Here you can discuss the Wikipedia:TeX markup for mathematical formulas, report bugs, request features etc.

Table of contents 1 Questions 2 Outstanding bugs and feature requests 2.1 sets of equations 2.2 Error messages for \begin and \end 2.3 \> 2.4 $$ inside \mbox 2.5 \TeX and \LaTeX 2.6 PNG transparency 2.7 Render to HTML or to PNG ? 3 Planned for Phase 4 4 Resolved bugs and feature requests

Questions

Is there a way to make a linebreak? Having trouble with the width on Matrix multiplication -- Tarquin 17:20 Jan 15, 2003 (UTC)

Outstanding bugs and feature requests

sets of equations A feature for aligning several equations underneath each other is needed. Could be done similarly to the new \begin{matrix}...\end{matrix}

• "aligning several equations" is feature of text formatting, not math markup. The same is the case with case-by-case definitions. I'm not saying they won't be supported. Just that they not really that relevant to what we are trying to solve with texvc.

I think this feature is really needed. Consider the following use of {matrix}, which is currently the only way to get aligned equations:

<math>\begin{matrix}

e^{i\pi} &=& \cos\pi + i \sin\pi \\ &=& -1 \end{matrix}</math>

The second line looks bad, because {matrix} center-aligns matrix elements. For sets of equations, the right hand side needs to be left-aligned. See, for example, the {eqnarray} mode in LaTeX. -- CYD

Error messages for \begin and \end

More correct error messages for \begin and \end. Now it it reports that it doesn't know these, but it does understand things like \begin{pmatrix}. -- Jan Hidders

texvc doesn't treat \begin and \end as functions. Problem has low priority. Taw 15:05 Jan 1, 2003 (UTC)

\>

• since the spacing commands \!, \; and \, are supported, \> should be supported as well
  • \> is not in usual documentation (for example http://www.giss.nasa.gov/latex/ltx-118 ), seems to be doing the same thing as \,, and is not used in any PlanetMath equation.
    • \> is halfway between \, and \;. (And since when is that link the usual documentation?) -- Toby
      • Well the Not So Short Guide doesn't mention it, though I just tried it and it worked. Bagpuss

$$ inside \mbox

• error messages need to be improved: the input S = \{ \frac{m}{n} \mid \mbox{$m$ is even and $n$ is odd} \} does not give a helpful error message, even though it is correct, standard and safe TeX.

\TeX and \LaTeX

• Could we have \TeX and \LaTeX working? The way it's formed in HTML in the TeX article doens't look too grand. Bagpuss
  • They aren't math symbols. Why should they be implemented this way ? You can upload images. Taw 22:42 19 May 2003 (UTC)

PNG transparency

• the png images should have transparent background
  • Yes, transparent pngs would be nice. Does anybody know what ImageMagick magic is needed to convert black-and-white image to black-and-background one ? I didn't have much luck with that. And there's still a problem that some old browsers don't handle PNG transparency well.

Taw 21:21 Jan 5, 2003 (UTC)

Render to HTML or to PNG ? Suggestion: where possible, <math>(a_1,b_1] \times (a_2,b_2]</math> should be rendered inline as (a₁,b₁] × (a₂,b₂], rather than expanded to a graphic.

And also that <math>\mathbf{F} = q \mathbf{v} + \mathbf{B}</math> should be rendered as F = qv + B wherever possible. -- Anon.

There are some elements which appear to force PNG rendering, which shouldn't:

• render <math>\dots</math> as ..., rather than as a PNG.
• <math>\sin^{-1}</math>

Planned for Phase 4

My browser (Mozilla 1.2) is capable of rendering MathML, and the MathML examples I've viewed using it previously have looked quite nice - much better than the autogenerated images used now, since they were actually text and fit in with the rest of the text on the page better. How about an option one can set in preferences so that the TeX equations are translated into MathML instead? Since most browsers don't support MathML, it would be off by default, but as time passes MathML could become more common. Bryan

It's planned, but a) somebody needs to write such conversion or find and adapt exising such code and b) inline MathML requires that our HTML be XHTML, which requires a better wikicode parser than we currently have to guarantee well-formed output. --Brion 19:58 Jan 19, 2003 (UTC)

It doesn't work in Konqueror, so it's not a priority for me now. Taw 14:46 Mar 7, 2003 (UTC)

Resolved bugs and feature requests

• \ddots needed to construct large matrices
  • Yes, \ddots is missing. One line to fix that. If you have some documentation with list of all symbols in AMS-LaTeX, please post it here, so all can be added at once.
    • http://wso.williams.edu/how/lshort2e/node61 is a complete list.

