Wikipedia talk:Manual of Style/Mathematics

Redundancy in descriptions

I and another editor disagree over the phrase "square, symmetric, positive definite matrix" in the Matrix decomposition article. I am of the opinion that squareness is implied by symmetric and therefore redundant. He takes the point of view that "some readers may not notice that symmetric implies square, so the redundancy makes it clearer". I disagree with that too but that's not really relevant to my current posting. (It's not really an argument between us as there has only been one revert but it raised for the first time for me an important question about Wikipedia's approach to these type of situations.) Obviously the Wikipedia:Use common sense guideline is always in effect but in this case it's not so clear which makes more sense. Could somebody point more to a section of the MoS that advises on redundancy issues? I skimmed Wikipedia:Manual of Style (mathematics) but did not find a section that addresses this problem specifically. Advice appreciated too. Jason Quinn (talk) 14:00, 20 February 2009 (UTC)

I doubt there is a specific guideline. I take no position on what is most clear in this case—calling the matrix square might help some readers, but it might wrongly suggest to others that there is a definition of a non-square symmetric positive definite matrix. If you and the other editors cannot come to an agreement as to what is most clear, you might try asking on Wikipedia talk:WikiProject Mathematics. Ozob (talk) 21:27, 20 February 2009 (UTC)

The readers who "may not notice that symmetric implies square" are the ones who just don't know what symmetric means in that context, so saying "square, symmetric" isn't going to help them any more than just "symmetric": in order to understand that sentence, they would have to look up "Symmetric matrix" anyway, which starts with "In linear algebra, a symmetric matrix is a square matrix ...". So I would be slightly in favour of omitting square there. --A. di M. (talk) 12:06, 23 February 2009 (UTC)

Using scriptstyle to make in-line symbols "fit"

User:CBM and I are having a discussion (User talk:CBM#MSE) about the use of \scriptstyle to adjust symbol size. Symbols with decorations (hat or tilde, for example) automatically display as PNG, and those without, or with simple super/sub scripts, displayed as HTML. When I was working on the Maximum spacing estimation article, I used \ss to make many of the decorated symbols appear "normalized" (in my opinion) with the in-line HTML, as I had my settings set as per the MoS (HTML if simple, PNG otherwise). CBM believes that they should always be shown as displaystyle, and the simple ones forced to display using \,. I pointed out that this was not in agreement with the Math MoS, and he suggested that we bring this for discussion here, as scriptstyle is too small in his opinion. Here is how the scriptstyle looks on my browser (FF 3.0 under WindowsXP) [1]. Here is a comparison on CBM's browser [2]. The article as it stands now has CBM's changes in it. What is the opinion of the greater WP:MATH community on this? Thank you. -- Avi (talk) 18:57, 6 March 2009 (UTC)

Both look bad. Why not use clean LaTeX source and simply wait for the math rendering to get fixed one day. If Planetmath can do it and commercial publishers can do it why not Wikipedia? Then there will be a lot of kludges to fix. Why add to them? Jmath666 (talk) 04:05, 9 March 2009 (UTC)

Because it has been so badly broken for so long (for many years), with not the smallest step taken towards fixing it, that even the most optimistic person has stopped hoping it will ever be fixed? Ghod, can't even show $-1$ in non-PNG mode without a space between the minus and the one which shouldn't be there... --A. di M. (talk) 07:31, 9 March 2009 (UTC)

I would say that scriptstyle is slightly too small, displaystyle is way too big, so the first is better. But Jmath666 might have a point... And what about the problem that inline math $g$ is very different from displayed $g\,?$ Some people write italic g to avoid this, but then, italic f is disastrous, so some people use ƒ, about which I have no idea where it comes from. A di M (Al di Meola?), what do you suggest for this problem? All of this is ridiculous and hopeless to optimize, I'm afraid. So, arriving at the end of this paragraph, I say that Jmath666 is right, and for the sake of our mental health, we should just write in normal LaTeX, and accept that it looks bad on wikipedia... A question: on WHOM or WHAT does it depend on when this rendering will be fixed? --GaborPete (talk) 08:08, 9 March 2009 (UTC)

Ultimately, the MediaWiki developers. However, they currently depend on a package called texvc. While several people have tried making replacements, so far none of them has displaced texvc. Ozob (talk) 18:20, 9 March 2009 (UTC)

