (UTC)

The user Rememberway has undone the edit that Gandalf61 made to turn (geometry). He's inserted τ back into the lead, and has even added a graphic using τ in place of π. This user has become something of an SPA recently. He's added τ to many articles and he wrote a BLP for Michael Hartl (which will be lucky to survive its AfD). Whenever anyone removes these τ references he undoes their edits. I had to back off and leave him to it because I was in danger of getting into an edit war. Gandalf61 made some changes to turn (geometry) and this was Rememberway's response. — Fly by Night (talk) 22:25, 29 June 2011 (UTC)

• David Eppstein reverted some of Rememberway's edits yesterday. Well, Rememberay undid David's edits claiming that they were bad faith edits that significantly damaged the article. I've undone his undo. But what are we going to do? He's reverting any edits that are made to that page... — Fly by Night (talk) 14:32, 30 June 2011 (UTC)

My advice for everyone involved in this (both Rememberway and the antagonists thereof) is (a) more talk page discussion (of the "what about this wording?" or "the article flows better if we introduce concept X at point Y instead of Z" sort, not the "you are evil and I can prove it by this wiki policy" sort), less reverting, (b) calm down and realize this is a traffic spike (Turn (geometry) went from 50 hits per day to 2000 on tau day, per traffic statistics, also with spikes to Pi and Tau), (c) keep in mind "wait and see" and other such advice at places like WP:10YT, (d) WP:AGF (both sides at times have said things not really in keeping with AGF). My reading of the edit summaries and other comments by Rememberway did not lead me to the conclusion that we needed to get all WP:3RR and WP:FRINGE and WP:UPINARMS about this, at least not yet. If people think τ is Just Too Weird we can use 2π some of the places where we might have used τ. Kingdon (talk) 02:05, 1 July 2011 (UTC)

Essentially we have used τ almost nowhere, instead we use 2π an that's the way it is supposed to be. We are not changing standard notations, just because some physicist has published a (mostly pointless) manifesto currently getting hyped by popular media during the silly season.--Kmhkmh (talk) 02:37, 1 July 2011 (UTC)

Well said Kmhkmh. Kingdon, I can see that you're trying to do the right thing and I admire that. However, no-one here has got all WP:3RR, but another uninvolved editor did warn him about edit warring and WP:3RR. It's hard to assume good faith when Rememberway reverts administrator edits claiming that the admin's edits are bad faith and damaging to the article. When he's undone my changes, he's undone Gandalf's changes, he's undone David's changes. When I undid the changes he made while accusing David of bad faith and disruptive editing; Rememberway came to my talk page to pick a fight. I archived the discussion (on my own talk page), and Rememberway undid that to say that my actions were pathetic and that he was not in an edit war. After which he went back to undo more edits and eventually get a 3RR warning. So he's undoing math project editor's work, he's accusing admins of bad faith and disruptive edits, and he's undoing user's edits on their own user pages. Like I said, I appreciate the sentiment; but come on... — Fly by Night (talk) 02:58, 1 July 2011 (UTC)

Turns you were were right about Rememberway as an editor (certainly looking at how he responded to being blocked clarified things for me). I still don't think the content dispute over τ needs to be that hard to deal with (if people would just calm down a bit). It all turns (pun intended) on fairly subtle things like where we say 2π, exactly what part of the article(s) should have a mention of τ or $\pi \!\;\!\!\!\pi$, etc. To me, the "centiturn" thing is far sillier than τ, but if that just becomes yet another battle, I'll probably regret mentioning it. Kingdon (talk) 14:54, 3 July 2011 (UTC)

The World has too much invested in using π rather than τ — documents (books, journal articles, class notes, etc.) and people's memories and skills. Thus a change from π to τ should not and will not happen. In any case, it is not the business of Wikipedia to promote neologisms (τ), but rather to follow the accepted usage (π). JRSpriggs (talk) 08:07, 2 July 2011 (UTC)

Advocates of τ appear either to be mad, daft, mischievous or have too much time on their hands and nothing very important to think about. My two-cents worth is to wait till it all dies down and then restructure the various affected pages so as to minimise the intrusiveness of all τ occurrences. --Matt Westwood 23:08, 3 July 2011 (UTC)

Here's the score: Michael Harl was deleted and tau (mathematics) was moved to Tau (2π). There was some discussion about merging tau (2π) elsewhere. Regardless of the outcome, I don't think tau (2π) is a good choice for the title because one Greek letter is spelled out and the other is not. (I.e., it could be tau (2 pi) or τ (2π), but not tau (2π).) Sławomir Biały (talk) 14:15, 8 July 2011 (UTC)

A request to those who mentioned "it's a bad idea" in the AfD: If you would be so kind as to leave a concrete example at Tau (2π)#Possible disadvantages that would improve the article and move it closer to neutrality. Thanks! CRGreathouse (t | c) 03:51, 11 July 2011 (UTC)

Use of "iff" in articles with definitions

An edit I made to the page on Groups (specifically the homomorphisms section) was reverted by a contributor to this project, saying that correcting an "if" statement to an "iff" statement was unnecessary jargon. Most people looking up group homomorphisms will be aware of the meaning of "iff", and it is indeed an acceptable word (you can even play it in scrabble). Is there a widespread dislike for saying iff?

ImperviusXR (talk) 01:06, 9 July 2011 (UTC)

See WP:MOSMATH#Writing style in mathematics. The preference here is to spell out "if and only if" rather than to abbreviate it as "iff", in part to avoid making our writing jargony and inaccessible. —David Eppstein (talk) 01:11, 9 July 2011 (UTC)

Also, there is no reason for a definition to use "if and only if"; just "if" is appropriate. As in: a natural number is called even if it is a multiple of 2. The "only if" part is implicit in the fact that the term is being defined. This is a common convention in mathematics (and law, and other areas). — Carl (CBM · talk) 01:29, 9 July 2011 (UTC)

(ec) Right. I would add further that this if is not a logical connective at all. It's more like an assignment operator. A definition is an action, not a proposition. So "if and only if" betrays a category confusion, by trying to make it a proposition. --Trovatore (talk) 01:48, 9 July 2011 (UTC)

Quite so. Although it is not incorrect to use if and only if in a definition, it is pointless and goes against convention. (This is the edit in question) — Fly by Night (talk) 01:46, 9 July 2011 (UTC)

Does it really go against convention, or does it only go beyond convention? Michael Hardy (talk) 19:08, 9 July 2011 (UTC)

Although it's not spelled out in the MOS, personally I think it is incorrect to use "if and only if" in a definition. It's wrong because it has the potential to mislead the reader: when I see a statement of the form "P if and only if Q", it looks like a statement of a theorem (or lemma, or some result that requires proof), rather than the definition of P. Of course it helps if the prose makes it clear that something is being defined; I've made a further edit to Group_(mathematics)#Group_homomorphisms along these lines. Jowa fan (talk) 04:11, 9 July 2011 (UTC)

I believe that we have had this argument before (probably more than once), but here goes.

In mathematics, a definition is a special kind of postulate and thus a proposition. Thus it is quite appropriate to use "if and only if". In fact, using "if" instead, although conventional, is a mistake because it gives a second meaning to "if" thus creating the opportunity for the kind of logical errors that result from using the same term to mean two different things in different places — when one derives a proposition using one meaning and then uses it with the other meaning. In this case, one might derive a mere conditional containing "if" and then someone might treat it like a definition and infer the converse of the truth. JRSpriggs (talk) 06:41, 9 July 2011 (UTC)

Yes, I've no doubt it comes up periodically. It would be great if we could reach a consensus and put something in MOS:MATH to address this. The issue is one of pragmatics versus formal logic. If a convention is well established, even if it's slightly illogical, then violating that convention is likely to cause misunderstandings. (Note that MOS:MATH already includes the advice highlight definitions with words such as "is defined by" in the text, which will help to avoid confusion.) Jowa fan (talk) 07:14, 9 July 2011 (UTC)

It's not illogical. I flatly disagree with JRSpriggs on this. A definition is not a proposition of any sort. --Trovatore (talk) 07:22, 9 July 2011 (UTC)

Really? A proposition is merely something that can be stated in a complete sentence. Michael Hardy (talk) 19:11, 9 July 2011 (UTC)

A proposition is true or false. A definition is neither true nor false; it's just a definition. You can think of it as being in the imperative rather than the indicative mood. --Trovatore (talk) 22:17, 9 July 2011 (UTC)

I think the proposition that definitions are neither true nor false is philosophically problematic. Michael Hardy (talk) 01:41, 11 July 2011 (UTC)

I agree with Trovatore. Using if and only if (or iff for that matter) in a definition is a hallmark of stilted and amateurish mathematics writing. I rarely see these locutions in definitions in mathematical works published in top journals. Sławomir Biały (talk) 12:55, 9 July 2011 (UTC)

(ec)Whether it's illogical or not misses the point. Our primary goal here is to transmit knowledge, often to people with little or no mathematical training. The phrase "if and only if" is jargon in the sense that it's not used by non-mathematicians and will be difficult to understand in an article written for the general public. So I'd say it shouldn't use in an article like "Group" even outside of a definition. Jargon is useful though in the sense that conveys information quickly and precisely to those who know the meaning. So I wouldn't hesitate to use the phrase at all in an article whose intended audience is graduate students or beyond. Where exactly the line should be drawn is arguable but I'd say that for an article that is viewed by several hundred people a day and is an introduction to a widely used subject (such as "Group") we can say the audience is the general public and mathematical jargon should only be used if absolutely necessary and then fully explained within the article. I've said this before but for most of us it goes against years of training to be deliberately imprecise for the sake of being understandable to a general audience, but that is the difference between writing for an encyclopedia and writing a journal article.--RDBury (talk) 13:08, 9 July 2011 (UTC)

