# Did mathcal stop working properly?

Does this question Basic algebra of $\mathcal{O}_0(\mathfrak{sl}_n(\mathbb{C}))$ — Reference request look like this for anyone else?:

Those squares are supposed to be \mathcal{O}'s. As far as I can tell the LaTeX code is fine but it is rendering wrong for some reason. I remember looking at this question a couple days ago and it looked fine.

EDIT: Maybe I should say I'm on Chrome on a Mac.

EDIT 2: Changing the math renderer (as mentioned in the comments) fixed this for me; thanks!

• I see it correctly (in Chrome under Linux).
– Stefan Kohl Mod
Nov 19 at 21:36
• Looks OK to me (also on Chrome on a Mac). Nov 19 at 21:37
• Hmm okay good to know, must be something wrong on my system. Nov 19 at 21:37
• Nov 20 at 10:15
• I use Chrome an Mac, and I got the same problem.
– Surb
Nov 20 at 12:49
• Have you tried changing the math renderer you're currently using for MathJax. From what I read here, not all of them rely on local fonts: What is the difference between the 3 math renderers? (I do not know enough about MathJax to help - but maybe knowing whether this behaves the same for all renderers might help somebody to diagnose the problem.) Unrelated: since the comments suggest that this might not actually be a bug, I have added the tag (support). Nov 20 at 14:59
• Another user recently posted a question about a similar problem on Mathematics Meta - so it might be worth checking later whether some new advice appeared there: Why using \mathcal command produce a square? Nov 20 at 15:02
• Using Chrome on MacOS, I am able to reproduce this when the math renderer is set to HTML-CSS. If I change it to any other math renderer, then it is displayed correctly. I have not yet tested this on other browsers/devices. Nov 21 at 8:33
• It is currently showing up correctly for me on Chromium even with the HTML-CSS renderer. yesterday
• The issue started for me after I updated to macOS Ventura. I left a comment about this on Mathematics Meta. I don't know whether it's the same for the OP. yesterday
• @TheAmplitwist: yes, I think updating to Ventura had something to do with it for me as well. yesterday