<script type="text/x-mathjax-config"> MathJax.Hub.Config({"HTML-CSS": { preferredFont: "TeX", availableFonts: ["STIX","TeX"], linebreaks: { automatic:true }, EqnChunk: (MathJax.Hub.Browser.isMobile ? 10 : 50) }, tex2jax: { inlineMath: [ ["$", "$"], ["\(","\)"] ], processEscapes: true, ignoreClass: "tex2jax_ignore|dno",skipTags: ['script', 'noscript', 'style', 'textarea', 'pre', 'code']}, TeX: { noUndefined: { attributes: { mathcolor: "red", mathbackground: "#FFEEEE", mathsize: "90%" } }, Macros: { href: "{}" } }, messageStyle: "none" }); </script> <script type="text/x-mathjax-config"> MathJax.Hub.Queue(function() { var all = MathJax.Hub.getAllJax(), i; for(i=0; i < all.length; i += 1) { all[i].SourceElement().parentNode.className += ' has-jax'; } });

What should I do in my own setting? Many thanks!

"(Re)process math with jsMath." is not consistent - sometimes the latex is smaller without context menu, sometimes it is the usual way with context menu.

we've just upgraded MathJax to 2.2-beta. Briefly, it was setup incorrectly, causing your issue. It should be resolved now (and is for me). If you're still seeing the problem, try the usual tricks for clearing your cache (restart your browser, clear the cache for mathoverflow.net), and if the problem is still there let us know.

If it continues, I'll work out how to move the mathjax files somewhere more reliable.

We consider the set

`$$ S = \left\lbrace (F,h)\;\;\middle\vert\;\genfrac{}{}{0pt}{}{F\text{ is a decreasing function from }R^{+}\text{ to }R^{+}, h\in R}{0=1- \dfrac{\theta + 1}{\theta} \dfrac {\int^{h}_{y=0} F(y) dy}{F(0)} \dfrac{F(0)-\frac{1}{2}F(h)}{F(0)-F(h)}} \right\rbrace $$`

The function $L$ is defined on $S$ by 

`$$L(F,h) = \dfrac{\int^{h}_{x=0} \int^{h}_{y=x} F(y) dy dx}{\int^{h}_{x=0} \int^{h}_{y=0} F(y) dy dx} h$$`

%%[ ProductName: Distiller ]%%
MathJax_Math-Italic not found, using Courier.
MathJax_Main-Regular not found, using Courier.
MathJax_Main-Bold not found, using Courier.
%%[ Error: invalidfont; OffendingCommand: show ]%%

Stack:
()


%%[ Flushing: rest of job (to end-of-file) will be ignored ]%%
%%[ Warning: PostScript error. No PDF file produced. ] %%

Print preview (and printing on an actual printer) both work, with the following horrible result:

I am using Windows Vista and IE9. I was trying to print http://mathoverflow.net/questions/88368/can-a-group-be-a-universal-turing-machine.

The math symbols like SL_3(Z) disappeared from the Question part.

The math symbols in the first answer look ok. Have trouble with printing the second answer.

Using Print Preview showed the same result. I'd like to know if it's my OS/browser/printer problem, or something I won't be able to fix on my end. Thanks.

Edit: I figured out what the problem was. I was connecting to the internet through a proxy server (the UC Berkeley library proxy, if it matters) and that was making MO not work. It seems that the problem was specific to StackExchange-type sites. I discovered it when I tried to find something on the AskUbuntu StackExchange site - there was a bar at the top saying that the page was trying to load JavaScript from another domain and that the browser was blocking it. Anyway, turning off the proxy worked - now I use the FireFox plugin FoxyProxy which allows you to switch proxies based on url patterns, so I don't have to manually change it all the time.

Apologize in advance if I'm posting in the wrong place

Yes you are. General MathJaX bugs should be reported on the MathJaX support site. This is for MathJaX rendering on MathOverflow, and only on MathOverflow.

For the basic result, start with

<a href="http://en.wikipedia.org/wiki/Johnson–Lindenstrauss_lemma/">Wikipedia</a>

or Google "Johnson-Lindenstrauss Lemma".

In the URL, there is a /. Since I cut-and-pasted from that to do all my experiments, a lot of them had a trailing slash. Sometimes that doesn't matter, sometimes it does. I will freely admit that I should have spotted that and removed it before doing further analysis. Ultimately, the en-dash was the real reason why it didn't work, the trailing slash was what meant that I didn't spot that putting in an ordinary hyphen did work.

