# Wikipedia talk:WikiProject Mathematics/Archive/2013/Aug

Template:Wikipedia talk:WikiProject Mathematics/archivelist

## Latex-to-HTML and HTML-to-Latex users

You all know 99.241.86.114, the famous “latex to html”. Observing Template:DiffTemplate:Diff, Template:User-multi can be classified as the inverse species, HTML-to-Latex. Let’s observe how formatting is changed back and forth? Why the WikiProject is reluctant to create a preference guideline? I would like to have <math> generally preferred in

and non-<math> forms – in inline mode. Also, I would like to discourage large-scale changes (to either direction) without fixing a substantial amount of outright errors. Are there other opinions?

BTW, not a long time ago I requested a new project for advanced wiki typesetting. Only Maschen replied. Are all clever guys but Maschen and me distracted by a goddamn VisualEditor? Incnis Mrsi (talk) 16:50, 29 July 2013 (UTC)

- I would suggest adding to the WP:MSM guideline a recommendation along the following lines: "Large scale formatting changes to an article or group of articles are likely to be controversial, and should generally be discussed on the talk page of the article before implementation. If more than one article is effected, consider notifying an appropriate Wikiproject (such as Wikiproject mathematics)." Sławomir Biały (talk) 17:15, 29 July 2013 (UTC)
- For cases of
*already existing reasonable*formatting I agree with the procedure proposed. But a prolific typesetting fixer, like me, would not be happy to notify the WikiProject on every instance of converting “\text{cos}” to “\cos”, “*a*∗*b*” to “{{math|*a*⋅*b*}}”, and “<math>7</math>” to “{{num|7}}”. A crap is a crap and shall be replaced with a valid form without deliberations. Incnis Mrsi (talk) 17:31, 29 July 2013 (UTC)

- For cases of
- I would like to have variables look the same when they are displayed inline as in displayed formulas. That means, if there are displayed formulas, we should also use <math> inline. I would strongly oppose a guideline that says that all inline math should be html. It would break this formatting, force some formulas into displays that should not be displays, be moving in the wrong direction in pushing WIkimedia to support mathjax better, and (personally) make the formatting I see in my own browsing (with mathjax turned on) look significantly worse. A recommendation in lines with WP:RETAIN as Sławomir suggests makes a lot more sense to me. Your special pleading on behalf of "prolific typesetting fixer"s while simultaneously complaining about the "latex to html" typesetting fixer looks hypocritical. I think you're capable of distinguishing fixes that change incorrect formatting or make things more consistent from mass html to latex or latex to html non-fix formatting changes. —David Eppstein (talk) 18:01, 29 July 2013 (UTC)
- Not a long time ago David hepled with Template:Diff, and now weeps how so named HTML formatting looks poorly for him. Instead of wait for resource-hungry MathJax to fill the universe, why not to entertain some efforts for improving appearance of "texhtml"? There was an attempt to Template:Diff. Though this implementation was recently Template:Diff by user:Edokter, but what does preclude Wikipedia from developing downloadable fonts features? Incnis Mrsi (talk) 18:21, 29 July 2013 (UTC)

- Template:Ec I would prefer using HTML for simple inline symbols or expressions and LaTeX displayed, because it's ugly to have "a quantum state vector in Dirac notation is an element of a Hilbert space..." or "the Mandelbrot set is generated by the recurrence where is the th complex-valued iterate starting from and is a complex-valued constant..."...

- However, as some IPs and logged in editors always change formats back and forth, I have simply given up on trying to make typography within articles "clean" and consistent - it is hardly possible. It is a formidable waste of improvement efforts and time to keep changing typography formats as they will decay into someone else's preference and the whole process keeps repeating.

- Naturally there are advantages and disadvantages to both systems, that inline HTML looks nicer for simple symbols/expressions, but cannot handle all mathematical symbols/typefaces, and cannot be used in complex displayed formulae. So there is a case for using LaTeX inline, since correctness of symbols and familiarity and power of LaTeX is more important than appearance. Actually most LaTeX symbols are clearer than the often hideously thick, blocky and sometimes unclear shapes of Arial (in general, most sans serif fonts) Greek and mathematical symbols. In HTML, symbols are clearer using the {{math}} template due to the Times font (as everyone here knows), but this forces other editors, new or experienced, to either remove/ignore/use the math template, ultimately wasting time in making formatting consistent. On the plus side, it automatically includes the {{nowrap}} template to prevent inline HTML formulae breaking from the end of one line to the next...

- Although I support a wikiproject for typesetting, I'm not sure how effective it will be: no matter how many guidelines, policies, and wikiprojects there are, people can effortlessly ignore them.

- It seems Sławomir's solution is enough, I support that too.

- Incnis will not like me for this, but I'll say it anyway: overall we should just write content using straight LaTeX (apart from absolutely 100% trivial symbols on the keyboard like 1-9, a-z, basic punctuation), and forget completely about messing around with typography. Which is in agreement with David Eppstein. Let those who alternate typography waste their time - as long as no errors are introduced it's not ultimately a problem.

**M∧***Ŝ**c*^{2}*ħ*ε*И*18:24, 29 July 2013 (UTC)_{τlk}- Actually, math-like templates depend on class="nowrap", but not on the homonymous template. Template coders are more tidy that you think about them. Incnis Mrsi (talk) 19:45, 30 July 2013 (UTC)

- I think it was a bad decision to remove the "HTML when simple" rendering option for TeX some years ago. The texhtml class was specifically designed to handle this option. It allowed inline math to be authored in LaTeX, but displayed in HTML. But with that option gone, using {{math}} is the only way to have inline math display properly. The current PNG rendering (which is default) is atrocious inline; MathJax is a vast improvement, but until MathJax is the
*only*option (with proper no-javascript fallback), we're somewhat stuck with HTML.

- I think it was a bad decision to remove the "HTML when simple" rendering option for TeX some years ago. The texhtml class was specifically designed to handle this option. It allowed inline math to be authored in LaTeX, but displayed in HTML. But with that option gone, using {{math}} is the only way to have inline math display properly. The current PNG rendering (which is default) is atrocious inline; MathJax is a vast improvement, but until MathJax is the

- I think the 'HTML for inline, LaTeX for display' is the best option we can recommend for now. What I did to {{unicode}} is not relevant; its implementation was very flawed and
**simple**math should not require special fonts anyway. In cases where some special symbols must be put inline, it should be done so using`<math>`

; it may look bad, but it would display properly for*all*users. —*E*dokter (talk) — 19:26, 29 July 2013 (UTC)

- I think the 'HTML for inline, LaTeX for display' is the best option we can recommend for now. What I did to {{unicode}} is not relevant; its implementation was very flawed and

Hello everyone. I am new to here. Actually I have been reading for years, but only decided to edit after getting unsatisfied with some entries and realized I can join to improve. Before editing I tried to searched for some rules that can apply but failed. So I followed the general practice of writing mathematical articles: making every mathematical content into TeX code. Happy to be informed and join the discussion here.

Regarding the previous discussions, I still hold my point of view that all mathematical content should be TeX code, including 100% trivial symbols (I think it is possible to separate mathematical use of "the ??? constant is " and common use of "there are 2 of them"). In this sense I am more radical than **M∧ Ŝ**.

My reasons for this are as follows. First, that style is what we read in daily (academic) life. That is what we see on books, papers, and commonly adopted in communities like mathoverflow and math.stackexchange. Writing in this way may not take more efforts (personally, I write a <mth></mth> in an empty line to quickly copy and paste). It is just common practice and no special reason to object to it as far as I am concerned.

And my reasons pro other options: First, plain html subject to page fonts, which is usually sans-serif nowadays. This is not suitable for math contents. In many cases as I see things like italics go into a mess. Second, Template:Mvr and Template:Mth mode forces serif, and looks plausible. But it is still html (I guess only with fonts forced), and fit math better than TeX. Subscripts is still <sb> thing. Also the "1=" initial is quite confusing (forgive me I didn't investigate into the meaning this). Third, I think it is better to keep it semantically consistent. I.e., when we write <mth>, we are indicating that it is a mathematical content using a unique markup, and present it follow the TeX rules (Yes, this is not present in trivial symbols). This is good for understanding the source code. Also, still, it is not so visually consistent with TeX rendered contents, if the latter exist.

P.S. I am currently turning on Mathjax, as I am zooming in. If it were png it would blur heavily (which is happening on many wordpress blogs). Another thing of interest is commutative diagrams. They are stored as svgs, compatible with zooming. But wikipedia only displays thumbnails which is png (or I haven't found how to make svg as default?). Now we have Mathjax and the /require{AMScd} environment is available for commutative diagrams. It is demonstrated on my sand box (url of my user page/sandbox). However, it is not supported by the png rendering engine. I believe high resolution will popularize in the next few years (actually it has on tablets and phones), and it is time that we considered for zooming-compatibility.

Regards. Zhongmou Zhang (talk) 20:05, 29 July 2013 (UTC)

- Welcome Zhongmou and thanks for your input. I was not specifically/personally referring to you, there have been IPs and editors that change HTML to LaTeX, even for symbols like ∇ to . In PNG it is rather jarring. But lets concentrate on content above making mathematics look pretty. Best regards!
**M∧***Ŝ**c*^{2}*ħ*ε*И*20:29, 29 July 2013 (UTC)_{τlk}

{{safesubst:#invoke:anchor|main}}So, may I put following two things to WP:MOSMATH?

`<math>`

to HTML. Mass changing of formatting from non-<math> to <math> without a clear improvement is also undesirable. Ask at the article talk page first. If there will be no positive response, or in cases involving several articles, ask a relevant WikiProject, such as WP:WikiProject Mathematics for mathematical articles.
Template:Serif. There is a consensus that `<math>`

is the preferred formatting for a formula on their own line, with a possible exception for simple strings of Latin letters, digits, common punctuation marks, and arithmetical operators. Even for simple formulae <math> might be preferred if required for the uniformity through an article. The community of mathematical editors of English Wikipedia currently has no consensus about preferences for formatting of in-line formulae.

Incnis Mrsi (talk) 20:21, 29 July 2013 (UTC)

- The principle is fine, but the wording needs a little cleaning up. E.g., the first sentence should be qualified with "mass" or "large-scale" like the second. Sławomir's wording gives a nice example of good tone. The root cause of the problem is of course that the formatting is broken, and countless hours are wasted as a result: David's suggestion would be ideal once this display problem is fixed, but not until then. However, I'm wondering whether MathJax will actually be a workable default within the next decade, and so don't think that we should bank on it. —
*Quondum*20:50, 29 July 2013 (UTC)

- The principle is fine, but the wording needs a little cleaning up. E.g., the first sentence should be qualified with "mass" or "large-scale" like the second. Sławomir's wording gives a nice example of good tone. The root cause of the problem is of course that the formatting is broken, and countless hours are wasted as a result: David's suggestion would be ideal once this display problem is fixed, but not until then. However, I'm wondering whether MathJax will actually be a workable default within the next decade, and so don't think that we should bank on it. —

- I agree that display math should use <math>. There
*should*be consensus for inline formulae. I would like to get some opinions on that, given that that the default PNG rendering is here to stay for the time being. —*E*dokter (talk) — 20:51, 29 July 2013 (UTC)

- Best not – we already know the current array of options is too devisive, and will side-track any real progress. If, however, you could find a HTML rendering for
`<math>`

that is*guaranteed*to render like MathJax for simple formulae, but does not have the overheads of MathJax, you might make some headway. But probably not until then. —*Quondum*21:34, 29 July 2013 (UTC)

- Best not – we already know the current array of options is too devisive, and will side-track any real progress. If, however, you could find a HTML rendering for

- There used to be... the render option "HTML when simple". I never understood why that was removed. —
*E*dokter (talk) — 18:17, 30 July 2013 (UTC)- Ironically, WP:texvc still generates HTML. It is just discarded now by the engine. Incnis Mrsi (talk) 19:45, 30 July 2013 (UTC)

- We can make such a renderer in WP:Lua. It can simultaneously generate HTML (class="texhtml"), when is able to do it, and envelop its input in <math>. Then, certain skin tricks have, in the case of HTML available, to select exactly one form for a user, the preferred one. Incnis Mrsi (talk) 19:45, 30 July 2013 (UTC)
- How close can it be made to match the MathJax output? As I remember it (which is fuzzily), the font selection was not changed (to say match the proper math font). In this sense, it did not meet the "guarantee" that I mention above. With correct (or close) font selection, this might be interesting. No MathJax delays, inline kerning correct, font matching... Though we'd still get those who find the inline font change more jarring than font mismatch of symbols between inline and display. If only browsers would support matched font sets. —
*Quondum*20:47, 30 July 2013 (UTC)- You can get a very close match mathjax and {{math}} Template:Mvar
^{2}render nearly identically for me with my style sheet User:Salix alba/vector.css. (The only difference is the mathjax is 1 pixel lower, so the template version is more correct.) While you cannot guarantee the same font will be used in different articles you can guarantee that in a single article with mathjax the fonts will be the same. A bit of tweaking might be needed to check different browsers and platforms, but you can basically just find the css mathjax uses and set that in the style sheet.--Salix (talk): 21:33, 30 July 2013 (UTC)

- You can get a very close match mathjax and {{math}} Template:Mvar

- How close can it be made to match the MathJax output? As I remember it (which is fuzzily), the font selection was not changed (to say match the proper math font). In this sense, it did not meet the "guarantee" that I mention above. With correct (or close) font selection, this might be interesting. No MathJax delays, inline kerning correct, font matching... Though we'd still get those who find the inline font change more jarring than font mismatch of symbols between inline and display. If only browsers would support matched font sets. —

- There used to be... the render option "HTML when simple". I never understood why that was removed. —

