Non italic (upright) greek letters - mathjax/MathJax-docs GitHub Wiki
From https://groups.google.com/d/msg/mathjax-users/VZB-ub85ioc/T_eenOOfDWsJ
How to get upshape greek letter?
The upper-case Greek letters can be obtained using \rm, eg, {\rm A B \Gamma}
. The MathJax web fonts only include lower-case Greek letters in italic form, so there are no upright versions available. You can use something like \unicode[Times]{x3B1}
to obtain the alpha symbol from the Times font (assuming the user has that installed), which will be an upright version.