Portal talk:Mathematics

Please use this talk page only for discussions related to the Mathematics Portal. For discussion of mathematics on Wikipedia go to Wikipedia talk:WikiProject Mathematics. Got a mathematics question? See the Mathematics Reference Desk. If you have suggestions for future featured articles, pictures, and factoids on this portal go to Portal:Mathematics/Suggestions. For discussion about Portals generally, please see the WikiProject on Portals.

Accessibility of the articles...

I have noticed in the past days that quite a few mathematical phenomenas can be explained in a simpler more formal language. I've seen the FAQ where it is stated that this is an encyclopedia rather than a pedagogical textbook. Nevertheless i, and many with me, feels the articles only lends themselves to people who already appreciates the subjects. Would the editorial community once again consider to add easier to understand descriptions, maybe as an own paragraph, sort of like "In laymans terms". I had for instance an experience where the Fourier transform was algorithmically explained to me using only plain english and multiplication in seven short sentences.

80.217.65.137 (talk) 10:16, 20 January 2011 (UTC)

Underdetermined system - Overdetermined system

Underdetermined system seems to be a copy of the article Overdetermined system. Problem was recognized by other people too, as is described in Talk:Underdetermined system. Because I cannot correct the whole article, I hope some one else can - otherwise it might be best to delete the whole example. Regards, --WissensDürster (talk) 09:21, 24 January 2011 (UTC) (knowledgethirster)

Hilbert_system

Hi

Any chance someone can take a look at this ?

I have replaced contradict tag with expert needed after the comments on the talk page Talk:Hilbert_system#Article_is_a_mess...

Chaosdruid (talk) 23:24, 2 February 2011 (UTC)

number 7

lots of people say 7 is a lucky number

70.187.228.11 (talk) 20:36, 16 April 2011 (UTC)

Not done: please be more specific about what needs to be changed. — Bility (talk) 21:42, 16 April 2011 (UTC)

Portal:Mathematics/Featured article template has formatting issues with FA star

A feature of the Portal:Mathematics/Featured article template in which a File:Nuvola apps edu mathematics blue-p.svg icon is added into the title bar overlaps any GA/FA star or spoken version icon that may also be included in an article (like on 0.999... and Monty Hall problem). This is the same issue that was discussed on Template talk:Use British English#Formatting issues with FA star. As mentioned there, there is no code or script that currently exists that detects all the icons or title templates being used, and then adjusts their placement accordingly. The only options is either to move the math icon 80px or more away from the right edge of the page to clear any possible FA star/GA symbol, spoken article icon, and page protection padlock icon; or remove the math icon completely. Based on the consensus on that older discussion, I am removing the math icon for now. Cheers. Zzyzx11 (talk) 04:36, 15 May 2011 (UTC)

I think it would be nice to have something on the articles showing that they have been Selected/Featured. We could try indenting unless anyone has a better idea? ―JuPitEer (talk) 06:38, 17 May 2011 (UTC)

I think that area of the screen should be reserved for only a few items. The FA and GA symbols, and the spoken version symbol. Anything more risks confusing readers who have come to know what to expect when they look at the top-right hand corner (or where-ever the symbols display in various Wikimedia skins). So I think it should be removed altogether and possibly the subpage deleted. I've raised this issue here and

will notify the two editors above on their talk pages, as one removed the icon and the other restored it (while moving it over), so clearly some discussion is needed. Carcharoth (talk) 13:59, 25 June 2011 (UTC)

Featured articles must comply with MOS and community-wide consensus, not the whims of individual editors or WikiProjects. Please do not re-add this teemplate unless you gain wide consensus at WP:LAYOUT or WP:MOS. It breaches LAYOUT, and featured articles must comply with MOS. The template should be deleted. Try to imagine the mess we'd have if every WP claiming some FAs could add a portal link to the right hand top corner-- won't work. Portals belong in See Also, per LAYOUT. SandyGeorgia (Talk) 23:07, 25 June 2011 (UTC)

Help with a figure

Hello,

I recently uploaded a picture to QR decomposition. I had created it with Inkspace and it looked fine on my machine, but it's messed up on the website. You can look at my talk page to see the list of problems. I posted more information on User_talk:Joel_B._Lewis#QR_decomposition.

If you do fix it, can you let me know what I did wrong, so that I can fix it myself next time?

Thanks, Tony (talk) 15:51, 11 August 2011 (UTC)

2D Spheres?