I would have thought that Wikipedia would automatically make redirects to "sanitised" versions of pages, but I can't find one for that page itself

Turns out that it does. There was another problem with the URL that you put in: the / at the end. The correct URL doesn't have that. Somehow in my experimenting with replacing the dash then I overlooked the slash and got false negatives.

Incidentally, when I cut-and-paste the URL using my browser from the page in question, then it gets correctly escaped. That is, when cut-and-pasting here I get:

http://en.wikipedia.org/wiki/Johnson%E2%80%93Lindenstrauss_lemma

Replacing the en-dash by an ordinary hyphen also works:

http://en.wikipedia.org/wiki/Johnson-Lindenstrauss_lemma leads to this link. If you click on that, then you'll notice that it goes to the correct page but just below the title is a little "Redirected from ..." message which tells you that the URL that you typed wasn't the real page name, but an alias.

There's ways to find these escapings, but I don't know of one off-hand. (I would have thought that Wikipedia would automatically make redirects to "sanitised" versions of pages, but I can't find one for that page itself).

Usually, Markdown's own syntax for links is better than using raw HTML, but in this case even that doesn't work. The escaping method is the only one that I can make work correctly. (On the other hand, the Markdown syntax does work correctly here: [Wikipedia](http://en.wikipedia.org/wiki/Johnson–Lindenstrauss_lemma) correctly produces Wikipedia).

I just tried on the SE2.0 system and witnessed the same behaviour, so this wouldn't be fixed by migrating!

http://mathoverflow.net/questions/79388/minimum-space-dimension-to-place-n-points-knowing-pairwise-distances/79395#79395

Andrew.

The link (and Scott's <pre> attempt) doesn't work here because the Markdown filter here strips out HTML tags before processing. So any HTML tags get escaped. (Although this stripping is not 100% safe).

On MO, some HTML is allowed, including <a> tags (what is and isn't allowed is governed by a "whitelist" that is listed somewhere on meta.SO). When I cut and paste the code you gave into a blank "Ask a Question" then the preview converts it to a link. So either there's a difference between the preview and what is actually rendered (unlikely in so simple an example) or there's more to your example than just the link. Could you link to the actual post?

More generally, Markdown and HTML are not really meant to mix.

That is about as wrong as it can be! Markdown and HTML are meant to mix. Markdown goes out of its way to be polite to HTML: if it spots any HTML then it says, "I assume that the user knows what they are doing and will just let this go through.". The problem is that many people who've implemented their own version of Markdown have decided that the average user does not know what they are doing and so put in a pre-filter to strip out anything Bad. These pre-filters are complicated because they have to understand both HTML and Markdown. What they should have done is put in a post-filter to check that the final rendering is clean as the post-filter only has to understand HTML.

(Naturally, the nLab and the nForum get it right.)

More generally, Markdown and HTML are not really meant to mix. (That is, the <pre>text</pre> syntax is preferred to using <a> tags), but of course it's convenient to do so. This sometimes results in some bumps.

<a href="http://en.wikipedia.org/wiki/Johnson%E2%80%93Lindenstrauss_lemma">Wikipedia</a>

in a post, but it did not render properly. I see that it also does not render here on Meta at all. Why? Survit edited it to

Wikipedia

which worked fine, but I thought ordinary HTML links worked.

That's a text command, not a maths command. MathJaX only supports mathematics commands (well, a subset thereof). If you really want to use proper LaTeX to write MO posts, contact me by email.

In the meantime, lists are done by Markdown syntax:

1. First item
1. Second item
1. Third item

Produces

1. First item
2. Second item
3. Third item

MathJax no longer loads a default configuration file; you must specify such files explicitly. This page seems to use the older default config/MathJax.js file, and so needs to be updated. This is explained further at

http://www.mathjax.org/help/configuration

Added: Clearing my browser cache seems to fix it.

Is this remedy in an FAQ somewhere?

http://mathoverflow.net/faq#latex , where it says "workaround".

If you want me to report the bug, I need to know details like which version of MathJax you're using and how it's configured.

The command \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.)

Actually, I'm a bit confused about our .htaccess files for latex.mathoverflow.net. @Anton, the .htaccess I added a line to didn't have anything about "Access-Control-Allow-Origin", and I couldn't find any others. Where did you do this?

On the other hand, if it ever comes to it we have some alternative hosts (sitting under various people's office desks, in Toronto or Berkeley) where I have root access and full control of apache.

@Scott M: (not in response to anything he's posted here recently) How much control do you have over Apache? Can you tell it to gzip MathJax as shogun70 suggests?

(Though it might be that the script is still trying to work on the page I was on before navigating to the main page; nonetheless, I feel as though I'm getting more of these than I used to.)