tea.mathoverflow.net - Category Feed (LaTeX)

Report bugs with LaTeX (MathJax) rendering here.

2010-08-28T17:16:57-07:00

MO LaTeX support is now .

Please report bugs or feature requests here.

The Tex Symbol for the Real/Complex Numbers

2013-04-06T07:47:31-07:00

How does one write in Tex for MathOverflow the symbols of the real numbers, and the complex numbers? Usually, one uses \mathds, but this doesn't seem to work.

Math render delay

2012-03-13T07:44:38-07:00

I see a great math render delay today, unlike yesterday. (Safari 5.1.4 just out, is that related?) I open a page, a short question and two answers. Yesterday, rendering took a couple of seconds. Today (I timed it) 90 seconds. At least it is better than math.stackexchange, where math doesn't render at all...
I tried it with an old Safari (3.0.4) and it has the same delay, so perhaps it is not the fault of the new version. Also tried Google Chrome, Firefox, Opera. All have the delay.

curly braces!

2011-09-07T12:33:47-07:00

Writing \{ a,b,c \} in TeX doesn't work on mathoverflow. Neither does \left\{ a,b,c \right\}. Neither does \left{ a,b,c \right}. All that appears is a,b,c. I'm quite surprised and appalled by this situation. (See my question on exchangeable normal r.v.s.)

Once works and twice fails

2011-05-19T09:48:27-07:00

If I type [ $k[x]_{x}$] , it renders as expected.But if I type[ $k[x]_{x}$ is $k[x]_{x}$], the rendering is completely botched.
Could somebody please explain what is going on? Sorry if this has already been mentioned.

xymatrix

2011-05-20T08:44:02-07:00

Can I use commands like xymatrix in mathoverflow? And how? I tried the backwards quote `` but it still doesn't work.

Why doesn't \mathit work?

2011-05-13T18:08:15-07:00

The commands \mathit seems to be completely ignored in LaTeX input. This yields exceptionally ugly results at times, eg, here. Why does this happen, and can it be fixed?

(\textit likewise does not work right.)

Tex Issue

2011-04-30T09:21:23-07:00

Can someone explain to me why LaTex is ignoring some of my dollar signs in this answer?

The problem was cropping up in several places; I managed to solve most of with small edits, though I have no idea why those edits worked. One remains unresolved.

Posts using defunct math rendering system

2011-03-13T12:14:17-07:00

In November of 2009, when MO was just a few weeks old, we were exploring different ways to render math. One of the systems we tried would generate images, but this system is now broken. The upshot is that there are a bunch of posts that look broken.

If you come across these posts while browsing, please do fix them so that you and others can read them. Here's a bash one-liner that should do a pretty good job. Click "edit" on the post and copy-paste the source into a file post.txt. Then run

cat post.txt | sed -e 's|(http://latex.mathoverflow.net/png[^)]*)|×|g' -e 's/\\sb /_/g' | sed -e 's/!\[\([^×]*\)\]×/$\1$/g'

and paste the output into the MO input box. This command changes something like ![V\sb {ij}](http://latex.mathoverflow.net/png?V%5F%7Bij%7D) into ![V_{ij}]×, and then into $V_{ij}$ . The funny symbol × is inserted to clearly delimit the LaTeX source. It's still a good idea to make sure the correction is sane. For example, you may have to add some backquotes (these ones: `) around the dollar signs if there are lots of underscores making things italic.

Report: How to fix wonky TeX characters

2011-01-06T23:00:33-08:00

For as long as MO has used MathJax, I've noticed that a lot of the characters were malfunctioning (in particular, symbols like \bigoplus, \bigotimes, \prod, \coprod, etc) (in particular, they were offset downwards (the baseline was assumed to be the middle of the character, not the bottom)).

Anyway, I realized that the thing causing the problem was that I had installed an old version of the "mathjax fonts" from the mathjax package, the public beta version of the STIX fonts, and the jsMath fonts. I deleted all of them and installed the 1.0 version of the Stix fonts, and now everything looks the way it should.

Just posting this in case anybody else had similar problems.

HTML entities in comments

2010-12-14T19:42:19-08:00

When writing a question or answer, I often try to use HTML entities when possible instead of mathjax, since they don't take time to render. But this doesn't seem to work when writing a comment; in that case HTML entities get escaped and thus don't show the way I want. Is that a known and desired feature?

Help fix the Math on this question?

2010-12-12T07:07:03-08:00

This question gives evil red text about bad math processing. I took a look at the LaTeX and don't see anything obviously wrong. Since MathJax preview has been broken since forever on my NetBook, if I were to proceed by trial and error I would be bumping the question all over the place. Can someone else take a look at it?