In the DYK section it says: '...that you cannot knot strings in 4-dimensions? You can, however, knot 2-dimensional surfaces like spheres.' I've not heard of a 2D sphere before. Am I missing something? Harland1 (^t/_c) 00:02, 7 September 2011 (UTC)

Probably what you're missing is that, in mathematical usage, the word "sphere" refers specifically to the surface of a spherical ball. The surface is two-dimensional. The three-dimensional solid is called a "ball". --Trovatore (talk) 00:06, 7 September 2011 (UTC)

Upcoming featured pictures

I've created Portal:Mathematics/Upcoming featured pictures to try to encourage people to keep pictures "in the queue" for display as "Picture of the month" on this portal page. Three times in the last couple of years I've come here to find a big "redlink" under "Picture of the month", because no one had created a page for that month yet. Let's try to keep the queue filled at least a few months in advance, so that doesn't keep happening. I've suggested (on the page I linked to above) some places to find good images that haven't been featured yet. If someone has some better ideas, please add them to the list. And please help find good mathematics-related pictures to add to the queue! - dcljr (talk) 22:54, 2 November 2011 (UTC)

Reformatted the intro subpage

1. Updated intro text with current text from WP:LEAD from main article, Mathematics.
2. Added randomized intro image selection, for increased dynamism for the main portal page, with all free use images taken from main article, Mathematics.
3. Listed (no-transcluded) link to this intro image subpage on the intro page, at Portal:Mathematics/Intro/Image.
4. Kept the paragraph format from the WP:LEAD at main article, Mathematics.
5. Added categorization of the intro subpage to Category:Mathematics portal.

Cheers, — Cirt (talk) 23:46, 17 December 2011 (UTC)

Handling of intentionally incorrectly written equations

Please advise to me about how to handle intentionally incorrectly written equations.

On the article Additive synthesis#Theory, some IP user posted intentionally incorrect equations in 2007. On his post in 2007, he introduced at least two wrong substitutions,

1. On simple substitution                 k f₀           →       f_k[n],
   he really substitute term     (2 π k f₀ / Fs)   →   (2 π / Fs)∑ ⁿ_i=1 f_k[i]

   Note: On the discussion in the article, the context requires substitution of constant   k f₀   with inharmonic version (on here, "inharmonic" means "arbitrary")   f_k .

   However, he declared substitution of constant   k f₀   with time-varying inharmonic version   f_k[i] .

   And his real substitution   ∑ ⁿ_i=1 f_k[i] / n   imply time-average of time-varying inharmonic version. (if he intent to extend equations towards "time-varying inharmonic" version, this average operation spoil the time-varying nature)

   His word and real substitution are contradicted, and also contracted with context.

2. On the case required multiple substitutions (by his definition), he irrationally erased several terms without showing details of each substitutions

   Note: it seems originally derived from 1.

As a result, equations he posted are totally incorrect. The mistake is too much bold and understandable at a glance (too complicated), probably nobody reads the equations, and problem seems to be neglected on last five years.

I want to correct it if possible. However, IP user (probably same person) is repeatedly reverting the corrections, and also posted delusions written in almost unreadable English, on article's talk page. (inability of conversation is a very sad thing) What is the best way to solve the problem ? I expect your kindly advices. sincerely, --Clusternote (talk) 05:32, 8 January 2012 (UTC)

P.S. Last my corrections seem not reverted yet : ) --Clusternote (talk) 05:39, 8 January 2012 (UTC)

I think you want Wikipedia talk:WikiProject Mathematics rather than the talk page of the portal which is just for improving the portal. The people there will helpyou with this and to cope with the other editor. Dmcq (talk) 23:22, 8 January 2012 (UTC)

Thanks for your kindly advice, I'll follow it. Sorry for my inappropriate post. ... --Clusternote (talk) 04:40, 9 January 2012 (UTC)

Helmholtz decomposition is wrong

Dear members of world mathematical community!