My understanding is that texvc is just a wrapper for LaTeX. It doesn't directly participate in the process of generating PNG images for the Wiki software. That job still belongs to LaTeX. So unless the Wiki development team is currently working on a replacement for LaTeX — which is extremely unlikely at any point in the foreseeable future — I suspect that this is a permanent problem with TeX on Wikipedia. Workarounds should therefore be encouraged, within reasonable limits. Sławomir Biały (talk) 16:23, 17 May 2009 (UTC)

Perhaps you mean replacement of a particular LaTeX rendering package that wikipedia uses and which is not working properly? LaTeX as such is fine. Other sites I mentioned above use LaTeX too and all is well there. Jmath666 (talk) 16:44, 17 May 2009 (UTC)

Layperson's understanding

I agree with the top post in this discussion page. I just came here to say exactly that, and noticed that somebody already had. I'd like to extend the notion a little bit to say that, even if Wikipedia is not *obligated* (ethically, or according to its own policies) to provide layman's explanations, it would really be nice if there were such an encyclopedia mathematica for laymen somewhere, and what better medium than Wikipedia to be that.

The problem with explaining mathematical ideas in jargon terms is that the learning curve for people who aren't already highly educated in mathematics to learn about a concept this way is ridiculously steep, maybe not even practical. Perhaps you might argue that someone not highly educated in mathematics wouldn't need to look up things like, for example, 4-d rotation, or how to make a Bezier spline, but I've found myself in this position *often*. Wikipedia could be a great portal between the layman's and the mathematician's worlds.

I'm sure those who *do* know their maths could argue that they shouldn't have to wade through descriptions put into layman's terms where a more concise terminology would suit them better, but I'm not proposing that the layman's-terms descriptions act as a replacement for the concise definitions - just that writing additional sections where things are thoroughly (or even summarily) explained in simple terms in a guiding way could be encouraged.

Also I'd like to see more algorithms posted for how to arrive at mathematical results. That's usually what I basically need, and having an algorithm there would be 1000x easier for me than trying to understand an abstract mathematical description and then coming up with my own algorithm. And even to people who understand these terms, I would think a formal definition alone doesn't necessarily imply some highly efficient algorithm for arriving at the given result that some mathematician may have come up with.

Maybe not every article can guide a layman to an understanding of the mathematical concept in a self-contained manner without including an entire lecture series in higher maths, but between having links to other articles and striking a good balance between generality and specificity, I think a very informative middle-ground could often be reached.

Inhahe (talk) 19:21, 20 April 2009 (UTC)

This question arises frequently. The consensus as I understand it is that while some mathematical articles are poorly written, much of the underlying content is difficult and cannot be made substantially easier to grasp. I invite you to browse the archives of Wikipedia talk:WikiProject Mathematics, where you'll find more discussion of this. Ozob (talk) 20:41, 20 April 2009 (UTC)

Blackboard bold

Is there a consensus as to when it's appropriate to use blackboard bold and when not? Right now, the MOS has a section, WP:MOSMATH#Common_sets_of_numbers, which, in my opinion, can be read to endorse either bold or blackboard bold for, e.g., the real numbers R, the complex numbers C, or the quaternions H. My own opinion is that blackboard bold is ugly and hard to read in print: The two vertical lines create a sharp, distracting contrast between whitespace and ink. For this reason I prefer to use blackboard bold only on blackboards. But we don't seem to have a policy. This became an issue recently at quaternion when an anonymous user switched boldface to blackboard bold and User:Virginia-American and I disagreed over which we should use. Does anyone have an argument for one or the other? Ozob (talk) 14:44, 2 June 2009 (UTC)

You have already stated the argument for using simply bold: it is typographically superior. On the other hand, many (most?) professionally published mathematics texts nowadays use blackboard bold in print, and the appearance is decent enough. The wikipedia tradition for these sorts of minor issues is to leave each article as it was formatted by the first major editor. — Carl (CBM · talk) 14:48, 2 June 2009 (UTC)

I would suggest the guiding principle should be simple: do what ever the majority of recent sources do. — ras52 (talk) 15:29, 2 June 2009 (UTC)

Angle brackets

Is there a preference with respect to the usage of "proper" Unicode angle brackets versus "faking" them with less than/greater than signs? Apparently, the angle brackets in an expression like 〈v,w〉 (using &lang; and &rang;) are not displayed properly for many users. Should one write this expression as <v,w> instead? —Tobias Bergemann (talk) 08:50, 10 June 2009 (UTC)

The proper use are the r/l angles. If they don't display correctly, these won't be the only things to not display correctly. This isn't the internet of 1995, and any modern browser uses default fonts which supports them.Headbomb {^ταλκ_{κοντριβς} – WP Physics} 06:49, 25 June 2009 (UTC)

Italicization of π / Pi

The Greek letter pi is italicized in some parts of the Pi article, and roman in others. That needs to be fixed, but which is correct?

