# Wikipedia talk:WikiProject Mathematics

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 This is a discussion page for WikiProject Mathematics This page is devoted to discussions of issues relating to mathematics articles on Wikipedia. Related discussion pages include: /Conventions /Graphics /PlanetMath Exchange /Proofs /Typography /Wikipedia 1.0 Mathematics Portal MoS Mathematics Reference desk (mathematics) (Please ask general questions of interest here). Please add new topics at the bottom of the page and sign your posts.

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## Is this web source adequate?

This web source: http://faculty.kutztown.edu/schaeffe/Tutorials/General/Polygons.html is being used to verify a long list of pretty names for naming polygons. Does this source represent, a) a reliable authority and b) sufficient use to establish the encyclopedic value of such a list? — Cheers, Steelpillow (Talk) 16:11, 14 February 2015 (UTC)

I'm happy to improve the published documentation, and ordered one mathematics dictionary to see if it'll help, but so far the referencing is basically up to 20-gon which all have articles. There's certainly some sources if you want to go to old books like this 1888 one on GoogleBooks, not to say old names are going to help what's used in modern books. [1] Tom Ruen (talk) 17:18, 14 February 2015 (UTC)
It's a plausible naming method, but not one I've seen before. In fact, to the best of my recollection, I've never seen the string "kai" within a word in a mathematical paper before. On the whole, I wouldn't consider it a reliable source, unless schaeffe's credentials can be established. I'm pretty sure I've seen pentaicosagon for a 25-gon. — Arthur Rubin (talk) 18:15, 14 February 2015 (UTC)
Regardless of the reliability of the personal web page of an obscure mathematics professor on subjects concerning ancient Greek nomenclature, I think the fact that this level of sourcing is the best that can be found for these names indicates that they are not in common use and should not be described on Wikipedia as if they are in common use. —David Eppstein (talk) 18:16, 14 February 2015 (UTC)
If Coxeter were still around, we could ask what reference he used. But I can't think of a way that we could now possibly determine "common use" for numbers over 20, except possibly 30, 40, 50, 60, 100, 1000, and 10000. — Arthur Rubin (talk) 18:27, 14 February 2015 (UTC)
Textbooks might be good.... — Arthur Rubin (talk) 18:41, 14 February 2015 (UTC)
I'll keep looking. A web source credited to John H. Conway is here [2], and George W. Hart repeats here [3]. Norman W. Johnson has web source copied here [4]. Johnson's names are more used with the polyhedra and 4-polytopes, like pentagonal hexecontahedron for a 60-hedron, pentagonal icositetrahedron for a 24-hedron, rhombic triacontahedron for a 30-hedron, tetracontoctachoron for 48-cell, and hecatonicosachoron for 120-cell, etc. So whatever varied systems are in use in polygons, polyhedra or higher, I think they can be traced and documented in some agreeable format. Tom Ruen (talk) 18:46, 14 February 2015 (UTC)
And I'd suggest that that is the core of the problem. No one system stands out as mainstream, they are all just different fringe suggestions. — Cheers, Steelpillow (Talk) 20:11, 14 February 2015 (UTC)
Luckily, the only articles we have on polygons with over 20 sides are 24, 30, 257, 1000, 65537, and 106. Of these, chiliagon (1000) has the best sourcing: the name goes all the way back to Descartes (except that he uses chiliogon), along with myriagon (Descartes: myriogon, 10000). The articles for 257 and 65537 just use the n-gon naming, so there is no problem there. Megagon (106) is a little shaky: no doubt it deserves an article, given the multitude of sources using it as an example; but it doesn't seem to be called "megagon" usually (and linguistically, it's a little shaky as "mega-" meaning 106 only started with SI). Instead a descriptive phrase along the lines of "polygon with a million sides" seems to get used instead. Icositetragon (24) and triacontagon (30) could be justified as fortunately these are prefixes that you find in common names for some polyhedra (e.g. deltoidal icositetrahedron, rhombic triacontahedron). Double sharp (talk) 04:24, 15 February 2015 (UTC)
Triacontagon is safe! Coxeter uses it in Regular Polytopes (p.249). And this (Topics in Mathematics for Elementary Teachers: A Technology-Enhanced Experiential Approach by Sergei Abramovich) gives (p.89) pentadecagon (15), hexadecagon (16), octadecagon (18), icosagon (20), icositetragon (24), triacontagon (30), and tetracontadigon (42). Dr. Euler's Fabulous Formula: Cures Many Mathematical Ills by Paul J. Nahin gives (p.46) icosagon (20), triacontagon (30), and tetracontagon (40), as well as giving up for the 5242880-gon ("?-gon"). Double sharp (talk) 04:31, 15 February 2015 (UTC)
I'm not surprised that up to triacontagon can be properly sourced. The rhombic triacontahedron is pretty well known. It's some of the higher ones, like 42 and 46 in the table below, that I'm more dubious about. (It's plausible we might have a name for the 96-gon, though, as that's the one Archimedes used to approximate π.) —David Eppstein (talk) 08:06, 15 February 2015 (UTC)

