# [Tex/LaTex] How to insert a backslash inside a mathematical statement

amssymbmath-modesymbols

I'm trying to write a set subtraction operation in an AMS formatted template. In the end, what I want should look like A\B. But I'm doing this in math-mode $A\B$ and this gives me errors. I've also tried using the \diagdown symbol, but it doesn't work either. Is there another way to do this?

\setminus should be what you are after.

\documentclass{article}
\usepackage{amssymb} % for \smallsetminus

\begin{document}
$\mbox{setminus: } A \setminus B,\quad \mbox{smallsetminus: } A \smallsetminus B, \quad \mbox{backslash: } A \backslash B$
\end{document}


Note that you can find more information here on How to look up a symbol?. In particular, you have the Comprehensive LaTeX symbols and the website Detexify. There is also this post which was mentioned earlier in a comment