Neither "iff" nor "if and only if" should be used in definitions. Paul August ☎ 01:53, 10 July 2011 (UTC)

I agree with Trovatore and the others here: definitions should not use iff or "if and only if". The issue of what kind of object definitions is is a more difficult one: unless you're using something like DZFC, it's ambiguous as to whether they are metalogical, axioms, or something else. There are some systems that explicitly treat them as axioms: Metamath, for one. But because they can be represented as many different things, it's important that they not be treated as just one of those (and an unpopular one, at that) by using iff, counter to convention. CRGreathouse (t | c) 02:24, 10 July 2011 (UTC)

It seems to me that a consensus has emerged here, so I decided to be bold and edit the Manual of Style (mathematics) (diff). Others should feel free to revise this edit as appropriate (or revert it if you think I've been too hasty). Jowa fan (talk) 01:10, 11 July 2011 (UTC)

I agree that "iff" should be avoided in definitions, but should we encourage the use of the word "if" instead? Many definitions can be rewritten to avoid it altogether. The example definition you added to the MOS, "A function f is even if $f(-x)=f(x)$ for all x," could be rewritten as, "An even function is a function f such that $f(-x)=f(x)$ for all x," which avoids the if/iff issue entirely, seems to be unambiguous to me, and more closely matches the style of definition used in the first sentence of most Wikipedia articles. —Bkell (talk) 01:21, 11 July 2011 (UTC)

Yes, I agree entirely. I just couldn't think of a good concise way of expressing it—I wanted to add a couple of sentences to the MOS, but not an essay. Feel free to make further edits to the MOS if you feel that you can improve things. Jowa fan (talk) 02:29, 11 July 2011 (UTC)

Parking problem

I just started parking problem (I'm surprised that this article didn't already exist). Please improve it. Sławomir Biały (talk) 13:45, 10 July 2011 (UTC)

The "parking problem" I'm familiar with has to do with the asymptotic density of "cars" (identical objects) randomly approaching an infinite "parking lot", with various algorithms as to where a car moves if its preferred location is occupied. — Arthur Rubin (talk) 15:30, 10 July 2011 (UTC)

Interesting. Perhaps "parallel parking problem" would resolve the naming conflict? Sławomir Biały (talk) 15:35, 10 July 2011 (UT54C)

I'd split it as "parking problem (control theory)" and "parking problem (random)", but I'm not about the correct disambiguator for "my" parking problem. "Parallel parking problem" seems unambiguous, though. — Arthur Rubin (talk) 15:44, 10 July 2011 (UTC)

I like "parallel parking problem". No particular feelings on the other (the only one I'd heard of, incidentally). CRGreathouse (t | c) 16:56, 10 July 2011 (UTC)

I moved it to parallel parking problem. Sławomir Biały (talk) 18:57, 10 July 2011 (UTC)

Bicycle length 1.1547 goes round a circle radius 1

I hope they cope with the path of the back wheels properly! You might like the picture I made showing a bicycle which is slightly longer than the radius of a circle, the front wheel goes along on the red circle and the back wheel goes on the black line. The blue lines are various positions of the bicycle. Dmcq (talk) 21:35, 10 July 2011 (UTC)

Victor Kolyvagin

Can someone take a quick look at Victor Kolyvagin to make sure I haven't added erroneous information. Math is not my suit at all. --Nuujinn (talk) 18:21, 10 July 2011 (UTC)

Request for Adminship: Control mathematician

A control theorist/engineer has applied for adminship. Your participation would be helpful to non-mathematicians struggling to evaluate the candidate's editing. Thanks,  Kiefer.Wolfowitz 22:02, 10 July 2011 (UTC)

The candidate withdrew his nomination (alas imho).  Kiefer.Wolfowitz 03:30, 12 July 2011 (UTC)

Walsh matrices and Hadamard matrices

I have no idea what a Walsh matrix is or how it is related to a Hadamard matrix, but there is something odd in the article on Walsh matrices. Is anyone familiar enough to fix it? — Carl (CBM · talk) 23:06, 10 July 2011 (UTC)

They are super-duper important in Discrete Fourier Analysis and the analysis of variance for factorial experiments. I'll take a look.  Kiefer.Wolfowitz 23:11, 10 July 2011 (UTC) It seems okay, although one must be careful to be consistent with notation, and I haven't checked details. (I think Maurey and Pisier used Walsh matrices to give some slick proofs of typical results in probability on Banach spaces; they are mentioned by Diestel, Jarchow and Tonge. Knuth probably talks about them in V. 4.) 23:15, 10 July 2011 (UTC)

Thanks. As far as I can tell the definition of a Walsh matrix in our article is exactly the same as the definition of a Hadamard matrix, and the Walsh matrix article spends most of its time talking about Hadamard matrices. — Carl (CBM · talk) 23:58, 10 July 2011 (UTC)

Analysis discusses "Walsh matrices" (after Walsh functions) while combinatorial design discusses "Hadamard matrices" (or Walsh-Hadamard matrices).  Kiefer.Wolfowitz 03:34, 12 July 2011 (UTC)

Quadratic function: "another derivation for the root of quadratic function"

Hello,
Is this relevant? --El Caro (talk) 11:46, 11 July 2011 (UTC)

If it was on my watch list, I would revert. Why do you not take the initiative and revert it? Alternatively, you could correct the errors in it. JRSpriggs (talk) 12:21, 11 July 2011 (UTC)

I have reverted it. Unformatted, poorly explained and not worth rewriting, IMHO. Gandalf61 (talk) 12:22, 11 July 2011 (UTC)

It's really just completing the square, but it probably doesn't seem that way to the 10th grader who wrote it. We do allow unformatted, etc. material, but we don't allow OR and this kind of thing is one of the reasons we have that policy. The article has only one cite and imo that tends to encourage people to add more unsourced material.--RDBury (talk) 14:56, 11 July 2011 (UTC)

Thank you. I didn't revert because, due to my level in English, I can't discuss with angry contributors on wp:en, nor explain their errors. But the same diff on wp:fr would have been reverted. --El Caro (talk) 16:13, 11 July 2011 (UTC)

I put a welcome message on the talk page (trying to be friendly, per WP:BITE or WP:AGF or however you want to put it). But I agree that reverting this edit was the right action. Kingdon (talk) 01:18, 12 July 2011 (UTC)

Irrational cable on a torus

I created Irrational cable on a torus article. Could somebody review it for errors and possibly source it, please? — Preceding unsigned comment added by Kallikanzarid (talk • contribs)

I've never heard that name, or indeed any name, for this counterexample before. At the moment I can't find it in a book, either. Do you have a source for that name? Ozob (talk) 22:06, 6 July 2011 (UTC)

I know of the idea, but certainly not presented the way the article does. The article needs a total rewrite, it needs to add some references, it need to "bring the reader in"; by that I mean, it would only take a paragraph or two to make the article accessible to most people with a high school maths certificate. The article claims that its subject is a "basic counterexample", but a counterexample to what? The article is written at the wrong level. The fact is that 99 out of 100 people (as a conservative estimate) did not study mathematics at university; so less than 1% of people will find this article intelligible, let alone useful. — Fly by Night (talk) 22:27, 6 July 2011 (UTC)

I wrote it relying on my scarce knowledge only, that's why I posted it here - to get help from more knowledgeable people. UPD: I didn't want to spend great deal of effort on it before it's approved by the community — Kallikanzarid^talk 09:12, 7 July 2011 (UTC)

I haven't heard that name either, but the instant I saw it, I realized what was probably meant. I wonder if we have another Wikipedia article about this, so that the two should get merged? I'd be surprised if it's not mentioned in various Wikipedia articles. Michael Hardy (talk) 22:33, 6 July 2011 (UTC)

It's (a leaf of) the Kronecker foliation. Jowa fan (talk) 06:09, 7 July 2011 (UTC)

I was presented with this example on a lecture (in Russian), and I found some weak dictionary references and mentions here and there in the Internet — Kallikanzarid^talk 08:53, 7 July 2011 (UTC)

Never seen under this name before. Probably a translational artifact form the Russian. I guess a more normal name for this would be "irrational winding of a torus". (I.e. a winding of a torus with an irrational winding numbers.) In the context of dynamical systems/chaos theory these are sometimes simply called "irrational tori".TR 09:42, 7 July 2011 (UTC)

It is actually closer to the Russian term, I picked up 'cable' in a few online dictionaries. So what to do with the article now - move it to Irrational winding on a torus or to develop it along the lines of Kronecker foliation? — Kallikanzarid^talk 11:52, 7 July 2011 (UTC)

The first step should be to find some proper sources. I think a proper discussion of this construction should be included somewhere on wikipedia, and it is probably notable enough to have its own article. Having some good sources can help both in finding a better well accepted name for the article, and in establishing its notability.TR 13:24, 7 July 2011 (UTC)

I found one source and moved the article to Irrational winding of a torus. The source is a monograph, though, so I'll look for a better one. — Preceding unsigned comment added by Kallikanzarid (talk • contribs) 10:59, 8 July 2011 (UTC)

Googling "irrational winding of a torus" returns 34 results, including AFAIK two books by Russian authors and 2 papers on Springer. Now what? — Kallikanzarid^talk 12:59, 12 July 2011 (UTC)

/dev/zero

At Wikipedia:WikiProject Mathematics/Current activity, under "new articles", one of the items dated 5 July is an article titled /dev/zero. What I saw there was a red link, suggesting the article had been deleted. But if you enter /dev/zero in the search box, you arrive at the article. And a bunch of other articles link to it, by the usual means: [[/dev/zero]] was typed in the editing space.

