Some users use MathJax to get italicized or bold text. This is sometimes done in titles (where MarkDown is not available), but some users do this also in body of a question, where MarkDown is used. They might be simply unaware of MarkDown, but maybe some users prefer how the text looks when Mathjax is used.

So they write something like this (there are probably many other variants):

  • $\textbf{bold text}$ $\textbf{bold text}$ instead of bold text **bold text**
  • $\textit{text in italics}$ $\textit{text in italics}$ or $text\ in\ italics$ $text\ in\ italics$ instead of text in italics *text in italics*

I am tempted to edit such posts to use MarkDown instead (or at least leave a comment explaining possibility of using MarkDown), since on other site I frequent (math.SE) using MathJax for this purpose is considered bad practice. However, I definitely do not want to impose standards of some other community on MO, so I decided to ask first.

  • Is using MathJax for formatting discouraged at MathOverflow?
  • Is it acceptable to use MathJax to achieve bold or italicized text in titles, where MarkDown is not available?
  • $\begingroup$ Markdown has also the option for Boldface italics! whereas MathJax doesn't. $\endgroup$
    – Asaf Karagila Mod
    Commented Jun 19, 2015 at 9:37
  • $\begingroup$ @AsafKaragila: You can use \boldsymbol as in $\boldsymbol{boldface\ italics}$. $\endgroup$ Commented Jun 19, 2015 at 12:03
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    $\begingroup$ @François: Doesn't look great, I have to admit. What happens if I do $\boldsymbol{Hello! My name is Inigo Montoya. You killed my father. Prepare to die!}$ does it retain proper spacing? Compare and contrast to Hello! My name is Inigo Montoya. You killed my father. Prepare to die! $\endgroup$
    – Asaf Karagila Mod
    Commented Jun 19, 2015 at 12:13
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    $\begingroup$ @AsafKaragila: Spacing in math mode is different from text mode spacing (and often looks terrible: $not\ boldface\ but\ italics$). This is one of the reasons using MathJax for styling text is a bad idea. $\endgroup$ Commented Jun 19, 2015 at 12:16
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    $\begingroup$ @François: I am full aware of this. I was the one who requested that \textsf will be added to the standard MathJax commands, to slightly improve in-math text formatting. And that was my point, that while MathJax supports \textbf,\textrm,\textsf,\textit,\texttt, it does not support any mixing of them while retaining "text mode spacing". $\endgroup$
    – Asaf Karagila Mod
    Commented Jun 19, 2015 at 12:25
  • $\begingroup$ I frequently use \textit when, for example, introducing terminology; the reason is that I find markdown italics not standing out sufficiently. I am happy with markdown bold though. I think if text versions of fonts (with proper spacing) are used, then it is perfectly OK. $\endgroup$ Commented Jun 30, 2015 at 5:35
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    $\begingroup$ @AsafKaragila, re, how does one summon boldface italics in Markdown? $\endgroup$
    – LSpice
    Commented Jan 30, 2021 at 19:24
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    $\begingroup$ @LSpice: ***, of course. $\endgroup$
    – Asaf Karagila Mod
    Commented Jan 30, 2021 at 19:30
  • $\begingroup$ @AsafKaragila, thanks! I guess humankind has not yet discovered what **** ****means****. $\endgroup$
    – LSpice
    Commented Jan 30, 2021 at 20:52

1 Answer 1


The general culture of the site, relative to other sites, is that rather little editing is done, and that people write as they see fit. There were some run-ins over edits of the type you mention in the past. Yet, some editing is still appreciated.

There is a recent moderator post on the general editing etiquette Editing etiquette The edits you describe are covered by "Embedding or re-uploading images, fixing formatting, etc."

To answer you specific questions:

Is using MathJax for formatting discouraged at MathOverflow?

To say it is discouraged at MO might be slightly too strong, but at least using Markdown for this type of formatting is encouraged.

A somewhat related discussion on On using MathJax to create 'white space' could give an idea of existing points of views.