I made proposed changes (closer to Sławomir’s wording in the part Template:Serif), as well as some update badly needed since early 2012, with Template:Diff. I was happy to work with you, guys. Incnis Mrsi (talk) 10:23, 3 August 2013 (UTC)

## Is 0 a divisor of 0 ?

Our article divisor said "Every integer is a divisor of 0, __except by convention 0 itself__ (see division by zero)". In this edit editor Template:User-multi modified this to say that 0 is a divisor of 0 because 0 x *k* = 0 for all integers *k*, although the ediotr accepts that 0/0 is undefined. I restored the original text in the article, and the editor has explained their reasoning at my talk page. Does anyone have views and/or reliable sources on this point ? Gandalf61 (talk) 12:48, 1 August 2013 (UTC)

- I agree with the anonymous user (though not with the tone of voice he used on your talk page). It seems from the article's first footnote that we may already have a source whose definition implies . I suspect most algebra textbooks or abstract algebra textbooks will furnish further sources. (Note in particular that as ideals, so in the ideal-theoretic sense also.) Ozob (talk) 13:37, 1 August 2013 (UTC)

- While I agree that 0 is a divisor of 0, I can easily imagine some situations where it is desirable to have conventions where this is not the case. Properly sourced, I think both points of view deserve mention. Sławomir Biały (talk) 14:15, 1 August 2013 (UTC)
- In the current version (restored by Gandalf61), the article Divisor contradicts the most usual mathematical convention, and, in particular the article Zero divisor. Moreover the convention of this article preserves of extending the statement of the fundamental theorem of arithmetic to include zero. Also, the article defines "divisor" by using Euclidean division, although such a definition may not be generalized to other rings than the integers. IMO, a correct definition would be:
*b is a divisor of a if there exists a non-zero c such that a*=*bc*. The restriction "non-zero" is meaningful only if*a*=0, for the definition of zero divisors. D.Lazard (talk) 14:42, 1 August 2013 (UTC)- So under that correct™ definition, , i.e. is undefined? 145.236.67.179 (talk) 16:06, 1 August 2013 (UTC)

- These are all good points. Sławomir Biały (talk) 15:53, 1 August 2013 (UTC)
- I view the locution "zero divisor" as having an implicit "nontrivial" at the front — if you have (nontrivial) zero divisors, then you're not in an integral domain. So neither 0 nor 1 is a "zero divisor" in that sense.
- However, both 0 and 1 should be taken to
*divide*zero. Otherwise the "divides" relation doesn't give you a lattice with 0 at the top, and that would be just silly; of course it's a lattice with 0 at the top. What else could it be? That's why, for example, gcd(0,0)=0 (it's the "greatest" divisor in the sense of the lattice relation, not in the sense of the ordinary ordering on the natural numbers). --Trovatore (talk) 16:01, 1 August 2013 (UTC)- All of these are good points, but do not address the only issue that matters, namely, what do reliable sources give as the definition. Discussion of what they might say, or ought to have said, are irrelevant: what do the sources actually say? Spectral sequence (talk) 16:52, 1 August 2013 (UTC)
- The page zero divisor provides the following definition:
*A commutative ring with 0 ≠ 1 and without zero divisors is called an integral domain.*This is of course the classical definition. If 0 were declared to be a zero divisor, then no ring will ever be an integral domain. Tkuvho (talk) 16:55, 1 August 2013 (UTC)- But being a "zero divisor" in this sense is not the same as dividing 0. --Trovatore (talk) 18:01, 1 August 2013 (UTC)
- Is encyclopediaofmath.org a correct source? Please, see [1] --El Caro (talk) 18:59, 1 August 2013 (UTC)
- Encyclopedias are tertiary sources and as such are generally considered less desirable than good secondary sources. They will do as a stopgap in a pinch, but for something as basic as this we should be able to find multiple reliable secondary sources. --Trovatore (talk) 19:05, 1 August 2013 (UTC)
- Wacław Sierpiński will do, I think. --El Caro (talk) 19:48, 1 August 2013 (UTC)
- Pretty clean and conclusive. To quote:
- "We say that an integer
*a*is*divisible*by an integer*b*if there is an integer*c*such that*a*=*bc*. We then write*b*|*a*. We call*b*a*divisor*of*a*and*a*a*multiple*of*b*. - "...every integer is a divisor of zero."

- "We say that an integer

- The article emphasises division a bit heavy and thus disguizes this definition of divisor, which is the article's topic. Sierpiński's definition of divisor (and the clarification that every integer (including zero) divides zero) should be readily available to someone seeking the formal mathematical definition. Similarly, in abstract algebra the same definition should be made (with a suitable reference, where I suspect Jacobson's
*Basic Algebra I*would suffice). —*Quondum*20:44, 1 August 2013 (UTC)- Excellent. So it needs to be explained somewhere that 0 and 47 are both "divisors of zero" in the sense that they bear to 0 the relation that Sierpiński was considering, but that neither is a "zero divisor" in the sense used when talking about whether a ring is an integral domain. I would hope that Sierpiński's definition is standard, but if not, then alternative usages may also need to be explained. --Trovatore (talk) 21:17, 1 August 2013 (UTC)
- This dicussion really belongs on the talk page. I've gone ahead and edited the page quite a bit (feel free to crit the result). I think that "all integers are divisors of zero" is sufficient, except that divisors of zero could be added under the examples section. That the phrase "zero divisor" has an implicit "nontrivial" prefix is an anomaly of that phrase, and doesn't need mention in divisor. —
*Quondum*00:31, 2 August 2013 (UTC)

- This dicussion really belongs on the talk page. I've gone ahead and edited the page quite a bit (feel free to crit the result). I think that "all integers are divisors of zero" is sufficient, except that divisors of zero could be added under the examples section. That the phrase "zero divisor" has an implicit "nontrivial" prefix is an anomaly of that phrase, and doesn't need mention in divisor. —

- Excellent. So it needs to be explained somewhere that 0 and 47 are both "divisors of zero" in the sense that they bear to 0 the relation that Sierpiński was considering, but that neither is a "zero divisor" in the sense used when talking about whether a ring is an integral domain. I would hope that Sierpiński's definition is standard, but if not, then alternative usages may also need to be explained. --Trovatore (talk) 21:17, 1 August 2013 (UTC)

- Pretty clean and conclusive. To quote:

- Wacław Sierpiński will do, I think. --El Caro (talk) 19:48, 1 August 2013 (UTC)

- Encyclopedias are tertiary sources and as such are generally considered less desirable than good secondary sources. They will do as a stopgap in a pinch, but for something as basic as this we should be able to find multiple reliable secondary sources. --Trovatore (talk) 19:05, 1 August 2013 (UTC)

- Is encyclopediaofmath.org a correct source? Please, see [1] --El Caro (talk) 18:59, 1 August 2013 (UTC)

- But being a "zero divisor" in this sense is not the same as dividing 0. --Trovatore (talk) 18:01, 1 August 2013 (UTC)

- The page zero divisor provides the following definition:

- All of these are good points, but do not address the only issue that matters, namely, what do reliable sources give as the definition. Discussion of what they might say, or ought to have said, are irrelevant: what do the sources actually say? Spectral sequence (talk) 16:52, 1 August 2013 (UTC)

- In the current version (restored by Gandalf61), the article Divisor contradicts the most usual mathematical convention, and, in particular the article Zero divisor. Moreover the convention of this article preserves of extending the statement of the fundamental theorem of arithmetic to include zero. Also, the article defines "divisor" by using Euclidean division, although such a definition may not be generalized to other rings than the integers. IMO, a correct definition would be:

- While I agree that 0 is a divisor of 0, I can easily imagine some situations where it is desirable to have conventions where this is not the case. Properly sourced, I think both points of view deserve mention. Sławomir Biały (talk) 14:15, 1 August 2013 (UTC)

- https://en.wikipedia.org/wiki/Glossary_of_ring_theory
- Bevezetés a matematikába (by Járai Antal et al, ISBN 963 463 729 9), p. 46 (definition of zero divisor), p. 78 (definition of divisibility in an integral domain with unity). A zero divisor (a "null divisor" by transliteration from Hungarian) is not to be confused with a divisor of 0.
- http://amath.nchu.edu.tw/~hsu/run/node42.html
- http://www.math.uchicago.edu/~yskim/M255/w080128.pdf
- http://primes.utm.edu/glossary/xpage/Divides.html

Although the above authors differ as to where divisibility should be defined (in an integral domain vs. in a commutative ring; with unity vs. without unity), one thing is consistent: if and only if there exists an such that . — Preceding unsigned comment added by 78.92.92.3 (talk) 00:56, 2 August 2013 (UTC)

- Not so fast - I'll bring this up on the talk page as well but felt that I should post it here. The question interested me enough to go scrambling through a number of texts (algebra, number theory, intro to proofs). I found both sides of the issue equally represented. About half define
*a*|*b*only for nonzero*a*. About half of those that permit*a*to be zero make no statement about 0 | 0, while the rest are quite explicit about this being true. The authors ran the gamut and included some very respectable mathematicians. Some quick examples:- Herstein is of the nonzero
*a*camp and states that if integer*m*≠ 0 then*m*| 0. - Paley & Weichsel permit
*a*= 0 and say "As a consequence of this definition, we see that any integer*a*divides 0. Indeed even 0 | 0." - Niven is of the nonzero
*a*camp and says "It is understood that we never use 0 as the left member ... in*a*|*b*." - Dean of the nonzero camp says "However, by definition, zero divides no integer."
- McCoy of the nonzero camp says (paraphrased) "We could just as well allow
*a*to be zero in the above definition, but this case is unimportant and it is convenient to exclude it."

- Herstein is of the nonzero

- Not so fast - I'll bring this up on the talk page as well but felt that I should post it here. The question interested me enough to go scrambling through a number of texts (algebra, number theory, intro to proofs). I found both sides of the issue equally represented. About half define

- Except for Dean, all I can see is that is not considered and defined by everyone. Of the authors you've just mentioned, only Dean says that .
- I think Niven is pretty explicit on this point as well. Remember, this was just a small sampling of what I looked at (over 20 texts) to give a flavor of what is out in the literature. Bill Cherowitzo (talk) 18:43, 2 August 2013 (UTC)
- To me, it doesn't look like Niven claims that , but instead that the logical value of "" is never questioned. 81.182.56.93 (talk) 00:59, 3 August 2013 (UTC)

- I think Niven is pretty explicit on this point as well. Remember, this was just a small sampling of what I looked at (over 20 texts) to give a flavor of what is out in the literature. Bill Cherowitzo (talk) 18:43, 2 August 2013 (UTC)
- What is Dean's definition? if and only if and there exists an such that ?
- Yes. Bill Cherowitzo (talk) 18:43, 2 August 2013 (UTC)

- Except for Dean, all I can see is that is not considered and defined by everyone. Of the authors you've just mentioned, only Dean says that .

- An analogous example: Some authors define whether an real-to-real (partial) function () is differentiable at an domain point of ( for a given ) only if is also an interior point of the domain of (), and simply don't consider differentiability otherwise, as opposed to saying that is not differentiable at non-interior points. Other authors do not require that be an interior point, only a limit point. For example, many authors say that an function with a closed-interval domain is differentiable on its domain (, ). 78.92.207.80 (talk) 11:16, 2 August 2013 (UTC)
- Your point being?? To say that there are fundamental concepts that are defined in slightly different ways by several authors is a well known fact in mathematics. I am just pointing out that this is just another example of such. Bill Cherowitzo (talk) 18:43, 2 August 2013 (UTC)

- An analogous example: Some authors define whether an real-to-real (partial) function () is differentiable at an domain point of ( for a given ) only if is also an interior point of the domain of (), and simply don't consider differentiability otherwise, as opposed to saying that is not differentiable at non-interior points. Other authors do not require that be an interior point, only a limit point. For example, many authors say that an function with a closed-interval domain is differentiable on its domain (, ). 78.92.207.80 (talk) 11:16, 2 August 2013 (UTC)

- The point is that the definitions for differentiable are compatible — one is an extension of the other, applicable to more functions.
*Let be a set with a commutative multiplication function having a null element.*Saying - is different than saying
- and an even newer definition would be:

- The point is that the definitions for differentiable are compatible — one is an extension of the other, applicable to more functions.

- Only the 2nd and 3rd definitions imply that . Only the 3rd definition implies that does not divide my ass. 81.182.56.93 (talk) 00:59, 3 August 2013 (UTC)

The one thing that I did not find was any statement about uniqueness in the definition of divisor. Personally I kind of like that wrinkle in the definition and it may appear in some education literature, but I don't have a citation for it. Bill Cherowitzo (talk) 03:41, 2 August 2013 (UTC)

- There is one in the book I listed above (on page 46). Translation:
*6.1.4. Divisibility in an integral domain with unity. [...] Excluding the case, there is at most one such , because if as well, then , from which follows due to the "simplification" rule.*84.2.117.242 (talk) 18:10, 2 August 2013 (UTC)- This is a theorem, not part of a definition. Bill Cherowitzo (talk) 18:43, 2 August 2013 (UTC)
- And it shows what difference it would not make if uniqueness were added to the definition. 81.182.56.93 (talk) 00:59, 3 August 2013 (UTC)

- This is a theorem, not part of a definition. Bill Cherowitzo (talk) 18:43, 2 August 2013 (UTC)

## Possible COPYVIO at List of NP-complete problems

See Talk:List of NP-complete problems#Copyright issues. RDBury (talk) 00:34, 4 August 2013 (UTC)

## Possible use of WP as a platform to link their own material

An editor appears to be using WP to publish a link to a primary paper on an alternative to quaternions (presumably their own), IMO of debatable merit, and almost certainly of no significant notability. — *Quondum* 13:36, 4 August 2013 (UTC)

## Requesting move: Lasker–Noether theorem -> primary decomposition

I started the discussion at Lasker–Noether theorem. Please participate if you're interested. -- Taku (talk) 01:20, 6 August 2013 (UTC)

## Bi-twin chain

There's a new article titled Bi-twin chain. It was tagged as "unreferenced", so I added the only reasonable reference I could find, the *CRC Concise Encyclopedia of Mathematics*, Second Edition, by Eric W. Weisstein, page 249. With Google Scholar, I found only a preprint that at first glance looked as if it might not have been published in any refereed journal. But Weisstein cites this: Jobling, P., "A BiTwin chain of length 6 discovered." NUMBRTHEORY@listserv.nodak.edu, posting 4 Oct 1999.

