Is there an “underscript” command?

Question

Is there a way to do underscripts? By "underscript" I mean a small font underneath the text object like limits or sums have. I don't want it to behave like a math operator though, where it is typeset as a subscript or underscript depending on the environment (like sums). I want there to always be an underscript in math environments with the possibility of adding a subscript in addition to the underscript. Is there anything like an \underscript{X}{a} command?

Is there even something like that that will only work in mathmode? I haven't been able to find it.

Answer 1

I would recommend using \underaccent from the accents package. For comparison purposes I have included the output \underset and \stackrel:

\documentclass{article}
\usepackage{amsmath}
\usepackage{accents}
\usepackage{xcolor}

\begin{document}
$\quad\color{blue} \text{underset: }    \underset{x}{A}$
$\quad\color{black}\text{stackrel: }    \stackrel{A}{x}$
$\quad\color{red}  \text{underaccent: } \underaccent{x}{A}$
\end{document}