Is it acceptable to use MathJax to achieve bold or italicized text in titles, where MarkDown is not available?

It might be acceptable but not few will consider it as quite unnecessary in almost all cases, and even the use of MathJax for formatting (simple) math in titles is not universally approved.

See the discussion at Editing titles to include $\mathfrak{LaTeX \; Math}$ (the original subject is somewhat different).

One should also keep in mind that titles specifically are also displayed, or at least could be displayed, at places where there is no rendering available (e.g., some ways to access MO on mobile devices will not render titles). Giving another reason to minimize use of MathJax in titles, especially for the purpose of formatting.

My specific recommendations are:

  • If you notice a new user using MathJax formatting to bold text and alike I think editing it with an explanation about Markdown is a good way to proceed. It is a lot more likely they did so as they thought it is the way to do it, or at least did not know another way, rather than deciding to do it in this way knowing both.

    Put differently they just formatted the post as they would in LaTeX (more or less), which they know. Sometimes one sees (non-working) \emph{some text} or LaTeX-style diacritics like "Pr\"ufer" on the site too.

  • For experienced users, especially if they use it a lot, I would be more careful. In case you want to avoid risk of confrontation, leave a comment, but better do not touch the post. (See the starting paragraph.) Also, try to avoid to comment the same thing on multiple posts of the same user.

  • For titles, I would recommend about the same but would encourage more editing for the reasons explained.

My very personal view would be to encourage rather more editing than I did above, but as a general recommendation I prefer to be more restraint.

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    $\begingroup$ The main technical issue with using LaTeX for bold, italics and diacritics is that it breaks full-text search. The other technical issue is that LaTeX will often produce bad spacing, possibly making text hard to read or render on devices other than the OP's. I do think this usage of LaTeX should be discouraged on MO. $\endgroup$ Commented Jun 19, 2015 at 12:00
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    $\begingroup$ In case it was not clear: personally, I agree strongly that MathJax should be used for the typesetting of mathematics only. I am glad you weighed in with your opinion, as I think this point of view is not universally shared. But, perhaps over time we can achieve more consensus on it. $\endgroup$
    – user9072
    Commented Jun 19, 2015 at 13:28
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    $\begingroup$ Do you have a link to one of these "run-ins"? I am curious to see if the original writer has a legitimate reason to want Mathjax formatting rather than Markdown formatting. No one has spoken in favour of Mathjax formatting in this thread. $\endgroup$ Commented Jun 20, 2015 at 9:21
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    $\begingroup$ @FedericoPoloni yes I do have at least one link and maybe could find more. But I do not consider it as productive or appropriate to single out one instance that I happen to recall. Moreover, the comments got cleaned up. As for "legitimate use" one construct used was $$Some \; title$$ that will give a "centered" heading (if you get lucky). Possibly, it being "centered" was the motivation for using it, as centered text is not supported by the usual formatting on the site (AFAIK). (cont.) $\endgroup$
    – user9072
    Commented Jun 20, 2015 at 12:03
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    $\begingroup$ However, even if this were so it would be a work around for a restriction that is there for a reasons. Indeed, no one has spoken in favor of MathJax formatting. But I supposed anybody so inclined would be free to do so. My stance is: while it is true that one can do some formatting with MathJax that is not supported otherwise, it is normally not supported for a reason. If somebody wants some new feature for formatting text they should request it so that it can be implemented in a decent way or declined. Abusing some tool to work around a restriction there by design is not a legitimate use. $\endgroup$
    – user9072
    Commented Jun 20, 2015 at 12:08
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    $\begingroup$ Let me add to the stern last sentence that if on some occasion somebody really wants to do something special as regards formatting and uses MJ I do not consider it as a big deal either. And, me too, I used MJ to write huge texts in comments or do some other fancy. What I do consider as problematic is when some formatting-hacks that have serious drawbacks are used frequently. ( @FedericoPoloni ) $\endgroup$
    – user9072
    Commented Jun 20, 2015 at 12:14

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