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This is an old revision of this page, as edited by Tsirel (talk | contribs) at 05:03, 13 May 2017 (→‎Equivalent definitions, again: meaning determined implicitly?). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

This is a discussion page for
WikiProject Mathematics
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New or newly categorized articles at User:Mathbot/Changes to mathlists

Here are the latest new or newly categorized articles at User:Mathbot/Changes to mathlists:

November 18, 2016

Removed Nonagonal prism (is a redirect to Enneagonal prism)
Added Enneagonal prism
Added Ten Rays Model
Mathematicians:removed Jayadeva
Mathematicians:added Jianqing Fan
Mathematicians:added Jun Li
Mathematicians:added Lexing Ying
Mathematicians:added Ngaiming Mok
Mathematicians:added Zhouping Xin

November 17, 2016

Removed Damping (is a redirect to Harmonic oscillator)
Removed Enneagonal prism (is a redirect to Nonagonal prism)
Added Convergence group
Added Moser–de Bruijn sequence
Added Nonagonal prism
Added Stefan Bergman Prize

November 16, 2016

Removed Maximum common edge subgraph problem (is a redirect to Maximum common edge subgraph)
Removed Maximum common subgraph isomorphism problem (is a redirect to Maximum common subgraph)
Removed Multidimensional Empirical Mode Decomposition (is a redirect to Multidimensional empirical mode decomposition)
Added Bailey's method (root finding)
Added Furstenberg–Sárközy theorem
Added Maximum common edge subgraph
Added Maximum common induced subgraph
Added Multidimensional empirical mode decomposition
Added Slim lattice
Added Vector-radix FFT algorithm
Mathematicians:removed Donal O’Shea (is a redirect to Donal O'Shea)
Mathematicians:added Donal O'Shea
Mathematicians:added Edward Neuman
Mathematicians:added Ralph Kenna
Mathematicians:added Ravindra Bapat

Additional eyes please on Exponential response formula

I'm requesting that some editors with more experience with math topics take a look at a relatively new article, Exponential response formula, by a relatively new editor, Wandalen. I haven't looked at enough of the articles in this project to have a good idea what constitutes sufficient notability, or how examples should be styled. Thanks. — jmcgnh(talk) (contribs) 00:45, 17 April 2017 (UTC)[reply]

FWIW, it is definitely a real thing and probably one can find textbook references. I suppose it is possible that the material exists under other names (but I don't have suggestions, sorry). --JBL (talk) 00:57, 17 April 2017 (UTC)[reply]
I have redirected to ordinary differential equation#Summary of exact solutions. --Izno (talk) 11:43, 17 April 2017 (UTC)[reply]
That table is horrible! --JBL (talk) 13:34, 17 April 2017 (UTC)[reply]
This has been unredirected and the creator has approached me on my talk page:

Hello Izno, I'm trying to bring here information which the encyclopedia does not have. I spent much a day of my free time reading articles and writing topic on math to share my knowledge with others. Wikipedia had no word about material which I'm trying bring here. I don't think that deleting the page without any word, message or discussion is an appropriate act. I don't feel that I'm welcome here and don't understand reasons for your hatred of new people on the platform.

The page on which you did redirection removing whole my article has nothing about ERF. If you are a mathematician, please let's talk how can we improve it. Wandalen (talk) 15:54, 22 April 2017 (UTC)

The target article does indeed cover ERF in that it covers the precise-same content as the topic called an "ERF" as presently in the article. @Michael Hardy: CC. Perhaps this is a less-general article to redirect it to, but I would guess the content already exists on Wikipedia, if not exactly in the form you have added. This is normal editing behavior. --Izno (talk) 00:15, 24 April 2017 (UTC)[reply]
By "the target article covers the same material" you mean that there is an entry in that awful table? This obviously does not preclude a stand-alone article. (Even more thorough coverage would not preclude it: for independently notable solution methods, I would expect an article like ordinary differential equation to have a brief summary and a {{main}} link.) Also, to the extent that what you are doing is making substantive discussion about the fate of the article (as opposed to drawing the attention of other editors), the article talk page is a much better venue. --JBL (talk) 01:41, 24 April 2017 (UTC)[reply]

The talk page of an article is occasionally insufficient, especially when the topic has been broached already in a more-communal venue. I could also have left a "Look over here again".