Here's what's going on. If you type [[/dev/zero]] in the article space, you get a link to the aritcle. But if you type this same thing in another namespace, here's what happens: /dev/zero (If you click on that link, you'll see where it leads. For now I see a red link, but maybe someone will enter something there?).

To create a link from other namespaces, type [[:/dev/zero]].

So, take that into account when creating links. I'll ask Jitse if his bot can be edited to do that as well. Michael Hardy (talk) 22:57, 6 July 2011 (UTC)

This is because of how the configuration setting wgNamespacesWithSubpages is set, by the way. — Carl (CBM · talk) 23:17, 6 July 2011 (UTC)

See Wikipedia:Naming conventions (technical restrictions)#Forward slashes and dots; basically you can put a slash in an article name but odd things will happen. Seems to be more a computer related topic anyway.--RDBury (talk) 01:46, 7 July 2011 (UTC)

The issue seems to be the placement of the slash at the start of the name; articles with slashes in the middle of the name (e.g. L/poly) link normally. —David Eppstein (talk) 04:57, 7 July 2011 (UTC)

L/poly isn't quite normal either: the talk page has a link to talk:L at the top. In any case, /dev/zero has been around since 2008 so it's not really a new issue. It's off-topic here as well, something for Wikipedia:WikiProject Computing.--RDBury (talk) 12:34, 7 July 2011 (UTC)

It's not off-topic here if it helps people understand things that are on the math WikiProject's "current activities" page. Michael Hardy (talk) 21:23, 7 July 2011 (UTC)

maybe not a serious bug, but something of an anomaly

I've reported the following to bugzilla:

The page called talk:L/poly is the discussion page for the Wikipedia article titled L/poly. But at the top of that discussion page, we find this link:

< Talk:L

as if it were a subpage to the discussion page for the article titled L.

(And when I put a link at talk:L that links to /poly, and click on it, I find myself at the discussion page for the article titled L/poly.)

Maybe (?) not a really serious bug, but an anomaly of sorts.

Michael Hardy (talk) 22:14, 7 July 2011 (UTC)

I think that's the default way the software treats all slashed names outside of articlespace. Perhaps there's a keyword to treat the page as the root page... and another one for subpages to indicate the number of slashes in the root page (though when you start moving pages about, something might get screwed up) 65.93.15.213 (talk) 08:40, 13 July 2011 (UTC)

Pythagorean addition

It is in my opinion misleading because the operation is not associative,

$(-a)\oplus (-b)\not =-(a\oplus b)$

and there are "inverse" values,

$a\oplus (\pm ia)=0$

What do you think? (Igny (talk) 11:00, 12 July 2011 (UTC))

The operation is associative. Your example shows that it isn't distributive with respect to multiplication by negative quantities. (It is distributive with respect to multiplication by positive quantities.) Also, a and b should at least be real, otherwise their Pythagorean sum is not uniquely defined (a branch needs to be chosen for the square root). The article is a little vague, since it doesn't place any explicit restriction on a and b. It's clear to me that they should at least be real, but maybe even requiring them to be nonnegative is reasonable as well. If they are just real, there is no additive identity, since $(-1)\oplus 0=1$, but there is an additive identity if they are restricted to be nonnegative. Sławomir Biały (talk) 11:23, 12 July 2011 (UTC)

Hi, I made some modest changes to the article to try to resolve these issues. I kind of oppose including "calling this 'addition' is misleading". The phrase was vague in its own right. I replaced it with some clarification of why it is not a group operation. Rschwieb (talk) 12:59, 12 July 2011 (UTC)

Derivative on a topological vector space

So far the most general derivative on a topological vector space mentioned on Wikipedia is Frechet derivative. However, Lang in his Introduction to differentiable manifolds (1962) defines a derivative of a function between two topological vector spaces (I'm not sure if there must be a requirement of either of them being Hausdorff or locally compact). First he defines that a function $f:U\to V$ (where U and V are some neighborhoods of zero in the respective topological vector spaces over R) is 'tangental to zero' (I'm using a Russian translation so I may screw up the terms) if for any neighborhood $V'\subset V$ of zero there exists a neighborhood $U'\subset U$ of zero such that $f(tU')=o(t)V'$ (small o notation). Then he defines that a function $f:U\to V$ is differentiable at a point x₀ if $f(x_{0}+y)-f(x_{0})-Ay$ is tangental to zero for some continuous linear operator A. He then defines such a (unique) A as the derivative of f at the point x₀.

Is this generalization in any wide use? Is it notable enough to be represented on Wikipedia? — Kallikanzarid^talk 12:41, 12 July 2011 (UTC)

I'm positive that definition appears in the first pages of (Bowen, Ray M.; Wang, C.-C. Introduction to vectors and tensors. Vol 2), and I'm pretty sure it appears in other well known resources. I'm not an expert so I don't know if it's in wide use, but still I'm a nonexpert who's familiar with the definition, so it's not very obscure! I was unable to find a page in wikipedia duplicating that definition. Rschwieb (talk) 13:34, 12 July 2011 (UTC)

What is the correct English term for what I called 'tangental to zero' here? Is some assumption (Hausdorffness, local compactness) necessary for the so defined derivative to be unique? How about we create an article about this definition of the derivative? How should we call it? Derivative of a function between topological vector spaces, is it too verbose? — Kallikanzarid^talk 13:55, 12 July 2011 (UTC)

I have a feeling that there is already an article written that this definition belongs in. However since I am new to that field I could be wrong. How close is the content to Pushforward (differential)? It may already appear in a differential topology article. Rschwieb (talk) 14:44, 12 July 2011 (UTC)

Not sufficiently closely related for a merge. Pushforwards are usually considered on finite-dimensional differentiable manifolds, whereas these derivatives are on infinite dimensional linear spaces. To K: Lang uses the phrase "tangent to zero" in English, if I recall. I don't think this is entirely standard though, so beware using it in an article. Sławomir Biały (talk) 14:50, 12 July 2011 (UTC)

Fréchet derivative is the most reliable definition indeed, but not the most general. There is also Gâteaux derivative, for example. Incnis Mrsi (talk) 14:49, 14 July 2011 (UTC)

Superscripting all inline PNG math notation?!

This edit partially "solves" the problem of inline LaTeX-generated PNGs misaligning with surrounding text, by making the inline PNGs HTML superscripts. But this is not policy, we should not be doing this, and I should revert it, right? Mgnbar (talk) 22:36, 14 July 2011 (UTC)

Right. This sort of thing is incredibly fragile, and will only make things worse in the future. — Carl (CBM · talk) 22:49, 14 July 2011 (UTC)

On the other hand, I don't remember math looking like this $\mathbb {R} ^{2}$ before. Is it a recent bug? We may be able to get it fixed. — Carl (CBM · talk) 22:51, 14 July 2011 (UTC)

It looks hideous. Badly misaligned. It doesn't solve anything. Maybe they'll iron the bugs out of mathJax and make it universal here. Barring that or something like it, we've still got a problem.

Besides, superscripting will only do anything worthwhile if the thing is otherwise set too low, which happens when you've got something at letter level with a superscript on it. If instead it has a subscript, then it gets set too high. Michael Hardy (talk) 01:38, 15 July 2011 (UTC)

It solves at most half the problem. On my machine the Pnged letters are twice the size of the surrounding text, so if even if you align the bottoms, the tops are out of alignment. I'd prefer ℝ² if people insist on blackboard bold, but I think it really just adds weight to the case that we should just use regular bold R² instead.--RDBury (talk) 01:48, 15 July 2011 (UTC)

Besides, for those of us already using MathJax, the formulas end up tiny and raised above the baseline (as you would expect superscripting them to do), which is not a good thing. I agree, this should be reverted. —David Eppstein (talk) 02:40, 15 July 2011 (UTC)

Thanks everyone. I just needed a check to make sure I hadn't gone insane. I've reverted it. Mgnbar (talk) 03:31, 15 July 2011 (UTC)

X–Y intersection

We have six articles, Plane–sphere intersection, Line–sphere intersection, Line-line intersection, Line-plane intersection, Sphere-sphere intersection, Sphere-cylinder intersection, about the intersections of objects in analytic geometry. Two of these are new articles. Most are unreferenced and in general the content seems ORish, mostly consisting of straightforward calculations. I'm sure the articles could be sourced, but material consisting of calculations and little else is in conflict with WP:NOTTEXTBOOK. I'm concerned also that the articles will inspire the creation of OR articles with similar titles, e.g. "Sphere–cone intersection", "Torus–Torus intersection", ad infinitum. What I'd like to see happen is:

1. Gather the formulas for the intersections of different objects (where sources are found) into a list type article. ("List of geometric intersection formulas" perhaps.)
2. Remove the derivations as unencyclopedic. (See WP:WikiProject Mathematics/Proofs.)
3. Keep and expand the articles where there is some historical notability, e.g. mention in Euclid. Perhaps there are more that could be created under this category such as "Plane–plane intersection".
4. Redirect the remaining articles to the list of formulas.
5. Improve the article names. Currently some use hyphens and some use n-dash, but perhaps something like "Intersection of X and Y" would be better. I suspect the names originated in similar MathWorld articles and were passed on through the now defunct Wikipedia:Missing science topics/Maths.

Any objections, better ideas, etc.?--RDBury (talk) 18:11, 14 July 2011 (UTC)

That plan seems roughly right. A quick glance seemed to show sources for many of them, at least in an applied setting (one of the first hits was ERIT: a collection of efficient and reliable intersection tests, Journal of Graphics Tools archive, Volume 2 Issue 4, April 1997, but there were others). I might prefer "X–Y intersection" to "Intersection of X and Y" (en dash is correct, per WP:DASH), but I'm not sure about that one.