Thanks.

How MathJax is Configured on MO?

2010-10-11T03:29:07-07:00

I asked this question on Meta.CSTheory, and the moderator offered me to ask it here.

To cut a long story short, the math support on MathOverflow (even on faketestsite) is much better than the support on CSTheory.

Specifically, when asking or answering a question, MO renders the formulas on the fly, while in CSTheory it takes quite some time before the formulas are processed.

I wanted to know how to tweak MathJax on CSTheory to behave like MO?

Brackets

2010-09-30T13:50:01-07:00

Hi, I'm sure this has been answered a few times, but I couldn't find where. How do I get the curly brackets {} to show up in a formula? (The LateX \{ command does not seem to work)

Help test MathJax

2010-06-24T21:54:03-07:00

MathJax 1.0 is due to be released very soon (in a week or so?). I think there are good reasons for switching from jsMath to MathJax when that happens. MathJax seems to be more stable and have more uniform behavior across browsers. Also, it allows for the option of converting to MathML in browsers that can handle it.

I've implemented MathJax on faketestsite and I invite you to go try it out.

It's configured to try to convert to MathML, but to use HTML-CSS if the browser doesn't support MathML (what browsers aside from Firefox support MML?).
All macros that work on MO should work on faketestsite.
The live preview should work.
Math in the comments should work properly.

One issue I've encountered is that when I use Firefox and get MathML output, it looks like I don't have enough fonts installed. For example, \mathfrak and \mathcal both come out as upright roman font. Does anybody know how to solve this?

It's likely to feel a bit slow right now. There are two reasons for this. One is that I'm hosting MathJax on my home computer, so fetching the scripts and fonts may be slow. The other is that MathJax is still being optimized for speed. Both of these will be resolved by the time we start using MathJax on MO.

Problem for displaying jsMath with IE8

2010-07-06T06:10:31-07:00

Hi,

I just wanted to report that I couldn't display Latex on the forum

I have posted on user's group of jsMath and someone says that it is a bug on the forum and that is has nothing to do with jsMath

Here is the link to the post I left on this forum

http://sourceforge.net/projects/jsmath/forums/forum/592273/topic/3761789

Any help appreciated

Regards

\underbrace stopped working

2010-05-31T12:59:24-07:00

Hello,

I've used an \underbrace in a reply to some question a while ago, and I remember it working fine. Now, it doesn't work anymore: on Opera it says "undefined control sequence \underbrace", on IE 8 it just destroys jsMath (it gets to trying to render the underbrace, and freezes: the counder freezes at something line 68% completed, reprocessing math or reloading the page does not help).

Should I remove the \underbrace? Will it work again? What happened?

Thanks,
Ilya.

P.S. Offending post:
http://mathoverflow.net/questions/14529/visualisation-of-riemann-stieltjes-integrals/14536#14536

Somebody else's post with an \underbrace , same symptoms, I think:
http://mathoverflow.net/questions/13270/orthogonality-relation-for-quadratic-dirichlet-characters/13382#13382

Latex Errors

2010-05-30T16:02:02-07:00

I recently upgraded to Internet Explorer 8. Now, on the vast majority of posts, the latex doesn't display correctly. Typically the very first part of the post displays correctly, and then, after some point, all of the latex is replaced by latex code mixed with a bunch of strikethrough W's. When this happens in the bottom left corner the status bar says "Processing Math: X%" (with X less than 100%) and, below that, "Error on page". Is there a fix for this?

It's likely this has been discussed elsewhere, but I haven't been able to find it if it has.

Editing LaTeX out of titles

2010-04-08T19:30:54-07:00

To improve readability, whenever I see LaTeX in titles, I remove it and replace it with unicode characters because it doesn't display properly on the front page, and having jsMath run on the front page significantly slows down the site (this was tried a while ago). If the expression is complicated, I often add in words to compensate for the missing symbols. I was wondering if something like the following could be added to the FAQ (I'm not going to claim that this is worded well):

Please try to avoid using LaTeX in the titles, since it does not render on the front page, and this makes it harder to read. If you do put LaTeX in the title, someone may edit it out to improve readability, so please don't be surprised if this happens.

Is there any opposition to something like this, or even the entire practice of editing LaTeX out of titles?

Why do I have to reload each question to make it render?

2010-03-17T14:18:10-07:00

Some of the LaTex renders correctly when I open a question, but I always have to reload the page to see all of it. Any ideas why? I'm using a Firefox 3.5 browser (if that matters).