As for "awful table", I would tend to agree, that table is awful. But regardless of the presentation there, I would expect this to be at a more-general article than one dealing specifically for the "response function" that is simply a typical solution to a linear ODE. --Izno (talk) 02:02, 24 April 2017 (UTC)[reply]

I am afraid I don't understand your last sentence; what is the referent of "this"? --JBL (talk) 02:05, 24 April 2017 (UTC)[reply]
The information regarding an ERF. --Izno (talk) 02:23, 24 April 2017 (UTC)[reply]

Izno help me to improve the page, please. I'm going to contribute to the page on weekends if you won't throw it in garbage. Saying ERF is typical solution to ODE is same as saying wolf is a mammal, lets make redirection from wolf page on mammal page and put all mammals in a table. Appreciate any help. Wandalen (talk) 17:21, 24 April 2017 (UTC)[reply]

There is less here than meets the eye. All the facts in the article would fit in a new line in Ordinary differential equations#Summary of exact solutions, and are covered adequately in Green's function. See Talk:Exponential response formula#Merge. — Arthur Rubin (talk) 14:31, 1 May 2017 (UTC)[reply]

Parallel projection

User:SharkD removed a new version of the article parallel projection, which I recently wrote. I would appreciate a third opinion on the talk page of the article. Thank You !--Ag2gaeh (talk) 15:11, 20 April 2017 (UTC)[reply]

Poincaré plot

The article Poincaré plot looks short to me. Can someone take a look at it? Thank you. RJFJR (talk) 16:20, 29 April 2017 (UTC)[reply]

Combinatorial Mathematics Society of Australasia

Combinatorial Mathematics Society of Australasia is newly created article which was moved directly to the mainspace from User:McKay/sandbox by its creator. The draft does not seem to have been submitted for review, and based upon its name it might fall within WP:WPM's scope. Anyway, I was wondering if someone from this WikiProject would mind taking a look at it and assessing it. Most of the sources cited appear to be primary ones, so it's not clear where the organization satisfies WP:NORG. -- Marchjuly (talk) 13:22, 1 May 2017 (UTC)[reply]

Alladi–Grinstead constant

Greetings all. Earlier today, I noticed a new page, Alladi–Grinstead constant, which looked in need of cleanup and reworking. I took a stab at it, but someone with a stronger background in number theory could probably do better. Another new page, Lueroth constant, should perhaps be merged into it, since the one constant is just the exponential of the other less one. XOR'easter (talk) 17:25, 1 May 2017 (UTC)[reply]

Mathematical universe hypothesis

Edit war here about a writer who may be a crackpot; someone with subject expertise please take a look? —swpbT 17:07, 5 May 2017 (UTC)[reply]

Perhaps you should try participating on the article talk page and not just demanding that others do so? --JBL (talk) 22:14, 5 May 2017 (UTC)[reply]
Umm...I did exactly what you're supposed to do when you suspect something is wrong but don't know enough about the topic – I asked for help from people who self-identify as knowing about the topic. What is your problem? —swpbT 13:17, 10 May 2017 (UTC)[reply]
It looks like you have made significant edits to the article and may be a participant in the edit war. Per WP:BRD, it is best to first discuss issues leading to the edit war on the article's talk page, to attempt to come to consensus. You appear to not have done that and instead have come directly to WP:MATH to appeal for help. That approach is no great sin, but as an editor with nearly 60,000 edits, you know better. --Mark viking (talk) 19:19, 10 May 2017 (UTC)[reply]
Right. In addition, your edit summaries have basically no content, so it is extremely difficult for anyone to tell what you think the problem is. --JBL (talk) 21:19, 10 May 2017 (UTC)[reply]

Templates and Navigation for Mathematics Articles

I've been working out a Template for "A Series on Discrete Mathematics", based on some of these:

More examples of these sort of things:

Examples more related to specific Mathematics topics

I think these sort of templates would add some structure to the Mathematics part of Wikipedia. What are people's thoughts on this? --- Popcrate (talk) 09:41, 8 May 2017 (UTC)[reply]

Normed algebra

Normed algebra has been proposed for deletion. Presumably it should be unprodded, but it's in pretty bad shape and needs help to make it more clearly notable first. Anyone want to have a go? —David Eppstein (talk) 05:49, 8 May 2017 (UTC)[reply]

Maybe merge into "Banach algebra"? Boris Tsirelson (talk) 08:36, 8 May 2017 (UTC)[reply]
"Normed algebra" usually means "finite dimensional Banach algebra". But in the area these are studied, I believe the standard term is actually "normed algebra", so I feel that's not quite an appropriate merge target. Sławomir Biały (talk) 10:11, 9 May 2017 (UTC)[reply]
Why f-dim? For example, take the ring of all smooth functions on some compact manifold (e.g., a circle). Then the ring is normed, say, with the sup norm (assume there is a metric on the manifold). But it's not Banach; how do you call that ring? -- Taku (talk) 23:06, 9 May 2017 (UTC)[reply]
Sure, there is such a mathematical structure. However, we have a theory of Banach algebras (with nontrivial theorems, not just definitions and examples); have we such a theory of normed algebras? Boris Tsirelson (talk) 03:40, 10 May 2017 (UTC)[reply]
Of course it make sense to allow infinite dimensions, but usually "normed algebra" refers to the finite-dimensional case in my experience. See Hurwitz's theorem (composition algebras), for example. Sławomir Biały (talk) 09:19, 10 May 2017 (UTC)[reply]
According to the lede of our Banach algebra, an infinite-dim case is allowed. Anyway, I do agree with both of you that the focus of the study is probably on the finite-dim case. -- Taku (talk) 09:44, 10 May 2017 (UTC)[reply]
I want to point out that a normed field is, as of this writing, a red link. But presumably it should be discussed in the "normed algebra" article; this argues against the merger. -- Taku (talk) 23:25, 8 May 2017 (UTC)[reply]