The Handy Math Answer Book by Patricia Barnes-Svarney and Thomas E. Svarney gives a table of names (pp.413–4). So far all the names I found sources for are below: they're all from the Svarney list except for: 1-gon (Coxeter, Regular Maps, p.388), 24-gon, 42-gon (Abramovich), 1000-gon, 10000-gon (the second ones from Descartes), and 1000000-gon (sources at megagon; this is kind of a fringe name, as I can't find many sources deriving it, but I do not think there is any other Greekish name for it).

I think this table includes the only names that would get derived regularly (and 24, 42, 46, 106 are just from one-off occurrences). I doubt any other polygons have been named anything other than n-gon, except perhaps as examples for name construction like 46-gon here.

 1 Monogon 2 Digon 3 Trigon, triangle 4 Tetragon, quadrilateral 5 Pentagon 6 Hexagon 7 Heptagon 8 Octagon 9 Enneagon, nonagon 10 Decagon 11 Hendecagon, undecagon, unidecagon 12 Dodecagon 13 Tridecagon, triskaidecagon 14 Tetradecagon, tetrakaidecagon 15 Pentadecagon, pentakaidecagon 16 Hexadecagon, hexakaidecagon 17 Heptadecagon, heptakaidecagon 18 Octadecagon, octakaidecagon 19 Enneadecagon, enneakaidecagon 20 Icosagon 24 Icositetragon 30 Triacontagon 40 Tetracontagon 42 Tetracontadigon 46 Tetracontakaihexagon 50 Pentacontagon 60 Hexacontagon 70 Heptacontagon 80 Octacontagon 90 Enneacontagon 100 Hecatontagon, hectogon 1000 Chiliagon, chiliogon 10000 Myriagon, myriogon 1000000 Megagon

While an extrapolation of the way Svarney constructs 46-gon (tens + kai + units for 21- to 99-gon) would give icosikaitetragon for 24-gon and tetracontakaidigon for 42-gon, they do not spell these out, and it appears that these names are not used at all barring one or two occurrences. (The top result for icosikaitetragon on Google Books is a mistake: the object being discussed is a polyhedron, so it should really be icositetrahedron or icosikaitetrahedron.) Double sharp (talk) 07:29, 15 February 2015 (UTC)

### Standard names

OK, so after searching for a while on Google Books, it looks like the following are the only names that seem to be standard (in that they will often appear in a listing of polygon names, and do not vary much between sources):

# Standard name
1 Monogon
2 Digon
3 Trigon, triangle
5 Pentagon
6 Hexagon
7 Heptagon
8 Octagon
9 Enneagon, nonagon
10 Decagon
11 Hendecagon, undecagon
12 Dodecagon, duodecagon
13 Tridecagon, triskaidecagon
20 Icosagon
24 Icositetragon
30 Triacontagon
40 Tetracontagon
50 Pentacontagon
60 Hexacontagon
70 Heptacontagon
80 Octacontagon
90 Enneacontagon
100 Hecatontagon, hectogon
1000 Chiliagon
10000 Myriagon
1000000 Megagon
Apeirogon

