# How can I draw a dot under a symbol in math mode?

I'm trying to find the equivalent to \d (or \textsubdot) for the math mode.

-

You can use the \underaccent command from the accents package. Something along these lines:

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

\newcommand*\underdot[1]{%
\underaccent{\dot}{#1}}

\begin{document}
$\underdot{A}$
\end{document}

-
To be more specific it's: \underaccent{\dot}{...} – Dejan Jan 2 '12 at 16:43
@Dejan: now I've updated my answer providing a complete MWE. – Gonzalo Medina Jan 2 '12 at 17:11

It's not in the TeX Book. If you don't mind cheating you could try the following but it's not nice:

\documentclass{minimal}
\usepackage{amsmath}

\def\myd#1{\text{\d{\ensuremath#1}}}
\begin{document}
$\myd{a}$
\end{document}

-
Understandably this is a minimal working example. However, rather use a documentclass other than minimal (like article, say). I think \ensuremath here is a bit much, since you want the contents of \myd to be in math mode always. As such, rather use \d{$#1$} - just a suggestion. – Werner Jan 2 '12 at 15:33