When I type braces in math mode in a post, like $\{1,2,3\}$, they don't show up in the preview. See the following screen shot.

enter image description here

I tried all the different Math Renderer options, and disabling Fast Preview, with the same results.

This affects the main MO site, but not Meta.MO (so don't try to test it on this post).

When I submit the post, the braces show up correctly. Likewise, existing posts seem to render fine, but if I try to edit them, I don't see braces in the preview.

Typing $\\{1,2,3\\}$ makes the braces appear in the preview, but I expect this would mess up the output in the actual post.

I'm pretty sure this just started recently, as I think I would have noticed it before.

I can reproduce this with Firefox 42.0 on Ubuntu and Safari 9.0 on iOS (using the Full Site).


1 Answer 1


This had to do with the citation helper script - mostly with how I implemented the integration with the editor.

The fix is being deployed right now.

  • $\begingroup$ Yes, I can confirm it is fixed. Thanks! $\endgroup$ Commented Nov 23, 2015 at 23:25
  • 4
    $\begingroup$ I still see this in 2023, both on mathoverflow and on math.stackexchange: \{ and \}are not rendered, and \|is rendered as a single |, not as two vert's. $\endgroup$ Commented Sep 24, 2023 at 16:28
  • 2
    $\begingroup$ Same here, 31 Dec 2023. $\endgroup$
    – Bedovlat
    Commented Dec 31, 2023 at 14:56
  • $\begingroup$ Still broken on Firefox 129 in July 2024... $\endgroup$ Commented 2 days ago

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