I've bolded the names I think we should use on Wikipedia. They're all articles, except 50-, 60-, 70-, 80-, 90-, and 100-gon. (I'm choosing "hecatontagon" over "hectagon" because the former is closer to the etymological source. They usually appear together as alternatives, but "hectagon" seems more popular on Google Books because it's a common typo and has been used for different meanings. Incidentally, alternative meanings are also why "megagon" has so many hits.)

Hmm, reconsidering: MathWorld and Wolfram Alpha appear to understand hectogon and not hecatontagon, and "hecto-" is more familiar as it's already an SI prefix (albeit not a commonly used one). So, changed my recommendation to hectogon. Double sharp (talk) 10:51, 18 February 2015 (UTC)

On my choice of nonagon over enneagon for the 9-gon: this was a bit difficult, as enneagon is etymologically superior and it fits well with enneadecagon and enneacontagon (where the nona- forms are just about unknown). But I went for nonagon because it's much more common, and because enneagon seems to often have non-mathematical connotations. Double sharp (talk) 10:34, 18 February 2015 (UTC)

What is just as important as giving the list itself is giving the sources from which you derived it. That way interested people, be they fellow editors or visiting readers, can check for themselves that the sources both support the names and are adequately reliable. There is no harm in giving two names if they are both verifiably significant. — Cheers, Steelpillow (Talk) 16:25, 18 February 2015 (UTC)
Here's some: one two three four. This (Dr. Math) might not absolutely qualify as an WP:RS, but is useful in that it agrees with the other lists, thus showing that at least for the numbers of sides I posted there are standard names. (Megagon isn't in any of these lists, but sources for that are on its article, and it does not appear to have any other name in common use.) Double sharp (talk) 05:18, 19 February 2015 (UTC)
Here's an old list from Charles Sanders Peirce, which seems to attempt to go very close to the original Greek (hence following Johnson's forms pentecontagon, hexecontagon, hebdomecontagon, ogdoëcontagon, enenecontagon, and creating new coinages like tessaragon). These, I guess, are referenceable alternative names.
As for the notability of these polygons: I originally thought of a strict cut-off at 12-gon, and strict demands for any higher ones to show their notability, but it seems clear from my 2012 AfD that this is never going to get consensus. So I think perhaps we could simply have an article on every polygon that has a standard name (i.e. a name that is used and agreed on by multiple sources), plus 257-gon and 65537-gon (as these have obvious notability). Double sharp (talk) 05:23, 19 February 2015 (UTC)
OK, carried out that plan: now everything with a standard name gets an article (only the ones in the table above), and nothing else does. Double sharp (talk) 07:53, 19 February 2015 (UTC)
Here's three that only occurred once: tetracontadigon for the 42-gon (first reference above), triacontakaidigon for 32-gon and hexacontakaitetragon for the 64-gon (here) So these names could be mentioned, but the primary usage should be just 32-gon, 42-gon, and 64-gon. Double sharp (talk) 05:41, 19 February 2015 (UTC)
P.S. I have no doubt that both names should be given usually, but the article can only be at one of them (with a redirect from the other), and it becomes irritating to keep saying "tetradecagon or tetrakaidecagon". Double sharp (talk) 07:05, 19 February 2015 (UTC)
One more source (except 14, 19, 24, 106). Double sharp (talk) 07:10, 19 February 2015 (UTC)
All of those sources that I can access given simply list a few example polygons (one or two refused access). That does not make them notable enough for their own articles. For that, they need some unique and notable discussion, as for example the chiliagon has received (hence the failure of that RfD). Even for a simple listing in the polygon article, several of those alternative names are clearly obscure (to coin a phrase) and, per WP:UNDUE, should not be included. The fact that people are scratching around the Internet seeking - and failing to find - sources to bolster their claims does not bode well for those claims. — Cheers, Steelpillow (Talk) 08:50, 19 February 2015 (UTC)
Yes, chiliagon should indeed have been kept (although that didn't seem so clear at the beginning of the AfD), but somehow all the articles like tridecagon also managed to be kept despite lacking much unique and notable discussion (a list of polygons articles seems like an interesting solution).
Of course they only list a few example polygons. Isn't that the point? And I'd argue that the use of these names in single instances, like "triacontagon" or "40-gon (tetracontagon)", but not in crazy cases like the 5242880-gon, speaks in favour of the fact that tetracontagon is standard for the 40-gon but something like pentacosiicositetrakismyriadischiliaoctacosioctacontagon isn't for the 5242880-gon.
The third and fourth ones I linked to give a large table with all names from 3–20, and then in tens from 30–100, and then 1000 and 10000. Given that two sources are deriving these particular names in exactly the same way seems to speak well for their being standard. Here is another that uses exactly the same names up to 100, and MathWorld (in its form as the CRC Concise Encyclopedia of Mathematics) also uses the exact same names, so that's four already using the same names. Standard? I think so. The fourth source even provides a general system to make every name from 21- to 99-gon, but you'll notice I didn't add it as this system doesn't seem to have been repeated explicitly elsewhere (and isn't always followed – note their use of "-kai-", which seems not to be the common form for the 24-gon).
You'll notice I didn't include all of Peirce's names, which contain lots of etymologically correct but unused things like heccædecagon (16-gon); I only included his names for 40-, 50-, 60-, 70-, 80-, and 90-gon because these were taken up and proposed again by Conway and Johnson (true, their endorsement isn't in RSes yet, but given that they are following something stated in an old RS it should count for something). So it seems to satisfy the second condition under WP:UNDUE: the names from tessaracontagon to enenecontagon may be a minority view, but it is easy to name prominent adherents, so it seems to be a significant enough minority, something that heccædecagon doesn't qualify for. Double sharp (talk) 03:07, 20 February 2015 (UTC)
I guess that every polygon has a different story to tell and we just have to take them one at a time. The problem we face is that some editors have boundless energy and a habit of going, "look at this piece of belly-button-fluff I found in this obscure paper, it simply has to go on Wikipedia" and before you know it, it is across a dozen articles and more, with a degree of OR worked in for luck. An example of this is where this discussion topic came in. Is there any way to contain such uneducated and ill-considered enthusiasm? — Cheers, Steelpillow (Talk) 11:08, 20 February 2015 (UTC)