So it looks as if maybe the term is used by number theorists in a "folk" manner but maybe nonetheless a somewhat standard manner.

Should something further be done about citing sources for this? E.g. does someone know a few number theorists they could ask about sources to cite? Michael Hardy (talk) 18:50, 4 August 2013 (UTC)

- I only know online sources and some of them don't satisfy our requirements. I think bitwins are borderline notable but I may be biased by personal involvement. The article creation [2] was copied from http://number.subwiki.org/wiki/Bitwin_chain without attribution. It has the same license as us so we should be OK as far as copyright goes after I gave attribution.[3] The term "bitwin" was introduced by Henri Lifchitz in http://www.primenumbers.net/Henri/us/NouvChPus.htm. Others have made computational searches and announced their results on number theory mailing lists or submitted to record pages. Prime records are an uncontroversial field where most types of results, including all bitwins, are easily verified by computer, but many records are only in selfpublished announcements and record pages. Lifchitz maintains a record page at http://www.primenumbers.net/Henri/fr-us/BiTwinRec.htm. I (Jens K. Andersen) have set many of the records there. Some bitwin records were also the record for any case of "simultaneous primes" at the time and are therefore in the record histories at "The Largest Known Simultaneous Primes" at http://users.cybercity.dk/~dsl522332/math/simultprime.htm. That's my own website with my own rules, probably unsuited for Wikipedia, but it shows a few people have been interested enough to find harder records than for the better known prime k-tuples and Cunningham chains. My webhost is not responding today but will probably soon be back. Click the little green triangle in the Google search Template:Google to see Google's cache. Here is an obsolete record claim in "Prime Curios!" at the Prime Pages: http://primes.utm.edu/curios/page.php?curio_id=6338. According to http://www.primenumbers.net/Henri/fr-us/BiTwinRec.htm there was actually a larger BiTwin known since 1999, but at least the prime curio shows the term "Bi-Twin" in a source normally accepted by Wikipedia. I guess your Weisstein reference is a print version of http://mathworld.wolfram.com/BitwinChain.html. It references an old dead url of Lifchitz's page http://www.primenumbers.net/Henri/us/NouvChPus.htm and of Paul Jobling's mailing list post "A BiTwin chain of length 6 discovered.", currently archived at https://listserv.nodak.edu/cgi-bin/wa.exe?A2=ind9910&L=NMBRTHRY&F=&S=&P=764. Entering bitwin in the search box there gives other record announcements by Jobling [4][5] and one by me [6]. Here are some OEIS sequences about the concept but not using the name "bitwin": OEIS:A066388, OEIS:A069175 (= OEIS:A178421+1), OEIS:A068635 (= OEIS:A069179-1). PrimeHunter (talk) 00:26, 10 August 2013 (UTC)

## Finsler geometry

Finsler geometry is as stubby an article as I've seen in a while. For a long time it redirected to Finsler manifold. What should be its fate? Michael Hardy (talk) 22:55, 6 August 2013 (UTC)

- I would restore the redirect. While there
*might*be scope for a separate article some time in the distant future, that day has certainly not yet arrived. Sławomir Biały (talk) 22:59, 6 August 2013 (UTC)- Template:Done, but without implying a prejudice against an article containing at least something that does not belong to “Finsler manifold”. Incnis Mrsi (talk) 12:10, 7 August 2013 (UTC)

- It is not correct to assert as the page currently does that "Finsler geometry is a kind of Differential". Tkuvho (talk) 12:01, 7 August 2013 (UTC)

## Spurious templates "citation needed"

A user has spammed the article Polynomial by adding a template {{cn}} after almost each assertion of the article, even the most trivial ones, such as "the sum of two polynomial is a polynomial" or "a polynomial function is a function which is defined by a polynomial". I have reverted him, but he reverted me. As I do not want to spent time for an edit war, it would be nice if someone else would have a look. D.Lazard (talk) 18:13, 9 August 2013 (UTC)

- It's not just fact-bombing, but a massive reorganization of content including, mostly, what seems to be removal of content and section headings. It's hard to follow the precise details of these edits owing in part to a lack of informative edit summaries and no talk page discussion. My overall impression of these edits is that they do not improve the article, but I am willing to give them the benefit of the doubt until others have looked at them. Moreover, apparently (based on the edit summary) accompanying what the editor views as the justified fact-bombing of the article, he or she demoted the article to "start class". I'm having trouble seeing how that is a correct assessment of the current state of the article (but I don't think it was solidly a B class article either). Sławomir Biały (talk) 18:51, 9 August 2013 (UTC)
- There was indeed a massive reorganization of the article, because there was a lot of redundancy, and it was very poorly organized. The article is a complete mess, and I intend on doing a lot of cleanup, but a first step towards that is laying out a reasonable structure for the article (i.e. not having a "history" section randomly thrown in between the sections Elementary Properties and Solving Polynomial equations; including the applications in calculus/abstract algebra in the section on applications, rather than just randomly thrown about; talking about graphs of polynomial functions in the section on polynomial functions (rather than in two widely separated parts of the article); not having detailed definitions/examples of the concept of "degree" and "coefficients" in two different places, etc.) ... The organization before I came to the article simply made no sense at all. Obviously, the article needs a ton of improvement, but it's impossible for me to do any writing if there is no sensible organization to the article at all. I'm hoping that I can now start adding references, doing cleanup/rewriting, and expanding the article.
- As far as the Template:Cn tags, it is not "spamming" to mark unreferenced content as needing a citation. As I said to D. Lazard on my talk page, WP:V reads:
*verifiability means that people reading and editing the encyclopedia can check that the information comes from a reliable source. Wikipedia does not publish original research. Its content is determined by previously published information rather than the beliefs or experiences of its editors. Even if you're sure something is true, it must be verifiable before you can add it.*... Personally, I am aware that polynomials are closed under addition and multiplication. But a reader who does not already know this would have no idea if it is actually true, or if it is something that some random editor just made up and added into the article. This is why it is crucial for*everything*, even if it is "simple" or "obvious" to be backed by a reliable source. The reason I tagged these things in the article is the same reason WP:V gives, namely:*If you want to request a source for an unsourced statement, you can tag a sentence with the {{ safesubst:#invoke:Unsubst||date=__DATE__ |$B=*

{{#invoke:Category handler|main}}{{#invoke:Category handler|main}}^{[citation needed]}
}}* ... Thus, whenever I used the Template:Cn tag, my intention was to request that somebody take this (correct) information, and find a reliable source that backs it up. In a math textbook, you would never find citations for every basic statement like this, but on Wikipedia it is policy that everything must be backed by a reference to a WP:RS. I'm hoping that the Template:Cn tags will highlight those parts of the article that are not yet referenced, so we can fix that quickly. -- Mesoderm (talk) 19:38, 9 August 2013 (UTC)*

- WP:SCICITE does not require online footnotes for every bit of noncontroversial information in an article. General references normally are sufficient. I'm not averse to footnotes: I think they're a really helpful thing. But it's just wrong to think that policy mandates every bit of basic information requires a footnote. Sławomir Biały (talk) 19:46, 9 August 2013 (UTC)
- As WP:IC says:
*Using inline citations, even for statements that are not absolutely required to have inline citations, helps Wikipedia maintain text–source integrity. Using inline citations allows other people to quickly determine whether the material is verifiable.*... Some of these things, by searching through the references for the article would be verifiable. But to improve the article, we should make it where readers don't have to waste their time searching through the references to try to verify it. We can do that part for them. I won't push this any further, though, and if you want to remove the Template:Cn tags, go ahead, but please don't remove the references I've added along with them (as D. Lazard did). Anyhow, sorry to cause a conflict. I'm really just trying to improve the article, and make it where everything is easily verifiable. -- Mesoderm (talk) 19:57, 9 August 2013 (UTC)- I agree with SB on this; a "letter of the law" interpretation of citation guidelines simply isn't practical much of the time for scientific and mathematical articles, hence the existence of the scientific citation guidelines. We don't need fact by fact cites for a paragraph when it's a summary of a section from a single source. We don't need cite facts that are obvious or common knowledge among people familiar with the subject. Non-scientific articles tend to glean information from many sources so individual cites are more necessary, Keep in mind that the goal is to be able to verify the article, not satisfy some guideline. I think time would be better spend on an article that's unsourced or more obviously undersourced; there are plenty of them. RDBury (talk) 21:07, 9 August 2013 (UTC)

- As WP:IC says:

- WP:SCICITE does not require online footnotes for every bit of noncontroversial information in an article. General references normally are sufficient. I'm not averse to footnotes: I think they're a really helpful thing. But it's just wrong to think that policy mandates every bit of basic information requires a footnote. Sławomir Biały (talk) 19:46, 9 August 2013 (UTC)

Related to the issue of demoting the article Polynomial to start class, I have initiated a a thread at the pump. Sławomir Biały (talk) 21:53, 9 August 2013 (UTC)

- I had a look and yes it does look like citation needed is being overused. WP:V talks about verifiability, not that every single statement should have an individual citation. The citation needed should be put in over statements that are disputed or where there seems a real need otherwise for verification, e.g. for a whole section missing any citation for people to look up. See criterion 2 in WP:GA? for the right level of citations. I had a look at Mesoderm's talk page and they seemed to think that having a German citation was insufficient. That would be rather silly in maths articles and isn't required in general but I have a bit of sympathy in an elementary article like this, we should be trying harder to make them more accessible. Dmcq (talk) 22:12, 9 August 2013 (UTC)
- They do seem to have problems following the guidelines if they marked it as start class because they don't like the references. Have they been pointed at Wikipedia:WikiProject Mathematics/Wikipedia 1.0/Grading scheme? Dmcq (talk) 22:20, 9 August 2013 (UTC)
- I didn't mark it as start class because I "didn't like the references". I marked it as start class because it lacked sufficient inline citations, was very poorly written, and was completely disorganized and incomplete. Nor did I mark "every single statement" with the Template:Cn tag. Nor did I say that German-language sources are insufficient (I am however saying that for 99%+ of the readers of the encyclopedia that it wouldn't be useful at all, and that if usability is a concern, then maybe it would be a good idea to use any of the tens of thousands of freely available English-language sources that exist on the subject) ... Anyhow, I don't feel like wasting any more energy here -- it seems as if the consensus is that inline citations are not needed for math articles, and I won't contest this any longer, so feel free to remove the Template:Cn tags if you prefer. -- Mesoderm (talk) 00:22, 10 August 2013 (UTC)
- It is not the consensus that {{cn}} tags are unneeded for mathematical articles. It
*is*the consensus that {{cn}} tags are not needed for every fact, in accordance with WP:SCICITE. Look at, for example, normal distribution, which has inline citations for some facts, general references for some of the rest, and {{cn}} tags for some facts that need citations. Ozob (talk) 03:35, 10 August 2013 (UTC)- Exactly and what I tried to point out by pointing to two other guidelines about citations. And about the start class there are fairly clear requirements for the various levels and C would be the appropriate one for those concerns, not start class. A citation is definitely needed in a section about polynomial properties so people can do further reading, but is one really needed on the individual properties like that the sum of two polynomials is a polynomial? Is that really 'material challenged or likely to be challenged'? Dmcq (talk) 07:14, 10 August 2013 (UTC)
- The user in question has agreed that he is not challenging the correctness of that assertion [7], but does not accept that it is adequately supported by the general references [8]. Spectral sequence (talk) 08:23, 10 August 2013 (UTC)
- They need a better imagination if they think a person who has read past the lead would want a citation on the sentence. Any citation needed where one doesn't personally feel a citation is needed should have a reason supplied why one is sticking it in. A general reference for the section is better for things like that. Dmcq (talk) 14:07, 10 August 2013 (UTC)

- The user in question has agreed that he is not challenging the correctness of that assertion [7], but does not accept that it is adequately supported by the general references [8]. Spectral sequence (talk) 08:23, 10 August 2013 (UTC)

- Exactly and what I tried to point out by pointing to two other guidelines about citations. And about the start class there are fairly clear requirements for the various levels and C would be the appropriate one for those concerns, not start class. A citation is definitely needed in a section about polynomial properties so people can do further reading, but is one really needed on the individual properties like that the sum of two polynomials is a polynomial? Is that really 'material challenged or likely to be challenged'? Dmcq (talk) 07:14, 10 August 2013 (UTC)

- It is not the consensus that {{cn}} tags are unneeded for mathematical articles. It

- I didn't mark it as start class because I "didn't like the references". I marked it as start class because it lacked sufficient inline citations, was very poorly written, and was completely disorganized and incomplete. Nor did I mark "every single statement" with the Template:Cn tag. Nor did I say that German-language sources are insufficient (I am however saying that for 99%+ of the readers of the encyclopedia that it wouldn't be useful at all, and that if usability is a concern, then maybe it would be a good idea to use any of the tens of thousands of freely available English-language sources that exist on the subject) ... Anyhow, I don't feel like wasting any more energy here -- it seems as if the consensus is that inline citations are not needed for math articles, and I won't contest this any longer, so feel free to remove the Template:Cn tags if you prefer. -- Mesoderm (talk) 00:22, 10 August 2013 (UTC)

## Khan Academy videos

Hi all

I have been talking to someone at the Khan Academy about changing the license of their content, I think the videos they produce are a very useful resource and would be very welcome on Wikiversity etc, but are they suitable to add to Wikipedia articles?

