Looking definition of \setminus to call with \DeclareMathSymbol [duplicate]

Question

I'm using Mnsymbol package but I don't like how looks \setminus. Because that I want use the default \setminux making

\documentclass{memoir}
\DeclareSymbolFont{Symbols}{OMS}{cmsy}{m}{n}
\DeclareMathSymbol{\Setminus}{\mathbin}{Symbols}{}

\usepackage{Mnsymbol}
\begin{document}
$\setminus$ $\Setminus$
\end{document}

but, as you can see, I miss something. How I get that?

Answer 1

The definition of \setminus and the setups for the symbols math font can be found in fontmath.ltx.

\documentclass{memoir}
\DeclareSymbolFont{Symbols}{OMS}{cmsy}{m}{n}
\SetSymbolFont{Symbols}{bold}{OMS}{cmsy}{b}{n}
\DeclareMathSymbol{\Setminus}{\mathbin}{Symbols}{"6E}

\usepackage{MnSymbol}
\begin{document}
$\setminus$ $\Setminus$
\end{document}

Package MnSymbol (with uppercase S) redefines the standard symbols font of LaTeX, thus it needs a different name (Symbols) to avoid a conflict.