Polyadic space is a new article. Currently no other articles link to it. Michael Hardy (talk) 20:50, 15 February 2015 (UTC)

I have added links to it from Alexandroff extension and Dyadic space. --Joshua Issac (talk) 14:56, 27 February 2015 (UTC)

## Buchstab function

• is a near orphan. Probably other articles should link to it; and
• does not tell us who Buchstab is. It says it's also called "Buchstab's function", suggesting that it's named after a person.

We don't seem to have an article listing special functions arising in analytic number theory. Should we? (We do have one on arithmetic functions; those have the positive integers as their domains.) Michael Hardy (talk) 22:01, 15 February 2015 (UTC)

Perhaps it was not obvious that the first reference of the article was a paper by Buchstab? I couldn't find much about Buchstab (probably it would be easier for someone who reads Russian) but apparently he is the same Alexander Buchstab redlinked as the advisor of Ilya Piatetski-Shapiro (and not mentioned but probably should be on Gregory Freiman). His name has been variously transliterated as Buchstab, Bukhstab, Buhštab, Bukhshtab, and probably other variations. —David Eppstein (talk) 22:50, 15 February 2015 (UTC)
I found a published obituary and from it started a new article: Alexander Buchstab. —David Eppstein (talk) 22:14, 16 February 2015 (UTC)

