Wikipedia talk:WikiProject Mathematics/Archive/2011/Aug

Page: "Synthetic logic"
http://en.wikipedia.org/wiki/Synthetic_logic

Due to the description: "Synthetic logic is based on the law of non-identity (A is not A) and the law of contradiction (A is −A).", "synthetic logic" is no difference from classic logic but redefine the words "is" and "is not". With mapping "is" in "synthetic logic" to "is not" in classic logic, mapping "is not" in "synthetic logic" to "is" in classic logic, "synthetic logic" is identical with classic logic.

My suggestion is, either refine the misleading description or declare that "synthetic logic" is just a trivial dialect of classic logic. — Preceding unsigned comment added by 112.96.65.22 (talk) 07:44, 24 July 2011 (UTC)


 * It looks to me like synthetic logic is the pet theory of Stephen Palmquist. I wasn't able to find any references to it by other authors.  Palmquist's article has an enormous bibliography and seems to be the work of User:Stevepq, who originally began the article on his user page, has edited nothing else, and has been inactive since November 2008.  I don't think that either of synthetic logic or Stephen Palmquist meets our notability guidelines, so I've prodded them. Ozob (talk) 12:57, 24 July 2011 (UTC)


 * This "synthetic logic" is not logic, but (like "fuzzy logic") an attempt to destroy (or ridicule) logic. As a hoax (or a pile of horse dung), it should be deleted forthwith from Wikipedia and indeed from all of existence. JRSpriggs (talk) 21:58, 24 July 2011 (UTC)


 * The word "synthetic" seems to be used sometimes in the literature, although I'm not sure always with the same meaning; does talk about Kant which is also mentioned in the article we're discussing. However, I'm fine with deleting this article. It is very short, not very clear, and could be re-created without too much effort if someone wanted to write this whole thing up with better explanation. It could be kept, of course, if someone could turn up some more sources, and/or a better explanation of what the potential of this article/concept is. Kingdon (talk) 01:17, 25 July 2011 (UTC)

I prodded these two articles, but the prods were declined. I have taken them to AfD now. See Articles for deletion/Stephen Palmquist and Articles for deletion/Synthetic logic. Ozob (talk) 01:35, 1 August 2011 (UTC)

Appalling articles
I was wondering if it would be useful to make a "Articles desperately in need of attention" or "Articles in appalling condition" or "Sadface articles" category to draw more attention to such articles as and other such top-priority start-class articles for which the dreariness of sheer lack of material (relative to the subject's importance) weighs heavily upon even a nonspecialist as me. Leonxlin (talk) 03:55, 31 July 2011 (UTC)
 * Equation
 * Linear algebra
 * Real analysis


 * Real analysis needs proper use of summary style to deserve its place at the head of the substantial Category:Real analysis. Charles Matthews (talk) 07:08, 31 July 2011 (UTC)
 * You can tag the articles using messages from Template messages/Cleanup, these articles get listed at WikiProject Mathematics/Current activity which helps draw attention to them. I've added a few tags them, but you may consider some more detailed ones, or detailing your concerns on the talk pages.--Salix (talk): 09:04, 31 July 2011 (UTC)
 * I agree, cleanup tags currently serves the purpose of an "Articles in need of attention" category and we have Pages needing attention/Mathematics where these articles are listed and sorted by the tag used. The real problem is the multitude of articles there and the lack of progress in reducing it. It would be nice to prioritize the list somehow so highly visible tagged articles like 'Equation' move to the top. That being said there simply aren't enough people working doing the cleanup. Not that I can blame anyone, it's often a tedious and thankless task and given the size of the problem it's a bit like trying to chop down a sequoia with a pen-knife. WP is a volunteer project and volunteers tend to work on the more interesting tasks while important yet boring tasks tend to be neglected.--RDBury (talk) 20:56, 31 July 2011 (UTC)
 * Unfortunately, though, the cleanup tags miss the bigger part of the problem, which is that the articles have very little in them that could be considered for cleaning up in the first place. Perhaps there ought to be a "This article is essentially unwritten" tag? Leonxlin (talk) 23:14, 1 August 2011 (UTC)
 * Just proposed a related WikiProject here, if you want to follow. Leonxlin (talk) 00:05, 2 August 2011 (UTC)
 * We have stub categories for that. A stub label can be misleading at times because the subject may only have a paragraph of noteworthy information published. But in general it serves the purpose you're talking about. It's easier to find high priority stubs than high priority articles with with cleanup tags.--RDBury (talk) 00:10, 2 August 2011 (UTC)
 * Indeed, stubs are typically on obscure topics, which makes this task harder. If I understand correctly, many start-class articles need more writing than editing as well. My intention is not only to find high priority, low quality articles, but also to draw attention to them. Leonxlin (talk) 00:21, 2 August 2011 (UTC)

Identification of such articles is one of the aims of the large article assessment effort.

We know there are 61 Start class top priority articles and 69 Stub class high priority articles. Which are probably those articles most in need of attention. I'm not convinced we need another mechanism to to almost the same job.

For mathematics article the best way to draw attention to them is to mention them on this talk page, we have already seem some improvement to Linear algebra, but nothing yet on Equation or Real analysis.--Salix (talk): 01:03, 2 August 2011 (UTC)

Tikhonov's theorem (dynamical systems)
I've created a quite imperfect new article titled Tikhonov's theorem (dynamical systems). Do what you can for it. Michael Hardy (talk) 18:53, 31 July 2011 (UTC)


 * A section containing an example application would be helpful, I can add that in a few days. Thanks for adding this, I'm surprised it wasn't on here already; pretty sure it's going to be on my qualifying exam. Compsonheir (talk) 02:06, 2 August 2011 (UTC)

Renaming discussion regarding article Copula (statistics)
The proposed renaming being discussed at Talk:Copula (statistics) may be of interest to members of this WikiProject. Favonian (talk) 08:20, 2 August 2011 (UTC)

Non-metrizable topological vector space
Does anyone have a nice example of a non-metrizable topological vector space in mind? I suspect there must be an elementary example. I had an idea to reference it in Normed vector space to show that not all vector spaces can be equipped with a norm. If you have an example by all means carry this out, no need to go through me. Rschwieb (talk) 01:09, 3 August 2011 (UTC)
 * Weak-star topologies are almost never metrizable. This includes spaces of distributions. Sławomir Biały  (talk) 01:32, 3 August 2011 (UTC)
 * Although if the goal is to produce topological vector spaces that are not normable, the best examples are $$C(0,1)$$, equipped with the topology of compact convergence (since the topology is not locally bounded), and $$\ell^p$$ for $$0 $$\oint$$ , but with a larger circle and two integral signs. I couldn't find such a symbol in any of the LaTeX guides. The article uses a hack
 *  $$\iint\!\!\!\!\!\!\!\!\!\!\!\subset\!\supset$$ 

but it just doesn't line up at all well using MathJax; although it does line up in plane TeX ( see here ). Does anyone if there is a command for the required symbol? If not, should we use  $$\oint\oint$$  or just  $$\iint$$ ? — Fly by Night  ( talk )  16:27, 3 August 2011 (UTC)
 * See Help:Displaying a formula, basically it's in TeX but we don't implement it and the article is using the recommended workaround. Is there a reason the circle has to be there? I'm thinking the easiest thing would be to use ordinary double integral notation. There are probably other options but they amount to different workarounds.--RDBury (talk) 19:43, 3 August 2011 (UTC)
 * I don't see a need for the circle. I can understand the circle on a single contour integral, but it's not necessary. I was never taught to use it during complex analysis courses; we just used integral signs. Like I said, I understand why some people (often applied mathematical scientists) use the circle. But following the idea, we should embellish the double integral with a sphere. — Fly by Night  ( talk )  20:13, 3 August 2011 (UTC)