There are a high volume of people coming to Wikipedia mathematics articles, I would guess that a significant chunk of these readers are like me people without much mathematical knowledge, I would certainly find them useful on articles. Any comments welcome.

--Mrjohncummings (talk) 11:26, 12 August 2013 (UTC)

- Where you know of a
*relevant*Khan video, it should be added to the "External links" section of an article. However, some people or bots may be inclined to revert you in the mistaken belief that the video may be a violation of copyright. So you may have to defend it by re-reverting and arguing on the talk page. As long as you are merely providing a link to something which is not itself violating copyright, there is no requirement in our rules that the thing linked have any specific type of license (such as GFDL or CC-BY-SA). So the Khan Academy should not have to change anything. JRSpriggs (talk) 12:12, 12 August 2013 (UTC)

- It's fine to have these in external links in most cases, but these can't be used as sources for articles. Also, in cases where Khan disagrees with reliable sources, I would oppose linking to the videos. Sławomir Biały (talk) 17:50, 12 August 2013 (UTC)

Thanks, I have tried to this before and been reverted, I don't have the time to argue them all individually. The main reason for me pushing for them to release things under a Wikipedia compatible license is I'm making an assumption many people give up before going to the external links section so it would be good to have them in the articles. --Mrjohncummings (talk) 13:53, 12 August 2013 (UTC)

- The external links section is where they would go. Even assuming it was legal, the Khan Academy videos are in the form of a lecture or tutorial, not an encyclopedia article, so I 'm not sure that incorporating them into WP would be appropriate. Plus, the videos cover mainly elementary subjects that where we generally already have good material. Another issue is whether the videos meet WP's reliable source criteria. It's tempting to say of course, but on the other hand there was an article (Fractal fractions) created based on a Vi Hart video which was actually a hoax.--RDBury (talk) 17:45, 12 August 2013 (UTC)

- I would recommend creating {{Khan Academy}} to link to KA material. Such external link templates are much less likely to be reverted than plain external links in my experience. —
*Ruud*17:42, 12 August 2013 (UTC)

## Chebyshev integral

Chebyshev integral is a new article. Initially no other articles linked to it. I put a link in the "See also" section of the article on Pafnuty Chebyshev. So if anyone knows of other articles that should link to it, could they add those. Michael Hardy (talk) 16:12, 12 August 2013 (UTC)

- Isn't this a synonym the incomplete beta function? Also, the name might be confusing as there is a Chebyshev integration formula that isn't related.--RDBury (talk) 17:20, 12 August 2013 (UTC)

## Foias constant

Foias constant is a new article. Currently only one article links to it. More such links are probably appropriate. Michael Hardy (talk) 16:56, 12 August 2013 (UTC)

- This is mentioned in the Mathematical constant article, so we have two links now. If we had an article on Grossman's Constant, it would be linked from and to there, as well. --Mark viking (talk) 17:30, 12 August 2013 (UTC)

## Minimum polynomials

Template:User-multi has written a new French article fr:Polynôme minimal des valeurs spéciales trigonométriques relating to the MathWorld page Trigonometry angles, and says the subject is not covered here. Maybe it should be? —David Eppstein (talk) 04:25, 14 August 2013 (UTC)

- Minimal polynomial (field theory) seems to cover the abstract concept of a minimal polynomial, but doesn't have anything related to the special algebraic numbers deriving from constructible angles. --Mark viking (talk) 05:04, 14 August 2013 (UTC)
- The French article was partially erroneous by confusing between "expressing with radicals" and "expressing with square roots" (I have corrected this). Otherwise, the subject is essentially covered by the union of roots of unity (as the values that are considered are simple expressions of the roots of unity) and Constructible polygon. D.Lazard (talk) 11:32, 14 August 2013 (UTC)
- Thank you for having forwarded here, David, I shall bookmark this page.
- Thank you for the correction about this confusion, D.Lazard.
- @Mark : these minimum polynomials also apply to non-constructible angles rationally commensurate with pi, e.g. 2 pi / 7.
- I disagree that the subject is covered by those two articles. The minimum polynomials of roots of unity are associated to the complex values e^(2 i k pi / n), while Mathworld's article focuses on the minimum polynomials associated to trigonometric values of form cos(k pi / n), sin(k pi / n) and tan(k pi / n), and deriving the latters from the formers is anything but obvious (to get convinced of that, it is enough to see how this is misanswered on every math forum on the web). Also, the French article goes a bit further than Mathworld's page, since it explains a practical method to compute these minimal polynomials. --MathsPoetry (talk) 11:42, 14 August 2013 (UTC)

- The French article was partially erroneous by confusing between "expressing with radicals" and "expressing with square roots" (I have corrected this). Otherwise, the subject is essentially covered by the union of roots of unity (as the values that are considered are simple expressions of the roots of unity) and Constructible polygon. D.Lazard (talk) 11:32, 14 August 2013 (UTC)

## Wikipedia talk:Articles for creation/Fractional Differential Equation

Dear mathematicians: The following article was submitted last year at Afc, declined as being too short and perhaps needing merging into another topic. The editor improved it somewhat, but never resubmitted. Is there any useful content here that should either be its own article or included in another article? It will probably be deleted soon as a stale draft unless someone takes it on. —Anne Delong (talk) 18:57, 14 August 2013 (UTC)

- Hi Anne, the article Fractional-order system has some of the very basics of fractional differential equations. One could argue that fractional differential equations and fractional-order systems are different topics (the basic math vs application to fractional dynamical systems), but I don't think there is enough material at the moment in either article to justify a split. Looking through the article, we could possibly add the first two references to the Fractional-order system article. Thanks, --Mark viking (talk) 19:20, 14 August 2013 (UTC)

## Prime gap

It would appear from [9] that #117 on this year’s GISHWHES is “Narrow the prime gap to 47”, and as a result, we’ve already had two people messing with the Prime gap article today. I wonder whether it would help to protect the article, I’m sure the amazing global creative community can do better than this.—Emil J. 14:50, 14 August 2013 (UTC)

- On the bright side, they seem to be cleaning up after themselves (once absolutely correctly, the other left a stray space). If this was the worst result of people trying to change Wikipedia for their own purposes, the Vandalism squad could retire. Having said that, temporary protection might be reasonable.Naraht (talk) 17:11, 14 August 2013 (UTC)

## Should saturated model be a disambig page?

For the second time, there's been a kerfuffle triggered by someone who was looking for a different concept of *saturated model* from the one I'm familiar with. This other concept, which I don't really know anything about, is apparently treated at the structural equation modeling page. That article is hatnoted at the top of the saturated model article, but this apparently was insufficient.

I'm not really in a position to say whether one of these is the "primary topic" for the search term; the only one I knew about was the model-theory one. Any thoughts? --Trovatore (talk) 19:01, 15 August 2013 (UTC)

- It's
*mentioned*in structural equation modeling, but not defined. Of course, I only know of the model-theory use, but we don't really have anything on the structural engineering use. The hat note is misleading. — Arthur Rubin (talk) 19:20, 15 August 2013 (UTC)- Google Scholar hits actually have a clear majority for the statistics use. I suspect we
*should*have an article on this, or at least a better redirect target. Does anyone here know anything about this topic? Michael Hardy maybe? --Trovatore (talk) 19:46, 15 August 2013 (UTC)

- Google Scholar hits actually have a clear majority for the statistics use. I suspect we

- In structural equation modeling, one evaluates the fit and explanatory quality of of alternatively structured statistical models, where structure in this case mean constraints on means or covariances. Then the best model becomes a tradeoff between parsimony and variance explained. In this context, a
*saturated model*is one in which there are no constraints on means or variances, so the degrees of freedom and variance explained are saturated. Saturated models are often used as a baseline model against which to compare more parsimonious models. I don't have a good citation ref for this, but general explanations, such as in [10] are fairly easy to find. I don't think the concept warrants its own page, but it could be better explained in the structural equation modeling article, to make the hatnote more relevant. --Mark viking (talk) 20:12, 15 August 2013 (UTC)

- In structural equation modeling, one evaluates the fit and explanatory quality of of alternatively structured statistical models, where structure in this case mean constraints on means or covariances. Then the best model becomes a tradeoff between parsimony and variance explained. In this context, a

## Difference quotient

The article titled Difference quotient somehow appeared on our Current Activities page although it's not new. It needs a lot of cleanup just as far as copy-editing is concern. As for content, I haven't attempted to think about that yet, beyond some obvious things such as a rather awkward intro. Michael Hardy (talk) 17:12, 4 August 2013 (UTC)

- I would favor seeing the article shortened up quite a bit. In my humble opinion, I see divided differences as a convenient notation (and method!) for describing higher derivatives in a finite difference stencil, and I don't see the point of describing "infinitesimal" difference quotients. I'm leery of deleting content, but I could have a go at the introduction and take a pass at rewriting the article. MathRocks2012 (talk) 19:14, 12 August 2013 (UTC)

- In Precalculus and perhaps Calculus in the U.S., difference quotients are often introduced, and limits separately, and then the derivative is defined as the infinitesimal limit of a difference quotient. ᛭ LokiClock (talk) 10:18, 17 August 2013 (UTC)

## Topic Progression Rules

To Whom this may concern. I have a personal interest in mathematics and 3 kids I am trying to teach. All, and I mean all, of the math pages are ridiculously difficult to read. I mean seriously you can not use mathematical expressions to teach or even communicate a mathematical expression until the expression is understood otherwise it wont add up for the reader. I thought the point of Wiki was to be an collaborative source of information not a post for subject elitism and snobbery. I can't express enough how frustrating it is to go to Wiki pages just to be blown away, baffled and utterly perplexity when all I'm looking for is a simple explanations in plain language about a term in a progressive way so I can gain an understanding. But when I get to Wiki I get slapped in the face and I feel like a complete moron because I immediately greeted with the most complex possible definition ever conceived! In other word I go to Wiki to learn or get a definition because I don't know, If I already knew then I wouldn't have to go to Wiki. So then it hit me, I can suggest Topic Progression Rules. So when a terms or words like "math theory", physics, quantum mechanics, chemistry etc. are looked up the pages would have Topic Progression Rules. The Topic progression rules could be something like. Fist progression: Discussion - which must explain in simple language the meaning of the term. Where simple language equals relevant examples and a postulation of the use of the term in meaningful ways. For example; currently the page of the term "one" starts off with: 1 (one; /ˈwʌn/ or UK /ˈwɒn/) is a number, a numeral, and the name of the glyph representing that number. It represents a single entity, the unit of counting or measurement. For example, a line segment of "unit length" is a line segment of length 1. Under the Topic Progression Rules idea; the "one" page would start with something like. One is the first whole number after zero and is used as a unit of measure so objects in the real world can be counted. For example; If you have 1 apple and 1 banana you have 2 pieces of fruit. One has many other uses and definitions in math and is an important part of all mathematics. So you see, the first progression of the term is for the less educated or informed members of our society and acts to stimulate interest and inform at the simplest level. Second Progression: Definition - must provide definition in progressive and specific terms before delving into abstract terms that rely on the acute knowledge of the reader for a given term. I think currently definitions of are not progressive or specific and rely on infinite abstract reference (links) to equally abstract reference. Just try to find a progressive and meaning full definition for Diophantine geometry. Third progression: historic - must provide progressive historic context or reference to historic context. For math; I think the historic context should have a rule to tell the story of the people and their challenges in simple terms that inspire and inform not in terms of re-expressions of expressions that do little to provide historic context. For example; Number theory doesn't really talk about Number Theory in progressive meaningful ways but waxes fantastic about a hodgepodge of loosely connected number theories and dates. In effect the whole Number Theory page is nothing more than an index of theories with little meaning that doesn't inform or inspire readership. The fourth progression would be everything else without progression rules e.g. the advanced reader space. — Preceding unsigned comment added by WikiiJoesky33 (talk • contribs) 08:45, 16 August 2013 (UTC)

- Some of what you suggest are clarifications or expansions of the existing text that you are welcome to add. But when it comes to progressive definitions there are limits for which you can learn the boundaries of through the edit/revert process. In particular, articles with a historical structure are not going to be converted to a didactic structure, and likely have a historical structure because there's change in meaning to document over time. You should not rely on encyclopedias for learning to do math. You would be a lot less troubled if you were to use Khan Academy or the Mathematics Stack Exchange. And for the level of study you're talking about - fractions, number lines, counting - elementary school teachers and their equivalents in other countries are endlessly innovative, and there are websites made to provide just the kind of strategies and explanations you're looking for. You can only expect to use an encyclopedia to learn what math there is, and to that end part of the education it provides is exposure to the terms the field actually use to describe something. On the other hand, people not in the field do not represent their interest in the articles by editing them, and while it seems obvious to you that most everyone will know what you're talking about if you change, "One is the first non-zero number in the natural numbers," to "One is the first non-zero number in the natural numbers
*or whole numbers*," I haven't thought of the words "whole number" in the last 8 years, and I could probably be avoiding some communication barriers if I was reminded of multiple terms through their population about basic articles. ᛭ LokiClock (talk) 10:06, 17 August 2013 (UTC)

- Your complaints are legitimate and your suggestions are reasonable. In fact, such complaints about the opacity of Wikipedia mathematics articles are so common that we have a FAQ at the top of this very talk page to address them. Also, Wikipedia:Manual of Style/Mathematics already requires historical context, motivations for concepts, etc.
- So why are Wikipedia math articles so "bad"? First, as LokiClock alluded to, Wikipedia:Wikipedia is not a textbook, but rather a reference work. Second, Wikipedia is a work in progress, made entirely by volunteer labor. It may not progress as quickly as you like, partly because of the need to build consensus around major (and sometimes even minor) changes. The introductions to articles, which is your first concern, tend to be especially contentious. It is not easy to balance accessibility and motivation (your priorities) with mathematical correctness (which a reference work must also prioritize). Simply put, writing a good encyclopedia is not easy. :) Mgnbar (talk) 19:40, 17 August 2013 (UTC)

## Article on "conjugation"

Is the use of the term "conjugation" to mean the sandwich product *qrq*^{−1} in ring theory notable? (Compare the closely related concept Conjugation (group theory).) It does not appear in the DAB page Conjugation, nor in Glossary of ring theory. If notable, it deserves a section and redirect, or an article; if not, its use in several articles should be edited. See also Inner automorphism#Ring case (the lead mentions the term *conjugation*). — *Quondum* 12:53, 16 August 2013 (UTC)

## Valid Routine Calculations and Summarizations at Wikipedia

To solve disputes into discussions about "what is valid" and "what is not" at Wikipedia, in "translation by Mathematics" and "synthesis of numerical data", we are building an essay: **Wikipedia:About Valid Routine Calculations**.