67.171.43.170 (talk) 02:37, 17 September 2008 (UTC)

Pi should be italicized; π should not be. Septentrionalis PMAnderson 16:58, 20 September 2008 (UTC)

Not exactly consensus, but I agree and boldly made the change throughout (in celebration of this glorious day), but e still appears italicized. Note that, as a constant, this is different from the several variables that appear italicized (d, r, etc.), although I'm not 100% sure what's proper there, either. Out of curiosity, would $\pi$ be an option for the article body? Or $e$? /Ninly (talk) 16:04, 14 March 2009 (UTC)

WRONG. π should always be italic, for the following reasons..

1. The tradition of mathematical typography is to italicize π. There is discussion of whether this is 'correct' but the lower-case italic form $\pi$ is the most widespread in the literature. (π is italic when it denotes the standard meaning of pi in trigonometry, calculus, physics, etc -- but deviant statisticians use π and Π to symbolize other stuff).
2. MathML, LaTeX, and Wikipedia tags {{math}} or <math> all italicize $\pi$.
3. From Edward Tufte's website:
“ These traditions are hundreds of years old. Italics help distinguish between variables and other things like numbers and operators. For instance cosine of x is written "cos $x\,\!$". (This issue comes up in other symbolic systems; programmers need that distinction too, but today almost universally use color coding instead.) But like any centuries-old tradition, there are a lot of quirks, for example vector variables are sometimes bold, non-italic. Also which letters you use for which variables is important. A lot of today's traditions were introduced by Descartes, like using the end of the alphabet for unknowns and the beginning for known quantities. At one point people used vowels vs. consonants, I think, but no longer. ”
4. According to Stephen Wolfram:
“ One of the things that Euler did that is quite famous is to popularize the letter $\pi$ for pi--a notation that had originally been suggested by a character called William Jones, who thought of it as a shorthand for the word perimeter. ”
5. Most fonts are non-mathematical and render &pi; as "π" (non-italic). But mathematical typesetting packages render \pi as "$\pi \,\!$" (italic).
6. The Pi article even shows this italic image of the letter! ---

I believe this article should follow mathematical convention, so I would prefer to italicize the π's. Any objections? ~~ Ropata (talk) 05:38, 17 June 2009 (UTC)

The Wikipedia Manual of Style clearly asks not to italicize π (or any other Greek letters for that matter, except possibly when they are variables). The discussion really belongs to WT:MSM, not here. — Emil J. 11:54, 17 June 2009 (UTC)

The discussion is already here, not at WT:MSM. The Manual of Style does not enforce rules, it merely states a few conventions. Wikipedia ought to follow mathematical convention not reinvent it. ~~ Ropata (talk) 11:00, 20 June 2009 (UTC)

That the discussion already started here does not make the choice any more appropriate. People who are interested in conventions for formatting Greek math symbols are supposed to watch the MoS page, they are not supposed to watch every article which uses the symbols such as this one. — Emil J. 14:25, 23 June 2009 (UTC)

My understanding is that italicizing Greek is redundant because Greek letters are already somewhat slanted (or at least their supposed be even though some computer fonts don't show them that way. For another project Angr wrote:

The Greek alphabet doesn't distinguish between italic and roman types; Greek letters themselves are usually printed slightly inclined to the right, especially in fonts used for Ancient Greek rather than Modern Greek. (Modern Greek fonts are often assimilated to the Latin alphabet, having completely vertical lines and distinguishing between serif and sans-serif fonts.) At any rate, even though the Greek will look slightly italicized to people used to the Latin alphabet, it shouldn't be set as italics.

--RDBury (talk) 05:37, 25 June 2009 (UTC)

Good advice

can be found at http://www.maths.ox.ac.uk/files/study-guide/index.shtml, esp. part II. I found this info out far too late to be of any use to me, but I felt good knowing that someone made explicit the process of writing theorems (or I was away at the lecture they told everyone else)...

Perhaps this should be basic knowledge for anyone actually writing a maths article on WP. Otherwise a link to it may be helpful. 118.90.74.32 (talk) 02:22, 16 July 2009 (UTC)