I have added code to mathJax for detecting those hacks. I was going to automatically replace instances of them by \oiint and \oiiint, but after adding support for these symbols I realized that they are not available in the TeX fonts. I need to ask the main developers for adding them. In the mean time I am duplicating the same kind of ugly hack though the results may still look a bit more off. Nageh (talk) 20:08, 3 August 2011 (UTC)
 * Thanks for taking such speedy action. Can you suggest a compromise for the meantime. — Fly by Night  ( talk )  21:45, 3 August 2011 (UTC)
 * I guess for backwards compatibility with PNG rendering we have to stay with these hacks. \oiint and \oiiint symbols are not available in common TeX packages and not supported by the MediaWiki texvc backend. Once these integral symbols will be made available in the MathJax TeX fonts I will change the code to automatically detect and replace the hacks by the proper symbols. Nageh (talk) 22:06, 3 August 2011 (UTC)
 * Is there anything you can do to fix the current alignment problems witnessed by MathJax users? — Fly by Night  ( talk )  22:40, 3 August 2011 (UTC)
 * Did you check the pages affected? I have implemented code to somewhat match MathJax rendering with PNG rendering. It's not perfect but I'd rather wait for the fonts to be updated so my code can automatically replace the hacks by the proper symbols. The MathJax developers are usually quick to respond so I guess it shouldn't take too long till new fonts are available. Nageh (talk) 08:07, 4 August 2011 (UTC)

Just a remark that when you can't find a LaTeX symbol, you should try Detexify: http://detexify.kirelabs.org/classify.html It's able to easily identify the symbol you want and tells you what package it comes from (in this case, esint). --Joel B. Lewis (talk) 00:30, 4 August 2011 (UTC)
 * That is the best thing I've ever seen! What a brilliant piece of kit. Sadly, not all symbols are equipped in the "Wikipedia brain", but it's wonderful for my own use. Thanks a lot! I'm going to email that to all the mathematicians I know. — Fly by Night  ( talk )  01:21, 4 August 2011 (UTC)
 * Neat!!! And it's working really well! Nageh (talk) 08:48, 4 August 2011 (UTC)
 * Glad to be of service -- truly, this is a tool whose name should be known far and wide :) --Joel B. Lewis (talk) 12:40, 4 August 2011 (UTC)

Mathematical optimization
A user has renewed his editing and suggested changes to Mathematical optimization. You may wish to examine his edits and welcome him! Kiefer .Wolfowitz 11:29, 4 August 2011 (UTC)

Pascal followup
The COPYVIO issues at Blaise Pascal have been resolved thanks mostly to User:NortyNort and User:Moonriddengirl. The article is still under FA review however; even though the original problem is gone the review brought up new issues. It's probably not too late to fix these issues and/or leave comments at the FAR.--RDBury (talk) 18:22, 4 August 2011 (UTC)

Dubious edits at Riemann curvature tensor
An editor is lobbying to include the misleading formula $$\nabla R=0$$ at Riemann curvature tensor, claiming that this is the Bianchi identity. (Under most typical interpretations of the notation, this is true iff the manifold is locally symmetric.). In addition, the same editor is adding irrelevant content about vector bundles and torsion, although the article clearly focuses only on the Levi-Civita case (whether or not this focus is appropriate. Someone please look into it. 166.137.141.212 (talk) 20:24, 4 August 2011 (UTC)

Progress in Physics
The journal claims to be covered by Zentralblatt MATH and Mathematical Reviews. Is this true, or just another BS claim from these crackpots (Smarandache et al.)? Headbomb {talk / contribs / physics / books} 05:58, 9 August 2011 (UTC)
 * Sorry to disappoint you, but those databases are pretty comprehensive. Yes, this journal is covered.  Not every single article is listed, and many appear with just a short summary rather than a detailed review, but the journal is definitely represented there.  If it cheers you up any, MathSciNet gives a "mathematical citation quotient" for each journal: the number of citations in the database divided by the total number of items published.  The aggregate total for all journals in 2010 was 0.26; some prestigious journals have quotients greater than 1.  Progress in Physics scores 0.03 by this metric (2 citations for 71 items). Jowa fan (talk) 06:28, 9 August 2011 (UTC)
 * It's not listed as "indexed cover to cover" as most typical math journals seem to be; I don't know what the significance of this is. --Joel B. Lewis (talk) 12:30, 9 August 2011 (UTC)

Identifying Euclid and Mullin
Our article titled Euclid–Mullin sequence doesn't say a word about who either Euclid or Mullin is. Euclid is easy. Is it Albert A. Mullin, or R. C. Mullin, or someone else? Michael Hardy (talk) 22:39, 9 August 2011 (UTC)
 * Based on the cited MathWorld article it's presumably the A. A. Mullin cited there. Paul August &#9742; 23:14, 9 August 2011 (UTC)
 * According to Naur (Proc. AMS 1984) it was A. A. Mullin ("Recursive function theory", Bull. AMS 1963). I'll look for some more detail and add to the article. —David Eppstein (talk) 23:15, 9 August 2011 (UTC)

Today's FA
Numerical weather prediction is today's featured article. Just in case you're not checking the main page everyday.--RDBury (talk) 10:14, 10 August 2011 (UTC)

RFC at Annals of Mathematics
I have opened an RFC at Talk:Annals_of_Mathematics about whether two abbreviations for the journal (the one used by Zentralblatt MATH, and the one used by Mathematical Reviews) should be mentioned in the lede. The other option proposed is to not include the Mathematical Reviews abbreviation. Please comment on that talk page if you're interested. &mdash; Carl (CBM · talk) 11:08, 10 August 2011 (UTC)

Shape similarity?
From two coastline maps I want to know a value for their similarity. Problem are this maps. The one of 1531 is the dominant Antarctica shape of the 16th century. I know a long dispute whether it is by chance or not. But it always goes along very subjective identifications of similar points. Is there some mathematical theory or algorithm that can applied to this over 50 year old problem? Where should I ask? -- Portolanero (talk) 15:37, 10 August 2011 (UTC)
 * This is more a question for Reference desk/Mathematics than the project page which is about mathematics articles. I'm copying your post there. Reference desk/Mathematics. --Salix (talk): 15:46, 10 August 2011 (UTC)

