Wikipedia talk:WikiProject Mathematics/Archive/2012/Jul

Forum of Mathematics, an article about two new journals published by Cambridge University Press, has been nominated for deletion. Here's its first paragraph:

Forum of Mathematics, Pi and Forum of Mathematics, Sigma are open-access peer-reviewed journals for mathematics licensed under creative commons which will be open to submissions from 1st October 2012 for initial publishing on 1st January 2013, published by Cambridge University Press.^[1] It is currently intended to be funded by an author-pays model with fee-waivers for those that can't afford the fees, and no fees at all for any author for the journals' first three years. Fields Medalists Terrence Tao and Tim Gowers are among the editors. Gowers is the mathematician whose blog post led to the Cost of Knowledge boycott of commercial publisher Elsevier.

An argument is that as a new journal it has not yet had time to achieve notability. Another is that it's getting mentioned in the new media in connection with the boycott and with the broader purposes of that movement and is therefore notable for other reasons.

Opine at this page. Michael Hardy (talk) 19:45, 7 July 2012 (UTC)

The article titled Cox–Zucker machine suddenly showed up in our "new articles" list although it's several years old and hasn't been edited since June 30th of this year.

It is an orphan i.e. no other articles link to it.

Here's most of the article:

The Cox–Zucker machine is an algorithm created by David A. Cox and Steven Zucker. This algorithm determines if a given set of sections provides a basis (up to torsion) for the Mordell–Weil group of an elliptic surface E → S where S is isomorphic to the projective line.

The algorithm was first published in the 1979 paper "Intersection numbers of sections of elliptic surfaces" by Cox and Zucker and it was later named the "Cox–Zucker machine" by Charles Schwartz in 1984.

Two tasks:

• Improve the article.
• Link to it from appropriate other articles.

Michael Hardy (talk) 18:17, 8 July 2012 (UTC)

Am I the only one who noticed the funny title? Maybe we should try to get this in shape for an April 1 DYK... Sławomir Biały (talk) 18:22, 8 July 2012 (UTC)

How do you pronounce the vowel in the second surname? It's a German name. In German, it would be something like "tsooker" (rhymes with "hooker"). Michael Hardy (talk) 19:15, 8 July 2012 (UTC)

Steven Zucker's surname is pronounced in a way that rhymes with "shucker". Sławomir Biały (talk) 19:37, 8 July 2012 (UTC)

Hiyas there Wikiproject Mathematics,

A new editor recently submitted a new article trough article's for creation on Nagao's theorem. The article itself looks fine, but mathematics is most definitely not a subject that i am to knowledgeable about, which means i have some difficulty reviewing it. On a sidenote i would mention that we did receive some bogus math article's as of late so i wondered if someone could glance over it and check two things:

• If what is written sounds decent and logical.
• If the article isn't a duplicate of some other topic.

If you are familiar with the article's for creation area, feel free to handle the entire page. If not, I'll happily take care of those matters. Also - Thanks in advance for the assistance! Excirial ^{(Contact me,Contribs)} 19:14, 9 July 2012 (UTC)

I'm not familiar with the process. Go ahead and create it, though. It's a worthy article, and there are some edits I would like to make. Sławomir Biały (talk) 19:31, 9 July 2012 (UTC)

Thanks for the quick check - the article has been created and is now available at Nagao's theorem for your editing and reading pleasure. Excirial ^{(Contact me,Contribs)} 19:54, 9 July 2012 (UTC)

Please see Wikipedia talk:WikiProject Physics#F=q(E+v^B) exposed as puppet master. As suggested there by Christopher Thomas, I am also notifying this project. JRSpriggs (talk) 06:39, 11 July 2012 (UTC)

Though the title here makes the situation seem resolved with no doubt, let's let a little more time pass and look at the evidence another time before we write F=... off for sure. Rschwieb (talk) 13:18, 11 July 2012 (UTC)

We are informed that:

Martin Bridson is the Whitehead Professor of Pure Mathematics at Magdalen College, University of Oxford.