It is under construction and need some help (!) --Krauss (talk) 01:53, 18 August 2013 (UTC)

You can colaborate:

- checking consensus about rules and recommendations;
- editing bad text and bad english;
- complementing topics;
- indicating links of old conclusions and discusstions (we are consolidating all);
- commenting, etc. at the talk page.

## Mathematics in VE

I have asked User:Whatamidoing (WMF) about the plans for mathematics under VE. I will quote her reply:

- Last I heard (which might have been two weeks ago now), there were some general ideas about the likely path but nothing set in stone, and someone (one of the volunteer devs?) had started work on the early versions. This would be a good time to hear about needs, preferences, and ideas. [11] The (very early and definitely experimental) math stuff is actually up at Mediawiki at the moment. If you want to take a look, go there (if SUL's set up for you, then your account/password are the same) and edit the Sandbox in VisualEditor ("Edit"). The center-right of the top toolbar will show an icon "Σ" (images, refs, reflist, templates, math as you read across). (Click in the test area first, if you're in the main sandbox.) Please let me know what you think of this beginning stage. [12]

Other Project members might be interested in contributing their thoughts. Spectral sequence (talk) 06:38, 3 August 2013 (UTC)

- I'm happy with the sigma button at MediaWiki. I feel Wikisyntax allowed people to get over code anxiety and that that encouraged more people to gain basic knowledge of LaTeX, but on the other hand this brings the LaTeX more readily into the basic editor's path by making it look like all the safe buttons that don't make code appear for you to edit. ᛭ LokiClock (talk) 08:23, 3 August 2013 (UTC)
- The person writing the math extension is mw:User:Jiabao wu. Probably the best way to provide your opinions or encouragement is to speak directly to this developer at Mediawiki (for most of you, your English Wikipedia account/password should work there via WP:Unified login). I suggest either the user talk page or the talk page for the project itself, which you can read about at mw:User:Jiabao wu/GSoC 2013 Project Work. There is Template:Bug, but most of you don't have Bugzilla accounts, and it might be awkward to carry on long conversations there anyway. Whatamidoing (WMF) (talk) 20:56, 4 August 2013 (UTC)

In related news, project members might like to look at Wikipedia_talk:Flow#Mathematics_under_Flow where it transpires that Flow will replace talk pages, VE will be mandatory for Flow, and there is no guarantee that mathematics editing will be possible when Flow is implemented. Spectral sequence (talk) 07:06, 10 August 2013 (UTC)

- VisualEditor will
**not**be mandatory for Flow. (Think about it: approximately 20% of users are*unable*to use VisualEditor due to their web browsers. Do you really think that the WMF would put out a talk-page system that would prevent 20% of users from replying to messages on their user-talk pages?) Whatamidoing (WMF) (talk) 15:32, 11 August 2013 (UTC)- If I am wrong then I welcome corrections. Indeed, an authoritative statement from a representative of WMF on the subject of mathematics editing under Flow would be very welcome.
__Please__engage with the community by telling us your plans for mathematics. Spectral sequence (talk) 15:54, 11 August 2013 (UTC)- The exact details are unknown at this time.
- Flow is
*expected*to fully support VisualEditor's capabilities. Therefore, whatever you are (eventually) able to do in VisualEditor, you will (eventually) be able to do in Flow. Flow is not*expected*to support a small subset of*broken*wikitext configurations (most importantly, templates that produce half of an HTML tag pair). I don't have any reason to believe that math editing will be affected by this, because math doesn't seem like the kind of wikitext that produces unstable or illegal HTML. - But at this point in time, Flow is still in the vaporware stage. Between now and December, you should not completely believe any promises given to you about its features, unless those promises are about a deliberate refusal to write code for some feature. (To date, I am aware of exactly one such refusal having been made, and it has nothing to do with math.) Creating new software at this scale is inherently an uncertain process. What will be supported in the early days, the exact methods that will be supported, and what it will look like are all things that will not be known with any certainty until late in the game. Whatamidoing (WMF) (talk) 16:12, 11 August 2013 (UTC)
- Thank you for that. By what means would you like the mathematics editing community to engage with the design and coding process — I assume that you will wish to make use of their specialised experience and expertise in this area, as well as taking into account any partocular requirement they may have? Spectral sequence (talk) 16:19, 11 August 2013 (UTC)
- The most important contribution would be talking directly to Jiabao Wu about supporting math markup in VisualEditor, by leaving a message at the Mediawiki pages given linked above. Whatamidoing (WMF) (talk) 22:19, 11 August 2013 (UTC)
- It turns out that there is a proposal that Flow should store discussions as HTML5+RDFa: indeed this has been stated by WMF staffers as if it were definite [13] [14], but it turns out it is a "strong leaning" not a decision [15]. If implemented that way, it would mean that mathematics markup could not be stored and would have to be relegated to a separate "scratchpad" [16]. Project members may wish to comment on that at Wikipedia talk:Flow. It appears to be a different issue to the one being discussed at the Mediawiki page mentioned above. Spectral sequence (talk) 15:56, 17 August 2013 (UTC)
- There is a relevant discussion at mw:Thread:Talk:Flow_Portal/Maths where Jorm (WMF) has stated "I cannot promise that there will be mathematics markeup in normal discussion comments. I can promise that there will be collaborative authoring areas in Topics that will accept and store mathematics output." Spectral sequence (talk) 21:21, 18 August 2013 (UTC)

- It turns out that there is a proposal that Flow should store discussions as HTML5+RDFa: indeed this has been stated by WMF staffers as if it were definite [13] [14], but it turns out it is a "strong leaning" not a decision [15]. If implemented that way, it would mean that mathematics markup could not be stored and would have to be relegated to a separate "scratchpad" [16]. Project members may wish to comment on that at Wikipedia talk:Flow. It appears to be a different issue to the one being discussed at the Mediawiki page mentioned above. Spectral sequence (talk) 15:56, 17 August 2013 (UTC)

- The most important contribution would be talking directly to Jiabao Wu about supporting math markup in VisualEditor, by leaving a message at the Mediawiki pages given linked above. Whatamidoing (WMF) (talk) 22:19, 11 August 2013 (UTC)

- Thank you for that. By what means would you like the mathematics editing community to engage with the design and coding process — I assume that you will wish to make use of their specialised experience and expertise in this area, as well as taking into account any partocular requirement they may have? Spectral sequence (talk) 16:19, 11 August 2013 (UTC)

- If I am wrong then I welcome corrections. Indeed, an authoritative statement from a representative of WMF on the subject of mathematics editing under Flow would be very welcome.

## Mental abacus

See Abacus system and Wikipedia:Articles_for_deletion/Abacus_system. Michael Hardy (talk) 23:00, 18 August 2013 (UTC)

## Is it time for mathematicians to leave Wikipedia?

In recent days, I have been putting some effort into trying to find out what the Wikimedia Foundation (WMF) is proposing in the way of new software for editors. It isn't easy, since the WMF adhere to a form of "Agile" development which appears to encourage putting very early versions of the software out to users. However, this is, I think, a summary as far as it affects mathematics contributors. My description may be inaccurate, and WMF plans are not all settled. I have reported some of my findings above, at Wikipedia talk:WikiProject Mathematics#Mathematics in VE

There will be a new editor, Visual Editor (VE), with a point-and-click interface. This will require a lot of work to get it to deliver the functions currently delivered by the many templates used to support current editing practices. Mathematics support for VE is not planned to be an early part of the software and is currently being worked on as a student project. We have been assured that the traditional source editor will always remain as an option for articles.

Talk pages will be completely replaced by Flow, which will look more like a bulletin board, and will structure the discussions much more tightly. VE will be the default editor, but something like the traditional source editor will be available, though of limited functionality compared to the traditional source editor. Flow may well store discussions entirely as HTML, and if that decision is taken then non-HTML elements such as mathematics will be stored separately in some kind of "scratchpad".

It seems to me that we, as mathematics contributors, have choices to make.

- We can spend time and energy trying to engage with the WMF design processes (which the community at large has not always found editor-friendly) and if we do, the end result may well be something nearly as convenient as we have today; if the engagement does not pay off, it may be significantly less convenient; it does not seem likely that either new system will be significantly better as regards mathematics.
- We can decline to engage and let the design proceed with little or no regard to the specific requirements of mathematics and mathematicians: if we do this, the end result is very likely to be significantly less convenient than what we have now.
- We can wait for a year or so, until the new software is in place, and at that time we can decide whether or not we can work with it, and if not, we will have no option but to leave.
- We can take a view about the likely outcome of the design process and leave now.

Which is it to be? Spectral sequence (talk) 16:23, 17 August 2013 (UTC)

- First, thank you (and Arthur Rubin, too) for being an advocate for maintaining mathematical editing capabilities in the ongoing/upcoming transition of the WP editing interface. It can be a challenge to get essential requirements across in a distributed, somewhat bureaucratic WP software development model. But I am more sanguine about this problem than you are. It is early days for Flow--a project manager just signed onto the project--and the project is planned to be run in an agile manner. Agile development is all about releasing early and often and modifying software according to customer feedback. That means that definite and sometimes wrong decisions are made in early versions of the software to give folks something concrete to complain about. But such decisions are not set in stone and we should be able to guide them on the path to full math editing capabilities in both articles and their talk pages. Flow is some tentative scratches on a blackboard right now, not a published paper. Despite the frustration brought about this issue, I hope you'll stay on at WP. --Mark viking (talk) 20:51, 17 August 2013 (UTC)
- Thanks for that, but it really isn't about me individually, it's about each and every one of us who contributes mathematics. The description you give of the WMF interpretation of Agile is depressing but I fear it may be quite accurate — that we can look forward to months of spending our time watching out for those wrong decisions for us to complain about. If we all decide to do that then it may work, assuming that WMF engage effectively with us as a community, and even then it may not. So this is about getting each of us to make a decision on whether to invest that time and effort or not: but it is clear we are at a decision point right now. Spectral sequence (talk) 21:21, 17 August 2013 (UTC)
- Mark's description of agile programming seems pretty accurate to me, although I'm not an expert. I disagree that it means months of your time spent watching for anything, though, and I also disagree that you need to make a decision today about how to react to software that will definitely not be available (even in the very earliest, most limited forms) for the next couple of months. Whatamidoing (WMF) (talk) 00:33, 18 August 2013 (UTC)
- WMF is developing an environment that we as mathematics editors will use. That environment is being designed right now, decisions are being made right now, and if those decisions are made without input from mathematicians, then it is possible, even probable, that the result will be less than effective for mathematics. Can you promise that WMF developers will notify mathematics editors proactively of every decisions that might have implications for mathematics — no, of course not. Developers do not have the time or expertise to pursue the implications of all those decisions across all specialist communities, nor do we expect them to. (As an example, no-one appears to have explicitly raised the implications of Flow storing in HTML5+RDFa until I did.) So if WMF is not going to do that, then we will have to: in other words, we have to track those decisions and intervene if they are likely to have an unforeseen but possibly detrimental effect on the way mathematics editors work, something about which we have a lot of collective experience. We need to make a decision right now about whether that effort, which appears likely to be considerable, is worth investing. Can Whatamidoing (WMF) say
*why*she thinks we do not need to involve ourselves over the coming months in contributing constructively to the design process? Of course we do not need to decide now how to react to software which has hardly been designed now — that would be impossible, and that is not what I suggested. Spectral sequence (talk) 06:42, 18 August 2013 (UTC)- You said Template:Xt That certainly sounds like you believe that it is necessary to decide now how to react to that planned change right now. Whatamidoing (WMF) (talk) 17:38, 19 August 2013 (UTC)
- Exactly: a decision about whether and how to engage with the design proposals. Do you disagree with that? Spectral sequence (talk) 18:14, 19 August 2013 (UTC)

- You said Template:Xt That certainly sounds like you believe that it is necessary to decide now how to react to that planned change right now. Whatamidoing (WMF) (talk) 17:38, 19 August 2013 (UTC)

- WMF is developing an environment that we as mathematics editors will use. That environment is being designed right now, decisions are being made right now, and if those decisions are made without input from mathematicians, then it is possible, even probable, that the result will be less than effective for mathematics. Can you promise that WMF developers will notify mathematics editors proactively of every decisions that might have implications for mathematics — no, of course not. Developers do not have the time or expertise to pursue the implications of all those decisions across all specialist communities, nor do we expect them to. (As an example, no-one appears to have explicitly raised the implications of Flow storing in HTML5+RDFa until I did.) So if WMF is not going to do that, then we will have to: in other words, we have to track those decisions and intervene if they are likely to have an unforeseen but possibly detrimental effect on the way mathematics editors work, something about which we have a lot of collective experience. We need to make a decision right now about whether that effort, which appears likely to be considerable, is worth investing. Can Whatamidoing (WMF) say