I think ERIT deals with the problem of whether two objects, e.g. triangle and line segment, intersect. I imagine that king of thing would be important in computer graphics and geographic databases and might be worthy of a different article, but it's not exactly the subject of the articles I listed.--RDBury (talk) 12:31, 15 July 2011 (UTC)

Disagree I'm going to stick my neck out and say that I think it would be a shame to lose these. I suspect they do fulfill a need for our audience; and part of the understanding we should aim to convey is not just what a formula might be, but also why it is -- at least, when we can outline that derivation simply in a few lines.

One other thing that's interesting about these articles is the way they show that different ways of representing the objects in the problem can lead to different-looking solutions -- eg representing the line and plane purely parametrically gives a matrix to invert; but representing the plane with a normal, only a couple of dot products are needed; and one could also look at representing the objects in homogeneous projective space or Plücker space, and derive an even shorter formula. It's then perhaps interesting to discuss the apparently different-looking formulas inter-relate -- how finding the normal can be a step in inverting that matrix, and so forth.

I think these are interesting standard problems, that interesting things can be said about, and that's a reason to have articles on them. Jheald (talk) 16:40, 15 July 2011 (UTC)

There is a whole field of Computer Science called Computational geometry which is devoted to such questions, where numeric accuracy and speed of calculations are of great importance. There probably is an extensive literature on each problem, but I don't think our articles really do them justice and may well be giving poor solutions.--Salix (talk): 18:23, 15 July 2011 (UTC)

Object/Object intersection looks a good resource for the best algorithms for these problems.--Salix (talk): 19:37, 15 July 2011 (UTC)

Anyone who wants to add sources is welcome to it as far as I'm concerned. Though my understanding is computational geometry deals with more complex problems such as finding convex hulls and linear optimization. It seems to me that we shouldn't limit the scope to computer algorithms anyway; 100 years ago drafters had to solve this kind of problem and they didn't have computers to help. The intersection of two planes is dual to the line containing two points. so calling these intersection problems may be misleading as well.--RDBury (talk) 04:23, 17 July 2011 (UTC)

I think there is some value in this content, but I think that some consolidation and condensing is desirable. I don't have any concrete ideas how the material should be consolidated. Object-object intersection seems to be too general. There already seems to be ample scope for an article about intersections of (possibly degenerate) quadrics in $\mathbb {R} ^{3}$, but it's hard to think what to title such a thing. Sławomir Biały (talk) 12:32, 17 July 2011 (UTC)

Blaise Pascal at FAR

I have nominated Blaise Pascal for a featured article review here. Please join the discussion on whether this article meets featured article criteria. Articles are typically reviewed for two weeks. If substantial concerns are not addressed during the review period, the article will be moved to the Featured Article Removal Candidates list for a further period, where editors may declare "Keep" or "Delist" the article's featured status. The instructions for the review process are here.--NortyNort (Holla) 03:48, 15 July 2011 (UTC)

The whole article is now just a notice about copyright concerns. Michael Hardy (talk) 04:43, 15 July 2011 (UTC)

This COPYVIO seems to be a false positive, I did a search on the pdf that's supposed to be the source and is doesn't seem to mention Pascal at all. Can someone check to make sure? It would be a shame to lose FA quality work due to a mistake.--RDBury (talk) 04:35, 17 July 2011 (UTC)

Ok, I redid the search a different way and found the Pascal material. I'm still convinced this is a false positive though. This article is the result of thousands of edits by dozens of editors. There was an incident in 2007 of copied material being added, but this was deleted almost immediately. The book that is supposed to be the source is not in encyclopedic style, so it's hard to see how text taken from it would survive review.--RDBury (talk) 04:56, 17 July 2011 (UTC)

Never mind, I wasn't looking in the right place. It seems that most of the material added here was a COPYVIO. This was 2005 so not sure how much remains.--RDBury (talk) 05:23, 17 July 2011 (UTC)

p-adic group

Should we have an article titled p-adic group? (At this time, it's a red link. Two articles link to it. One of those links was created in recent minutes by me.) Michael Hardy (talk) 04:41, 15 July 2011 (UTC)

Are you talking about the p-adic numbers, Finite fields, or something else? JRSpriggs (talk) 07:39, 15 July 2011 (UTC)

Or are you thinking about groups like $GL(n,\mathbb {Q} _{p})$? That seems like a reasonable thing to have an article about. Aenar (talk) 11:23, 15 July 2011 (UTC)

The term p-adic group is a widespread one and should appear on wikipedia, however its meaning varies depending on who's saying it when. It often refers to a (topological) group that is the Q_p-points of a linear algebraic group over Q_p. In this sense, the two current uses on wikipedia are incorrect in that they are too specific: the groups in question could also be the points of an algebraic group over a local field of characteristic p. Of course, some authors might include this latter type of group under the term p-adic group. One might also want to include the Z_p-points of a linear algebraic group (or a more complicated notion that means about the same thing), such as Z_p itself, or GL(n,Z_p). Or more generally, one could mean just a pro-p-group, I suppose. I think it would be difficult to determine what we think the term means. Perhaps, it could be a disambiguation page. RobHar (talk) 13:43, 15 July 2011 (UTC)

p-adic analytic group? But that's basically pro-p group? (I don't really know). -- Taku (talk)

Ah, yes, I forgot to mention those. One must distinguish between locally analytic and rigid analytic, and in the latter case one might really mean something that isn't an actual group (like when saying "group" to mean "group scheme"). Lazard proved that every p-adic (locally) analytic group has an open subgroup which is a pro-p group of finite rank, so the two concepts aren't too far off. I think the term p-adic Lie group is used interchangeably with p-adic (locally) analytic group (this is what Serre seems to do in his book Lie algebras and Lie group. It really does seem the link p-adic group should be a dab page. RobHar (talk) 14:43, 17 July 2011 (UTC)

To RobHar: Since you seem to have the best grasp of this, would you please create the disambiguation page? JRSpriggs (talk) 20:02, 17 July 2011 (UTC)

normal mode

Opinions of this edit? Michael Hardy (talk) 03:48, 18 July 2011 (UTC)

Although the edit may be an improvement generally, I think that the first sentence, "A normal mode is a mode of a linear field among a chosen set of orthogonal modes.", is confusing and should be rewritten. In particular, it is: (1) not clear why a solid object or the air is described as a "linear field"; and (2) why is there any choice involved? JRSpriggs (talk) 05:58, 18 July 2011 (UTC)

The lead, especially, the first sentence, needs to establish a context for the rest of the article. In this respect, I prefer the earlier version. Jowa fan (talk) 08:17, 18 July 2011 (UTC)

Tree of primitive Pythagorean triples

The tree of primitive Pythagorean triples.

I've created this graphic showing the natural tree structure of the set of all primitive Pythagorean triples. Next we need to either put it into an appropriate place in an existing article or created a new article about it.

We'll need some disambiguation, possibly just with hatnotes and possibly with a proper disambiguation page, because the term Pythagoras tree apparently refers to something else.

I'll get to all of this probably within a couple of days unless someone beats me to it. Michael Hardy (talk) 01:42, 15 July 2011 (UTC)

One possibility is Pythagorean Tree but trying to distinguish between that and Pythagoras tree is, I suppose, a losing battle. Other choices might be Family tree of Pythagorean triples, Tree of Pythagorean triples, or perhaps Barning–Hall tree or Barning–Hall tree of Pythagorean triples (assuming that is the tree you mean, I didn't read enough literature to follow all the trees beyond noticing that there are several which have at least been mentioned). Kingdon (talk) 01:52, 20 July 2011 (UTC)

Problem user trisecting angles

User:Ahmed elsamin has tried several times to add his "own" angle trisection method (along with his e-mail address) to Angle trisection -- someone who knows what the appropriate thing to do in this context should do it :). (The actual edits have been removed.) Joel B. Lewis (talk) 01:43, 20 July 2011 (UTC)

I added a note to his talk page pointing out wikipedia policy. With well-intentioned users like this, the vast majority of the time you just need to inform them of the policies and that is the end of the matter. Kingdon (talk) 02:40, 20 July 2011 (UTC)

What is pseudocode?

There seems to be a dispute in the article Sieve of Eratosthenes concerning what constitutes "pseudocode", specifically whether "higher-order function" (such as those found in Haskell) are acceptable. If others could weigh-in to help settle this matter, it would be appreciated. Justin W Smith ^talk/_stalk 19:12, 19 July 2011 (UTC)

To clarify, the piece in dispute is a pseudocode under "unbounded sieve", a re-write of a Haskell one-liner which I claim was NOT in violation of WP:NOTREPOSITORY and could be left in as is. Would appreciate any comments on that question as well. WillNess (talk) 20:00, 19 July 2011 (UTC)

I've found this discussion at WP CS, which may or may not be helpful: Wikipedia_talk:WikiProject_Computer_science/Manual_of_style_(computer_science)#Functional_pseudocode. In general, I think that we should keep in mind that many readers will have next to no experience in functional programming, and a poorly developed understanding of recursion. This does of course not apply to specialized topics related to functional programming and lambda calculus. Hermel (talk) 19:22, 22 July 2011 (UTC)

WP:JCW and mathematics

A while ago, I think it was CBM that came up with some semi-automated article creator for mathematics journals (Journal Helper). Anyway, the JCW compilation has updated, and here are the top-cited missing journals of mathematics.