Is this professorship named after Alfred North Whitehead, or J. H. C. Whitehead, or someone else? The article about A. N. Whitehead doesn't mention his having a professorship named after him. Can the information be added to the articles with appropriate links among them? Michael Hardy (talk) 18:31, 13 July 2012 (UTC)

The GA review of the 136th most viewed mathematics article is open for comment.--Gilderien Chat|List of good deeds 18:24, 15 July 2012 (UTC)

I notice the use of the term notion in a number of articles where I would have used the term concept. The former seems to have semantics of vagueness associated with it, apparently corroborated by several dictionary definitions, whereas the latter seems more appropriate for use in the mathematical context where the thing described is usually precise. Would there be any objections to me replacing notion with concept in articles when this seems to apply? — Quondum^☏ 15:33, 15 July 2012 (UTC)

To me, notion suggests a proposition (sentence) while concept could refer to a term (noun phrase). JRSpriggs (talk) 16:07, 15 July 2012 (UTC)

Excellent point. One would thus expect to see a distinction in the grammar: the notion that ... and the concept of .... I concur. — Quondum^☏ 17:05, 15 July 2012 (UTC)

The terms notion and concept are synonymous. However, the preferred term among those who study them formally is "concept". Greg Bard (talk) 18:30, 15 July 2012 (UTC)

I don't think that the distinction is particularly important in the vast majority of our articles. For example, if I write about the notion of Lebesgue measure or the concept of Lebesgue measure I mean the same thing in either case, and if there is any philosophical distinction it will not matter for the subject of Lebesgue measure. I don't see a reason to go through replacing one with the other just for the sake of it. — Carl (CBM · talk) 18:35, 15 July 2012 (UTC)

This probably arose because of some squabble over whether "concept" or "conceit" should be used in a particular place, and in order to defuse the situation whereby the protagonists were about to start beating each other over the head with their teddy-bears, someone suggested to replace it with "notion". I think that was earlier today, but I lose track of time, and I have no idea where. My own view is to use the word "concept", as "conceit" has emotional overtones and "notion" smacks of imprecision. --Matt Westwood 23:40, 15 July 2012 (UTC)

Okay, this general perception was what I was trying to gauge. My own perception is that the use of notion as a direct synonym for concept is moderately recent and regional. If this sense has gained enough mainstream global usage, its use in WP would be reasonable. And as Carl says: it is not actually important (there is no ambiguity), and wholesale replacement for its own sake is not warranted. I may still be unable to resist replacing it in text I'm copyediting for other reasons, when it feels particularly out of place to me. — Quondum^☏ 05:30, 16 July 2012 (UTC)

A classical subject of dissertation for French agregation of philosophy was "the notion of concept and the concept of notion". I do not remember if it was an actual subject or a joke. D.Lazard (talk) 08:46, 16 July 2012 (UTC)

Dominant functor is a orphaned article (i.e. no others link to it) and lacks references. It's also very very short. Do what you can. Michael Hardy (talk) 20:06, 15 July 2012 (UTC)

Category theory is out of my area, but it seems to me that the key word "retract" should not be linked to deformation retract (a topological concept). Perhaps it should link to retract (category theory). Although even then, I do not know how the objects in category D can be considered as morphisms (which such a retract is supposed to be).

In any case, I suspect that the "dominant functor" concept is supposed to be similar to a cofinal function. JRSpriggs (talk) 05:59, 16 July 2012 (UTC)

Presumably what is intended here is the definition of J. Adámek; Jiří Rosický C; E. M. Vitale (2010). Algebraic Theories: A Categorical Introduction to General Algebra. Cambridge Tracts in Mathematics. Vol. 184. Cambridge University Press. p. 8. ISBN 0-521-11922-7. Here a retract is defined as the target of a split epimorphism: B is a retract if e:A → B, s:B → A with e epi and e.s = 1_B. In other words, a retract is the object at the end of a retraction. Single-sentence definitions like the article in question should probably be in Glossary of category theory. Spectral sequence (talk) 12:15, 16 July 2012 (UTC)

The article titled Böttcher equation begins like this:

The Böttcher equation is a functional equation F(h) = Fⁿ, where h is an analytic function with a superattracting fixed point a, which means that

${\displaystyle h(z)=a+c(z-a)^{n}+O((z-a)^{n+1}),\quad z\to a}$

with n ≥ 2.