Semiotics of the structure
Semiotics of the structure has been PRODed and dePRODed. It seems to be the work of a single editor and I'm having trouble finding any meaningful mathematics in the article; the references mostly link to a website in Estonian. Can someone with some graph theory expertise have a look and determine if this is a notable subject?--RDBury (talk) 17:24, 12 August 2011 (UTC)


 * I disclaim the expertise, but I think we could risk the chance that this approach is going to lead to a proof of the reconstruction conjecture and take it to AfD. SPA creation. Charles Matthews (talk) 19:37, 12 August 2011 (UTC)


 * How likely is it that this article will survive? It has numerous English language issues which need to be patched, but if the whole thing will be scrapped anyway I won't have to worry about them... Rschwieb (talk) 14:04, 13 August 2011 (UTC)

Infinite Numbers
New editor has requested that a mathematician give their opinion on the article he created, Infinite Numbers, currently proposed for deletion. --88.104.39.209 (talk) 05:35, 13 August 2011 (UTC)
 * The deletion notice pretty much covers it, the editor apparently did not understand the no OR policy. As to whether the math itself is valid, this isn't really the place to ask; we leave peer review to publications. To me it appears to be a combination of real numbers and q-adic numbers and I doubt those can be combined in a consistent way, but that's just an initial impression.--RDBury (talk) 08:16, 13 August 2011 (UTC)
 * In the end I decided I thought that the author's request for a mathematician to say something about it was not unreasonable, even if not exactly according to WP protocol, so I responded at talk:Infinite Numbers, basically saying that it looked something like the p-adics but not quite, and that as the p-adics are not typically thought of as infinite, it didn't make sense for the redirect to go there. --Trovatore (talk) 09:35, 13 August 2011 (UTC)

I notice that Infinite number and Infinite Numbers now redirect to different articles, which doesn't make much sense. I was going to change Infinite number to point to Transfinite number, but I'm not sure whether that's a good idea - the problem is that Transfinite number only deals with infinite cardinals and ordinals, whereas "infinite number" could also refer to other things (e.g., in hyperreal fields). Maybe a disambiguation page would be appropriate. --Zundark (talk) 10:55, 13 August 2011 (UTC)
 * I've made a couple of WP:BOLD edits. Of course the two pages should redirect to the same place.  For now I've pointed them both to transfinite number, and edited the lead of the latter so that there is a link to infinity in the first sentence.  Probably hyperreal number should be mentioned in the transfinite number article; I'm not sure whether that belongs in the lead or in the "see also" section. Jowa fan (talk) 13:42, 13 August 2011 (UTC)

Thanks to those who were useful in their response. I don't know why anyone would think a peer review was being requested; the point was to get one or more recognised mathematics editors to say, "No, this isn't a known concept."

If someone does decide to create a disambiguation page out of "infinite number(s)", do give me a call. In my experience, expert editors tend to bugger up the formatting. TTFN, 88.104.39.209 (talk) 17:58, 13 August 2011 (UTC)

There's a dispute on the merge of Super-logarithm and Super-root to Tetration.
There is a need of more mathmatical judgement on the situation to bring it to a resolution. Anyone interested in joining the discusion is welcome to join it at Dispute resolution noticeboard. Robo37 (talk) 20:23, 13 August 2011 (UTC)

Pages needing attention/Mathematics not updated / more structured list possible?
Following a thread above, I noticed that this page does not seem to be updated. Is it possible to do so automatically? (The page says it already is, but the history of the page shows it is actually not, for ages). Even better, is it possible to have an automatically updated list (Carl?) which groups the articles with problems according to the topics (Algebra, Geometry, etc.). I think a more structured list would be quite some improvement, for example I have zero to epsilon knowledge in statistics, so I am unlikely to supply requested sources / deal with the "expert needed" tag in those articles. Jakob.scholbach (talk) 20:07, 13 August 2011 (UTC)
 * It is being updated, see . (most of the content is from a different page.)--RDBury (talk) 12:49, 14 August 2011 (UTC)

RFC on identifiers
There is an RFC on the addition of identifier links to citations by bots. Please comment. Headbomb {talk / contribs / physics / books} 15:52, 15 August 2011 (UTC)

Original research at confluent hypergeometric function
User:A. Pichler, who has a very long history of adding original research to special functions articles, is trying to include a piece of original research in the confluent hypergeometric function article. When pressed for a citation, the one he gave completely failed to support the added content. The situation may need to be monitored by someone. 166.205.11.236 (talk) 23:34, 15 August 2011 (UTC)

deletion of equidistant
See Articles for deletion/Equidistant. Michael Hardy (talk) 02:56, 3 August 2011 (UTC)
 * It's a pity Redirects for discussion/Log/2011 July 25 wasn't mentioned here earlier. The redirect to Wiktionary strikes me as an unsatisfactory solution: non-mathematicians won't be familiar with the range of things that "distance" can mean in mathematics, and it's unlikely that Wiktionary will ever address this.  I wonder if it's worth reopening the discussion, with a view to changing it back to a redirect to distance. Jowa fan (talk) 06:11, 3 August 2011 (UTC)
 * Agreed, and WP:BOLDly changed. CRGreathouse (t | c) 13:09, 3 August 2011 (UTC)

Jowa fan informed me of this discussion on my talk page as I converted the redirect into a soft-redirect in accordance with the outcome of the unanimous discussion at redirects for discussion (in which I proposed the soft-redirect). Having looked again at the distance article after reading the above, I am still of the opinion that the soft-redirect is the best option. This is primarily because the word "equidistant" does not appear in the article and so readers (the majority of whom will, like me, not be mathematicians - indeed most of the article is way above my head) will not be any the wiser about what "equidistant" means, either in a mathematical sense or in common usage. If the topic of being equally distant from two or more points can sustain an encyclopaedia article (my guess would that this would be more likely at a title like equidistance) then write one, although as a lay person I can't comprehend how it can - the definitions at equidistant seem to cover everything, both commonly and at least two mathematical uses (one labeled though as "cartography"). If there are more meanings in mathematics then add them to the Wiktionary article, tagging them with if that definition is not in general usage. Wiktionary's goal is to include all definitions in all languages, but it is currently even less complete than Wikipedia is - the good news though is that you can help! If you still think that a redirect to distance is the best option, then start a new RfD (which is the correct venue for discussions about soft redirects) with a link to the one just closed, giving your reasons why the previous consensus was wrong, along with the evidence for why "equidistant" should redirect to "distance" (and that "non-mathematicians wont understand everything distance can mean" isn't a reason that will likely sway many people without an explanation of what other things "equidistant" can mean that are not definitions that can be covered at Wiktionary). Alternatively, DRV is always an option. Thryduulf (talk) 01:58, 4 August 2011 (UTC)

What is the standard English term for the line formed by the points that are equidistant to two objects. (For example the locus of points that are equidistant to a line and a point form a parabola.) In Dutch such a line is called a "conflictlijn", my best guess in English would be "equidistant" of "equidistant line". For now, I can't even an article on the English wikipedia that discusses this subject. (I would be really surprised if it doesn't exist since this is standard high school geometry.) Whatever this article is called, equidistant should probably redirect there.TR 09:43, 4 August 2011 (UTC)


