Perhaps the more graceful approach ;) would be to research the various SAGE options (SAGE has LOTS of options) and determine why it is producing \over and what options there might be to avoid that. The person responsible for the function I believe is:
William Stein <email@example.com>The literature I have read suggests that while \frac is core Latex, \over is a primitive that "is out of place in a LaTeX document", and hence should be probably avoided anyway..... though in its defense Davide's jsmath does parse it correctly
"\overand friends are primitive TeX commands whose unusual
syntax is out of place in a LaTeX document. Using them at surface
level in a document also makes it very difficult to achieve certain kinds
of typesetting improvements that would otherwise be possible. Some
additional details are given in the file technote.tex. "
Source code for the function I believe is here:
which offers some latitude in addressing this without rewriting asciimathml, and I am curious as to the impact of using the jsmath attribute .......