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
$b=y$) but, as well known, this is foreign to LaTeX.
The standard reply I found (and LaTeX warning suggestion) is to use
\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?