Use katex instead of mathjax

[SamLau95]

I managed to get KaTeX to render in Gitbooks: https://github.com/SamLau95/plugin-katex

This fixes the mathjax initialization issue in a non-hacky way (no appending to the DOM, etc):

However, as the GIF above shows this breaks usages of \mbox. It looks like mbox isn't recommended (https://tex.stackexchange.com/questions/146909/what-does-mbox-do) and when I replace \mbox with \text the math renders just fine:

Another change is that the align* environment needs to be wrapped in $$ and replaced with aligned (this also renders in a notebook correctly). After doing that, math like this renders fine:

One perhaps easier thing to do is to just find and replace across all the notebooks for usage of \mbox and the align* environment during the notebook conversion step. What do you think?

[dibyaghosh]

Can we fix the wrap-around issues?

[SamLau95]

Hm. Looks like the wrap-around issues are appearing in the live version of the textbook as well: https://textbook.prob140.org/notebooks-md/1_2_Equally_Likely_Outcomes.html

I don't know of an easy way to fix this since in both cases the math is being rendered differently than normal text in the DOM.

We can, however, attach a horizontal scroll bar when the content overflows so the user can at least view the entire equation instead of it being simply chopped off:

.katex {
  width: 100%;
  overflow-x: scroll;
}

I've pushed this update to the PR.

[dibyaghosh]

MathJax has an option to account for wrap-around (at render-time): this change was part of my most recent push. It looks like this with MathJax

Maybe KaTeX has a similar option?

[SamLau95]

Looks like KaTeX's doesn't have equation wrapping for block-level equations, unfortunately: KaTeX/KaTeX#327 . I posted a comment requesting for MathJax-style functionality.

I've found a way to add linebreaks to equations by making words wrap. It's not as nice as MathJax's:

What are your thoughts?