 * In reply to Rias is a perpendicular bisector see also Locus (mathematics). This indicates to me that there is a non trivial article for equidistant which covers its meaning and its uses. Topological skeleton is an other important use. It could go to Deletion review or an article just be written. --Salix (talk): 10:34, 4 August 2011 (UTC)
 * Actually, perpendicular bisector is just a particular case of a "conflictlijn". Namely, the case where the two objects are both points. More generally given two geometrical objects/sets A and B (in a plane), the "conflictlijn" between A and B is the locus of points that have equal distance to A and B. I guess you could call it an "equidistant locus", or something, but googling that does reveal it as very standard. As far as I can tell, there doesn't seem to be a standard term for this in English.TR 12:22, 4 August 2011 (UTC)
 * Hum the dutch name suggest "Conflict strata" of which the medial axis is one example. That would fit you definition as well.--Salix (talk): 12:46, 4 August 2011 (UTC)

If a single soft-redirect to wiktionary seems unsatisfactory to some maybe a disambiguation page would help? Nageh (talk) 11:23, 4 August 2011 (UTC)
 * The soft-redirect is terrible and disagrees with every !vote at the AfD. But I'm not prepared to fight it out with Thryduulf. CRGreathouse (t | c) 13:38, 4 August 2011 (UTC)
 * However it was the unanimous opinion of everyone who commented at the RfD (the correct venue to discuss redirects and soft-redirects). Wikipedia is not a fight, I am merely stating my opinion and have no more claim of right or ownership than you. However if you truly believe that the closure of any deletion discussion is wrong (which you seem to think is the case for the AfD at least) then you should discuss this with the closing admin (which wasn't me for either RfD or AfD - I wasn't even aware of the latter before it was closed), and then take it to DRV if this does not resolve things. Reading the posts since my previous comment, I've still not seen anything that convinces me that "equidistant" should redirect to distance nor have an article at that title. What I can make out from the geometry discussions (which are more advanced than anything I did at GCSE) is that there might be an article that can be written to which equidistant should redirect - if so, this should be written and then the soft-redirect proposed for retargetting at a new RfD (linking to the old one but making clear that the proposed target didn't exist at the time of the first discussion). Thryduulf (talk) 14:31, 4 August 2011 (UTC)
 * Again, not willing to fight this out. I disagree but I like WP:0RR and don't have time for DRV nonsense. CRGreathouse (t | c) 15:21, 4 August 2011 (UTC)

I've sketched out a draft stub article at Talk:Equidistant, there definately seem to enough material for an article an I've not even looked at other notions of distance.--Salix (talk): 22:49, 4 August 2011 (UTC)
 * I still think that a disambiguation page for the term would be more appropriate. It is primarily a dictionary definition, and it is a common term not only in computer graphics/computational geometry but also in numerical analysis, geodesy, and used in many other fields. Nageh (talk) 09:45, 5 August 2011 (UTC)
 * I'm not opposed to a dab page. The range of meanings is certainly broad enough. CRGreathouse (t | c) 13:01, 5 August 2011 (UTC)
 * The closing admin said it was alright to recreate and I've now done so. For the other uses you could work them into the text of the article or maybe has hat notes at the top.--Salix (talk): 13:35, 5 August 2011 (UTC)

Thryduulf's comment that it is "primarily because the word 'equidistant' does not appear in the article" makes his position seem silly. Michael Hardy (talk) 23:48, 5 August 2011 (UTC)


 * For courtesy, I note that I took this to RfD to reverse the redirect, to use equidistance as the article title, per WP:NOUN, and is now at Wp:RM, from which there are links to the RfDs, previous RfD and PROD. I am not suggesting to change the article content, just the title (and the lead syntactically of course to say Equidistance not Equidistant, but that is just a syntactic change, not proposing to change the meaning.) Si Trew (talk) 06:50, 18 August 2011 (UTC)

Request for reference on Annihilator (ring theory)
If someone can contribute a citation to this section I think the unreferenced tag can finally be cleared. Please drop in and see if you can do something. Rschwieb (talk) 13:41, 16 August 2011 (UTC)

Fermat
Fermat's 410th birthday is currently being commemorated by Google. Could someone keep an eye on the (anonymous) edits at Fermat's Last Theorem and Pierre de Fermat? Cheers, —Ruud 21:19, 17 August 2011 (UTC)
 * An 'In popular culture' section has been added since yesterday. This kind of material is often unencyclopedic trivia but I'm on the fence in this case. Second opinion?--RDBury (talk) 02:20, 18 August 2011 (UTC)

New content at Iterated function
A lot of new content has recently been added to the page iterated function, under the subheading Iterated_function. Someone might like to review this. Jowa fan (talk) 01:21, 18 August 2011 (UTC)
 * The new content is unreferenced and appears ORish, it's hard to complain about it though because the entire article is basically unreferenced.--RDBury (talk) 02:10, 18 August 2011 (UTC)
 * Having done such things (for fun), I agree that the formulas are original, and omit discussion of the (rare) conditions when they apply. $$f'(a)$$ must be positive and not equal to 1 for any possible interpolation to work for fractional values to work.  But perhaps other discussion of fractional iteration might fit in with Abel functions.  — Arthur Rubin  (talk) 14:54, 19 August 2011 (UTC)

Split Partition (number theory)?
In 2006, the articles Integer partition and Partition function (number theory) were merged to create the article Partition (number theory). Most of the article as currently written is about the partition function, with a few sections (e.g. on Ferrers diagrams) that are about partitions themselves. It seems to me that the original separation into two articles was more sensible, as (e.g.) the discussion of Ramanujan's congruences is really completely distinct from a discussion of Young diagrams or Young's lattice (the latter of which is currently not mentioned in the body of the article, unfortunately). Splitting the article as currently written would, I think, be not too hard -- most of it would go into Partition function (number theory), the rest into integer partition, and the latter article would have a short section with a link to the former and a brief summary of the most important points. (The latter article would need to be expanded.) What do you think?

On a not-totally-unrelated note, it seems to me that the content of the article is much more about combinatorics than it is about number theory. This is less egregious than for Composition (number theory) (an article with no number-theoretic content whatsoever, as far as I can tell) -- is there some good reason this is classed as number theory and not combinatorics?

