How to prevent spaces around a binary relation in math mode?

Question

I'm trying to add a subscript both before and after the \cong symbol, but the problem I'm having is that because it is a binary operator, I'm getting spacing between the prescript and the symbol. I have:

_{A}\cong_{B}

And this produces:

Notice how the spacing is uneven.

Is there a way I can convince LaTeX to not treat \cong as an operator that adds spaces around it, so that I can get both subscripts evenly spaced?

Answer 1

{\cong} will be a mathord with normal letter spacing, so you probably want

\mathrel{{}_{A}{\cong}{}_{B}}

to get a relation with the subscripts around an inner mathord \cong.