Wikipedia talk:Manual of Style/Mathematics

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WikiProject Manual of Style
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Default vs. \textstyle: example shows no differences, \scriptstyle unexplained, outdated documentation referenced[edit]

With FireFox 26.0 and Wikipedia.Preferences.Appearance.Math=MathJax, I see the examples illustrating the value of \textstyle in Wikipedia:Manual_of_Style/Mathematics#Using_LaTeX_markup as identical, with limits after the sigma. I tried adding \scriptstyle to the example, but it did not change. In Help:Displaying_a_formula I found no explanation of these elements. I searched for them in Wikipedia: and MediaWiki:, but found no documentation (but a great deal of what in this situation was noise) in the first 100 hits, though I did find “\displaystyle” – which helps, but adds to the confusion – (and “:<math>”) in Wikipedia:WikiProject_Mathematics/Typography. I suspect that the introduction of MathJax has something to do with all this. In case the page changes, the examples of rendering – which I see as identical with the exception of \displaystyle — are:

  • Code: “<math>\sum_{n=1}^\infty 1/n^2 = \pi^2/6</math>
  • Default (no \*style): \sum_{n=1}^\infty 1/n^2 = \pi^2/6
  • With \textstyle: \textstyle\sum_{n=1}^\infty 1/n^2 = \pi^2/6
  • With \scriptstyle: \scriptstyle\sum_{n=1}^\infty 1/n^2 = \pi^2/6
  • With \displaystyle: \displaystyle\sum_{n=1}^\infty 1/n^2 = \pi^2/6
  • With :<math>: :\sum_{n=1}^\infty 1/n^2 = \pi^2/6

The lead of Wikipedia:Manual_of_Style/Mathematics refers to meta:Help:Formula, which says it is outdated and looks rather like Help:Displaying_a_formula, though it does not refer to that.

It would be helpful if someone (or ones) could:

  • Document these markup elements (and the default) in Help:Displaying_a_formula, including the effect any settings may have.
    • Also document :<math>, if that is supported (but say it is redundant if it is default).
  • Update Wikipedia:Manual_of_Style/Mathematics#Using_LaTeX_markup so that the examples render differently and/or warn that they depend on settings and refer to the added documentation section for details.
  • If \scriptstyle is obsolete, then this should be explained in both places.
  • If Help:Displaying_a_formula supersedes meta:Help:Formula, then:
    1. Refer to it from the outdated page,
    2. Merge the outdated page to the new page — this could be done in steps, replacing sections by references to the up to date version.

And if experts do not know, then state that honestly in the documentation! PJTraill (talk) 22:37, 9 February 2014 (UTC)

The current way to explain symbols in formulae needs motivation[edit]

The old motivation for why explanations of symbols in formulae (see article section Explanation of symbols in formulae) should be written as prose, was simply because the list "has no reason to be bulleted". This is simply incorrect — there are probably several reasons for why the list should be bulleted, although the only good reason I can come up with for the moment is that it makes it much easier to quickly find the variable you want to read about. I therefore rewrote the sentence so that it now only says that lists should be written in prose.

Now, however, the statement lacks motivation for why the list should be written in prose, and such should therefore be added. Otherwise, we should probably revise the statement altogether and make it generally acceptable to list explanations of symbols in formulae as bullet lists, as an alternative to as in prose. —Kri (talk) 21:24, 9 March 2014 (UTC)

