Basically, I want to definite a flalign environment where all the math uses mathsf by default.
I can't just wrap the whole thing in a mathsf command because there might be line breaks and & separators that break things.
Is there a version of mathsf that works like \color where it sets the font style for the entire block, instead of just for the argument?
You can use sansmath, supplementing it with a sans serif font for large operators.
\documentclass{article}
\usepackage{amsmath}
\usepackage{sansmath}
\SetSymbolFont{largesymbols}{sans}{OMX}{iwona}{m}{n}
\begin{document}
\sansmath
\begin{flalign}
A&=B & C&=D & u&=v \
x&=\sum_{i=1}^n a_i & y&=M\otimes N & z&=U^v & x\ne z
\end{flalign}
\unsansmath
\begin{flalign}
A&=B & C&=D & u&=v \
x&=\sum_{i=1}^n a_i & y&=M\otimes N & z&=U^v & x\ne z
\end{flalign}
\end{document}
\SetMathAlphabet{\mathsfsl}{sans}{\sansmathencoding}{\sfdefault}{m}{n}– egreg Jan 07 '23 at 16:33\mathrm{...}inside thesansmathenvironment, it just ignores it and prints it as sans. Is there a way to have sans as the default for the environment, but to still be able to use all the normal font commands in the sans environment? – Joey Eremondi Jan 07 '23 at 16:58