Thanks! --Joel B. Lewis (talk) 03:13, 19 August 2011 (UTC)
 * There is enough material to make 'Partition function (number theory)' a full article, but I'm not so sure whether the remaining material on 'Integer partition'. Much of that is rather TEXTBOOKy and could easily be removed, leaving not much more than a stub. There is more to say on integer partitions that's not in the article, I'm thinking specifically of the dominance relation which we don't seem to cover anywhere, but much is probably already in other articles so if may be hard to expand without CFORK issues. So perhaps a more comprehensive reorganization is in order, but in general I'd prefer to avoid a split if one of the resulting articles is going to be Start or Stub quality.
 * I think the reason Partition function is considered a topic in number theory is is because Hardy and Ramanujan applied the techniques of analytic number theory to study it. Certainly many textbooks on number theory cover it, though combinatorics texts cover it as well. I don't think there's a corresponding reason for compositions to be considered number theory; the "composition function" is just 2n.--RDBury (talk) 13:08, 19 August 2011 (UTC)
 * Correction, we do cover the dominance relation here.--RDBury (talk) 13:22, 19 August 2011 (UTC)
 * Sorry, I don't mean that I don't think the partition function belongs to number theory, I just meant that I felt the article as written was more combinatorial than number-theoretic. I've begun expanding the "integer partitions" part of the article; I'm going to add some information on orders on partitions, plus the Durfee square (an article that should probably just be merged in as a subsection anyhow).  Anyone who wants to lend a hand is more than welcome.  Perhaps I'll re-raise the question later.
 * I don't thing I agree about textbookyness -- the discussion has a bunch of definitions and simple examples, but that's what I would expect from an article titled "Integer partitions".
 * What does "CFORK" mean?
 * I'm going to go ahead and move Composition (number theory) to Composition (combinatorics) unless anyone objects. --Joel B. Lewis (talk) 15:22, 19 August 2011 (UTC)
 * Sorry for the wikijargon, CFORK is WP:Content forking.--RDBury (talk) 15:54, 19 August 2011 (UTC)

Riemann invariant
I just reviewed and copy-edited the Riemann invariant article for WP:AFC. I didn't see any red flag, and I shaped it up as best I could, so I gave it the thumbs up, but it definitely could use more eyes. Especially about the categories, and also there is a reference to an article by Riemann which I haven't been able to find. Help would be appreciated. Headbomb {talk / contribs / physics / books} 02:13, 20 August 2011 (UTC)
 * A similar citation appears here. Could it be this instead? "Ueber die Fortpflanzung ebener Luftwellen von endlicher Schwingungsweite" (1860)  For Riemann's publications, I was looking at this resource . Rschwieb (talk) 14:25, 20 August 2011 (UTC)


 * Concerning the first, that might be it, but I can't see the reference (google doesn't show me). No idea about the second (there are similar papers in Abhandlungen der Königlichen Gesellschaft der Wissenschaften zu Göttingen and Göttinger Nachrichten. I've seen hints that he might have done the work in 1858 and published later circa 1867, but again no solid lead. Headbomb {talk / contribs / physics / books} 14:45, 20 August 2011 (UTC)


 * Here's a link for "Ueber die Fortpflanzung ebener Luftwellen von endlicher Schwingungsweite" you should be able to access: You can obtain the paper in other formats at . Riemann did apparenty write the paper "Ueber die Flache vom kleinsten Inhalt bei gegebener Begrenzung" in 1858 (per ; published later in 1867 -- this must have been what you were referring to), but this paper did not deal with "plane waves in gas dynamics" as mentioned in the Riemann invariant article (link ). &mdash; Myasuda (talk) 16:20, 20 August 2011 (UTC)

Boubaker polynomials
Yes, again. If I'm not mistaken the consensus following the last deletion review was that the subject may be notable if written about in a neutral way by someone other than User:Mmbmmmbm and his socks. Well, now we have an AfC submission from an IP with no other contributions. If someone with expertise could look it over and decide whether the article is sufficiently POV-free to be accepted it would be appreciated. joe&bull;roet&bull;c 15:45, 20 August 2011 (UTC)
 * Not sure that it takes a lot of expertise, unless you count knowledge of how people can game WP notability guidelines. For example the reference I checked only listed the subject as part of one title of about 30 in a bibliography. So I guess the strategy is to paste Google search results into the article as references without regard for whether they are relevant to much less verify article content with the idea that the subject will look notable to a casual reader. To me, the point of not covering obscure research topics here is we can't be expected to have experts of the required degree of specialization to verify the content. So it defeats the purpose if a similar degree of expertise is needed to check the article against notability guidelines.--RDBury (talk) 19:29, 20 August 2011 (UTC)
 * You are challenged to prove it is a "pasted Google search results"
 * Sorry, but this version contains tens of sources which are all REACHABLE, please check. — Preceding unsigned comment added by 41.227.28.18 (talk) 00:56, 21 August 2011 (UTC)

The very first citation, that most of the article seems to be based on, is published by Nova Publishers, which seems to be a dubious enterprise. Sławomir Biały (talk) 02:39, 21 August 2011 (UTC)

Note also the spelling: "Boubaker Polynomıals" rather than "Boubaker Polynomials", presumably to avoid being detected as the same article that's been repeatedly pushed. CRGreathouse (t | c) 04:47, 21 August 2011 (UTC)
 * That's pretty damning to me. —David Eppstein (talk) 06:25, 21 August 2011 (UTC)

Formula help
Hey, could someone give a hand with writing the formula in IBM Award in formula style  Purpleback pack  89  ≈≈≈≈  22:16, 20 August 2011 (UTC)


 * Okay, I slavishly converted it to TeX, but I'm not sure I understand what it was I just typed. For example, is the meaning of "FGA" in the numerator the same as the meaning of "FGA" in the denominator, or is the thing in the numerator "player FGA" while the thing in the denominator is "team FGA"? The formula alone is not entirely informative—it needs a paragraph of English prose explaining exactly what all the abbreviations stand for, and which ones refer to player stats as opposed to team stats. —Bkell (talk) 22:50, 20 August 2011 (UTC)


 * Also, I don't understand why the formula says $$(\mathrm{team\ wins}\times10)\times250$$ instead of just $$(\mathrm{team\ wins}\times2500)$$. Are you sure the formula is transcribed correctly from the source? —Bkell (talk) 22:52, 20 August 2011 (UTC)


 * I forgot a set of parenthesis. I added that in, as well as the player and team info and a sentence explain the abbreviations.  I hope that satisfies your clarification concerns.  Also, somehow, player points came out in italics.  Could you fix it?  Again, thanks!  Purpleback  pack  89  ≈≈≈≈  23:21, 20 August 2011 (UTC)


 * Okay, now I don't understand why the "× 250" is there at all—it only serves to scale up the score, but has no effect on rankings. —Bkell (talk) 23:28, 20 August 2011 (UTC)


 * Beats me. I'm not IBM.  I think it's to guarantee that the numbers will be sufficiently large.  This is how the formula appeared in the ESPN Sports Almanac.  Other than that, have your clarity concerns been addressed?  Purpleback  pack  89  ≈≈≈≈  23:37, 20 August 2011 (UTC)


 * Yes, I think so. Thanks. —Bkell (talk) 23:47, 20 August 2011 (UTC)

Proposal for descriptive redirects
I claim benefits to math articles in a proposal I posted at the pump: Village pump (proposals). ᛭ LokiClock (talk) 02:35, 21 August 2011 (UTC)

"Region (analysis)" or "Region (mathematical analysis)"?
Opinions of this edit?

