[Tex/LaTex] \DeclareSymbolFont undesired effect

Question

I would like to have math operator names in Sans Serif.
\DeclareSymbolFont{operators}{OT1}{cmss}{m}{n} does the job but has also an effect on Greek capitals.
How do I change font for operator names keeping the rest of the formatting intact?

Answer 1

If your aim is to change the typesetting of operator names to use sans serif type, you should define a new symbol font:

\documentclass{article}
\usepackage{amsmath}

% a new symbol font for names of operators
\DeclareSymbolFont{sfoperators}{OT1}{cmss}{m}{n}
% don't waste a math group
\DeclareSymbolFontAlphabet{\mathsf}{sfoperators}
% tell LaTeX to use sfoperators for names of operators
\makeatletter
\renewcommand{\operator@font}{\mathgroup\symsfoperators}
\makeatother

\DeclareMathOperator{\foo}{foo}

\begin{document}

$\sin\Gamma+\log(x-\Phi)-\foo(y)$

\end{document}