Relevant discussion at WP:ANI

There is a discussion at the administrators' noticeboard concerning the edits of Hesselp (talk · contribs · deleted contribs · logs · filter log · block user · block log) to Series (mathematics) and Talk:Series (mathematics) that members of this project might be willing and able to comment on. Sławomir Biały (talk) 13:57, 8 May 2017 (UTC)[reply]

Citation overkill proposal at WP:Citation overkill talk page

Opinions are needed on the following: Wikipedia talk:Citation overkill#Citations. A permalink for it is here. Flyer22 Reborn (talk) 06:35, 9 May 2017 (UTC)[reply]

Graham's number

There is a discussion on the talk-page concerning whether the current first sentence (including its footnote) is correct, encyclopedic, and appropriately supported by citation. More voices would be welcome. --JBL (talk) 23:44, 10 May 2017 (UTC)[reply]

XOR, (Exclusive or), page needs some help

The lead paragraph needs help, in particular. There's been a "needs verification" template on the page since 2013. Currently the lead paragraph reads as:

Exclusive or or exclusive disjunction is a logical operation that outputs true only when inputs differ (one is true, the other is false). It is symbolized by the prefix operator J[citation needed] and by the infix operators XOR (/ˌɛks ˈɔːr/), EOR, EXOR, ⊻, ⊕, ↮, and ≢. The negation of XOR is logical biconditional, which outputs true only when both inputs are the same.

Personally, I couldn't find a solid example of J being a symbol for Exclusive Or (maybe it's used in a specific programming language?) Any thoughts? - Popcrate (talk) 06:39, 11 May 2017 (UTC)[reply]

 Erledigt I added a source. It's not from programming, it's from the Polish notation for mathematical logic. —David Eppstein (talk) 06:49, 11 May 2017 (UTC)[reply]

Equivalent definitions, again

Three years ago the article "Affine space" was attacked by a non-expert. His position: the notion of affine space (like any other) must have just one definition treated literally; not only the structure, but also its implementation (encoding in the set theory) must be fixed once and for all; otherwise mathematics is not rigorous. The attack was repulsed, but, bothered by the vulnerability, after a short discussion here, I built a bastion against possible attacks of this kind: equivalent definitions of mathematical structures. A quote therefrom: A person acquainted with topological spaces knows basic relations between neighborhoods, convergence, continuity, boundary, closure, interior, open sets, closed sets, and does not need to know that some of these notions are "primary", stipulated in the definition of a topological space, while others are "secondary", characterized in terms of "primary" notions.

Now we observe another attack toward "Series (mathematics)" (see "Relevant discussion at WP:ANI" above); User:Hesselp insists on a single definition of a series as a sequence (of terms). For now the article defines a series as (a special case of) an infinite expression. Another equivalent definition in use is, a pair of sequences (terms, and partial sums). Regretfully, this case is not covered by my "bastion", since the set of series is itself not quite an instance of a well-known mathematical structure (though some useful structures on this set are mentioned in our article). And still, it would be useful to write something like A person acquainted with series knows basic relations between terms and partial sums, and does not need to know that some of these notions are "primary", stipulated in the definition of a series, while others are "secondary", characterized in terms of "primary" notions. Implementation need not be unique. When several implementations are in use, should we choose one? or mention them all "with due weight"? or what? Any opinion? Boris Tsirelson (talk) 16:40, 12 May 2017 (UTC)[reply]

