Center the \not to the letter

Question

I searched but I didn't find anything: does anyone know how to center the \not{A} to the letter instead of typing it a little before?

Answer 1

As I said in my earlier comment, I think \not is supposed to work with \mathrel objects, of which A is not (it is \mathord).

With that in mind, here are two possible ways.

\documentclass{article}
\usepackage{stackengine}
\stackMath
\begin{document}
\begin{equation}
B\mathord{\not\mathrel{A}}C
\end{equation}
\begin{equation}
B\stackengine{0pt}{A}{/}{O}{c}{F}{F}{L}C
\end{equation}
\end{document}

Answer 2

You can use slashed. In the example, the default placement (as ordinary symbol) is used. Then it's shown how to fine tune the position of the slash (experiment yourself) and to make the symbol a relation symbol.

Of course, the \declareslash instruction will go in the document preamble, when you have chosen the final parameters.

\documentclass{article}
\usepackage{slashed}

\begin{document}

$\slashed{A}$

\declareslashed{}{/}{0.05}{0}{A}

$\slashed{A}$

\end{document}

Answer 3

This may be much simpler

\usepackage{centernot}
\begin{document}

$\centernot{\infty}$

\end{document}