- Mark's description of agile programming seems pretty accurate to me, although I'm not an expert. I disagree that it means months of your time spent watching for anything, though, and I also disagree that you need to make a decision today about how to react to software that will definitely not be available (even in the very earliest, most limited forms) for the next couple of months. Whatamidoing (WMF) (talk) 00:33, 18 August 2013 (UTC)

- Thanks for that, but it really isn't about me individually, it's about each and every one of us who contributes mathematics. The description you give of the WMF interpretation of Agile is depressing but I fear it may be quite accurate — that we can look forward to months of spending our time watching out for those wrong decisions for us to complain about. If we all decide to do that then it may work, assuming that WMF engage effectively with us as a community, and even then it may not. So this is about getting each of us to make a decision on whether to invest that time and effort or not: but it is clear we are at a decision point right now. Spectral sequence (talk) 21:21, 17 August 2013 (UTC)
- Regardless of if they manage to make math support work, I will leave if the text editor with WikiSyntax disappears, becomes hard to use, or is no longer available while logged out. The code is there in the first place because everything that Wikipedia needs has to be built by some user. Where an abstraction ends, the capabilities end, and if there's a way to abstract an interface to every permutation of the code, they haven't found it yet. Even programs like PureData dedicated solely to the effort of creating a visual interface for programming require module contributions in the source language. It's also unlikely they're going to implement a real visual coding environment, like the diagrammatic languages for monoidal categories, which is what's necessary to replicate a coding environment's complexity. But until the apocalypse comes, there's nothing to worry about. If there are discussions with designers that math editors should be a part of, links would be appreciated. ᛭ LokiClock (talk) 22:01, 17 August 2013 (UTC)
- I don't think that losing access to code is something that you need to worry about happening. Last I checked, what Spectral describes above as a "point and click interface" looked like "click on the math icon, and then type raw LaTeX code in the box". It might be nice to have a simple little interface for simple purposes, but it looks like LaTeX is being used as the basis for all math work in VisualEditor. Whatamidoing (WMF) (talk) 00:33, 18 August 2013 (UTC)
- "I don't think that losing access to code is something that you need to worry about happening.". Firstly, under Flow it is very definitely something we do need to worry about. There is a proposal (described as a decision [17], but actually not [18]) that Flow will store data for discussions boards in HTML5+RDFa. That means that mathematics markup is not going to be stored as an integral part of the discussion. Various proposals have been made for how Flow might handle mathematics (in scratchpads for example), but we will need to worry about it in the absence of a commitment to provide it and clear design decision which reflects the reality of the way we work — frankly it looks as if nobody had explicitly addressed the format point until I raised it. Secondly, under VE what we have right now is a partially complete GSoC project that currently allows us to enter LaTeX markup, but so far does not allow us to edit it. In that sense there is currently no demonstrated access to the source code. Again, until it's demonstrated, it is very natural to worry about it. It would be really helpful for Whatamidoing (WMF) to explain the grounds for her optimism. Spectral sequence (talk) 11:57, 18 August 2013 (UTC)
- My grounds for optimism are basically having more experience with Wikipedia than you do. I've been around for seven years or so, compared to your one year. Problems routinely appear in early versions, and they just as routinely get fixed. People regularly make assertions that something is going to be completely disastrous (like your assertion that HTML5 is incompatible with math, but NB that it happens on policy and guideline pages even more often than in software development discussions), and almost every time, it turns out that these assertions are either wrong or that the problems can be addressed in other ways.
- I think you also have a very different idea of "decision". In the WMF's programming style, "decision" is more like "trying something out to see if it works". If it doesn't work, then they try something else, until they find something that does work. Whatamidoing (WMF) (talk) 17:38, 19 August 2013 (UTC)
- If this represents the WMF's views of editors who are trying to engage constructively with their design processes, then I think it answers the question at the head of this thread. Spectral sequence (talk) 18:27, 19 August 2013 (UTC)
- Update: it does [19]. Spectral sequence (talk) 05:50, 20 August 2013 (UTC)
- The "I regret, more than you know, that we can't deliver to every community member everything that they want." comment is very telling, especially when what we want is primarily the ability to continue including technical notation (in our case mathematics but the same issues exist for other subjects) in an encyclopedia. Getting rid of the encyclopedic parts of the encyclopedia may indeed make it easier to edit, which they seem to see as their only goal. —David Eppstein (talk) 05:55, 20 August 2013 (UTC)

- "I don't think that losing access to code is something that you need to worry about happening.". Firstly, under Flow it is very definitely something we do need to worry about. There is a proposal (described as a decision [17], but actually not [18]) that Flow will store data for discussions boards in HTML5+RDFa. That means that mathematics markup is not going to be stored as an integral part of the discussion. Various proposals have been made for how Flow might handle mathematics (in scratchpads for example), but we will need to worry about it in the absence of a commitment to provide it and clear design decision which reflects the reality of the way we work — frankly it looks as if nobody had explicitly addressed the format point until I raised it. Secondly, under VE what we have right now is a partially complete GSoC project that currently allows us to enter LaTeX markup, but so far does not allow us to edit it. In that sense there is currently no demonstrated access to the source code. Again, until it's demonstrated, it is very natural to worry about it. It would be really helpful for Whatamidoing (WMF) to explain the grounds for her optimism. Spectral sequence (talk) 11:57, 18 August 2013 (UTC)

- I don't think that losing access to code is something that you need to worry about happening. Last I checked, what Spectral describes above as a "point and click interface" looked like "click on the math icon, and then type raw LaTeX code in the box". It might be nice to have a simple little interface for simple purposes, but it looks like LaTeX is being used as the basis for all math work in VisualEditor. Whatamidoing (WMF) (talk) 00:33, 18 August 2013 (UTC)

Why are these changes being presented as a fait accompli anyway? The purpose of the WMF is to raise money to keep the encyclopedia and other projects running. The tail is wagging the dog: there is simply no demand for this software among the users. I would be willing to sign a petition that if flow is released, then I will leave the project for good if that's what it takes for the WMF to come to its senses. Sławomir Biały (talk) 13:10, 18 August 2013 (UTC)

- I personally believe that a GoodBye petition would be a waste of your time. However, it might be interesting to you to read the substantial research they've done on what new and experienced editors are demanding. That research is driving Flow. Whatamidoing (WMF) (talk) 17:38, 19 August 2013 (UTC)
- Surely you are not referring to mw:Flow Portal/Research as "substantial research", so I wonder what it was you wanted me to read. Sławomir Biały (talk) 18:49, 19 August 2013 (UTC)
- Without wikitext being available in Flow, it will become essentially impossible to discuss any seriously technical topic, since doing so will require cutting-and-pasting wikitext into talk. If the WMF does this, this will be the Visual Editor debacle all over again -- removing core functionality for no good reason without providing something demonstrably superior, all for the sake of hitting management-driven targets based on unproven assumptions that doing so will somehow bring about an Underpants Gnomes-type miracle that will do more good than harm. For some reason, burning the bridges to prevent retreat was apparently thought of as being a good idea. The goal of the WMF is to further the encyclopedia, not vice versa. -- The Anome (talk) 18:49, 18 August 2013 (UTC)
**Wikitext will be available in Flow**. It*probably*will not, however, support wikitext that produces malformed HTML (like broken templates). That's why they're talking about providing alternatives like scratchpads (think post-it notes stuck onto your message, and using only classic, full, unlimited wikitext, that works—or in a few instances fails to work—exactly like it did last year). Whatamidoing (WMF) (talk) 17:38, 19 August 2013 (UTC)- Do you mean,
*any*template call will be available except those rendering into bad HTML? Can you give a link to a discussion or a mail list where this decision is formulated? And how will it be stored: as a template call or as an HTML code? Incnis Mrsi (talk) 17:55, 19 August 2013 (UTC)- I don't believe that anyone knows the answer to your question. Really: the product manager got the assignment
*a couple of days ago*. The specifications documents have not been written yet. Nothing is carved in stone, or even inscribed in wet sand, at this stage. As I've tried to communicate to Spectral, if you want to talk about specific details like this, then you really are going to have to wait a while. Realistically, you may well have to wait several months before you will get a reliable answer to questions about templates and non-VE-based math editing. (For VE-based math editing, Jorm has said that whatever VisualEditor gives Flow will be accepted.) - I realize that this is frustrating: you want to know exactly what will happen, and you want to know it now. Perhaps, as Johnuniq said elsewhere, telling people about Flow really was a mistake. Of course, in the past, when people are told about a project later in the development cycle, at a point when questions like these can usefully be answered, then they complain that they weren't dropped into the middle of the confusing and uncertain early design process. I would be interested in your opinion on whether people really would prefer the "surprise product" approach to the "months of significant uncertainty" approach. Whatamidoing (WMF) (talk) 18:32, 19 August 2013 (UTC)
- My question was addressed to all people with some considerations about the problem, not specifically to WMF’s spokespersons. And your job is to help with communications, by the way, not to guess why one is frustrated. Incnis Mrsi (talk) 16:28, 21 August 2013 (UTC)

- I don't believe that anyone knows the answer to your question. Really: the product manager got the assignment

- I think readers here are most interested in mathematics markup <math>...</math>, not malformed HTML. I also believe that the editor used for classic wikitext will be of limited functionality. More information on these topics would be helpful. Spectral sequence (talk) 18:05, 19 August 2013 (UTC)
- When more information actually exists, then you will receive it. In the meantime, you can improve Wikipedia's handling of math by helping with the VisualEditor extension, since that will be useful to editors (especially new editors, who often use VE equally as often as the old wikitext approach) and is expected to be fully compatible with Flow. The link is mw:User:Jiabao_wu/GSoC_2013_Project_Work for anyone who hasn't looked yet. (I need to get over there myself later, because I've got a fatal bug this morning: there was no 'apply changes' button on my math window!) Whatamidoing (WMF) (talk) 18:32, 19 August 2013 (UTC)
- I am an active editor here for about two years (in this wiki; in total I’m editing since 2006). I cleansed tens thousands of typographical errors. And I’m interested in templates, for reasons discussed not a long time ago, more than in <math>. Incnis Mrsi (talk) 16:28, 21 August 2013 (UTC)

- Do you mean,

- Without wikitext being available in Flow, it will become essentially impossible to discuss any seriously technical topic, since doing so will require cutting-and-pasting wikitext into talk. If the WMF does this, this will be the Visual Editor debacle all over again -- removing core functionality for no good reason without providing something demonstrably superior, all for the sake of hitting management-driven targets based on unproven assumptions that doing so will somehow bring about an Underpants Gnomes-type miracle that will do more good than harm. For some reason, burning the bridges to prevent retreat was apparently thought of as being a good idea. The goal of the WMF is to further the encyclopedia, not vice versa. -- The Anome (talk) 18:49, 18 August 2013 (UTC)

- Surely you are not referring to mw:Flow Portal/Research as "substantial research", so I wonder what it was you wanted me to read. Sławomir Biały (talk) 18:49, 19 August 2013 (UTC)
- Given the attitude of WMF towards VE and Flow, I do not think there is a way of bringing it to its senses. Personally, I expect to quietly leave the project in the next year or so. Ozob (talk) 15:23, 18 August 2013 (UTC)

- What means
*non-HTML elements such as mathematics*? Does it mean only <math>? Or rather reasonable repertoire of templates? BTW, what are arguments against templates on talk pages? What will break if a talk page stores some non-HTML stuff? Incnis Mrsi (talk) 15:11, 19 August 2013 (UTC)- So, I just had a conversation with the lead developer of Parsoid, and he says that support for savinga and rendering <math> via Parsoid (as HTML5/RDF) is
*already done*- there's just no VisualEditor hook for it, which doesn't impact Flow at all. So maybe we can stop worrying about this.--Jorm (WMF) (talk) 18:30, 19 August 2013 (UTC)- The use case was "the requirement to collaborate by copying mathematics over to discussion pages and back into articles". Does this news mean that you are now confident that this will be possible and reasonably convenient? Spectral sequence (talk) 18:57, 19 August 2013 (UTC)
- I
*literally*just watched someone do that with our internal builds. So yes. Can we drop this now?--Jorm (WMF) (talk) 19:03, 19 August 2013 (UTC)- Thank you for clarifying that. Spectral sequence (talk) 19:36, 19 August 2013 (UTC)

- I
- (ec) Just to be clear, does "saving" mean saving as math markup, or as HTML5/RDF? If the latter, is there a provision for recovering the original math markup, so it can be modified later? (I'm unfamiliar with Parsoid; don't know whether the answer is supposed to be obvious if you know Parsoid.) --Trovatore (talk) 18:59, 19 August 2013 (UTC)
- Saved as HTML5/RDF, rendered, and then recovered. --Jorm (WMF) (talk) 19:03, 19 August 2013 (UTC)
- (edit conflict) Parsoid is a tool that translates between wikitext and HTML. In theory, it should do exactly that. In practice, it's software, so it may contain some bugs. Math 'translation' hasn't been tested, because the primary tool for testing it is VisualEditor, and the math extension is not ready for deployment yet. The most important thing anyone can do to move math support forward is to provide opinions or other support to the work on the math extension at Mediawiki. Whatamidoing (WMF) (talk) 19:05, 19 August 2013 (UTC)
- Thank you for clarifying that. Spectral sequence (talk) 19:36, 19 August 2013 (UTC)

- The use case was "the requirement to collaborate by copying mathematics over to discussion pages and back into articles". Does this news mean that you are now confident that this will be possible and reasonably convenient? Spectral sequence (talk) 18:57, 19 August 2013 (UTC)

- So, I just had a conversation with the lead developer of Parsoid, and he says that support for savinga and rendering <math> via Parsoid (as HTML5/RDF) is

### Bring the developers into this discussion (and don't be so pessimistic)

I have usually found Wikipedia software developers receptive to the needs of those who edit mathematical notation. I wouldn't assume in advance that they will neglect such things if the needs are explained, with specifics.

