how to print long relation operators like simeq and sim with text above in latex

Question

ENV

xelatex --version
XeTeX 3.14159265-2.6-0.99991 (TeX Live 2014)
bibtex --version
BibTeX 0.99d (TeX Live 2014)

• \mathrel{\simeq\!\simeq} not what I want.

• \stackrel{\text{mytext}{\simeq}} the operator not long.

Any idea? Thanks.

Answer 1

Based on my answer at Big tilde in math mode, in introduce \reallywidesim and \reallywidesimeq.

\documentclass{article}
\usepackage{scalerel}
\usepackage{stackengine,amsmath}
\newcommand\reallywidesimeq[1]{\mathrel{\ThisStyle{%
  \setbox0=\hbox{$\SavedStyle\mkern2mu_{\text{#1}}\mkern2mu$}%
  \mkern1mu\stackengine{1\LMpt}{%
    \stretchto{\scaleto{\SavedStyle\mkern-1mu\simeq\mkern-1mu}{.72\wd0}}{1\ht0}%
  }{$\SavedStyle_{\text{#1}}$}{O}{c}{F}{T}{S}\mkern1mu%
}}}
\newcommand\reallywidesim[1]{\mathrel{\ThisStyle{%
  \setbox0=\hbox{$\SavedStyle\mkern3mu_{\text{#1}}\mkern3mu$}%
  \mkern1mu\stackengine{1\LMpt}{%
    \stretchto{\scaleto{\SavedStyle\mkern-1mu\sim\mkern-1mu}{.54\wd0}}{1\ht0}%
  }{$\SavedStyle_{\text{#1}}$}{O}{c}{F}{T}{S}\mkern1mu%
}}}
\def\testeq#1{$%
  \reallywidesimeq{#1}\,
  \scriptstyle\reallywidesimeq{#1}\,
  \scriptscriptstyle\reallywidesimeq{#1}
$\par}
\def\test#1{$%
  \reallywidesim{#1}\,
  \scriptstyle\reallywidesim{#1}\,
  \scriptscriptstyle\reallywidesim{#1}
$}
\parskip 1ex
\begin{document}
\test{abcdefghijklm}\quad\testeq{ab}
\test{abcdefghijk}\quad\testeq{abc}
\test{abcdefghi}\quad\testeq{abcde}
\test{abcdefg}\quad\testeq{abcdefg}
\test{abcde}\quad\testeq{abcdefghi}
\test{abc}\quad\testeq{abcdefghijk}
\test{ab}\quad\testeq{abcdefghijklm}\par
$A \reallywidesim{mytext} B \reallywidesimeq{mytext} C$
\end{document}

Answer 2

You can abuse the tilde accent together with a \vrule to build your own \simeq. However, you need a font with an extensible \widetilde for that. The non-free font mtpro2 has this accent.

\documentclass{article}
\usepackage{amsmath}
\usepackage[lite]{mtpro2}
\begin{document}
$A \stackrel{\text{mytext}}{\lower 2.5pt \hbox{$\widetilde{\vrule width 25pt height 3.9pt depth -3.5pt}$}} B$
\end{document}

---

My advice is to not use the above but rather have something like

\documentclass{article}
\begin{document}
\[ A \stackrel{(*)}{\simeq} B \] where $(*)$ is mytext.
\end{document}