Upgrading to Mathjax 4

After realizing that the 2024 polyfill.io supply chain attack affected this website, I upgraded from Mathjax 3 to Mathjax 4. Also, Mathjax is now included without the previously recommended reference to polyfill.io.

This has had a number of minor, visible effects (for instance, mathematical formulas are now rendered in a different, and I believe, clearer font). But one consequence is that very old browsers are no longer supported. The Mathjax documentation itself states that its current versions rely “on more modern browser features, and so older browsers are no longer supported.”

So, if math on this site does not seem to render properly anymore: it may really be time to upgrade your browser!