I don't know if Fⁿ means n-fold composition of functions, or n-fold multiplication of the value of the function. Also, if it's supposed to be evaluated at the same point h, it wouldn't hurt to be clear about that, and if it's not, then what is meant is not clear. Then it says "where h is an analytic function with[ . . . etc . . . ]". Does that mean for every analytic function with that property, or for some analytic function with that property, or does it mean for some special analytic function with that property? Does "with n ≥ 0" mean for some n ≥ 0 (so that as long as there is some such value of n, this is an instance of the Böttcher equation, or for every n ≥ 0, or what? Michael Hardy (talk) 18:31, 17 July 2012 (UTC)

This is just a guess, so you would have to check the sources to be sure, but I think the conclusion means

${\displaystyle F(h(z))=(F(z))^{n}\,}$

for all z. In words, ordinary multiplication, not composition.

For every n≥2, for every analytic h satisfying the hypothesis, there is an analytic F satisfying the conclusion. JRSpriggs (talk) 11:29, 18 July 2012 (UTC)

Since the article says F(a)=0, composition does not make sense (since a≠0 in general).

However, it occurs to me that just using the constant function 0 for F would work. Being thus trivial, this is unlikely to be right. I think that the intention is for

${\displaystyle F(z)=c^{1 \over n-1}(z-a)+O((z-a)^{2}),\quad z\to a\,.}$

JRSpriggs (talk) 11:44, 18 July 2012 (UTC)

The fifth result for my Google search of "Böttcher equation" was this article: Carl C. Cowen (1982). "Analytic solutions of Böttcher's functional equation in the unit disk" (PDF). Aeq. Math. 24: 187–194. Zbl 0526.30033. This reference makes it clear that you start with an analytic function h with an n-fold zero at zero [the wiki article considers the trivial variation h(z-a)+a] and look for a function F such that F(h(z)) = F(z)ⁿ where the RHS is indeed the n-th power of F(z). In fact the reference observes that if n is fixed by the condition on h having an n-fold zero at zero, then the only value of k in an equation F(h(z)) = F(z)^k that gives an interesting result is k=n. Spectral sequence (talk) 13:59, 18 July 2012 (UTC)

Property of equivalence in gaussian primes has been around for most of a year, but with a bad category that prevented it from showing up in our new article lists. It needs either a lot of help, or deletion, I'm not sure which. Please do what you can. —David Eppstein (talk) 23:40, 17 July 2012 (UTC)

I looked at it and did a few edits and moved it to Equivalence of Gaussian prime numbers. It's one of the worst-written articles I've seen in a while. I might have cleaned it up quite a lot more if I were sure I understood what it says. Michael Hardy (talk) 04:15, 18 July 2012 (UTC)

Indeed. "equivalence" is never defined or used. - Virginia-American (talk) 10:55, 18 July 2012 (UTC)

Probably makes sense to discuss with the author? (At least as far as the goal is to understand what the article is about.) I note that s/he failed twice to get this through Articles for Creation, without apparently improving it in the process. --JBL (talk) 12:46, 18 July 2012 (UTC)

Surely the discussion should take place at the article talk page? I have commented there and notified the author, which strangely nobody else has done yet. Spectral sequence (talk) 13:33, 18 July 2012 (UTC)