@Tsirel.   Five remarks.
a.   Mentioning different worded - equivalent - definitions in "Series (mathematics)" :  no objections from my side.   Provided the wording is logically consistent and complete.
b.   To be able to judge to which extend the 'infinite-expression' version satisfies this condition, the notion infinite expression should be clear first: the link to Infinite expression is not sufficient. See Talk:Infinite expression, and the unanswered questions A-E in Talk page 18:49, 10 May 2017.
c.   Moreover, as every expression,  also an infinite expression should refer to some (mathematical or non-mathematical) object.   The 'infinite-expression' version leds to the self-referreing: "A series is an infinite expression.... denoting a series." Isn't it?
d.   On: "User:Hesselp insists on a single definition of a series as a sequence (of terms)."
Not at all. See section Definition in this edit.
e.   The Bourbaki-definition (series = the couple: sequence; its sum sequence) refers to the former (also Cauchy's) meaning of 'series':  a sequence of terms allowing partial sums. -- Hesselp (talk) 18:49, 12 May 2017 (UTC)[reply]
(a): I am glad. (b) "an infinite tree labeled with symbols of various types" (quoted from that talk page) — I am able to turn this hint to a definition; I agree that our "Infinite expression" article gives only informal explanation (for non-mathematicians), not a definition; and again, we are not a professional mathematical encyclopedia... (c) sure; see my (b) above; and in general an expression has no value (but in "good" cases it has); (d) I am glad (again; see my (a) above); (e) nice. Boris Tsirelson (talk) 19:15, 12 May 2017 (UTC)[reply]

It is somewhat ironic that, although mathematics is one of the most precise fields, the basic concepts are often not defined identically. For example, the talk page of the article on "function" shows much effort about how to present that concept in a way that is both accurate and accessible to those learning basic algebra and calculus. The same applies to "series": it is a standard, basic concept, which everyone agrees on. But, because it is typically defined in calculus and lower-level books, the definitions that are often given in the books lack something that would be present in a graduate level text. This does not mean, however, that we should try to present "series" in the style of Bourbaki. Instead, we should follow the sources and present the same general understanding that they convey. To some extent, I agree with the proposition above that in articles about *elementary* subjects, it is not necessary to focus too heavily on axiomatics. Of course, more advanced articles will naturally have a more axiomatic focus. — Carl (CBM · talk) 20:00, 12 May 2017 (UTC)[reply]

Then, maybe, it is desirable (whenever feasible) to first give an informal explanation, but afterwards, closer to the end of the article, give rigorous definition(s)? Boris Tsirelson (talk) 20:07, 12 May 2017 (UTC)[reply]
I think this can be reasonable, but only when there are clear formal definitions in the literature. In many cases, it turns out that advanced texts simply don't bother giving definitions of concepts such as "series", which they assume the reader is familiar with, while introductory texts give only informal definitions. In such cases, I think it is better to avoid trying to invent a formal definition out of thin air (although certainly many people could create one). If numerous sources all find it possible to discuss a concept without a formal definition, we can certainly do so as well. — Carl (CBM · talk) 20:09, 12 May 2017 (UTC)[reply]
Well. But for series, if I am not mistaken, we need not invent it, since Hesselp gave us such sources. Boris Tsirelson (talk) 20:13, 12 May 2017 (UTC)[reply]
And surely it would be an overkill, to first define infinite expression in general. A sequence (or two) is much more economical implementation (while not the most intuitive one, which is typical: either intuitive or economical...). Boris Tsirelson (talk) 20:15, 12 May 2017 (UTC)[reply]
I agree with Carl that we lack a formal definition of a series, which covers all aspects of the concept and is widely accepted. In fact, the situation is similar to the case of a sum: There is no definition in Addition, and it is difficult to give one, as "sum" denotes the processus (operation) as well as its result. Another example is Line (geometry), where the usual "Definition" section is replaced by a section Line (geometry)#Definitions versus descriptions, which contains a discussion that is strongly related to this one. In any case, a series is not a sequence nor a pair of sequences nor an expression. It is an object which is built from a sequence. Who think to a Taylor series as a sequence? D.Lazard (talk) 20:43, 12 May 2017 (UTC)[reply]
Yes... Likewise, who thinks on a real number as a cut in rationals?.. "Object built from a sequence", yes. Lot of objects are (for instance, words, queues, stacks, and even files). In programming this is a matter of "abstract data type"; a pity that we have no such notion in mathematics. We have "structure (up to isomorphism)", but this does not cover all needs. Boris Tsirelson (talk) 20:48, 12 May 2017 (UTC)[reply]
So... should we add a section "Definitions versus descriptions" into "series" (and a number of other articles, such as "Formal power series")? Boris Tsirelson (talk) 20:51, 12 May 2017 (UTC)[reply]

I stay puzzled. Some notions are primitive (undefined), some are defined, and some appear to be... elementary? undergraduate? Well, I do not argue about names. But let us imagine that we are preparing a proof of a theorem for verification on a proof assistant. In the middle we face series. What now? Say "this theorem is not formalizable in ZFC"? Surely not. Surely we continue. What does it mean? A vague term whose meaning is determined implicitly by the context, case-by-case? Boris Tsirelson (talk) 05:02, 13 May 2017 (UTC)[reply]

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