[Tex/LaTex] \vec conflict between llncs.cls and MnSymbol

Question

I would like to use MnSymbol alongside Springer's LNCS class file, llncs.cls, which can be found in this zip file and in many other places on the web.

\documentclass{llncs}
\usepackage{MnSymbol}
\begin{document}
\end{document}

I get the dreaded ! LaTeX Error: Command\vec' already defined.`

What's the cleanest, simplest way to undefine the \vec introduced by llncs.cls so that I can \usepackage{MnSymbol}?

Answer 1

The class llncs redefines \vec unless the orivec option is used.

\documentclass[orivec]{llncs}
\usepackage{MnSymbol}
\begin{document}

Hello! $\vec{x}$

\end{document}

Usual caveat: using MnSymbol without setting the main font to Minion is not really typographically sound, as MnSymbol changes all symbols to a style that's rather different from other fonts' style.