Without noticing this discussion I noticed the article myself on the daily new maths articles update, and also being unable to identify any notable or even comprehensible content nominated it for deletion.--JohnBlackburne^words_deeds 17:37, 19 July 2012 (UTC)

There is a slow-moving discussion at Talk:Club filter involving a series of merges. I was hoping some math folks could head over there and continue the discussion, and merge the article, as I know nothing of these topics. Thanks, Ego White Tray (talk) 03:39, 19 July 2012 (UTC)

I terminated the merger. JRSpriggs (talk) 14:53, 19 July 2012 (UTC)

Another reminder of the hazards of the word "any". This is from a new article titled Tsen rank:

We say that F is a T_i-field if any such system, of degrees d₁, ..., d_m has a common non-zero solution whenever[...etc...]

Does this mean "[...]if there is any system of degrees that has a common non-zero solution whenever[...etc...]", or does it mean "[...]if it is the case that _any_ such system, no matter which one, has a common non-zero solution whenever[...etc...]"? A reasonable person might read it either way. In the first case, changing "any" to "some" would resolve the ambiguity; in the second case, changing "any" to "every" would do it. "Any" is sometimes a hazardous word. I've changed it to "every" in the article. Michael Hardy (talk) 20:23, 15 July 2012 (UTC)

This seems to me to be a grammatical parsing ambiguity rather than any ambiguity of the word. Not being familiar with the context, I can't judge this instance, but my suggestion would be to try to solve this type of problem by using grammatically unambiguous sentence structures. Simply replacing the word does not technically resolve the grammatical ambiguity. — Quondum^☏ 05:09, 16 July 2012 (UTC)

I disagree. In mathematical usage, "... any X has property P" can mean either "for all X, P is true" or "there exists an X such that P is true". Changing "any" to "every" removes the ambiguity: the first meaning is indicated. For the case under discussion, this seems to be the only interpretation that makes sense. (I'm not a specialist in this area, but it seems clear that if the other interpretation is followed then every field would have Tsen rank zero.) Jowa fan (talk) 05:33, 16 July 2012 (UTC)

Nicely explained. I stand corrected. — Quondum^☏ 06:35, 16 July 2012 (UTC)

If the whole sentence just says "Any A is B", I would take it to mean "every". But if it says "If any A is B, then...", then it could reasonably be construed as meaning "If there is any A that is B, then...", which would be the same as "If there is some A that is B". So in that case it's ambiguous. Michael Hardy (talk) 23:05, 16 July 2012 (UTC)

Template:Ring structures has been nominated for deletion. You are invited to comment on the discussion at the template's entry on the Templates for discussion page. DH85868993 (talk) 11:07, 21 July 2012 (UTC)

Members of the Mathematics WikiProject are cordially invited to chime-in in the on-going discussion of the pro and con of placing Mizar system external deep links on mathematical articles. Yaniv256 (talk) 16:19, 24 July 2012 (UTC)

Professor Griewank is one of the principal architects of automatic differentiation, a co-founder of the theory of partially separable functions (the usage of which is an important part of the success of AMPL's modeling language and the large-scale optimization packages Lancelot and Galahad), an initiate of the mysteries of semi-analytic geometry, and an amateur guitarist:

• Griewank, Andreas (2010), Tuning guitars and reading music in major thirds (html), Matheon preprints, vol. 695, Rosestr. 3a, 12524 Berlin, Germany: DFG research center "MATHEON, Mathematics for key technologies" Berlin, Postscript file and Pdf file {{citation}}: Invalid |ref=harv (help); Unknown parameter |month= ignored (help); Unknown parameter |urn= ignored (|id= suggested) (help)CS1 maint: location (link)

His would be an interesting biography.

