# How to disable math packages in XeLaTeX?

I'm using musixtex in xelatex, and there's a problem: command \breve is defined in musixtex and in "math mode" (is it a package "amsmath"?). So, I have a warning due compilation:

LaTeX Error: Command `\breve' already defined.

There is no \usepackage{amsmath} or \usepackage{amssymb} in document, but xelatex loads it himself (line from log):

(/usr/share/texlive/texmf-dist/tex/latex/amsmath/amsmath.sty

• Welcome to TeX.SX! Please help us help you and add a minimal working example (MWE) that illustrates your problem. Reproducing the problem and finding out what the issue is will be much easier when we see compilable code, starting with \documentclass{...} and ending with \end{document}. – Romain Picot Nov 23 '15 at 7:47
• \breve is a math accent which is include in plain LaTeX, as well as in plain TeX. You can only disable it by rebuildung the format without it. Or you could just \let\breve=\relax before loading musixtex. – Henri Menke Nov 23 '15 at 8:27
• as Henri says you can "undefine" \breve but you are not correct that xetex automatically loads amsmath. You have not shown any information to guess what is loading it but either the class file or one of your othe packages. (the log would show, by matching the ( and ) around file names. – David Carlisle Nov 23 '15 at 8:51
• if \breve is "build-in" LaTeX command, amsmath doesn't matter. But it means, that musiaxtex developers are using a command, that's already used in base LaTeX, isn't it? So, I will always receive a message about "Command \breve already defined", becouse I can't disable \breve in base-latex, right? – Mike Nov 23 '15 at 9:39