My view is that the title should sufficiently disambiguate and tell the reader something about the nature of the topic. "Analysis" is a word that has many different meanings in many different fields. It fails to tell the lay reader that mathematics is what the article is about. Michael Hardy (talk) 03:12, 21 August 2011 (UTC)
 * Since the first sentence of the article includes the word "mathematical", I don't see much potential for confusion. (And how would people arrive at that page, other than by following a link from a mathematics article or a search involving a mathematical topic?)  Personally I think "Region (mathematics)" is more elegant than "Region (mathematical analysis)", but I don't think it's worth making too much fuss over. Jowa fan (talk) 10:05, 21 August 2011 (UTC)
 * Jowa fan: Some of your comments don't make sense. You say "how would people arrive at that page, other than by following a link from a mathematics article or a search involving a mathematical topic?", to which obvious answers are:
 * By following a link from a disambiguation page;
 * By following a link that says "region (analysis) when the author intends the word analysis in the sense used in the field of omphalology, or linguistics, or theology, or coin collecting, or paleontology, or something. As I said: analysis has many meanings in different fields, some of which you probably don't know about!  Did you miss that?
 * If you don't see potential for confusion, you haven't thought about it much. Michael Hardy (talk) 23:35, 22 August 2011 (UTC)
 * Thanks for the explanation (and no need for you to be patronising about it). My thought was that, although it's possible for someone to foolishly create links of that sort, such things don't currently exist (according to the "what links here" tool), and don't seem likely to pop up.  A disambiguation page would generally include a few words of text describing each link, if the title doesn't already make it obvious.  Someone adding a link to an article would usually check that the page linked to does in fact exist and contain something appropriate.  But it seems anyway that you've solved the problem, so there's no need for further discussion. Jowa fan (talk) 00:43, 23 August 2011 (UTC)


 * I agree, "Region (mathematics)" would be most appropriate. (Unless there is some other mathematical meaning of Region that I'm unaware of.TR 09:02, 22 August 2011 (UTC)

First, I was unaware of Hardy's previous edit. I don't even recall why I made that move. But a general principle I follow is "mathematics" is usually superfluous in disambiguating an article title since the point is to resolve name conflicts. It's like, often xyz (lawer) is good enough. If not, you use xyz (Iowa lawer) or something. -- Taku (talk) 12:42, 21 August 2011 (UTC)


 * Good point by Michael Hardy. See Analysis to see some of the many possible meanings of this word. JRSpriggs (talk) 14:01, 21 August 2011 (UTC)
 * Agree. "Analysis" by itself is inadequate disambiguation.  Sławomir Biały  (talk) 00:17, 22 August 2011 (UTC)

Operator of proper-time-derivative
Operator of proper-time-derivative looks as if it was written by someone who's better at Russian than at English. Maybe I'll do some editing on it tomorrow if someone doesn't make it flawless before I get to it. Michael Hardy (talk) 03:27, 21 August 2011 (UTC)


 * See Wikipedia talk:WikiProject Physics. JRSpriggs (talk) 14:04, 21 August 2011 (UTC)

Orthogonal polynomials split
Orthogonal polynomials was recently split with much of the material now in Classical orthogonal polynomials. The split is probably a good idea, there is certainly a dichotomy between the general theory and the study of important specific examples, but I couldn't find much discussion on the split so I thought it would be a good idea to mention it in case people want to review.--RDBury (talk) 16:44, 22 August 2011 (UTC)

Continuous function
Following a clean-up tag, I started tidying continuous function. Maybe someone is interested in the topic, too? (Not only w.r.t. to tidying up!) Jakob.scholbach (talk) 22:15, 22 August 2011 (UTC)
 * Wow. My first reaction is "OMG a kudzu in the continuous function article!" Let's think a bit about which topics are not too distantly related, and decide which ones are too far afield. Rschwieb (talk) 00:59, 23 August 2011 (UTC)

Soliciting opinions on symbolic formulas for Sieve of Eratosthenes
Please make your comments here: Talk:Sieve_of_Eratosthenes.

Only two editors had so far participated in the discussion. Need more opinions to put the matter at rest.

Your help will be greatly appreciated. WillNess (talk) 13:07, 22 August 2011 (UTC)


 * The issue is closed. Thanks to all for your participation. WillNess (talk) 14:30, 23 August 2011 (UTC)

Extrapolation
Hi everyone,

Reading the article Radius of convergence, I had some troubles to understand the following lines :

When the behavior of the coefficients is one of constant sign or alternating sign, Domb and Sykes proposed plotting $$c_n/c_{n-1}$$ against $$1/n$$ and then fitting a straight line extrapolation to $$1/n=0$$ estimates the reciprocal $$1/r$$ of the radius of convergence.

I have no idea whether it is fully understandable for a native speaker, but I, poor Frenchman, don't understand it :-) These lines were written altogether, and I can't ask the author what he means (he's away from WP). My question is : what does it mean, a straight line extrapolation to $$1/n=0$$ ? Sorry if this is a common way to say it ; otherwise it should be rewritten properly. Thanks by advance. Mutatis mutandis (talk) 13:21, 22 August 2011 (UTC)


 * I'd start by Googling "Domb-Sykes plot".  Sławomir Biały  (talk) 14:41, 22 August 2011 (UTC)


 * This does seem to be a common technique for applications. I think the idea is you plot (xn, yn) with xn=1/n and yn=cn/cn-1 and try to fit a curve to the points. Where the curve intersects the y-axis is the (estimated) radius of convergence. It's true that the phrase "1/n=0" doesn't really make sense.--RDBury (talk) 17:07, 22 August 2011 (UTC)
 * Okay, intersection with the y-axis seems reasonable. Thank you ! (I have no suggestion of a better sentence, feel free to improve it in the article. :-) Mutatis mutandis (talk) 09:38, 23 August 2011 (UTC)
 * That was an awful sentence. I've changed it, but left some ambiguity (namely, about which axis you're taking the intercept with, because which axis is which aren't specified).  If you like it, consider changing the next paragraph at well, maybe?  --Joel B. Lewis (talk) 14:29, 23 August 2011 (UTC)

I have to agree with Mutatis mutandis that the sentence is quite unclearly written. Michael Hardy (talk) 00:47, 26 August 2011 (UTC)

Is there a policy or guideline regarding the use of 'if and only if' vs 'iff'?
Regarding this edit, can someone please point me to the applicable policy or guideline regarding the appropriateness of using iff or if and only if in definitions? I would appreciate to be pointed to the passage of text explicitly justifying this reversion by User:Rschwieb. Toshio Yamaguchi (talk) 15:45, 23 August 2011 (UTC)


 * Neither "iff" nor "if and only if" should be used in definitions. CRGreathouse (t | c) 15:49, 23 August 2011 (UTC)


 * Can you show me the policy or guideline where this is written? Not that I don't trust what you say, but I would like to see the applicable piece of text. Toshio Yamaguchi (talk) 15:53, 23 August 2011 (UTC)
 * MOSMATHElen of the Roads (talk) 15:55, 23 August 2011 (UTC)
 * This only says that "if and only if" should be used instead of "iff". This still does not justify this edit. Toshio Yamaguchi (talk) 16:00, 23 August 2011 (UTC)
 * No, it specifically talks about if and only if in definitions. Sławomir Biały  (talk) 16:04, 23 August 2011 (UTC)