• Annals of Pure and Applied Logic
• Annals of Probability
• Archive for History of Exact Sciences
• Canadian Mathematical Bulletin
• Czechoslovak Mathematical Journal
• Discrete Applied Mathematics
• Journal of Algorithms
• Journal of Integer Sequences
• Illinois Journal of Mathematics

There's also Proceedings of the London Mathematical Society which currently redirects to London Mathematical Society, but should really get it's own article. Same for the Bulletin of the London Mathematical Society and the Journal of the London Mathematical Society, which also redirect there.

See WP:WikiProject Academic Journals/Writing guide for guidance, and don't forget to add them to List of mathematics journals once they are created. Many thanks for all the help you can give us. Headbomb {talk / contribs / physics / books} 15:55, 21 July 2011 (UTC)

Note: Journal of Algorithms seems to have a less-than-boring history, considering the board resigned en-masse at the behest of Donald Knuth as a way to protest the Elsevier prices. They went on to establish the ACM Transactions on Algorithms which is also missing an article. See [5][6] for some sources on this. Headbomb {talk / contribs / physics / books} 17:08, 21 July 2011 (UTC)

"Human Accomplishment" as source

There is a long debate at Talk:Leonhard_Euler#Removing_Charles_Murray.27s_Human_Accomplishment regarding whether the historiometric book Human Accomplishment is an acceptable source. As far as I can tell the main objection is dislike of the author due to writing another book in a controversial area. Further input would be appreciated.Miradre (talk) 09:22, 22 July 2011 (UTC)

My opinion: the reference to Charles Murray's book is silly trivia and distracts from the main subject. What Murray thinks about Euler is surely not one of those key, important things that one would like to find out from the introduction to an article about Euler; the preceding paragraphs (which state the fields on which Euler had an impact, and give the views of actual mathematicians about Euler's impact on mathematics) make the point far better. This makes me the 4th person to take this position; so far you have found no one who agrees with you. (Also, your summary of the position of others on that talk page seems questionable.) I think it's time to give it up. Joel B. Lewis (talk) 13:42, 22 July 2011 (UTC)

"Long debate" is not how I would describe what Miradre engaged in on Talk:Leonhard Euler. I agree completely with the use of the words "silly" and "trivia". Articles on Newton, Einstein and Euler were simultaneously spammed using material from the same book. Mathsci (talk) 15:03, 22 July 2011 (UTC)

I think the best objection to Murray's book policywise is that it's primary research. It's not our job to evaluate the validity or significance of the book but adding such results to an article implicitly makes that evaluation.--RDBury (talk) 16:38, 22 July 2011 (UTC)

math.wikia.com

I just ran across a cite using math.wikia.com as a source. My first instinct is that, just like Wikipedia, this is not a reliable source (in the WP sense) since it's content added by the public. Does anyone know if there is any kind of editorial review there to prove me wrong?--RDBury (talk) 17:43, 22 July 2011 (UTC)

Use of an asterisk

I've noticed that in a lot of mathematical articles people put an asterisk as superscript, i.e. the use ^*. The problem is that an asterisk is already raised in HTML: without a superscript we get V* while adding the superscript gives V^*. If you're using the same set-up as me then you'll be able to see how silly V^* looks compared to V*. The asterisk isn't even contained in the same line band as the V, it's between its own and the previous line bands. I know we use ^* in LaTeX, bit that's because an asterisk in LaTeX appears centrally aligned, and needs raising. What does WP:MOSMATH have to say, and what you you guys have to say? — Fly by Night (talk) 17:49, 22 July 2011 (UTC)

I use &lowast;, but this often draws complaints from the my-browser-doesn't-understand-standard-character-sets crowd. Sławomir Biały (talk) 18:14, 22 July 2011 (UTC)

{{log-star}} uses some complicated coding to put the raised star in the right place: log*. —David Eppstein (talk) 18:23, 22 July 2011 (UTC)

No, it's just the span part that sets the asterisk: log* = log<span style="vertical-align: 10%">*</span>. Nageh (talk) 18:59, 22 July 2011 (UTC)

I think that I might not have explained myself properly. I was asking about why people put the already superscript asterisk in superscript. Is this mentioned in WP:MOSMATH, and what do you guys think? David's example is nice. I suggest log*, the {{log-star}} gives log*, while the ^* gives log^*. I've seen articles changed, quoting WP:MOS, so that ω^* is used in place of ω*. I can't find anything in WP:MOS or WP:MOSMATH, and to be honest ω* looks better than ω^*. If it's not mentioned, then should we add something? — Fly by Night (talk) 19:36, 22 July 2011 (UTC)

I agree that ω* looks better than ω^*. I'm not sure how this should be reflected in policy, if at all. CRGreathouse (t | c) 20:09, 22 July 2011 (UTC)

The raised star really looks odd. Maybe recommend both the normal star (*) and a slightly raised star in a {{starred}} template? Nageh (talk) 20:22, 22 July 2011 (UTC)

From your earlier post you mentioned <span style="vertical-align: 10%">*</span> to give V* and ω*. My common usage is V* and ω*, while the raised usage is V^* and ω^*. Side-by-side we have (V*,V*,V^*) and (ω*,ω*,ω^*). I would say that Nageh's <span style="vertical-align: 10%">*</span> works brilliantly for capital letters (it was the first in each of the last triples). Also, is there a space thinner than & ? Because using the code mentioned by Nageh for a capital, italicised letter gives V* and W*. The height of the asterisk seems perfect, but it's squashed into the letters. Using &  gives V * and W *. Is there an HTML quarter space? If so then we could make a template. — Fly by Night (talk) 20:36, 22 July 2011 (UTC)

That would be V * (with hairspace unicode) or V* (with margin of 10% of a letter 'm' width). The latter is fully compatible among systems; not sure about the unicode symbol. Nageh (talk) 21:12, 22 July 2011 (UTC)

I really like that; it looks great. I've created a template, {{starred}} using your code. I've accredited you for the code. I decided to be bold. The template looks like this: V*, ω*. (I have substituted these two exampled in case the template is changed during the revision process.) The only problem seems to be that it's too far away from the lower case letter. Although if the Greek letters are italicised then it looks fine: ω*(X). I'm not sure on WP:MOSMATH with regards to italicised Greek letters. Although I've seen some users, e.g. Michael Hardy, leave italicised Greek letters in place; while I've seen other editors, e.g. Ozob, remove italics from Greek letters while quoting WP:MOS. If italicised Greek letters are what WP:MOSMATH suggests then we're in business. I think it looks great! — Fly by Night (talk) 21:46, 22 July 2011 (UTC)

I am pretty confident that at one time or another, some MoS somewhere said not to italicize Greek letters. And also that superscript asterisks, since they're semantically superscripted, should be written using <sup>. (But {{starred}} is a much better solution.) If I recall correctly, what induced me to make the edit you referenced above was that all the  s needed to be replaced by {{nowrap}}s. I figured that as long as I was making style changes, I ought to go all the way... Ozob (talk) 22:14, 22 July 2011 (UTC)

…and I've used {{nowrap}} ever since; it's one of the best tips I've been given. Thanks a lot for that! I didn't mean to single you out, I'm sorry. I've seen a lot of people using the superscript asterisk, and that's why I made my original post. I can believe that it was in an MOS somewhere. I wasn't trying to say that you (or anyone else) made it up. That's why I was asking people about WP:MOSMATH, just to see how it was and how it is. Thanks again for {{nowrap}}. — Fly by Night (talk) 22:26, 22 July 2011 (UTC)

Cool! Well, thanks for the credits! Nageh (talk) 22:03, 22 July 2011 (UTC)

No need for thanks. Credit given where credit is due. I was very impressed by you know-how. — Fly by Night (talk) 23:58, 22 July 2011 (UTC)

Like I said originally, use &lowast;. Like V^∗ or f∗g. The alignment is perfect. Sławomir Biały (talk) 01:46, 23 July 2011 (UTC)

Thanks Sławomir, I did see that you mentioned it earlier. I didn't really see how it related to my OP. I was asking about the asterisk * and its hight level; then you said that you use something totally different. I mean to be jovial now, I feel we've known each other virtually for long enough for me to make a joke, so please don't be offended. But it felt like I was asking people about how they use their cars, and you replied "…but I use a unicycle". To be honest, the fact that some people can't see ∗ with their web browser is a real problem. Different people have different operating systems and use different software. We should make our articles as accessible as possible; especially since almost everyone above the age of 10 seems to hate mathematics. I think that ∗ is too big for a superscript. It does look great for a convolution, e.g. (a∗b)(x), but as a superscript, e.g. H^∗(M) it seems oversized as a posed to H*(M). Although, it depends which set-up you're using too. I know that FireFox does some wacky things. I always use Google Chrome. Let me know your thoughts Sławomir. — Fly by Night (talk) 02:38, 23 July 2011 (UTC)

I see that it is a little larger than the asterisk that your template produces. One advantage though is that we don't need to change anything about the syntax; to produce a raised star, we just type ^∗. Is there any chance that the {{starred}} template might behave unexpectedly or incorrectly in some situations? Otherwise I can't think of any reason not to use it. (And maybe also produce another one for convolution as well.) Sławomir Biały (talk) 11:39, 23 July 2011 (UTC)

{{starred}} is quite simple, and fully compatible across virtually all browsers and systems. If it were not for systems that still do not have proper unicode fonts I would prefer &lowast;. Nageh (talk) 21:28, 23 July 2011 (UTC)

GAR: A Beautiful Mind (film)

A Beautiful Mind (film) is on Good Article review (Wikipedia:Good article reassessment/A Beautiful Mind (film)/1). Many of the issues can be fixed easily enough and it would be nice to have a few people take a look and fix them while the discussion is still open. It's easier to retain GA status than to get it back once it's been lost. The article gets about 3000 hits per day so it's highly visible.--RDBury (talk) 21:11, 23 July 2011 (UTC)

I don't recall the film much getting into the math, so you won't have any special need for the math experts here. StuRat (talk) 21:14, 23 July 2011 (UTC)

True, it does have our tag on it though so I'm thinking it's a matter of project pride. But if you don't want to work on it then don't.--RDBury (talk) 03:15, 24 July 2011 (UTC)

Cartesian coordinates illustration

Illustration of a Cartesian coordinate plane. Four points are marked and labeled with their coordinates: (2, 3) in green, (−3, 1) in red, (−1.5, −2.5) in blue, and the origin (0, 0) in purple.