Thanks! Kiefer.Wolfowitz 17:04, 24 July 2012 (UTC)

CV on Homepage. --LutzL (talk) 18:10, 24 July 2012 (UTC)

Help! We're getting another drive-by deletion being pushed bynon-physicists of a physics topic. Wikipedia:Categories for discussion/Log/2012 July 13#Category:Introductory physics. To express my frustration: the drive-by deletion process brings out the very worst in wikipedia behavior, and creates a huge amount of damage (remember the deletion of Category:Proof, carefully nurtured for years, here, and shot dead with only three votes?) Please help get these hooligans under control. linas (talk) 01:35, 21 July 2012 (UTC)

At least some ongoing/old CfDs are listed at Wikipedia:WikiProject Mathematics/Current activity. But it is not clear how any given category is counted as part of the project. There may be several layers of bots involved, which I can't follow. Melcombe (talk) 07:38, 25 July 2012 (UTC)

The article Indefinite logarithm has been nominated for deletion. Discussion is at Wikipedia:Articles for deletion/Indefinite logarithm.  --Lambiam 23:15, 25 July 2012 (UTC)

It looks like the bug fixes in MathJax implementation are now working so we can have less than signs ${\displaystyle x<y}$ and matrices ${\displaystyle {\begin{pmatrix}1&0\\0&1\end{pmatrix}}}$.--Salix (talk): 07:03, 26 July 2012 (UTC)

Good news! I'm trying the switch from Nageh's version to the built in support. So far it seems a little slower to render but no appearance glitches. —David Eppstein (talk) 07:39, 26 July 2012 (UTC)

Yep seems good. I just had a look at Help:Math and there are a few square boxes instead of characters for special characters and when doing \limsup and \liminf but the Nageh version does the same. Overall I'm very pleased and will use the system version of MathJax as default. Dmcq (talk) 08:36, 26 July 2012 (UTC)

Well it all depends on what renderer I've switch on. Seemingly that was with the SVG one. With the HTML-CSS they all come out okay though the special characters are half the size. And with MathML it warns me not all the features are supported by the browser. It's a hard choice, I think I'll try the HTML-CSS for a while. Dmcq (talk) 09:01, 26 July 2012 (UTC)

MathJax is excellent, but expensive. Sadly, nobody cares about such cheapie as class="texhtml", the font in which should match MathJax's one. Incnis Mrsi (talk) 09:05, 26 July 2012 (UTC)

You get that automatically if you use {{math}} and there's some ancillary templates that go with it e.g. {{mvar}} to just format a variable quickly. However some people here have a very strong dislike of serif font in the middle of non-serif. Not that MathJax will satisfy them immediately. There's also a couple of gotchas like having to put 1= in if one uses equal signs so it is another language again. As for me I'll be putting less effort into trying to use the math tempate in future and will use <math> more even if it is a little slower. Dmcq (talk) 11:43, 26 July 2012 (UTC)

Maybe we do not understand each other. I see x or x₁ markedly different from MathJax equivalents (${\displaystyle x_{1}}$). I suppose, although not completely sure, than this can be cheaply fixed by altering texhtml's font-family to those used by MathJax. I hope, sysops just are not aware about the problem. But if someone is aware, but deliberately keeps a substandard appearance of {{math}}, then it is definitely an unfair trick to mount a prejudice against "texhtml" typesetting. Incnis Mrsi (talk) 13:07, 26 July 2012 (UTC)

You need italics as in {{math|''x''₁}} which gives x₁. I think it is fairly close but it depends on what method MathJax uses for rendering and your browser. By the way MathJax uses the STIX fonts and MathJax will run a bit faster if you install them instead of using web fonts. I guess texhtml could put the STIX fonts as the first ones to check for but they are close enough to the usual Times one for most purposes I believe, possibly the size needs to be tweaked slightly as currently it is set to match the old png render program. Dmcq (talk) 19:17, 26 July 2012 (UTC)

It was just a typo in x₁, sorry. Incnis Mrsi (talk) 09:17, 27 July 2012 (UTC)