Have any of the developers been notified of this present discussion on this page? If not, why not bring them in? Michael Hardy (talk) 17:24, 18 August 2013 (UTC)

- Where can we find a complete list of their usernames?—Wavelength (talk) 18:17, 18 August 2013 (UTC)
- If there's no complete list of their usernames, there may still be forums in which they communicate among each other, to which we can post. Michael Hardy (talk) 22:37, 18 August 2013 (UTC)

- I have made no assumptions about the attitude of the developers. If you follow the link in this discussion to a previous topic on this board, you will find several links to areas where discussions have been taking place. As I stated, I have attempted to summarise those discussions fairly here. As far as notification is concerned, you will see that both topics have already been contributed to by Whatamidoing (WMF), who is Community Liaison (Product Development), Wikimedia Foundation, charged with "ensuring that our community is represented in the decision-making process and that our planned software adequately reflects user needs". Spectral sequence (talk) 18:40, 18 August 2013 (UTC)
- That would be myself and Maryana. --Jorm (WMF) (talk) 00:31, 19 August 2013 (UTC)

### If it is, then where to?

Any thoughts? Spectral sequence (talk) 06:19, 20 August 2013 (UTC)

- Huh? As far as I can tell, the answer to your original question "Is it time for mathematicians to leave Wikipedia?" is "No". Mgnbar (talk) 11:42, 20 August 2013 (UTC)

- To answer, I assume the hypothesis in the question is satisfied. Then the canonical answer seems (as of now) Encyclopedia of Mathematics. Not only they have better math support, not only we can expect more timely and better tech support, they are also math-only encyclopedia; so fewer distractions from non-math editors, for instance. Another park is that in a certain areas, in particular, graduate/research-level and some high-energy physics (from what I can tell), they have a better coverage than Wikipedia. In terms of licenses, we can move contents here to there, but not vice versa.

- But I'm hoping the hypothesis turns out not be satisfied :) -- Taku (talk) 12:36, 20 August 2013 (UTC)
- Not that I would intend to move there, but in what sense do they have better math support? What I can see are equations rendered as awful grainy images jumping up and down from the baseline.—Emil J. 13:05, 20 August 2013 (UTC)
- For example, they use mathjax by default (see the top page). I looked around and old articles seem to use image files direct (see [20]); but they will be replaced by latex code by hand or by content here. Also, they use "$" instead of "<math>"; the former is much easier to type. If I'm not mistaken, the other sites like stack exchange also uses mathjax. To attract contributors, it is desirable to use systems that they are accustomed to. -- Taku (talk) 13:25, 20 August 2013 (UTC)
- Like Wikipedia, the Encyclopedia of Mathematics operates under a CC-BY-SA license. That means that any content from Wikipedia can be copied there, and vice versa, so long as attribution is provided. It seems to me that this would be a good proving ground, a place to write math articles in a community of experts, away from the distractions of Wikipedia's internal politics, which could later be copied to Wikipedia.
**bd2412****T**13:46, 20 August 2013 (UTC)

- Like Wikipedia, the Encyclopedia of Mathematics operates under a CC-BY-SA license. That means that any content from Wikipedia can be copied there, and vice versa, so long as attribution is provided. It seems to me that this would be a good proving ground, a place to write math articles in a community of experts, away from the distractions of Wikipedia's internal politics, which could later be copied to Wikipedia.

- For example, they use mathjax by default (see the top page). I looked around and old articles seem to use image files direct (see [20]); but they will be replaced by latex code by hand or by content here. Also, they use "$" instead of "<math>"; the former is much easier to type. If I'm not mistaken, the other sites like stack exchange also uses mathjax. To attract contributors, it is desirable to use systems that they are accustomed to. -- Taku (talk) 13:25, 20 August 2013 (UTC)

- Not that I would intend to move there, but in what sense do they have better math support? What I can see are equations rendered as awful grainy images jumping up and down from the baseline.—Emil J. 13:05, 20 August 2013 (UTC)

On EoM, *original* articles are copyrighted by Springer and cannot be copied to WP; however, after they are changed (even a little) they become CC.

Also, original articles (unfortunately) have very bad formulas (yes, images). However, volunteers are welcome to manually turn them into TeX, and then they are processed by MathJax, and look quite nicely.

Also, rules are very strict there. Only one user, the chief editor, is an admin, and is able to change templates. I am on editorial board, and still, cannot edit templates myself.

See also project talk there, in particular, major new contributions and asymptote. Boris Tsirelson (talk) 14:14, 20 August 2013 (UTC)

- Please let me say that, from my point of view, a collaboration of wikipedians with EoM is very desirable. Everybody is cordially invited to help with EoM.
- Yes, it is correct that our old articles are TeXnically in a bad shape, that's caused by the history of the encyclopedia. The files have been ported from an old cdrom edition into mediawiki format, and as far as I know, the TeX sources have been lost, only the old fashioned (ugly) png-based pages have been rescued.
- I have designed some tools to help transcribing the old material into TeX, so everybody who is familiar with emacs and likes to edit wiki pages via "It's all text" or similar should have no problems to adopt old pages into TeX (thereby putting those pages automatically into CC !).
- Concerning the overall structure of EoM, I am certainly open to discuss and help implementing useful modifications.--Urehmann (talk) 16:08, 20 August 2013 (UTC)

## Wikipedia talk:Articles for creation/Intrinsic Flat Convergence

Hello mathematicians! This article: Wikipedia talk:Articles for creation/Intrinsic Flat Convergence hasn't been edited in a long time and may soon be deleted as an old draft. Is it worth saving? —Anne Delong (talk) 11:31, 19 August 2013 (UTC)

- Most of the content seems to be already at the existing article Intrinsic flat distance, so there is no need to keep the old draft. Sławomir Biały (talk) 11:36, 19 August 2013 (UTC)
- Okay! Thanks for checking this out. —Anne Delong (talk) 16:09, 19 August 2013 (UTC)
- You may want to redirect Intrinsic Flat Convergence (and Intrinsic flat convergence) to Intrinsic flat distance. Cheers!
**bd2412****T**18:29, 20 August 2013 (UTC)

- You may want to redirect Intrinsic Flat Convergence (and Intrinsic flat convergence) to Intrinsic flat distance. Cheers!

- Okay! Thanks for checking this out. —Anne Delong (talk) 16:09, 19 August 2013 (UTC)

## Boubaker redux

The self-promotion of "Boubaker polynomials" has returned. For context, see Wikipedia:Articles for deletion/Boubaker polynomials (3rd nomination), and the previous AfDs and sockpuppet investigations linked there. For recent activity, see http://en.wikipedia.org/w/index.php?title=Chebyshev_polynomials&curid=184539&action=history and Special:Contributions/Uskudargideriken. In particular, Chebyshev polynomials could use watching, reverting, and/or protecting. —David Eppstein (talk) 17:50, 21 August 2013 (UTC)

- Wikipedia:Sockpuppet_investigations/Mmbmmmbm. Ozob (talk) 02:34, 22 August 2013 (UTC)

## mass observation

Do we have an article on this statistical/epidemiological method? -- 76.65.128.222 (talk) 02:15, 19 August 2013 (UTC)

- Where did you read about it? It doesn't sound like it's necessarily a technical term. ᛭ LokiClock (talk) 13:24, 22 August 2013 (UTC)

## {{Science}}

FYI, there's a note at WT:PHYSICS about a discussion at template talk:Science concerning Template:Lt -- 76.65.128.222 (talk) 06:08, 23 August 2013 (UTC)

## Matrix analysis

We have no article titled matrix analysis, and only one article that links to it. Should we alter that situation? Michael Hardy (talk) 19:47, 17 July 2013 (UTC)

- I genuitely can't tell if this is a rhetorical question or not. But the answer is yes. -- Taku (talk) 19:55, 17 July 2013 (UTC)

- I just noticed that Matrix theory redirects to Matrix (mathematics), which looks quite long. One option is to create matrix theory and redirect matrix analysis to it. -- Taku (talk) 22:18, 17 July 2013 (UTC)

- Matrix analysis is the branch of mathematical analysis that focuses specifically on the properties of matrices. The classic reference work on matrix analysis is the two volume work by Horn and Johnson. "Matrix theory" is much more ill-defined. It seems legitimate to have a separate article on matrix analysis, but there is less of a case for an article "matrix theory". Sławomir Biały (talk) 08:42, 19 July 2013 (UTC)

- "ill-defined" isn't an argument for not having an article. (what is reality? is it a matrix?) The case for matrix theory can be made, for instance, we have group theory and ring theory. "what links here" shows matrix theory is much commonly linked. On the other hand, "matrix analysis" seems little too narrow. I was just reading about Serre's problem (on projective module) and [21] gives the "'matrix-theoretic" formulation of Serre's problem. (the author uses the word "matrix-theoretic" explicitly.) Indeed, if I understand, a part of
*K*-theory has some matrix theoretic aspect (here "theory" again). -- Taku (talk) 11:31, 19 July 2013 (UTC)- I don't see how you can possibly come to the conclusion that matrix analysis is too narrow for the topic of an encyclopedia article. There is an entire two-volume reference work dedicated to it, one that is highly regarded in the numerical analysis community. Also, you're making an error in thinking that the incidental juxtaposition of two English nouns ("matrix" and "theory") means that therefore the juxtaposition is worthy of a separate encyclopedia article, or that we should base any such hypothetical article on sources in which "matrix" and "theory" happen to appear side by side in print. That's a ridiculous suggestion. What's needed are sources that clearly delineate the scope of the subject "matrix theory" (if indeed there is such a subject). The sources for a hypothetical article "matrix analysis" are comparatively much more solid. Sławomir Biały (talk) 12:34, 19 July 2013 (UTC)

- "ill-defined" isn't an argument for not having an article. (what is reality? is it a matrix?) The case for matrix theory can be made, for instance, we have group theory and ring theory. "what links here" shows matrix theory is much commonly linked. On the other hand, "matrix analysis" seems little too narrow. I was just reading about Serre's problem (on projective module) and [21] gives the "'matrix-theoretic" formulation of Serre's problem. (the author uses the word "matrix-theoretic" explicitly.) Indeed, if I understand, a part of

- Well, at least no one so far bothered to create "matrix analysis". I should have said "matrix analysis" is narrower the topic than matrix theory: the latter presumably contains the former. As for the word game "X theory", of course, not every English word can be substituted into
*X*. But "matrix" does work, as supposed by Wikipedia search (e.g., what links here), Google and Amazon search. (Amazon gives a lot of books with titles that are exactly or contains matrix theory.) Finally, when did we begin requiring "clearly delineate the scope of the subject" before the creation of an article? that sounds*much*harder criterion to satisfy than the notability. The subject matter "matrix theory" does exist and the only question is if it should be separated from matrix (mathematics). -- Taku (talk) 11:28, 20 July 2013 (UTC)

- Well, at least no one so far bothered to create "matrix analysis". I should have said "matrix analysis" is narrower the topic than matrix theory: the latter presumably contains the former. As for the word game "X theory", of course, not every English word can be substituted into

- (For the interest of full disclosure, I'm interested in the matrix theory over a general ring, like, normal forms stuff and many deep fheorems like when certain matrices form a normal subfroup. We currently lack a a survey/overview type article that provides links to specific results. This is why I suggested "matrix theory" instead of "matrix analysis".) -- Taku (talk) 11:33, 20 July 2013 (UTC)

- "Matrix-theoretic" seems like a catch-all for treating something using matrices as opposed to linear maps or anything that can be formulated as a linear system of equations. Matrix theory would ultimately be a document of applications to matrices in other subjects, as well as an explanation of how matrices are linear maps. It would be very helpful, but it's perhaps making up a subject called matrix theory. ᛭ LokiClock (talk) 10:06, 23 August 2013 (UTC)

Matrix theory is different from matrix analysis, although obviously there's considerable interaction. "Analysis" is concerned with limits and derivatives and integrals. Michael Hardy (talk) 17:16, 4 August 2013 (UTC)

- Is matrix analysis really analysis? Surely, some aspects of it has a flavor of functional analysis. But some other parts feel more like matrix algebra (stuff like normal form/canonical form). -- Taku (talk) 21:30, 4 August 2013 (UTC)
- I thought it was more like stuff about integration and differentiation of matrix-valued functions. Michael Hardy (talk) 01:03, 13 August 2013 (UTC)
- There are matrix norms and whatnot for studying convergence of a sequence of matrices, which leads to definitions of matrix exponentiation and whatnot. ᛭ LokiClock (talk) 10:06, 23 August 2013 (UTC)
- Differentiation of matrix-valued functions and functions of a matrix is discussed in matrix calculus. -- Jitse Niesen (talk) 10:38, 23 August 2013 (UTC)

- There are matrix norms and whatnot for studying convergence of a sequence of matrices, which leads to definitions of matrix exponentiation and whatnot. ᛭ LokiClock (talk) 10:06, 23 August 2013 (UTC)

- I thought it was more like stuff about integration and differentiation of matrix-valued functions. Michael Hardy (talk) 01:03, 13 August 2013 (UTC)

## TeX weirdness in Conical combination

Sometimes when I view this page it reads α_{i} > 0 and sometimes it reads α_{i} ≥ 0. The TeX code is correct (\ge). Anyone know what's going on, experiencing the same thing, etc.? --RDBury (talk) 07:30, 21 August 2013 (UTC)

- Actually I think the problem is I'm viewing the page zoomed out on a crappy monitor. The PNG renderer in Firefox decided to drop the row of pixels that changes the > to a ≥ when reducing the resolution, I'm theorizing. --RDBury (talk) 07:44, 21 August 2013 (UTC)

- Ah, I see what happens. The horizontal line in the "≥" sign is quite thin. Being zoomed out, it can fall between two rows of pixels! I got it after seeing it once
*almost*invisible, but still visible. It is not a matter of TeX, but of screen resolution. Boris Tsirelson (talk) 16:37, 24 August 2013 (UTC)

- Ah, I see what happens. The horizontal line in the "≥" sign is quite thin. Being zoomed out, it can fall between two rows of pixels! I got it after seeing it once

## Grace–Walsh–Szegő theorem

Grace–Walsh–Szegő theorem is a new article. To do:

- Expand and improve the article. Proof of the theorem? Applications of the theorem? Other stuff? And is the material that's there now correct?
- Which articles should link to it besides the ones about the people it's named after?
- Redirects: There are various combinations of hyphens instead of en-dashes, "o" instead of "ő", capital or lower-case initial "t" in "theorem", the phrase Grace–Walsh–Szegő coincidence theorem with those combinations of punctuation and form of letter and capital-versus lower-case initials on each word. Then any standard or probable alternative names, etc.