The Fundamental theorem of vector calculus, (Helmholtz decomposition) states that any sufficiently smooth, rapidly decaying vector field in three dimensions ${\mathbf{F}}$ can be constructed with the sum of an irrotational (curl-free) vector field and a solenoidal (divergence-free) vector field (scalar potential $\varphi$ and a vector potential ${\mathbf{A}}$)

${\mathbf{F}} = - \operatorname{grad} \psi + \operatorname{rot} {\mathbf{A}} \Rightarrow {\mathbf{F}} = \operatorname{grad} \varphi + \operatorname{rot} {\mathbf{A}}$ (1)

However, the gradient of scalar function does not form the vector field. As well known from textbook [1, p. 15] « … under co-ordinate change the gradient of function transforms differently from a vector »: hence the theory requiring (1) must be false. The next unpleasant things we can see for such well-known classical rules. In mathematics and physics the rot (or curl) is an operation which takes the vector field ${\mathbf{A}}$ and produces another vector field $\operatorname{rot} {\mathbf{A}}$ . However it is well-known that $\operatorname{rot} {\mathbf{A}}$ is an Antisymmetric Tensor . Therefore under co-ordinate change the tensor $\operatorname{rot} {\mathbf{A}}$ transforms differently from a true vector. For elimination of these contradictions the Fundamental theorem of vector calculus can be written as follows:

$\vec F = \operatorname{grad} \varphi + \operatorname{rot} \operatorname{rot} \vec A$. (2)

This formula completely corresponds to transformed Navier–Stokes equations(NSE) for incompressible fluids ( $\operatorname{div} \dot \vec u = 0$)

$\rho \vec F - \operatorname{grad} p + \mu \nabla ^2 \dot \vec u = \rho \ddot \vec u \Rightarrow \rho (\vec F - \ddot \vec u) = \operatorname{grad} p + \operatorname{rotrot} \mu \dot \vec u$ . (3)

Here, $\vec F = \vec F_1 + \vec F_2 + ...$ -¬¬ vectors sum of a given, externally applied forces (e.g. gravity $\vec F_1$ , magnetic $\vec F_2$ and other), $p$- pressure (scalar function), $\dot \vec u$- velocity vector, $\ddot \vec u = d\dot \vec u/dt$ - acceleration vector, $\rho$ - density (const), $\mu$ - viscosity (const), $\nabla ^2$ - Laplace operator.

Equations (3) and (2) are consistent. Hence there is no reason to say that the theory requiring (2) must be false. As we can see from NSE the sum - $\operatorname{grad} p + \mu \nabla ^2 \dot \vec u = - (\operatorname{grad} p + \operatorname{rotrot} \mu \dot \vec u)$ forms the vector field.

Note that we will receive the formula (2) also after similar transformation of the Navier–Stokes for a compressible fluid and after transformation of the Lame equations for an elastic media.

From this brief note follows that Helmholtz decomposition is wrong and demands major revision. This follows from comparison of two articles in Wikipedia (http://en.wikipedia.org/wiki/Navier%E2%80%93Stokes_equations and http://en.wikipedia.org/wiki/Helmholtz_decomposition ).

Therefore let's try to formulate the text for editing of this article.

1.B. A.; Fomenko, A. T.; Novikov, Sergeĭ Petrovich (1992). Modern Geometry--methods and Applications: The geometry of surfaces, transformation groups, and fields] (2nd ed.) . Springer. (p. 15).ISBN 0387976639.

--Alexandr 17:58, 4 February 2012 (UTC) — Preceding unsigned comment added by Continuum-paradoxes (talk • contribs)

I see you have already started a discussion about this at Talk:Helmholtz_decomposition, that's good. If you don't get a response there then Wikipedia talk:WikiProject Mathematics would be where to ask. This is the talk page for improving the portal, not the talk page for the project. It is better to ask people at the project to go to Talk:Helmholtz_decomposition for the discussion rather than repeating yourself at the project. Dmcq (talk) 21:38, 4 February 2012 (UTC)

Thanks for your help!--Alexandr (talk) 18:17, 7 February 2012 (UTC)

Vedic Mathematics

Need a section on Vedic Mathematics 20.143.240.21 (talk) 11:36, 13 February 2012 (UTC)

Did you try typing in Vedic mathematics? Dmcq (talk) 13:43, 13 February 2012 (UTC)

Error in an image of the complex graph of the sine function

Not sure if this is the right place to mention it, but I thought I'd bring attention to the mistakes I just noted on File talk:Sine.png. The image is hosted on commons but I'm more familiar with how wikipedia works so I've brought attention to it here. Hopefully I've pointed this out in a useful place. 78.105.8.153 (talk) 23:15, 17 February 2012 (UTC)

Portal:Mathematics/Featured article template at MfD

Portal:Mathematics/Featured article template has been nominated for deletion. The nomination page is Wikipedia:Miscellany for deletion/Portal:Mathematics/Featured article template. Chris Cunningham (user:thumperward) (talk) 16:59, 23 February 2012 (UTC)