## New bug in our math notation rendering

The align environment has lately begun to put an inappropriate lack of spacing in this like this:

\begin{align}
a & = some expresion \\
& = some other expression
\end{align}

Thus:

\begin{align} a & = \text{some expresion} \\ & = \text{some other expression} \end{align}

There should be a space between a and "=", but it's not there. Michael Hardy (talk) 22:37, 15 February 2015 (UTC)

What math rendering preferences and browser are you seeing this in? It looks ok to me with client-side mathjax as well as not-logged-in. —David Eppstein (talk) 22:52, 15 February 2015 (UTC)
I can confirm the bug. I'm on iPad with MathML with png and I see no space between a and =. -- Taku (talk) 00:04, 19 February 2015 (UTC)
Png + Firefox on XP desktop = ok. YohanN7 (talk) 06:35, 19 February 2015 (UTC)
Please file a bug reportTheDJ (talkcontribs) 12:14, 19 February 2015 (UTC)

## Lattice path categorization

I categorized Lattice path under Cat-Enumerative combinatorics, please refine as needed. Thanks. MicroPaLeo (talk) 21:44, 17 February 2015 (UTC)

## Root group

I've prodded root group and abelian root group. Although there are a fair number of occurrences of the phrase "root group" in the mathematical literature, they all appear to refer to something else (more than one other thing). While the concept defined in the article makes sense mathematically (a group in which every element has a pth root, for p in some given set) it doesn't seem to be known under this name. But I'd be happy to be proven to be mistaken and get the articles properly sourced and unprodded. —David Eppstein (talk) 06:30, 18 February 2015 (UTC)

## Laver property has "graduated" from AFC to mainspace

It was previously discussed here while it was a draft, now that it is in mainspace do with it as you will. Roger (Dodger67) (talk) 17:49, 18 February 2015 (UTC)

## 1 for hypotenuse and 90 for the angle that is opposite of the hypotenuse

the post was edit request for Pythagorean Identities:where$\sin^2(x)+\cos^2(x)=1^2$ when x is > or equal to 1 the following examples are true.I don't know if this is original research or not but it states that for all integers bigger than one and equal to one, examples: c,d,e show that the hypotenuse which faces the angle of right angle triangles is one, and 90 degrees for the angle which is opposite of the hypotenuse, and in radian: 90 degrees is$\frac{\pi}{2}$ . I don't see these examples listed in any article concerning trigonometric functions.

c)$f^{1}(x)=\frac{1}{x}+\frac{x-1}{x}=1$

d)$f^{2}(x)=\sin^{-1}\sqrt\frac{1}{x}+\sin^{-1}\sqrt\frac{x-1}{x}=90$

e)$f^{3}(x)=\cos^{-1}\sqrt\frac{1}{x}+\cos^{-1}\sqrt\frac{x-1}{x}=90$

f)$\sqrt\frac{x-1}{x}$
where $\sqrt{x-1)}$ is a slope and included in $\tan^{-1}\sqrt{x-1}$

199.7.157.45 (talk) 15:32, 5 September 2014 (UTC) Although this is original research,It fits in the discussion of trigonometry project group because it's a fact for a right angle triangles to have the bigger angle to be the inverse of the tangent $\sin\tan^-1 (4)$ and for the smallest angle it's inverse of tangent $sin\tan^-1\frac{1}{4}$, the tangent being the inverse of the slope or the biggest angle,where the biggest angle being 90 degree.Trenteans123 (talk) 08:55, 19 February 2015 (UTC)

cos A={c^2+b^2-a^}/{2×b×c}
c^2=a^2+b^2

## Comment on Draft:Sacks property wanted

I can't speak for the other editors having reviewed Draft:Sacks property, but I can say frankly that I am not able to pass a qualified judgement. Could some of you gals/guys add a comment here that I can pass on? Or review it yourself? Thanks, -- Sam Sing! 18:12, 19 February 2015 (UTC) (please WP:PING when replying)