As for the edit in question, I'd say that the first "if and only if" is inappropriate, since it's a definition. The second "if and only if" seems more appropriate to me, since it's not obvious that the sentence is a characterization of the W primes without it. (Maybe the section title should be "Equivalent characterization..." rather than "Definition...", or the first sentence should be rewritten do it's clearly a definition.) Sławomir Biały  (talk) 16:04, 23 August 2011 (UTC)
 * All four statements are equivalent. If one of the four definitions applies, then also do the other three. Toshio Yamaguchi (talk) 16:13, 23 August 2011 (UTC)
 * I understand that. It needs to be made clear somehow that these are definitions.  It is currently poorly written.  Sławomir Biały  (talk) 16:20, 23 August 2011 (UTC)
 * I am not sure how much clearer than "Definition via ..." I could get. Can you please give me an example of what in your opinion would count as not "poorly written"? Toshio Yamaguchi (talk) 16:27, 23 August 2011 (UTC)
 * I rephrased all of the definitions to avoid the word "if" completely. —Bkell (talk) 16:29, 23 August 2011 (UTC)
 * Yes, this works. Sławomir Biały  (talk) 16:46, 23 August 2011 (UTC)
 * Thanks to all of you. Toshio Yamaguchi (talk) 17:02, 23 August 2011 (UTC)


 * See Wikipedia talk:WikiProject Mathematics/Archive/2011/Jul and many earlier discussions of this same topic. The MOS and the majority view on this subject is wrong. We should use "if and only if" in definitions. JRSpriggs (talk) 09:02, 24 August 2011 (UTC)


 * I tend to agree with JRSpriggs that "if and only if" (though certainly not "iff") should be acceptable, but it seems to me that the most convincing comment in the previous discussion was the one suggesting that we should avoid "if", as well. For example, in this case, "The Wolstenholme primes are those prime numbers $p > 7$ that satisfy the congruence relation ..." or "The Wolstenholme primes are those prime numbers that divide ..." or similar.  --Joel B. Lewis (talk) 13:26, 24 August 2011 (UTC)
 * The Handbook of writing for the mathematical sciences by Nicholas Higham says not to use "if and only if" in definitions. Most published mathematics I have read seems to follow this advice.   Sławomir Biały  (talk) 14:06, 24 August 2011 (UTC)


 * Also, I'd like to reiterate a point made by Trovotore in an earlier thread. Definitions in mathematics are set in the imperative mood.  If you read many mathematical definitions in the indicative mood instead (treating them as logical propositions), then you are going to have problems.  For instance "A positive integer is called prime if/iff it is not equal to 1, and its only divisors are 1 and itself."  This seems a reasonable definition in the imperative mood, but in the indicative mood it states something about the predicate "called".  In fact, it's something that is unlikely to be true: there are many situations where, say, the number 5 is not "called" prime, instead it is "called" 5, or maybe "fifth Fibonacci number", etc.  Many definitions could probably be rewritten in the indicative mood to avoid this sort of issue, but the fact is&mdash;like it or not&mdash;most mathematical definitions are not written this way.  Sławomir Biały  (talk) 14:35, 24 August 2011 (UTC)


 * Hi Sławomir Biały, I've read the earlier posts and you don't need to repeat the points made there for my benefit -- I happen to disagree with the majority opinion here, but this is not so important (as, e.g., I'm certainly not planning on spending my time going around and making changes to articles for this reason). It would be more interesting to me if you would respond to the second half of my comment. --Joel B. Lewis (talk) 17:16, 24 August 2011 (UTC)
 * Thanks. I was responding to JRSprigg's blithe dogmatic assertion that the majority opinion is  wrong (as if this were a pure matter of fact rather than one of style).  As for avoiding logical connectives, many definitions do read more clearly without either, but I don't think it's a good idea to insist on this as a general rule.  18:01, 24 August 2011 (UTC)
 * I hadn't intended to cause so much trouble :) I think Sławomir Biały's explanation sums it up: there is a subtle semantic point. The absurdity of including "only if" is a little more apparent if you use "is defined to be" instead of "is called a". I would be surprised if "defined to be" could ever be used in a consequent in this way: you would have to believe that "An X is defined to be a Y only if Z". What antecedent could possibly cause something to be defined to be something? After definition occurs, you can then begin to identify objects with property Z as Y's. This identification looks like an "iff", but it can't be that way before definition occurs. Rschwieb (talk) 20:26, 24 August 2011 (UTC)

Right: definitions are a different sort of object from propositions. Usually they're not even part of the formal system, making them pretty clearly different; systems like DZFC and proofless text/LPT/PST. CRGreathouse (t | c) 14:18, 25 August 2011 (UTC)

Given (mathematics)
Should something be done with Given (mathematics)? It's essentially a dictionary definition now. That Euclid wrote a book with this title (Data) causes me to hesitate before agreeing with the deletion proposal. Michael Hardy (talk) 19:22, 25 August 2011 (UTC)
 * My immediate reaction is we have far too many of these things and it's probably best deleted. Encyclopedia articles should not be written just to navel-gaze on how mathematicians use language.  That said, if someone could show me a serious treatment of the subject about which there's really something to say, I could be persuaded otherwise. --Trovatore (talk) 19:28, 25 August 2011 (UTC)


 * Article was de-prodded; I have nominated it at AfD. --Trovatore (talk) 08:38, 29 August 2011 (UTC)

List of dualities
I have just learned that the following article does not exist:

List of dualities.

We have zillions (maybe dozens or hundreds?) of articles about particular dualities. Michael Hardy (talk) 00:50, 26 August 2011 (UTC)


 * ....and now it exists but it needs a lot of work. Some organization and maybe some commentary could be added to each section. Michael Hardy (talk) 01:55, 26 August 2011 (UTC)
 * Amazing: Less than two hours after I created this article, I enter "list of dualities" into Google and it's the fourth item listed. Michael Hardy (talk) 03:05, 26 August 2011 (UTC)


 * That's Freshbot for you. CRGreathouse (t | c) 03:08, 26 August 2011 (UTC)
 * According to this it typically takes 15 min. for Google to find a new WP page.--RDBury (talk) 10:25, 26 August 2011 (UTC)

Is mirror symmetry a duality? Since I'm not a physicist, wikipedia artciles on this topic are almost unintelligible. -- Taku (talk) 12:58, 26 August 2011 (UTC)
 * I'd say yes. TR 13:24, 26 August 2011 (UTC)

Question about editing and who can edit
I was looking at the page for chi distribution. Like a great many pages on statistics here, the definition is techincal and it is likely correct, but unhelpful to people--like me--looking up the article to gain insight from a introductory level. I assume that would be the goal? Or am I mistaken (of course it needs to be technically correct, too...).