The font of the {{math}} template could be made compatible with MathJax by adding the CSS rule span.texhtml { font-family: MathJax_Math, serif; }. You can try this in your skin.css and if we are happy with it roll it out to MediaWiki:Common.css or ask a dev to change skins/common/shared.css. I'm not sure quite how the MathJax_Math font is loaded so the font might only change if MathJax is enabled.--Salix (talk): 06:29, 27 July 2012 (UTC)

Thanks for explanations, Salix. I have MathJax's fonts locally. I will be completely satisfied if "texhtml" had to switch to MathJax's fonts if these fonts are currently available in the browser. So, do you recommend to proceed with bugzilla: and not wait for further conclusions in this discussion? Incnis Mrsi (talk) 09:17, 27 July 2012 (UTC)

P.S. apart of the problem of font-family, there is another problem with font-size in <sup>s and <sub>s. I'm afraid that, due to CSS limitation, the best solution is to supersede that explicit HTML elements by {{ssup}}s and {{ssub}}s respectively, such as x₁. Yeah, it is another language again, Dmcq is right. Incnis Mrsi (talk) 10:09, 27 July 2012 (UTC)

After yet some meditation I realized that, since class="texhtml" is defined in templates, not by the engine itself, it would be unwise to request changes to MediaWiki. So, I started small. Incnis Mrsi (talk) 11:30, 27 July 2012 (UTC)

Should we also ask for "font-size:larger" to be added. At least for me the following two match x ${\displaystyle x}$. (across multiple display settings). Not sure if this is true for all configurations of browsers/system.TR 12:36, 27 July 2012 (UTC)

I agree. Even in a browser without font-family:MathJax_Math this produces a serif text which does not looks too large. Incnis Mrsi (talk) 12:53, 27 July 2012 (UTC)

Just checked IE8 and Opera, neither of which actually pick up the mathjax font.TR 12:42, 27 July 2012 (UTC)

Did you install these fonts locally? It is useful also for the MathJax proper. Incnis Mrsi (talk) 12:53, 27 July 2012 (UTC)

Now I am in doubt again. Should font-size be better placed to {{math}} rather than to CSS? Incnis Mrsi (talk) 13:20, 27 July 2012 (UTC)

No, because then it cannot be customized by user CSS.—Emil J. 13:28, 27 July 2012 (UTC)

I see no difference between increasing font-size in CSS and doing the same in all <span>s which use the class. Both are subject to user customization. Actually, there are two templates, {{math}} and {{bigmath}}. What do you propose: To merge (effectively) these two presentations? Or to make {{bigmath}} even larger? Incnis Mrsi (talk) 13:43, 27 July 2012 (UTC)

What (I think) Emil was getting at, is that if it is conrtolled through the CSS a user/reader can specify a custom css style which changes the way math output looks. So, for example, if you detest seeing a serif font inline, you can load your own css style that set the texhtml class to a sans-serif font. As a user, you cannot load a custom version of a template.TR 15:33, 27 July 2012 (UTC)

With a bit of messing around the closes set of styles I've managed to come to is

span.texhtml {       font-family: MathJax_Main, serif; font-size: 123%;}
span.texhtml var {       font-family: MathJax_Math, serif;}
span.texhtml sup {       font-size: 70.7%; }
span.texhtml sub {       font-size: 70.7%; }

Using those styles in skin.css the following two are virtually indistinguishable.

${\displaystyle -3\sin(x_{2i})+\ e^{3t}}$ MathJax

−3 sin(x_2i)+e^3t Using {{math}} {{math|3 sin(<var>x</var><sub>2<var>i</var></sub>) e<sup>3<var>t</var></sup>}}

MathJax uses a different font for variables, MathJax_Math, than for other content, MathJax_Main, and slightly different sizes 123% as opposed to 118%. The code is dynamically generated so it might be different in other browsers.--Salix (talk): 21:34, 27 July 2012 (UTC)

what happened to V. J. Havel (see too: S. L. Hakimi) - --Rovnet (talk) 16:35, 27 July 2012 (UTC) (w:es)