• \textrm{for all} should give the same as \mbox{for all}, i.e. the space between the words should be shown.
  • A space would not be correct TeX. -- Toby
    • Hmmm, works for me in TeX. Bagpuss
      • You are right, because it is \textrm, not \mathrm. My bad. -- Toby 17:43 Mar 19, 2003 (UTC)
        • That's okay. Bagpuss

• \big is missing; parenthesis size cannot be adjusted properly. This makes many formulas ugly, and some formulas unreadable.
  • \big nor any other function with so insane semantics will not be supported. Taw 20:45 Jan 5, 2003 (UTC)
    • The semantics of \big is not any worse than \left and \right.
      • OK, \big \bigg \Big \Bigg will be available. Taw 16:10 Mar 7, 2003 (UTC)

There's a bug in the handling of \left and \right: If a \left is given without a corresponding \right, texvc won't complain but TeX will and no png is produced:

\left ( a + b ) <math>\left ( a + b )</math>

and also

\left\right xy <math>\left\right xy</math>

Every \left and every right has to be followed by a delimiter, and every \left has to be paired with a \right. AxelBoldt 00:06 Jan 9, 2003 (UTC)

Will be fixed. Taw 15:33 Mar 7, 2003 (UTC)

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There is an error rendering the following (remove the "nowiki"s to see the error):

: <math>E = \frac{m_0 c^2}{\sqrt{1 - v^2/c^2}}</math>

which should render as the (equivalent):

<math>E = {{m_0 c^2} \over {\sqrt{1 - v^2/c^2}}}</math>

but instead spews a whole bunch of junk before the header, along the lines of the following:

Warning: pack type H: not enough input, need 16, have 15 in /usr/local/apache/htdocs/w/OutputPage.php on line 72

Warning: Cannot add header information - headers already sent by (output started at /usr/local/apache/htdocs/w/OutputPage.php:72) in /usr/local/apache/htdocs/w/OutputPage.php on line 219

Hope the above helps. Cheers Chas zzz brown 10:21 Jan 13, 2003 (UTC)

Slightly modifying the formula makes it work, so it seems that it's not a bug in the parser but a corrupt cached png. AxelBoldt 02:08 Jan 14, 2003 (UTC)

Okay, these kinds of problems should be fixed now. The column that stores the hash has been changed from CHAR to VARCHAR so it doesn't crop off the final bye if it's a 0x20, and I've cleared the bad rows from the cache table. --Brion 20:04 Jan 19, 2003 (UTC)

Guess what, I lied. Still broken! --Brion 20:05 Jan 19, 2003 (UTC)

Seems okay to me. Bagpuss

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We have \arcsin and \arctan, but why not the other inverse trig functions? Seems kind of inconsistent and arbitrary to me. Eric119 00:33 Mar 5, 2003 (UTC)

because <math>\sin^{-1}</math> is nicer? -- Tarquin 11:25 Mar 5, 2003 (UTC)

I think you're misinterpreting. My point is that TeX support DOES include arc* functions, but not all of them. There are six inverse trigonometric functions. Two of them are recognized (arcsin and arctan), but the other four aren't. There should be support either for all of them or for none of them. Eric119 23:15 Mar 5, 2003 (UTC)

Will be fixed. Taw 14:46 Mar 7, 2003 (UTC)

Can somebody take a look at Schroedinger equation, where something went seriously wrong (see this old version (/w/wiki.phtml?title=Schroedinger_equation&oldid=598401) and the talk page for the gory details). I don't have a clue about this sort of thing myself, I'm afraid. --Camembert

Actually, I think I've somehow fixed it. It must have been a similar caching error to that mentioned above, because the content of the page hasn't actually changed at all. Odd. --Camembert

OK, I thought I'd fixed it, but I'd not - the equation which appeared wasn't the right one - I was pretty sure I'd pasted the right one into the article, but it rendered the first equation in that article instead (the problem could simply be me going insane, however). I guess this fits in with what Brion's doing just above me (as 'twere), though, so I'll shut up about this now. --Camembert

It appears to be impossible to typeset a dollar-sign in the version of TeX being used here. It is needed in Time value of money and similar articles. Michael Hardy 01:31 Apr 13, 2003 (UTC)

Will be fixed - use either $ or \$ after new code is uploaded. Taw 22:31 19 May 2003 (UTC)

Done. --Brion

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I have a suggestion for an improvement to the <math> tag: the addition of a caption option, so that we can change the caption text to something that makes sense if you can't read TeX. For example, look at the very first rendered TeX image on Wikipedia:TeX markup -- that caption isn't for the TeX-illiterate, and there are much worse. This would make TeXed pages much more friendly, and I've seen comments that complain about TeX because this option doesn't seem to be available. (Of course, if it is already available, please tell me how to do it!)

I was also going to ask for a hyperlink option, but I see that one can do:

[[expected value|<math>\textrm{E}(X)</math>]]

<math>\textrm{E}(X)</math>

which is exactly what I was imagining. The only problem is that the link does not appear to be correctly coloured if the page to which one is trying to link doesn't exist yet (usually red on my browser, IE6, though I suppose it could be a browser problem).

--Ben Cairns 23:44 1 Jun 2003 (UTC)

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Can we have support for \overbrace, please? See Yet another treatment of tensors[?]. -- The Anome 11:58 2 Jul 2003 (UTC)