Descriptions of variables should generally be in prose because Wikipedia articles are written in prose. A list of variables is an index, and an index is intended to be referenced, not to be read. Ozob (talk) 23:31, 9 March 2014 (UTC)
And why should Wikipedia be written in prose? The primary reason for any guideline is presumably to optimise the accessibility of the information for some target audience, but it is reasonable to ask if that guideline is suitable for a given field. I have a suspicion that a style of thinking favoured by those leaning to humanities is being imposed on those of a technical bent. The argument “an index is intended to be referenced, not to be read” does not convince me, especially in a reference work, which I think Wikipedia is; I think the reader should be able to choose to read or reference the explanations, and consider both slightly easier in list form because the visual structure better reinforces the logical structure. I am however not sure if the small increase in ease justifies the extra space required. It would be nice to have markup that left the choice with the reader, but that seems impracticable. PJTraill (talk) 11:04, 10 March 2014 (UTC)
Because we want the whole encyclopedia to have a consistent style? See WP:PROSE: "Prose is preferred in articles as prose allows the presentation of detail and clarification of context, in a way that a simple list may not. Prose flows, like one person speaking to another. It is best suited to articles, because their purpose is to explain." —David Eppstein (talk) 14:35, 10 March 2014 (UTC)
I think that when justified, exceptions from this principle are acceptable. No one would argue that the tables in Wikipedia rather should be written in prose, for example. —Kri (talk) 17:15, 15 March 2014 (UTC)

For what it's worth this section may be useful, at least it's recent and relevant, possibly one motivation behind this thread.

I agree that lists are good for easy and quick reference, and also that prose allows symbols to be explained in brief detail. Using both is too much explanation, so we just have to decide which one or the other is best for any particular situation. M∧Ŝc2ħεИτlk 17:54, 10 March 2014 (UTC)


Hey, Dave! What are your objections to my rewrite?

Duxwing (talk) 06:37, 10 April 2014 (UTC)

  1. I prefer "David" to "Dave".
  2. For the short version, read my edit summary.
  3. Given the fact that discussion on Talk:Waring's problem did not seem to make much difference to your idiosyncratic views on what is grammatical or idiomatic or standardly phrased, I am not optimistic about the discussion here, nevertheless...
  4. There are lots of little things I could quibble with (like, it's not true that the lead section is the same as an introduction), but the big one that caused me to immediately revert was your replacement of "The lead should as far as possible be accessible to a general reader, so specialized terminology and symbols should be avoided as much as possible." with "The lead should be accessible to general readers: avoid special terminology and symbols." It is simply not true that all mathematics articles can have a lead that is written to be accessible at the high school level (using that as an approximation to general readers). A good heuristic is that they should be written to be one level of education lower than the typical level at which the subject is studied. So, for subjects studied in elementary or secondary school, yes, the lead should be accessible to general readers. For subjects at a level that might be studied by mathematics majors in college (say Waring's problem), the lead should be accessible to interested high school students. For subjects typically left to graduate school (maybe meromorphic functions are an appropriate example) the lead should be accessible to college mathematics majors. And for subjects of current research the lead should be accessible to mathematics graduate students. Additionally, you omitted the "as much as possible" part of avoiding terminology and symbols: it is not always possible to avoid them completely, so hardening this rule is a bad idea.
  5. In general, for big sets of changes to guidelines like this, it works better to break them into smaller changes that we can discuss individually, and build consensus on talk for each of them. It would be a mistake to read my previous point and think that you should just do all the same changes except the one I'm complaining about. I'm sure there are several other things in there that I would object to enough to revert, or at least argue about, but I didn't look for them because that one already gave me enough reason to revert just by itself. —David Eppstein (talk) 07:24, 10 April 2014 (UTC)
  1. Ok. :)
  2. I read your summary and want more
  3. Coincidentally, this Manual of Style explicitly states my point about not using technical language in the lead.
  4. The Math MoS states that leads should not require expertise or references to understand; I hope I said "leads" and not articles and am sorry if I did not. Caveats like "as far as possible" are redundant here because Manuals of Style are guidelines and therefore inherently not hard-and-fast. Obviously, my argument from MoS therefore is not necessarily true.
  5. Sorry, long edits are bad habit of mine, and I will try to avoid them.
Do you want to collaboratively copy-edit with me? Duxwing (talk) 09:13, 10 April 2014 (UTC)
On point 3: this subpage, which reflects a 10-year-old consensus, explicitly states that it may replace the general style: "For matters of style not treated on this subpage, follow the main Manual of Style". The technical language point is treated on this page, and the consensus wording is "as far as possible". A change like this would make it impossible to write articles on any serious technical subject at all. Deltahedron (talk) 21:57, 10 April 2014 (UTC)
I would normally try avoiding saying this so bluntly Duxwing, but your styling yourself as a grammar hammer indicates to me that this needs to be stated forcefully. After reading your edit to this MOS I had a look at your user page and I have come to the conclusion that good copy-editing is not in your skill set - you don't have a good grasp of how to write idiomatic and easy to understand English. Your reading of 'as possible' as meaning for the general reader also indicates you are unable to read instructions properly. You should stop when others disagree with you rather than fighting them. I agree with all of David Eppstein's comments above and believe the heuristic there for the level to aim at is a good one. Dmcq (talk) 11:35, 11 April 2014 (UTC)

