Strike-through Tilde Accent
A variation on my answer at Big tilde in math mode, showing \reallywidetile
and \reallywidenotilde
.
\documentclass{article}
\usepackage{scalerel}
\usepackage{stackengine,wasysym}
\newcommand\reallywidetilde[1]{\reallywideXtilde{#1}{\AC}}
\newcommand\reallywidenotilde[1]{\reallywideXtilde{#1}{\NAC}}
\newcommand\NAC{\stackengine{1.5\LMpt}{$\SavedStyle\AC$}{\smash{$\SavedStyle\vstretch{.35}{/}$}}{O}{c}{F}{F}{L}}
\newcommand\reallywideXtilde[2]{\ThisStyle{%
\setbox0=\hbox{$\SavedStyle#1$}%
\stackengine{-.1\LMpt}{$\SavedStyle#1$}{\kern.3ex%
\stretchto{\scaleto{\SavedStyle\mkern.2mu#2}{.5150\wd0}}{.6\ht0}%
}{O}{c}{F}{T}{S}%
}}
\def\test#1{$%
\reallywidetilde{#1}\,
\scriptstyle\reallywidetilde{#1}\,
\scriptscriptstyle\reallywidetilde{#1}\qquad
\textstyle\reallywidenotilde{#1}\,
\scriptstyle\reallywidenotilde{#1}\,
\scriptscriptstyle\reallywidenotilde{#1}
$\par}
\parskip 1ex
\begin{document}
\test{abcdefghijklm}
\test{abcdefghijk}
\test{abcdefghi}
\test{abcdefg}
\test{abcde}
\test{abc}
\test{ab}
\test{a}
\test{f}
\test{A}
\end{document}
What about this?
\documentclass{article}
\usepackage{amsmath,amssymb}
\def\nottilde#1{\overset{\ifx#1f\hspace{.5ex}\fi\lower0.8ex\hbox{\tiny$\nsim$}}{#1}}
\def\xtilde#1{\overset{\ifx#1f\hspace{.5ex}\fi\lower0.8ex\hbox{\tiny$\sim$}}{#1}}
\begin{document}
$\tilde{e}\xtilde{e}\nottilde{e}\xtilde{f}\nottilde{f}$
\end{document}