# [Tex/LaTex] On \atop again: how to obtain the same result without warning

amsmath

I know this question has been already discussed but the answer does not seem to work in my case.

I am using the \atop command with the amsmath package to stack two symbols (more specifically $a=x$ and $b=y$) but, as well known, this is foreign to LaTeX.

The standard reply I found (and LaTeX warning suggestion) is to use \frac or \genfrac, but these will insert a line between the two symbols, that I do not want. The other suggestion is to use \overset, but this treats the symbol below as main and prints it bigger than the one above.

How do I obtain the same result as \atop without getting the LaTeX warning?

\genfrac won't produce a line if the third argument (which control the thickness of the rule) is set to 0pt; the syntax for \genfrac is

\genfrac{<left-delim>}{<right-delim>}{<thickness>}{<mathstyle>}{<numerator>}{<denominator>}


A little example:

\documentclass{article}
\usepackage{amsmath}

\newcommand\mycom[2]{\genfrac{}{}{0pt}{}{#1}{#2}}

\begin{document}
$A\mycom{a=x}{b=y}B$
\end{document}