This illustration shows arrows at the ends of the axes pointing in both directions. By one not infrequent convention, the arrows should indicate the positive direction. Should the illustration get replaced? Michael Hardy (talk) 00:34, 20 July 2011 (UTC)

In my experience both conventions are common; I don't really see what's gained by changing it, but I don't see why anyone would object, either. Joel B. Lewis (talk) 01:50, 20 July 2011 (UTC)

The image is an SVG, which is a vector graphics format. So in principle anyone with an SVG editor could open it, remove arrowheads, and upload the changed version. — Carl (CBM · talk) 23:41, 20 July 2011 (UTC)

I did that as the double arrows were clearly not appropriate. Johnuniq (talk) 03:13, 22 July 2011 (UTC)

For the context in which the illustration is used, the double arrows are more appropriate than the single ones, IMHO. The double arrows are there to indicate that the coordinate system continues indefinitely in all directions, something that is not necessarily obvious to a reader unfamiliar with the subject. Indicating single arrows on a coordinate system is normally done to indicate the positive direction of the coordinates. Since in this case the are also numbers on the axes, that function is redundant. I'm going to revert to the old version. Or not since files do not have a revert function.TR 09:58, 22 July 2011 (UTC)

I don't have an opinion on this, but for the record: the file isn't hosted on this wiki, so you need to head over to commons and ... Cheers, Ben (talk) 10:57, 22 July 2011 (UTC).

Yes, I was just about to post the following...

The image is used at three articles: Analytic geometry and Cartesian coordinate system and Coordinate system. In each case, there are other diagrams in the same article that only use single arrows, so I did not think it would be controversial to remove the double arrows. However, if discussion here concludes otherwise, I think my upload can be undone by using the history page of the file where it really is, which is at Commons (click the image here, then click the link on the image page which says "Information from its description page there"). Johnuniq (talk) 10:59, 22 July 2011 (UTC)

It would seem that someone has now edited the file so that the arrows point only in the positive direction. (I suspect I learned that particular usage in 8th or 9th grade, but I don't remember. Maybe the fact that I don't remember means it's not all that important.....) Michael Hardy (talk) 23:44, 25 July 2011 (UTC)

Edit war

There is an edit war in progress at Sieve of Eratosthenes‎. Please review this (short) article and discuss or edit appropriately.

CRGreathouse (t | c) 19:03, 22 July 2011 (UTC)

Needless to say, be sure to review the article's history and past pages. Last non-disrupted state is this. Any comments will be much appreciated. WillNess (talk) 20:29, 22 July 2011 (UTC)

Yes, please review the history. The above link is one party's preferred version. CRGreathouse (t | c) 06:17, 23 July 2011 (UTC)

It is not the preferred version, it is a last version before the first disruptive unsubstantiated wholesale removal of a whole section in the article by yourself, code snippets, discussion and references all at once. There was already a discussion on talk page about this issue; you didnt engage in that discussion but acted unilaterally. When I tried to engage you in talk page discussion, I received no arguments back from you, just more of unilateral actions. I incorporated your suggestions, replaced a code example with pseudocode, but you kept removing the well sourced paragraph (altogether with its source) that you didn't like, based on a blog apparently which you gave as your source eventually. WillNess (talk) 12:10, 23 July 2011 (UTC)

Having had a look at the article I would side with CRGreathouse. Wikipedia is built on WP:CONSENSUS and WP:CIVILITY, lets see a bit more please. I think the main problem here before the arguing is targeting the audience for the article. The algorithm did not need Haskell and is perfectly well explained without it. The target audience is not expected to know Haskell and would gain nothing in this instance by learning it, it conveys no better explanation of the topic of the article. The articles are to describe the the topic to the readers not for the writers to show off they know more. Dmcq (talk) 13:01, 23 July 2011 (UTC)

I dont understand how acting in unilateral manner reflects consensus. The matter is not that first removal; as I said above I encorporated those changes, replaced code with pseudocode etc. But that new material was been removed summarily without discussion either. I should be the one calling out WP:CONSENSUS and WP:DISRUPT, but I'm not a Wikilegalist and I dont like to be forced to become one. I'll rather choose to go away from WP. I'll admit to loosing cool; it is only natural when the other party acts in total disregard to talk page discussions, which seems to be in contradiction to CONSENSUS policy btw. WillNess (talk) 13:28, 23 July 2011 (UTC)

And where did you get the idea about "showing off"? Why assume egotistical motives? WP:AGF instead! Both code fragments that the other editor removed (along with whole discussion that went along), to me, seemed important, relevant, illuminating. That is what I wanted to show, to the reader. It is all now gone. No mention of trial division e.g. No comparative exposition of SoE, SoEuler, TrialDivision all in one place, each next to the other, in a 3-liner. To replace just one line of it, it takes about 10 lines of pseudocode, how's that contributing to the clarity of exposition? WillNess (talk) 06:06, 24 July 2011 (UTC)

My 2c: The Haskell fragments are almost completely incomprehensible to someone who knows a lot of programming languages (me) but does not know Haskell. They make the article worse, not better, and are a gross violation of WP:TECHNICAL. You should give up and accept defeat rather than being so tendentious. —David Eppstein (talk) 06:21, 24 July 2011 (UTC)

Thanks for your feedback. Actually, Haskell is long gone; other stuff I've removed yesterday, so there's no problems left to resolve. Issue closed. WillNess (talk) 19:50, 25 July 2011 (UTC)

After a glance at the talk page, I find that I don't wish to read any further. It would be easy to lose a couple of hours trying to follow the discussion so far, and it wouldn't be a pleasant process. It looks to me as though mediation might be useful here. If people can agree on a short and clear statement of the issues that need to be resolved, and do so in a civil manner, then it will be easier to get others to join in. Jowa fan (talk) 07:46, 24 July 2011 (UTC)

It may be more productive to channel efforts toward improving the article rather than marking out lines in the sand. There's a lot of work to be done and if a dozen WPM members would write just one new paragraph or revise two or three existing ones we could have this article in much better shape. It's my sincere hope to resolve this issue by improving the article to make contentious issues moot rather than wasting overmuch time on them. Having said that, in a pinch I would be willing to go through the process. CRGreathouse (t | c) 16:23, 24 July 2011 (UTC)

Link at Fractal

There is some controversy at the Fractal article (with editors at 2 reverts each), the main point of contention seems to be whether the link [7] should be in the external links section. The page being linked is basically a Power Point presentation with narration. The 'no' editor cites WP:EL though I don't see how it applies. An additional viewpoint might be helpful.--RDBury (talk) 16:23, 25 July 2011 (UTC)

The link is ok. To me the removal looks like wikilawyering or an overly zealous literal inpterpretation of WP:EL. The link is clearly useful and not spam and the article definitely doesn't suffer from an over supply of links.--Kmhkmh (talk) 17:10, 25 July 2011 (UTC)

Looks ok to me too. Sławomir Biały (talk) 18:02, 25 July 2011 (UTC)

Thanks for fast response.--RDBury (talk) 18:37, 25 July 2011 (UTC)

As for the content, falls under the WP:ELYES criterion of "Sites that contain neutral and accurate material that is relevant to an encyclopedic understanding of the subject and cannot be integrated into the Wikipedia article due to . . . amount of detail". That it is in flash is, however, covered by "Direct links to documents that require external applications or plugins (such as Flash or Java)" in WP:ELNO. I'd lean towards including it, but anyone interested in continuing to wikilawyer the thing (in either direction) can find ammunition at WP:EL and pages it links to. Kingdon (talk) 00:38, 26 July 2011 (UTC)

RFC: Should MW developers drop the rendering preferences for math?

Please give feedback on talk page of mw:Requests for comment/Reduce math rendering preferences

Hi!

I noticed a new thread on wikitech[?] about dropping preferences for math:

• RFC: Should we drop the rendering preferences for math?

I think it is good idea to have some comments about that on-wiki, since the final decision will eventually affect users on en-wiki, so if you want to add some comment/suggestion about the proposal and are not subscribed to that mailing list, feel free to comment below. Helder 17:41, 19 July 2011 (UTC)

There is no way I am going to post to a newsgroup with my regular email account, and I am not going to get one just for this discussion. So I'll just leave a comment here.

