# How do I use a font package but keep math font unchanged?

I am using two font packages: fourier (which is in fact Utopia) for overall text and chivo for sans-serif.

However, I don't like the changes these packages make to math font. I tried to revert math back to Computer Modern with the following commands:

% Revert mathcal back to cms -- it works
\DeclareMathAlphabet{\mathcal}{OMS}{cmsy}{m}{n}

% Attempt to revert all math back to cms: does not work
\DeclareMathAlphabet{\mathsf}{OMS}{cmsy}{m}{n}


I also tried replacing \mathsf with \mathnormal and \mathroman to no avail.

Here's my minimal reproducible example:

\documentclass[11pt]{report}
\usepackage[T1]{fontenc}

\usepackage{fourier}
\usepackage[scale=0.9]{Chivo}

% Fix \mathcal but no success changing overall math font
\DeclareMathAlphabet{\mathcal}{OMS}{cmsy}{m}{n}
\DeclareMathAlphabet{\mathsf}{OMS}{cmsy}{m}{n}

\begin{document}
Math calligraphy looks ok, but arrows are ugly:
$$P \rightarrow \mathcal{O}(n^2) \wedge \leftrightarrow 8$$
\end{document}

• Compiter Modern for maths and utopia don't match well. You shouldn't do that. – Bernard Sep 20 '19 at 20:15
• What should I use instead? – giusti Sep 20 '19 at 20:32
• @Bernard To anser the question you made in the answer below, I don't like math caligraphy and operators: brackets and arrows are short, and \vee doesn't stand out too much from the letter v. – giusti Sep 20 '19 at 20:40
• Did you try mathdesign with option utopia? (it laso defines maths packages for Bitstream Charter and URW Garamond). – Bernard Sep 20 '19 at 20:57
• That's a good suggestion, but it breaks my attempt to change \mathcal. Could you also suggest a way to fix that? – giusti Sep 20 '19 at 22:24

It is better to avoid that fourier change the math, so don't load the package but change only the font family:

\documentclass{article}
\renewcommand{\rmdefault}{futs}
\RequirePackage[T1]{fontenc}
\usepackage[scale=0.9]{Chivo}

\begin{document}

abc \sffamily abc

\end{document}

• Then you didn't use my example, I'm switching to T1-encoding. – Ulrike Fischer Sep 20 '19 at 19:56
• What is the problem with fourier maths fonts? – Bernard Sep 20 '19 at 20:17