Use of mathematical notation in non-math articles[edit]

I have edited the first sentence to say that some aspects of this manual apply not only to articles on mathematics but also to the use of mathematical notation in articles on other subjects than mathematics. It would be absurd to say that because an article using mathematiacl notation is on chemistry, it should be exempt from standard conventions when it uses mathematical notation.

The article titled Duckworth–Lewis method begins by saying:

The Duckworth–Lewis method (often written as D/L method) is a mathematical formulation designed to calculate the target score for the team batting second in a limited overs cricket match interrupted by weather or other circumstances.

But someone is saying on its talk page that WP:MOS does not apply to it since it is not a mathematics article, so that one should write things like 3<5 instead of 3 < 5 or 3 x 5 instead of 3 × 5, etc. Michael Hardy (talk) 12:06, 5 May 2014 (UTC)

phi problems[edit]

There are two different ways to include the phi symbol:

a wrong φ  ampersant phi semicollumn


a right   \phi  math phi math

and in some articles they both appear for example in Angle of parallelism is it not possible to make a script that automaticly change the wrong form into the right form? (for beginners it can be unclear that they have the same meaning)

see also Phi the page about the symbol — Preceding unsigned comment added by (talk) 10:49, 13 July 2014 (UTC)

Bad idea I think. I've seen both variants of epsilon used together for different things. They are just math symbols, we are not writing Greek. They are not right or wrong. Dmcq (talk) 12:28, 13 July 2014 (UTC)
You can also get the "open" phi with varphi in math mode, i.e. \varphi. I think it is the preferred choice for e.g. the golden ratio. I see no point in prohibiting it or the other one. —David Eppstein (talk) 14:16, 13 July 2014 (UTC)
Consistency within an article is good, but is there a way of ensuring that across all combinations of HTML rendering and LaTeX rendering? Deltahedron (talk) 16:38, 13 July 2014 (UTC)

Variable re-use[edit]

Do we need an admonishment to avoid using the same variable name for multiple unrelated meanings? This has come up in Closed subgroup theorem. (There doesn't seem to be any disagreement there that this is a bad idea, but it happened because one contributor was following the style of a reference that did this.) —David Eppstein (talk) 16:49, 18 July 2014 (UTC)

Recommending against variable reuse is a good idea. It should come up only rarely, but the advice is certainly in keeping with the general principle of providing maximum clarity in an article. Something like
  • Avoid using the same variable or symbol for two different mathematical objects.
--Mark viking (talk) 17:48, 18 July 2014 (UTC)
I think some qualifier such as "where confusion is likely to arise" is needed. There are quite standard ways of writing which would be excluded by this if rigorously enforced. For example, if (X,T) is a topological space with underlying set X and topology T, it is quite usual to refer to it as X if there is only ever going to be one topology on it. Similarly we use +, ×, ⋅ etc to denote operations in different groups freely without confusion. The reuse of place-holders such as i,j for summation is also usual. Deltahedron (talk) 08:29, 19 July 2014 (UTC)