It looks like a typical short new article in research mathematics. The fact that Shelah put the subject of the article in the title of one of his papers is enough by itself to convince me that the topic is notable. It's quite WP:TECHNICAL, but perhaps unavoidably so considering its subject matter. So while some improvement would be welcome, I don't see any reason to prevent its creation. —David Eppstein (talk) 18:33, 19 February 2015 (UTC)
, I agree. --JBL (talk) 18:35, 19 February 2015 (UTC)

──────────────────────────────────────────────────────────────────────────────────────────────────── Thank you David Eppstein and Joel B. Lewis. Did you get a ping from my use of {{U}}? I did not get one from JBL's use of {{reply to}} above. Similar to Sacks property, could you comment on Draft:Kane's Method. -- Sam Sing! 21:36, 19 February 2015 (UTC)

I did get the ping, yes. Re Kane's method: too equation-heavy and too much unsourced material to accept yet. It should be cut down to a description of the method, not a derivation of it, and ideally every paragraph should have at least one footnote. —David Eppstein (talk) 22:06, 19 February 2015 (UTC)
Thanks, I'll pass your comment on. -- Sam Sing! 23:21, 19 February 2015 (UTC)

## Root group

Should Root group and Abelian root group be deleted? Michael Hardy (talk) 18:05, 20 February 2015 (UTC)

See four sections up in this talk page. —David Eppstein (talk) 21:50, 20 February 2015 (UTC)
Just for the record, I tried to find in-depth references for root group, but failed. There are mentions out there, some corresponding to the prose in the article, but nothing that would demonstrate notability. It seems somewhat related to a p-group, but I don't know the field well enough to determine if a redirect is warranted. --Mark viking (talk) 22:41, 20 February 2015 (UTC)

Comments on Draft:Cokurtosis are welcomed. Use Preferences → Gadgets → Yet Another AFC Helper Script, or use {{afc comment|your comment here}} directly in the draft. -- Sam Sing! 00:00, 23 February 2015 (UTC)

This submission looks fine, except for the minor stylistic issue that the "Properties" section shouldn't be a list of bullets. Ozob (talk) 03:39, 23 February 2015 (UTC)

## Wikipedia:Core math, science and technology topics

Someone from this project may be interested in reviewing and cleaning up the two lists of maths articles here: Wikipedia:Core math, science and technology topics. Not only is calendar included in the top nine articles, but the top six articles are not a subset of the top nine --76.14.68.103 (talk) 07:31, 23 February 2015 (UTC)

I edited the top 9 list so that it wasn't so ridiculous. However that page hasn't seen any edits since June 2013 so I'm not sure it's being used for anything anymore. Ozob (talk) 12:48, 23 February 2015 (UTC)
This does rather duplicate Wikipedia:Vital articles#Mathematics (55 articles), I'm not sure what the purpose of the core list is.--Salix alba (talk): 07:16, 25 February 2015 (UTC)
In a semi-joking defence of "calendar", for thousands of years, a central preoccupation of mathematicians was to establish "calendars" (that is, to ascertain patterns in the heavens for marking time). This is no small achievement of mathematics, given that the same kind of patterns were discovered, in many cases independently, by every ancient civilization on the planet. Sławomir Biały (talk) 19:37, 25 February 2015 (UTC)

I tried to start a discussion on the talk page of Wikipedia:WikiProject Mathematics/Proofs to add a template Proof (see suggestion). This page seems to have unfrequent visitors as no answer has been posted in one month, so I thought I would post to here to gain more discussion. Here is what I would like to suggest:

Suggestion originally posted on Wikipedia_talk:WikiProject_Mathematics/Proofs

The guidelines page on proofs mentions the possibility to use collapse boxes to include non-essential proofs. I was wondering whether it would make sense to have a specific template for this, as (for example) the french wikipedia has: fr:Modèle:Démonstration ? Are there reasons for this not to be used also in the English wikipedia? Note I am asking about this, although I would not be able to implement it myself. EtudiantEco (talk) 05:24, 11 January 2015 (UTC)

EtudiantEco (talk) 06:04, 25 February 2015 (UTC)

## General complaint 608

On Examples

IN WHICH an article talks about a structure, and most (if not all) of the examples of the structure are examples of a special case.