Is it possible to use xypic commands?

2010-03-21T16:16:54-07:00

I would like to ask a question that includes some diagrams. I have tried using \xymatrix{...}, but that did not work. Is there any way to use xymatrix in MathOverflow?

What's the deal with LaTeX errors?

2009-12-17T10:23:53-08:00

I'm writing this here, so I can link to it thereafter. Many of our users have noticed confusing errors where LaTeX code does not behave as expected. If you are a one-time user, you probably just want to leave the buggy code in place and figure that a moderator will clean it up. But, if you come here frequently, you might want to understand what is going on. This is my attempt at an explanation a bit more detailed than the one in the FAQ. I should note that the real expert here is Anton, who has put in a great deal of effort getting things to work as well as they do; I'm just a bystander.

When mathoverflow displays your question (or answer), there are two javascript programs which parse your text. The first is wmd. This inserts links and images, makes words bold and italic, and strips out any HTML that might be inserted by malicious users. It probably also does some other things that I am not thinking of right now. The second is jsmath. This creates equations. The important thing to understand is that jsmath is operating on the output of wmd, not on your raw input.

This can cause problems when wmd modifies your input in unexpected ways. The main workaround is to enclose your equations in back-single-quotes. (This character `.) This tells wmd to leave them alone. You can also try to make wmd produce output which will be valid LaTeX. I do this sometimes, but it is probably not good practice because wmd may change and then your solution will likely break. (Paging the experts: are there any known cases where the back-single-quote solution does not work as expected?)

Here are the main known issues:

* and _ are special characters for wmd, involved in the encoding of bold and italics. Fortunately, the contexts in which wmd modifies these characters are largely, but not completely, disjoint from those in these characters appear in equations. If you have used one of these characters, and something is going horribly wrong, you should definitely try back-single-quoting the equation that contains it.

\{ , \} and \\ Both jsmath and wmd use backslash for special purposes. When wmd sees \* , for example, it replaces it by * . When wmd sees \{ , \} or \\ , it replaces them by { , } and \ respectively. Then jsmath sees these characters and responds accordingly; which is to say, it usually does nothing which is visible to the user. Users tend to find this experience frustrating. :)

PREVIEW VERSUS DISPLAY

There is a further issue. Remember how I said that there are two javascript programs? There are actually three. For reasons known only to Fog Creek (who wrote StackExchange, the underlying software of this website), there are two different versions of wmd. One of these is used to produce the preview that you see while writing a question/answer and the other one of which is used to produce the final displayed version. They are very subtly different, but the differences tend to be exactly in the areas which effect the interaction with jsmath. To make things worse, we don't have access to the code for the wmd which does the final display, and we do not have the ability to modify it

Anton has responded by trying to write a clone of the final display wmd and using it in place of the standard preview wmd that came with the website. At this point, his clone is very good, so you probably won't see any differences between the previewed version and the final one. However, if you do spot such a difference, please mention it at http://tea.mathoverflow.net/discussion/30/2/report-bugs-with-latex-jsmath-rendering-here/#Item_34

Report problems with the LaTeX sidebar here.

2009-11-03T16:18:49-08:00

We've just setup some LaTeX support, thanks to the great work of "OlegK", the author of the "SELaTeX" project, and John Forkosh, the author of the mathtex project.

You'll see a sidebar on the right, which allows you to type LaTeX and provides a real-time preview. When you're done, you can copy and paste the code over to your post. The code it produces is MarkDown syntax for an image tag. It generates alt-text containing the original LaTeX, so you can edit and see other people's source if you need to.

We've modified the original SELaTeX code in order to use our own LaTeX renderer, rather than the one over at codecogs.com. It's possible we'll have issues with this, so please report any problems.

We are well aware of the insufficiencies of this solution. In particular, it would be lovely to provide MathML to browsers that can handle it, but for now that's beyond us. It would be great to be able to write LaTeX inline in your post, rather than having to jump to the sidebar, but that will have to wait on support from FogCreek, the makers of the StackExchange software. Anyway -- perfect is the enemy of good, so for now we're going with this.

What are our options for getting LaTeX support?

2009-10-21T10:06:10-07:00

I think the main candidate is to hope that once StackExchange is out of beta, FogCreek allows us to add plugins to the MarkDown engine. If we can do that, it should be easy to render LaTeX by using a standard web service to produce an image.

What is the preferred mark-up for LaTeX?

2009-10-21T10:06:45-07:00

My preference is $ ... $, followed by double-dollar signs (which I can't write at the moment, because of the (still broken) LaTeX support on the forum!).