Indeed, the stats articles overall seem to discourage undertanding for general readers by assuming a level of sophistication that is too high. For example, if you don't know what the chi-distribution is, you likely don't know what it means to say that "a k-dimensional vector's orthogonal components are independent." I would argue that a more "instructional" and less "technical dictionary" approach needs to be taken to the style of such articles. Sorry I cannot help provide such editing, as I don't have the stats background to do so. However, as a college teacher as well as frequent wikipedia reader, I would argue for such a switch in style. Or am I misunderstanding the goal? — Preceding unsigned comment added by 68.239.82.231 (talk) 13:56, 27 August 2011 (UTC)
 * I have altered the language at the beginning of the article, expunging the part about vectors. As far as I can tell, that's the only thing in the first paragraph to which one could object on the grounds mentioned here. Michael Hardy (talk) 03:52, 29 August 2011 (UTC)
 * You put your finger on the conundrum we've all struggled with :) If you scroll up to the top of this page, you can see in the FAQ we try to address this. Consider putting appropriate flags like "too technical" on pages you are interested in. Rschwieb (talk) 14:05, 27 August 2011 (UTC)


 * Yes, I agree. There are lots of math articles (and textbooks and research papers) that would be a lot better if someone invested a lot of effort in making them easier to understand.  When you encounter one that is bad and that you can't help with, placing an appropriate tag will help later editors.  (See Cleanup.)  Ozob (talk) 19:20, 27 August 2011 (UTC)

I believe the fundamental problem is that we don't motivate by example first (unlike other parts of WP, where at the very least an introductory section giving a specific concrete way into the topic is standard). I think the maths article style guide should be modified to strongly encourage presentation of a motivating example up-front, before the topic is set out in full generality.

At the moment the pattern for probably the majority of our articles is to give a general definition first, and then (almost as a tacked on addition) to have a paragraph where a number of examples are given (usually in fairly abstract terms). That may be considered good style in lecture notes, and may be interpreted by many as what is being advocated by the maths article style guide as currently written; but it is not appropriate if our intention is to try to make at least the first few sections of our articles as broadly accessible as possible. So I think the advice in this area needs a rewrite. Jheald (talk) 20:32, 27 August 2011 (UTC)


 * I'm not sure that this advice needs to be rewritten so much as it needs to be heeded. The advice is to put a non-technical example and/or motivation in the lead and I have not seen this advice followed often enough. I would not want to advocate a standard "example" before "definition" approach, although I do support this when it is appropriate. The problem as I see it is that, especially for some of our more exotic concepts, the examples are just as technically challenging as the definitions and having them presented first does not help to simplify the discussion. In cases like this one should attempt to talk around the concept - providing motivation for why the concept is needed/important in a non-technical way. Wcherowi (talk) 18:31, 28 August 2011 (UTC)
 * Often the leads of our articles are criticized because they do just that: they talk around a concept rather than defining it. I think we should attempt to define the topic in a way that the casual reader can understand (as far as possible, given the likely readership), and also to provide motivation for why the topic is important.  These are both requirements of WP:LEAD.  It is very challenging to do this for mathematics articles, though, which is why you see so many leads that don't even attempt to be accessible, and so many that try too much and thus "talk around the topic" and in so doing lose their sense of encyclopedic authority.   Sławomir Biały  (talk) 18:49, 28 August 2011 (UTC)
 * I would agree that "talking around the topic" is unhelpful, but so is an excessively technical definition, which only makes sense if you already understand the topic. On the other hand, I'm not wild about, for example, Abelian group, in that "group in which the result of applying the group operation to two group elements does not depend on their order" seems to me less clear than "a group where a • b = b • a." In many cases, articles would also benefit from negative examples, at least via a link (e.g. that the dihedral group of order 6 is a non-abelian group), lest some reader think "but isn't that always true?". Writing a good mathematics article is a great challenge, which requires taking account of the level of knowledge that can be expected of the reader. All too often, in the attempt to make articles authoritative, they become incomprehensible to the average reader. -- 202.124.73.250 (talk) 05:26, 29 August 2011 (UTC)
 * I think we're basically in agreement. One does need to take into account that the "average" reader for an article Grothendieck topos is not going to be the same as the average reader for the article Pokemon.  The lead should attempt to define the topic as clearly as possible for the widest class of likely readers of the article.  The lead should also summarize the contents of the article, even the more technical parts of it.  Often this goal is in conflict with making the lead more accessible, but it is also an important priority.   Sławomir Biały  (talk) 13:30, 29 August 2011 (UTC)

+ C in the solution of integrals
The pages linked to from Lists of integrals currently differ a bit in their display of formulae. Some add the integration constant C at the end, whereas some leave it out. What is the current convention on this? You know, I find it pretty confusing having it on some pages, but leaving it out on others. --The Evil IP address (talk) 12:53, 29 August 2011 (UTC)
 * I worked on the trig list a few years ago and one of things I did was to add +c everywhere. You can get some odd results if you leave out the constant, e.g. (from the talk comment I left then) integrating $$2 \cos x \sin x$$ two different ways gives $$\sin^2 x$$ and $$-\cos^2 x$$; without the +c you get $$\sin^2 x = -\cos^2 x$$, which is wrong. In formulas where the integral is reduced to another integral, the +c is already implied in the other integral and so it should be left out. I personally prefer +c over +C but the capital seems to be more standard.--RDBury (talk) 13:13, 29 August 2011 (UTC)
 * Perhaps add a sentence at the top of such articles noting that each of the antiderivatives displayed is a single example of a family of antiderivatives, each two of which differ by a constant (with, say, a link to Constant of integration)? And perhaps in cases like the ones RDBury mentions actually making an explicit note of this? --Joel B. Lewis (talk) 14:19, 29 August 2011 (UTC)
 * List of integrals of exponential functions says "Indefinite integrals are antiderivative functions. A constant (the constant of integration) may be added to the right hand side of any of these formulas, but has been suppressed here in the interest of brevity.". JRSpriggs (talk) 00:25, 30 August 2011 (UTC)

Annihilator (ring theory)
At Annihilator (ring theory) this phrase appears: "determined by the adjunct map of the identity M→M along the Hom-tensor adjunction." I wanted to fix the redlink caused by "adjunct map" but I'm having a hard time getting hits for "adjunct map" on the web and thought perhaps the author meant "adjoint map" instead. The whole sentence is outside of my expertise: can anyone help? Rschwieb (talk) 14:22, 31 August 2011 (UTC)


 * It's really not clearly expressed. The module structure of M is a morphism $$m:R\otimes M\to M$$ satisfying certain axioms.  That is, an element of $$\operatorname{Hom}_R(R\otimes M,M)$$.  The tensor-hom adjunction gives a map $$\phi:\operatorname{Hom}_R(R\otimes M,M)\to\operatorname{Hom}(R,\operatorname{End}_R(M))$$.  So there is a canonical morphism $$\phi(m) : R\to \operatorname{End}_R(M)$$.  The kernel of this morphism is the annihilator.   Sławomir Biały  (talk) 14:50, 31 August 2011 (UTC)


 * Please, if you have time, work this information into Annihilator (ring theory) to clarify that sentence. Also, that whole section probably needs a reference, if you are aware of one. Thanks, Rschwieb (talk) 17:16, 31 August 2011 (UTC)