答案1
您可以使用较低级别的命令。
\documentclass{article}
\usepackage{amsmath}
\makeatletter
\newcommand{\simeqdot}{\mathrel{\mathpalette\simeqdot@\relax}}
\newcommand{\simeqdot@}[2]{%
\vtop{%
\offinterlineskip % no space between lines
\ialign{%
\hfil##\hfil\cr % one centered column
$\m@th#1\simeq$\cr % \simeq
\noalign{\sbox\z@{$\m@th#1\mkern1.5mu$}\vspace{\wd\z@}}% some space
$\m@th#1.$\cr % the dot
}%
}%
}
\makeatother
\begin{document}
\[
A\simeqdot B \scriptstyle \quad A\simeqdot B
\]
\begin{center}
\setlength{\fboxsep}{0pt}\fbox{$\simeqdot$} % show the bounding box
\end{center}
\end{document}
如果你\vtop
用替换\vcenter
,你会得到