My computer is a MacBook Pro, using the 13.0 version (Ventura), and I'm using Chrome. See for example enter image description here

or that

enter image description here

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    $\begingroup$ Related: Did mathcal stop working properly? (Also when submitting bug reports it is generally expected to include some technical information, e.g. which browser? operating system? how many moongoats did you try sacrificing to the sharkgod D'mntzghutu in an attempt to fix this problem?) $\endgroup$
    – Asaf Karagila Mod
    Commented Nov 20, 2022 at 12:46
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    $\begingroup$ Moongoats?! Crap... no wonder I've been having problems. I've been sacrificing sungoats! $\endgroup$
    – Xander Henderson Mod
    Commented Nov 20, 2022 at 13:29
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    $\begingroup$ This is apt to be dependent on the user's platform, esp. which calligraphic fonts are installed. On one of my Linux laptop PC's I get $\mathcal D$ as one presumably would like. You might try experimenting with the Math Renderer submenu options to see if it affects this. I'd guess the choices of fonts wind up giving you one that lacks a capital D. $\endgroup$
    – hardmath
    Commented Nov 20, 2022 at 19:01
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    $\begingroup$ 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. $\endgroup$ Commented Nov 21, 2022 at 8:34
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    $\begingroup$ This: $$\mathcal D \subset \mathcal E \implies \sigma \mathcal D \subset \sigma \mathcal E$$ looks like this if you are using the Common HTML renderer, and like this with the HTML-CSS renderer if you have STIX math fonts installed (which are installed by default on a Mac). Your symbols look different from both of these. I would guess switching to the Common HTML renderer would fix this. See: How do I change math renderer for MathJax $\endgroup$ Commented Nov 21, 2022 at 8:34
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    $\begingroup$ @CalvinKhor This bug started appearing only after I updated to macOS Ventura, so I suppose it has something to do with that. I have checked that the STIX Two fonts are installed on my device. On the other hand, it seems that MathJax version 3 only supports the MathJax TeX font, and MathJax version 2 provides the STIX General font: docs.mathjax.org/en/latest/output/fonts.html. $\endgroup$ Commented Nov 23, 2022 at 15:49
  • $\begingroup$ Ah, I see thanks. I clearly have not yet updated... @TheAmplitwist $\endgroup$ Commented Nov 24, 2022 at 1:57
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    $\begingroup$ For anybody interested, basically the same issue is now reported on the network Meta site at I think there is a Mathjax bug for mathcal typesetting on some platforms. $\endgroup$ Commented Dec 17, 2022 at 23:14

1 Answer 1


The HTML-CSS renderer in MathJax v2 tries to detect whether there are local copies of the MathJax or STIX fonts and will use those in place of web-based fonts if they are available (to reduce the amount of information that a user must download over the network). Apple has shipped the STIX1 fonts as part of Mac OS and iOS for a number years, but in Ventura, they have switched to the STIX2 fonts. These are packaged differently (the STIX1 fonts came in 29 separate fonts, but STIX2 combines these into 5, one each for regular, bold, italic, and bold-italic, plus a math font). In order to try to keep things backward compatible, Apple still allows access to the STIX1 fonts by (what appears to be) mapping the original 29 fonts into the new 5 fonts. This is largely effective, but not completely. In particular, the calligraphic characters are not part of the Unicode standard, and so STIX includes them in the Private Use Are (PUA) of their fonts. Unfortunately, the location in the PUA Changed between STIX1 and STIX2, and Apple mapping from the old fonts to the new ones doesn't take that into account.

The upshot is, when MathJax asks the local system whether STIXGeneral-Regular (the old STIX1 font) is available, Ventura says "yes" and MathJax believes that the 29 original fonts are there, and tries to use them in the layout that the original fonts actually have. But in Ventura, the calligraphic characters are not in the same location, so you get the missing character symbol instead.

This issue only affects the HTML-CSS output, since it is the only one that uses local STIX fonts. So if you switch to the CommonHTML or SVG output (using the MathJax contextual menu if you are a user, or changing the configuration file if you manage the website), or configuring MathJax to not look for local STIX fonts, then that should show these characters as they should be. Also, version 3, and the upcoming version 4, doesn't use local STIX fonts, and so updating to a current version of MathJax would also resolve the issue.

The issue is not related to Chrome in particular, and should affect all browser on Ventura (and above).

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    $\begingroup$ Note for people trying to quickly solve this: Davide's explanation is excellent, but the way to solve the problem is buried in his penultimate paragraph. Here are stupid-simple instructions with screenshots. (Also, Davide's final paragraph is incorrect. He has fixed this in other copies of his answer.) $\endgroup$ Commented Aug 2, 2023 at 16:12
  • $\begingroup$ I have the similar issue on a Jekyll website that runs mathjax via kramdown, and it does seem to be a problem only on Chrome, i.e. Safari renders the \mathcal character perfectly fine. Do you know what this could be? $\endgroup$ Commented May 28 at 20:06

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