Do we need to list the letters P, Q, and the number 6 as being bogus? And explain why they are bogus? Is it not sufficient to just say "All garthices (such as the letters P, Q, and the number 6) are bogus?"

If we took an axe to these examples, the resulting article would often be content-free, and I am tempted to conclude the examples were added just to disguise the lack of content. --192.75.48.8 (talk) 16:11, 25 February 2015 (UTC)

Can anyone decipher this? --JBL (talk) 16:21, 25 February 2015 (UTC)
Proposing removal of content from sections as per deletion process outlined inWP:POINTLESSEXAMPLES#MATHEMATICS. Something something consensus, something encyclopedic something? --192.75.48.8 (talk) 16:30, 25 February 2015 (UTC)
No, not at all. Maybe the poster could give an example article?MicroPaLeo (talk) 16:41, 25 February 2015 (UTC)
The second comment makes me think it's just trolling. --JBL (talk) 16:59, 25 February 2015 (UTC)
I thought so, but the IP made a good edit in an article, so it seems worthwhile trying to find out if there is more. You could be right. MicroPaLeo (talk) 17:02, 25 February 2015 (UTC)
The first sentence has a point: suppose in an article on group theory, all the examples given are Abelian. While not wrong, the examples leave out an important class of groups. It would be good for the poster to provide pointers to articles where this is the case. The second point I think is kvetching about math articles that list a bunch of examples of a mathematical structure without well-describing properties of the structure itself. I have seen article like this, too. Both of these are just a fact of life on WP: articles are incomplete and could use improving. --Mark viking (talk) 17:20, 25 February 2015 (UTC)
One might lodge the same complaint against just about any treatment of groups for someone totally unfamiliar with the concept. The classic undergraduate texts of Hungerford and Herstein come to mind. For pedagogical purposes, it is often useful to focus first on a special case that does not contain all of the nuances of the full theory. Sławomir Biały (talk) 19:32, 25 February 2015 (UTC)

All examples of anything are necessarily special cases. Michael Hardy (talk) 02:37, 26 February 2015 (UTC)

But one should take care when selecting examples. Quercus durata, would not be a good example for the sole species in the lead section of an article or if only a small number of species were mentioned in a short article on section Quercus of the genus. 'Q. alba could be ideal in the lead, but one could use Q. douglasii or Q. virginiana or Q. arizonica as examples, all of which are also endemics. If not as desirable as Q. alba or Q. robur, they would be good additional mentions, could be reasonable examples, and not bad choices like Q. durata. Not all special cases are equal. Although this is a biology example, and in math one may have a case where all examples are equal, you mention "special cases," meaning they are not. Examples should be chosen with care and clearly show understanding of the topic. MicroPaLeo (talk) 04:30, 26 February 2015 (UTC)

## Smooth maximum is an orphan

No articles currently link to smooth maximum. Michael Hardy (talk) 02:35, 26 February 2015 (UTC)

## Stars and bars (combinatorics)

In Theorem two, the solution of the problem is $\tbinom{n + k - 1}{n}$? I think it's $\tbinom{n + k - 1}{k}$. --Eric4266 (talk) 03:47, 26 February 2015 (UTC)

You are thinking of $\tbinom{n + k - 1}{k - 1}$ (you are dividing objects into k sets, so you need k − 1 separators). This is equal to the solution given in the article. See the proofs section of the article. Ozob (talk) 13:40, 26 February 2015 (UTC)

## LaTeX versus HTML again

Could anyone weigh in at Talk:Hilbert transform regarding LaTeX versus HTML issues? I'm not sure what our current recommendation is regarding inline mathematics (presumably {{math}}). It seems like Hilbert transform has made something of an effort to avoid rendering inline PNG images, and now someone wants to change that. Sławomir Biały (talk) 12:46, 2 March 2015 (UTC)