The PNGs are atrocious, which is why I avoid the math tags to the greatest extent possible in my own articles. Wrong size, not properly aligned, and when you print an article you get HUGE pixels. This is an enormous problem for WikiProject Mathematics. There is an eternal slow edit war in which formulas are being converted back and forth between math tag format and free-style format that avoids the math tag. The MathJax hack still has a few problems but is already far superior to the other options in most cases. Hans Adler 18:28, 19 July 2011 (UTC)

• TeX output rendering is used by the mathJax script, as already been noted. As for the other options, this simple example should exemplify why anything but "Render as PNG" should be killed off: $a+b\equiv c$ but $a+b\not \equiv d$. If you are using the default "Recommended for modern browsers" the first equation will get rendered in HTML but with missing spaces around the congruence symbol, while the second gets displayed as that behated, much too large PNG image. At least, "Render as PNG" would leave a consistent display. Nageh (talk) 18:43, 19 July 2011 (UTC)

I agree entirely with Hans. The proposed change to stick to one (bad) format and drop support for all others would appear to break support for MathJax, so I oppose it. But I don't want to bother joining a new community just to say so: proposals for technical changes to Wikipedia should be made on-wiki, not elsewhere. —David Eppstein (talk) 18:44, 19 July 2011 (UTC)

Just to clarify, this is an email list, not a newsgroup, although the link above is to a newsgroup mirror. The list address is [email protected], it is run by Wikimedia, and the official archive on lists.wikimedia.org is at [8]. The list gets a decent amount of traffic from developers (including Wikimedia employees and volunteers) who are working on the Mediawiki software. I try to keep an eye on it and post there when things come up that are of interest. I don't think technical changes to Mediawiki are discussed on-wiki very often; if they were it would probably be on meta.wikimedia.org. Threaded discussions are usually on the Wikimedia bugzilla server and on the email lists. And the paid devs of course have meetings where they talk to each other face to face. — Carl (CBM · talk) 19:27, 19 July 2011 (UTC)

Thanks for clarifying this. My first post was a little confusing. Sorry for that. Helder 19:37, 19 July 2011 (UTC)

• Without answering the hard question right now, I want to note that higher-resolution rendering of generated PNGs in PDF and print versions of articles *is* something the developers can and should fix. There's no reason printouts of math articles should be all pixelated. This affects a lot of things like Wikipedia:Books, etc. Dcoetzee 19:51, 19 July 2011 (UTC)

  This problem was reported on bug #27574. It is possible to vote on that bug (e.g. to make it more noticeable in the list of most voted bugs). Helder 11:42, 20 July 2011 (UTC)

I have my preference set to PNG only. The HTML output is very ugly, and the size mismatch is a small price to pay for avoiding it IMO. I'd like to see MathJax happen, though, and it seems worthwhile to keep preferences if only between that and PNG. CRGreathouse (t | c) 20:21, 19 July 2011 (UTC)

It's not only the size that doesn't match. In expressions like 2³, the 2 gets set lower than the surrounding letters. Obviously the 2 should be at the same level as the surrounding text and the superscript 3 higher. Michael Hardy (talk) 01:10, 20 July 2011 (UTC)

Helder, would you please tell us how to subscribe to that list? Michael Hardy (talk) 02:46, 20 July 2011 (UTC)

Go to https://lists.wikimedia.org/mailman/listinfo/wikitech-l to subscribe.

One person has mentioned that a proposal for a Gadget for MathJax be submitted this sounds like a very good idea to me, as it would increase the visibility and make it easier to install.--Salix (talk): 08:32, 20 July 2011 (UTC)

As mentioned by Salix, to subscribe to the list you just need to go to its main page and fill in the fields on the section "Subscribing to Wikitech-l" with an e-mail and a password. Helder 11:42, 20 July 2011 (UTC)

There are people that love/hate PNGs and there are people that love/hate HTML. This is the reason the options exist; to let the reader choose. I wish editors would stop hacking formulas into forcing PNG, as that totaly defeats the preference of the reader, and only flows from the editor's personal preference; those editors should simply select "Always render as PNG" in their preferences. — Edokter (talk) — 10:28, 20 July 2011 (UTC)

The deeper issue is what to do for the majority of readers, who are not logged in and therefore do not have the ability to set preferences. — Carl (CBM · talk) 10:38, 20 July 2011 (UTC)

It would be nice to have something like <math hint="png">a^2+b^2=c^2</math> that would set display style for those without preferences but allow preset preferences to override those. That would stop the ugly negative spacing hacks. CRGreathouse (t | c) 14:47, 20 July 2011 (UTC)

Since no one mentioned it: What is wrong with the blahtex solution? As far as I remember there were no problems with its MathML rendering and the png-rendering included baseline information. Heck, even mimetex/mathtex have baseline support.--LutzL (talk) 11:16, 20 July 2011 (UTC)

At the moment I don't want to muddy the waters with additional technology decisions that would require more work to finalize review, compatibility testing, etc -- we can make a quick change here that will improve the overall appearance, make things more consistent, and still keep support for custom scripts that need access to the raw tex.

That said, this is exactly the sort of information that we need to hear about what's wrong with the current renderings. I've added a note into the RFC page that that's something to look at for the future. Re-reviewing and adopting blahtex may well be the right thing to do next! --brion (talk) 18:34, 21 July 2011 (UTC)

SERIOUSLY: How can one post to that discussion?

"to subscribe to the list, you just need to[...]" but I've tried twice now to post something to the list and it hasn't appeared. After going through the rigamarole, I got an email saying "you are now authorized to post" etc. Then looking at the page that Helder linked to, I saw a button that says "Action", that gives you a menu on which one item is "post". I clicked on that and it says "compose a message" etc., so I did, and then copied the captcha word and pushed the button that says "Post this article". But it has not appeared on the page to which Helder linked. It's annoying that it takes several days merely to reach this point, rather than a few seconds. How can I post there? Michael Hardy (talk) 22:26, 20 July 2011 (UTC)

Are you trying to use the newsgroup interface? I have never tried it. You should be be able to just send the message via email. The main page for the list is at [9], there is a section titled "Using Wikitech-l". It does say you have to subscribe to the list to pos, you can subscribe directly from the page I linked. — Carl (CBM · talk) 23:40, 20 July 2011 (UTC)

All right, I've made my fourth attempt to post there. This time I emailed to [email protected] rather than use the web-browswer interface. We'll see if it gets through this time. Michael Hardy (talk) 01:20, 21 July 2011 (UTC)

It didn't work. It's been more than 20 minutes. When I click on Helder's link above, I don't see my posting. Michael Hardy (talk) 01:40, 21 July 2011 (UTC)

Now I've made my fifth attempt. We'll see what happens. Michael Hardy (talk) 01:52, 21 July 2011 (UTC)

Five attempts have failed. Michael Hardy (talk) 02:08, 21 July 2011 (UTC)

My sixth attempt was partially successful. But I didn't say anything substantive. My whole day was taken up by my attempts to submit a short posting, none of the content of which was in my partially successful posting, and I'm in no mood to make some thoughtful on-topic comments.

It is baffling that the input to that thread by the regular posters to this page was not actively sought. It is lunacy. Michael Hardy (talk) 02:46, 21 July 2011 (UTC)

I have no idea why a link to the newsgroup archive was posted initially instead of a link to the regular mailing list archive. The mailing list uses standard software that is used by lots of other mailing lists, not just by Wikimedia, you use it like any other mailing list.

The wikitech mailing list is the standard place for this sort of discussion. The developers are thinking of all projects, not just enwiki, and even if they were thinking of enwiki they would think of the village pump rather than a WikiProject page. The whole point of the mailing list thread was to make a public request for comments about math rendering [10]. I was not surprised by the location of the discussion in any way. — Carl (CBM · talk) 02:59, 21 July 2011 (UTC)

The wikitech-l mailing list has been the standard place for the most involved end of these discussions since February 2002 -- but of course we want your feedback! I've set up an RFC page on mediawiki.org: mw:Requests for comment/Reduce math rendering preferences which should be easier for some people to comment at than the mailing list. --brion (talk) 18:24, 21 July 2011 (UTC)

I'd also appreciate very much if those of you who have contacts with math-heavy editors on non-English Wikipedias can help spread the issue around. I know there are also other internationalization issues such as lack of support for some characters which aren't on the immediate table, but I need that feedback to know where we should concentrate effort next! --brion (talk) 18:34, 21 July 2011 (UTC)

I've attempted to post a notice about the above RFC to the French, German, Italian, Polish, Spanish, Japanese, and Russian mathematics Wikiprojects. Together with Dutch and Portuguese (who don't appear to have math projects), these are the top ten Wikipedias by size. So the discussion should get some notice. However I used Google Translate a lot in this effort, and I would appreciate it if others checked to see if I made sense. Ozob (talk) 02:24, 22 July 2011 (UTC)

 Done on French WP. --El Caro (talk) 09:32, 22 July 2011 (UTC)

 Done on Portuguese Wikipedia. Helder 14:33, 22 July 2011 (UTC)

And you people wonder why there is less involvement, and people criticize Wikimedia for being inaccessible. Mailing lists are horrible, and it boggles my mind that there are still serious decisions being made on them. Sheesh!
— V = IR (Talk • Contribs) 15:02, 27 July 2011 (UTC)

The scourge that is \mbox

I have written this: Wikipedia:Manual of Style (mathematics)/Why you should never use \mbox within Wikipedia.