It was deleted by WP:PROD in March with the rationale "Poorly-sourced BLP with questionable notability". I can undelete it for you, if you want. —David Eppstein (talk) 17:08, 27 July 2012 (UTC)

I've un-deleted it for now. I'll try to notify interested parties. Michael Hardy (talk) 17:16, 27 July 2012 (UTC)

I was the one who proposed the article for deletion. I'm not a mathematician, but at the time I found it frustrating that there was next-to-no information about the person. Havel still appears to fail WP:BLP1E and the WP:GNG, but if the article was fixed, a date of birth mentioned, and some external links offered to confirm any notability, of course I wouldn't mind if the article stayed. Jared Preston (talk) 18:42, 27 July 2012 (UTC)

He also appears to fail WP:PROF. Although I think unprodding was the right thing to do, unless more evidence comes up I'd support deletion in an AfD. —David Eppstein (talk) 22:29, 27 July 2012 (UTC)

There is also Václav Havel, a famous Czech writer who is not the same person. Sławomir Biały (talk) 18:55, 27 July 2012 (UTC)

thx . --Rovnet (talk) 04:33, 28 July 2012 (UTC)

What a mess! Arabic numerals and Hindu–Arabic numeral system (with an en-dash, not a hyphen) are two separate articles, and Hindu-Arabic numeral system (with a hyphen) does not redirect to Hindu–Arabic numeral system (with an en-dash) but to Arabic numerals, and Arabic numeral system does not redirect to Arabic numerals but to Hindu–Arabic numeral system.

Welcome to the earliest days of Wikipedia. In 2002 and 2003 this would be expected. Michael Hardy (talk) 16:29, 28 July 2012 (UTC)

Is there any reason why Hurwitz quaternion order and Hurwitz quaternion should be distinct article which don't even link to each other? Deltahedron (talk) 17:16, 28 July 2012 (UTC)

The first one was linked to the second one through a redirect. I have replaced it by a direct link. However the subjects are distinct: the first article consider a subalgebra in a quaternion algebra, while the second one consider only usual quaternions. As a non specialist of non commutative algebra, I have the impression that both articles concern the integral elements in a quaternion algebra, but none of the articles make clear if the notion of integer element make sense here. I have no opinion about a merger or not. D.Lazard (talk) 19:57, 28 July 2012 (UTC)

The article Udita fractional operator is at AfD. Please comment there. Sławomir Biały (talk) 13:56, 28 July 2012 (UTC)

In related news, more eyes would be appreciated on Fractional calculus and Erdelyi–Kober operator, where a gang of SPAs are POV-pushing to include mention of the so-called "Udita fractional operator". Sławomir Biały (talk) 17:05, 29 July 2012 (UTC)

These three SPA, namely MathProff, MathBuddy and Uditanalin lock like sockpuppetts. Can someone investigate this? D.Lazard (talk) 09:37, 30 July 2012 (UTC)

If I recall correctly, a function ${\displaystyle f:\mathbb {C} \to \mathbb {C} }$ is holomorphic in a neighbourhood of ${\displaystyle z_{0}}$ if ${\displaystyle (\operatorname {d} \!f/\operatorname {d} \!{\overline {z}})(z_{0})=0}$. There is no mention of this in the article. I'm assuming that this is a well known fact. Should we add something to the article? — Fly by Night (talk) 21:33, 29 July 2012 (UTC)

It is not sufficient that the Wirtinger derivative vanish at ${\displaystyle z_{0}}$, rather it should be zero in a neighborhood. Vanishing of the Wirtinger derivative is equivalent to the Cauchy-Riemann equations (and is mentioned in that article). Sławomir Biały (talk) 22:31, 29 July 2012 (UTC)

If anyone is interested, I've recently made what I consider to be a number of improvements throughout the article on Elementary algebra, and submitted it as a Good Article nominee (see the article Talk page template for details). --Iantresman (talk) 16:29, 30 July 2012 (UTC)