Michael Hardy (talk) 19:36, 23 August 2013 (UTC)

- I'd be interested in seeing a sketch of the proof, if you have the references handy. Sławomir Biały (talk) 18:24, 24 August 2013 (UTC)

## Categorising tilings on Wikimedia Commons

There are a couple of discussions at http://commons.wikimedia.org/wiki/Category_talk:Tilings-db and http://commons.wikimedia.org/wiki/Commons:Categories_for_discussion/2013/08/Category:Tessellations — Cheers, Steelpillow (Talk) 10:51, 24 August 2013 (UTC)

## I think we should put links to didactic/textbook material near the top of the math/technical articles...

So reading the FAQ it says: "Wikipedia is an encyclopedia, not a textbook. Wikipedia articles are not supposed to be pedagogic treatments of their topics."

Now it's clear why all math found in the Wiki is so incomprehensible... Most of the time these articles can be used only to check if you remember correctly to some formula (and otherwise know the whole topic inside out). So lately I started adding "-wikipedia" to my searches, because I know I'll only get pissed off anyway here...

But I recently discovered many articles *often point to good courses and lectures in the references section, but they are buried deep into the list of difficult papers*.

Also **I think most people won't read beyond the See also section anyway.**

So I suggest having a box near the top of the article to collect the good resources where the reader can learn about the topic.

Calmarius (talk) 12:00, 24 August 2013 (UTC)

- References and external links go at the bottom of Wikipedia articles, as per Wikipedia:Manual of Style/Layout. And they aren't "buried", they are consistently in same place in all Wikipedia articles (whether those articles about mathematics, botany, or Pokemon.) Sławomir Biały (talk) 14:35, 24 August 2013 (UTC)

- Some articles cite a few general references in the lead. That puts them at the top of the reference list so they are easier to find. RockMagnetist (talk) 15:23, 24 August 2013 (UTC)
- Alternatively, if you use a style that separates short footnotes from a listing of more detailed information about each source, you can separate out the sources into different categories, making the more general introductions to the subject easier to find. A recent example of an article where I used this style is Upward planar drawing. —David Eppstein (talk) 16:24, 24 August 2013 (UTC)

- I think you're misinterpreting the NOTTEXTBOOK guideline. Articles can and should be accessible even if they summarize secondary sources. It's actually more difficult to explain a concept in few words than in many words, so it takes a good amount of skill and practice to write an article well. I think the problem you're experiencing with many WP articles is the BGSFGS (by graduate students for graduate students) phenomenon which is a symptom of the skill of the people actually creating the articles. It's not the result of any guidelines, in fact my interpretation of the guidelines is that articles should accessible to as wide as audience as possible, so what you're complaining about is the result of
**not**following the guidelines. But WP is, has been, and always will be a work in progress so hopefully we are converging on accessibility as well as fixing other issues. --RDBury (talk) 04:42, 25 August 2013 (UTC)

## Variable ranges not defined

The ranges for the variables in Harmonograph are not defined. Could someone look over them and say whether the variables range between 0 and 1 or 0 and 2*pi or whatever? Thanks! SharkD Talk 03:25, 26 August 2013 (UTC)

- It seems implicit that the range of t is t>0, i.e. once it starts you let it go indefinitely, which in practical terms means until the motion is too small to see. Damped sine wave uses similar equations. --RDBury (talk) 07:27, 26 August 2013 (UTC)

## Conical combinations and weighted sums

Weighted sum currently redirects to Weight function, which has a section on weighted sums, saying they are also called conical combinations, and links to that article. Since weighted sums are the same thing as conical combinations, should the latter title be the redirect target? Michael Hardy (talk) 03:55, 26 August 2013 (UTC)

- My linear programming book calls them nonnegative combinations which isn't even a redirect and the set of them the nonnegative hull or pos cone. So it seems the terminology isn't standard, though perhaps there is no standard. I'm thinking "weighted sum" is used more in analysis and statistics while the other terms are used in convex geometry and linear programming.
- While we're on the subject, there are four pairs of related topics: linear combination and linear span, affine combination and affine hull, convex combination and convex hull, and conical combination and conical hull. For the first three pairs there are separate articles which I think should be merged, so we'd have 4 articles instead of 7. --RDBury (talk) 07:13, 26 August 2013 (UTC)

## No new articles in current activity for three days?

I suspect one of the bots needs to be restarted. —David Eppstein (talk) 01:53, 26 August 2013 (UTC)

- I just sent Jitse Niesen an email about this. Apparently new articles are getting added to the list of mathematics articles, and Jitse's bot is updating the "current activities" page, but nonetheless new articles are not getting listed on the latter page. If he reads his email regularly, he will know. Michael Hardy (talk) 03:36, 26 August 2013 (UTC)
- Yes, I got the message. It's a bit more complicated than restarted the bot, as I need to move the software to a different server. -- Jitse Niesen (talk) 10:01, 26 August 2013 (UTC)
- Okay, it is partially updated. Some data seem to be lost though, which is why the list of new articles is longer than it should be. -- Jitse Niesen (talk) 15:10, 29 August 2013 (UTC)

## Missing topics page

I have updated Missing topics about Mathematics - Skysmith (talk) 10:53, 29 August 2013 (UTC)

## RFC - Visualization of the exponential function

Comments from members of the project would be valuable at this request in the Graphics Lab. Thanks! --Waldir ^{talk} 04:56, 30 August 2013 (UTC)

## Combinatorial principles

This page started as a list of links but someone added short intros. Imo the article is not in the right form to be an article proper, so I'd propose several alternatives:

- Remove the intros and rename as "List of combinatorial principles".
- Add links and move to the book namespace, say "book:Combinatorics".
- Merge with Outline of combinatorics
- Submit for deletion or change to redirect.

I'm not sure if there is any operational difference between a theorem and a principle, or some theorems are just called principles because of historical accident. If the latter, then since we already have Category:Theorems in combinatorics, it's unclear what purpose the article is serving. Anyone have a preference, better idea, etc.? --RDBury (talk) 05:17, 30 August 2013 (UTC)

I have noticed several IP editors adding references to work by Rutger-Jan Lange to a variety of articles that are of peripheral relevance at best. Lange has apparently written an article in the JHEP on the Laplacian of the indicator function. How such an article ever passed peer review is an open question, since there is certainly nothing new or remarkable about the Laplacian of the indicator (which already appears explicitly in Gelfand and Shilov's *Generalized functions, Vol I*, and was very likely well-known much earlier to Sobolev, Schwartz, etc). Apart from the questionable article Laplacian of the indicator, other affected articles are Distribution (mathematics), Dirac delta function, Heaviside function. I have removed as undue weight some of the offending material, but the situation could use monitoring. Also the article Laplacian of the indicator could at least use some NPOV work, since it suggests that the formula was due to Lange when in actuality such formulas were already very well-known at least fifty years prior to Lange's work. Sławomir Biały (talk) 14:48, 30 August 2013 (UTC)

- Could you be speaking about Special:Contributions/24.132.172.87? This IP has not edited since January, though a review of their edits may be worthwhile. I guess you made one removal here from Distribution (mathematics) and one here from Heaviside step function. EdJohnston (talk) 15:33, 30 August 2013 (UTC)
- Most recently fron 131.111.165.55 Template:Toolbar and 131.111.184.30 Template:Toolbar. Although as you point out, this has been going on for a long time and from many different IP addresses (in addition to the named account Rutgerjanlange Template:Toolbar), hence the need to monitor the situation. Sławomir Biały (talk) 15:44, 30 August 2013 (UTC)

## Do we need complex analysis for the limits of the Fresnel integrals?

See Talk:Fresnel integral#Computation of limits without complex analysis.--Jasper Deng (talk) 04:22, 31 August 2013 (UTC)

## Conservative vector field

Additional eyes would be welcome at conservative vector field. See my post at Talk:Conservative vector field#Recent edits for details. Sławomir Biały (talk) 11:35, 29 August 2013 (UTC)

- I'm beginning to get a bit more generally worried about the edits of Reddi Template:Toolbar. The references added to Non-standard analysis and to Helmholtz decomposition have the feel of something added from a raw Google books search, rather than a carefully regarded addition. I very much doubt that Reddi has even read these sources, let alone understood them. This seems to fit the same pattern as at conservative vector field. This is
*quite alarming*if true, since Reddi is an established editor with over 50,000 edits. Sławomir Biały (talk) 21:44, 30 August 2013 (UTC)

- In addition to my worries expressed above, it has come to my attention that the user in question added the text of a source word-for-word to the article functional (mathematics) without attribution. While the text in question seems to be in the public domain, even public domain sources need WP:INTEXT attribution. I fear a Jaggedesque scenario on the horizon. Sławomir Biały (talk) 22:36, 30 August 2013 (UTC)
- That edit also shows strong evidence of not understanding the distinction between functions and functionals, and instead going by syntax (the word "functional" in the phrase "functional notation"). If there is a pattern of copying sources that are not out of copyright, WP:CCI may be appropriate. —David Eppstein (talk) 23:04, 30 August 2013 (UTC)
- Well, after this edit which is (almost) a word-for-word copy of a sentence in A Dictionary of Science, Literature, & Art (just as the aforementioned PRODed article was), I have little doubt that this is just the tip of the iceberg. I think that WP:CCI intervention is clearly warranted. Moreover, I will likely escalate this to WP:AN assuming that the editor in question continues to refuse to "come clean" about the other obvious issues with his edits (copyvios aside) that I have pointed out. Sławomir Biały (talk) 03:04, 31 August 2013 (UTC)
- If that dictionary was published in 1866 as it says, then copyright should not be an issue. Perhaps plagiarism? JRSpriggs (talk) 11:47, 31 August 2013 (UTC)
- Yes, I mention this above. I am worried though that the editor in question seems to think that plagiarism and copyright infringement are the same thing [24]. Alarmingly, he sees nothing inherently wrong with passing off the works of others as his own, and seems unwilling to accept that not only is it wrong to do so, it is also against the WP:PLAGIARISM guideline. Sławomir Biały (talk) 13:26, 31 August 2013 (UTC)
- Or this: "One cannot plagiarize public domain material. Nonsense." Yikes. Sławomir Biały (talk) 14:05, 31 August 2013 (UTC)

- If that dictionary was published in 1866 as it says, then copyright should not be an issue. Perhaps plagiarism? JRSpriggs (talk) 11:47, 31 August 2013 (UTC)

- Well, after this edit which is (almost) a word-for-word copy of a sentence in A Dictionary of Science, Literature, & Art (just as the aforementioned PRODed article was), I have little doubt that this is just the tip of the iceberg. I think that WP:CCI intervention is clearly warranted. Moreover, I will likely escalate this to WP:AN assuming that the editor in question continues to refuse to "come clean" about the other obvious issues with his edits (copyvios aside) that I have pointed out. Sławomir Biały (talk) 03:04, 31 August 2013 (UTC)

- That edit also shows strong evidence of not understanding the distinction between functions and functionals, and instead going by syntax (the word "functional" in the phrase "functional notation"). If there is a pattern of copying sources that are not out of copyright, WP:CCI may be appropriate. —David Eppstein (talk) 23:04, 30 August 2013 (UTC)

## Cohn-Vossen's inequality

I've just created an article titled Cohn-Vossen's inequality. Could those who know differential geometry check it for correctness?

Other improvements could also be done, including perhaps (1) a proof, and (2) some applications, and (3) other articles linking to the new article; so far I think there are three, all created in recent minutes by me (not counting redirects, of which I think I also created three). Michael Hardy (talk) 17:15, 31 August 2013 (UTC)

- It looks good to me. Is is more commonly called
*Cohn-Vossen's inequality*or the*Cohn-Vossen inequality*? The latter is used for instance in the EOM reference. --Mark viking (talk) 19:30, 31 August 2013 (UTC)- I think mathematicians should alter their habitual ways of thinking about such nomenclature questions. Giving either form in the definition should be taken as licensing the use of either form, as the context may make suitable. One can say "This book is..." or "These books are..." and one is merely changing the
**forms**of the words according to rules of language whose statement belongs elsewhere than in the dictionary. Michael Hardy (talk) 21:52, 31 August 2013 (UTC)

- I think mathematicians should alter their habitual ways of thinking about such nomenclature questions. Giving either form in the definition should be taken as licensing the use of either form, as the context may make suitable. One can say "This book is..." or "These books are..." and one is merely changing the

- I would give some examples: the plane where the inequality is strict: , the sphere where the inequality is an equality; and also a hemisphere and maybe a flat rectangle (in both cases, the inequality is strict with an explicit remainder). I think the case of equality should also be discussed (geometric rigidity). Sławomir Biały (talk) 23:52, 31 August 2013 (UTC)