Opinions? Michael Hardy (talk) 23:37, 25 July 2011 (UTC)

Generally looks good. To be very fussy: in your "more than 3" example, the line break is more elegantly prevented using a nonbreaking space: "more than~3". So maybe it's better to just stick to the "x+y" example. Setting aside minor quibbles, this looks like a useful essay. Jowa fan (talk) 02:22, 26 July 2011 (UTC)

So currently \mbox is used in Quadratic reciprocity#Fermat, we should change that to \text? I.e. change

$p=x^{2}+\;\,y^{2}{\mbox{ if and only if }}p=2{\mbox{ or }}p\equiv 1{\pmod {4}},$

to

$p=x^{2}+\;\,y^{2}{\text{ if and only if }}p=2{\text{ or }}p\equiv 1{\pmod {4}}?$

(They appear the same on my machine.) Right now Help:Displaying a formula does not mention mbox, so I assume only people who use TeX outside WP would even know about it.--RDBury (talk) 15:31, 26 July 2011 (UTC)

For years after \text became available it was actually prescribed in WP:MOSMATH! Probably because of that it became widespread in Wikipedia's mathematics articles. It hadn't occurred to me the the page on displaying a formula might also be a place to look. But I believe that it's radiation outward from Wikipedia is why it now sometimes occurs in stackexchange and mathoverflow and various other places. Michael Hardy (talk) 17:01, 26 July 2011 (UTC)

I've looked at some of these pages with several browsers, both logged in and not. To me, using the present browser, whether logged in or not, the two lines above both look the same, but $\int _{\mbox{this}}$ looks different from $\int _{\text{this}}$. \text automatically makes text in subscripts and superscripts smaller than normal text, but \mbox does not. Michael Hardy (talk) 22:19, 26 July 2011 (UTC)

There is no reason whatsoever to use \mbox in math formulas when you have the AMS package. Quoting from the documentation for amstext: "The \text macro is a sophisticated command which allows the user to insert 'normal text' into math formulas without worrying about correct sizes in sub- or superscripts. It can also be used in ordinary text; there it produces an unbreakable unit similar to \mbox." In other words, \text can be understood as a "superset" of \mbox.

The essay should probably also cover similar examples of wrong usage of TeX commands. People frequently misuse \mathrm to denote ordinary text within formulas while really they should use \text (using \mathrm, TeX interprets the upright characters still as independent letter variables, and the font is not the same as with \text). Similarly, operator names (e.g., Arg) should be declared using the \operatorname command and not \mathrm. For modulo, there are \mod, \bmod, and \pmod. Nageh (talk) 16:07, 26 July 2011 (UTC)

No, \text is not a superset of \mbox in normal TeX usage because \mbox does not have the effect of making letters appear in text mode rather than in math mode (except in Wikipedia and similar web sites). \mbox can include both text and math modes. Michael Hardy (talk) 17:06, 26 July 2011 (UTC)

Right, I stand corrected. Just people use it normally for text within math formulas. Nageh (talk) 18:11, 26 July 2011 (UTC)

Naming of Category:Rotational symmetry

I was wondering about the naming of the naming of Category:Rotational symmetry.

At the moment the cat carries a rubric saying that it is specifically for three-dimensional spherical symmetry.

• Should the category therefore be renamed to Category:Rotational symmetry in three dimensions ? Some of the items are indeed directly specific to 3D.
• Or, should the rubric be changed, and the cat made to be for rotational symmetry in any dimension ? Some of the items are indeed applicable to any dimension; though there may be particular value in being able to find collected together those relevant in 3D, regardless of whether they are relevant in other spaces as well.

So I thought I should canvass the question here to see what people's views are. Jheald (talk) 14:59, 27 July 2011 (UTC)

WT:PHYSICS notified of this thread, as they're the wikiproject that actually have the category templated. Jheald (talk) 15:09, 27 July 2011 (UTC)

The category currently has article that one would be hard pressed to say belong the same category, e.g. Taijitu and Angular momentum. So whatever the rubric says it looks like people have been adding articles based on different interpretations of the name. That either means the title should be changed to avoid further confusion or it shouldn't be changed because that would mean having to figure out where the articles should moved. I can't make up mind at the moment.--RDBury (talk) 15:45, 27 July 2011 (UTC)

Yes, but. While the category may appear disparate, if we compare it to its containing category Category:Rotation, the sub-cat does appear to have isolated items that do have at least some coherence -- objects that either have this symmetry, mathematical operators that effect it (and which are themselves transformed by rotation of the reference way in a systematic, direction-independent way), groups that describe such symmetry, etc. So I think the current contents of the cat may actually not be as incoherent as all that, even if that might not first be evident. Jheald (talk) 09:01, 29 July 2011 (UTC)

I think, we should make a category: Rotation in three dimensions (without mentioning of the symmetry) as another (independent) subcategory of "Rotation". Incnis Mrsi (talk) 14:54, 29 July 2011 (UTC)

I suggest to remove that strange introduction, relying on contributors' default common sense. Also, I think that SU(2) and other spinor topics are not directly related to rotation, as for rotation is crucial that 360° turn is identical, not 720° as for spinors. Incnis Mrsi (talk) 15:56, 27 July 2011 (UTC)

SU(2) topics and spinors certainly ought IMO to be there, because the "quaternion sandwich", x -> R x R^-1 is one of the most efficient ways to represent and code rotations in 3D; so things like R are very much relevant here, as are the properties of things like half vectors under one-sided application of R (ie ρ -> R ρ, where ρρ^T = x). That's true never mind whether some of these things pick up a factor of -1 when you rotate the co-ordinate axes through 360°. Jheald (talk) 16:17, 27 July 2011 (UTC)

Recall that the category in question is named "Rotational symmetry", not just "Rotation" (which would definitely be more general), and not yet "Rotation in three dimensions" (which would be quite different topic, excluding some things related to discrete spaces). Of course, I am aware of numerous applications of quaternions including computer graphic algorithms like slerp, but that all is not about the symmetry. Incnis Mrsi (talk) 16:33, 27 July 2011 (UTC)

Michel Demazure

Yesterday someone created a new article on Michel Demazure, a student of Grothendieck, Bourbakiste, president of French Mathematical Society, etc. Immediately someone else tried to get it deleted, but never mind that. Anyway, I've cleaned it up somewhat, but I could use some help. I think I have the factual parts of the article reasonably in hand, though some things could still stand better sourcing, but what I hardly have any of is a description of his mathematical contributions, which seem significant. In particular: he has multiple works with over 100 citations each in Google scholar, and there are many papers (not by him) about things called Demazure modules and the Demazure character formula, neither of which we have articles on. This is not my area of mathematics at all, so if someone else understands this stuff and can add something about it that would be great. Thanks! —David Eppstein (talk) 17:39, 27 July 2011 (UTC)

Good work, by the way. Charles Matthews (talk) 09:06, 30 July 2011 (UTC)

+1. Nageh (talk) 09:42, 30 July 2011 (UTC)

Tikhonov's theorem at AfD

Tikhonov's theorem is up for deletion.  --Lambiam 18:57, 29 July 2011 (UTC)

• I think the redlink causing the trouble concerns the theorem called Tikhonov's here. (If not that would a further meaning, but while I'm not an expert on all this, the general setting seems right.) In which case a stub creation could resolve the matter in a satisfactory way. Charles Matthews (talk) 09:04, 30 July 2011 (UTC)

One issue is that we also have Tychonoff's theorem, same person but different romanizations of the Russian. Is there a reason not to make the spelling consistent?--RDBury (talk) 10:52, 30 July 2011 (UTC)

Classic can of worms. If you understand Chaikovskiy at first reading there's no problem at all. There are something like four romanisations of Russian Cyrillic around, and if you want to start in on moving Lusin's theorem to Luzin's theorem, Egorov's theorem to Yegorov's theorem and so on, that would be actual consistency. Yuryson's lemma, anyone? Charles Matthews (talk) 20:19, 30 July 2011 (UTC)

If the dab is kept, Tychonoff's theorem should be renamed to something like Tikhonov product theorem, and then the resulting redirect should be pointed to the disambiguation page. Sławomir Biały (talk) 11:30, 30 July 2011 (UTC)

But "Tychonoff's theorem" is by far the most common name for this theorem (I have never heard it called anything else, and I have never seen this name refer to anything else), so I certainly don't think that article should be renamed. RobHar (talk) 16:12, 30 July 2011 (UTC)

Fine, then move it to Tychonoff product theorem instead. The issue is that there is no sense in disambiguating one transliteration and not the other. (Although I'd probably argue that Tikhonov is the correct transliteration.) Sławomir Biały (talk) 17:17, 30 July 2011 (UTC)

I think the article at Tychonoff's theorem should stay at Tychonoff's theorem and the dab should be at Tychonoff's theorem (disambiguation) where Tikhonov's theorem can point. CRGreathouse (t | c) 19:01, 30 July 2011 (UTC)

I don't understand why the two spellings should take you to different pages. Is the k spelling more ambiguous than the c spelling? --Trovatore (talk) 19:19, 30 July 2011 (UTC)

A survey of my topology books (both of them): T. O. Moore spells it Tychonoff and Christenson & Voxman spell it Tihonov (sans k). Also, Springer EoM spells it 'Tikhonov theorem'. So there is at least some variation in the literature. If 'Tychonoff's theorem' is used in predominantly then I'd say leave the title alone whatever the 'correct' spelling is, e.g. we have Bill Clinton and not 'William Clinton'. But that doesn't seem to be the case here. According to our article, we use 'Tikhonov' for the person because that's what he used when writing in German, So I'd say in the absence of overwhelming prevalence of a particular spelling in use, go with the person's own preference.--RDBury (talk) 20:11, 30 July 2011 (UTC)

Well, that's a slightly different issue. I wasn't addressing whether we should use a k or a c, but whether it makes sense to send the user to a different place depending on k versus c, which I don't think it does. --Trovatore (talk) 20:13, 30 July 2011 (UTC)

I agree that different transliterations shouldn't send the user to different articles. As for the article's claim (mentioned by RDBury) that he spelt his name Tikhonov in German, this appears to be an error introduced by Greyhood on 4 July when he moved the article. --Zundark (talk) 21:13, 30 July 2011 (UTC)

The main thing I'm suggesting is that the main page stay where it is and the dab page gets (disambiguation). I don't care about which romanizations are used and where they point. CRGreathouse (t | c) 22:55, 30 July 2011 (UTC)