How can I find or implement a symbol in LaTeX type of \fint, but having tilda (\sim) crossing the \int?

Question

I tried

\newcommand{\pathint}{\mathrel{\int\!\!\!\!\!\!\!\sim}}

It looks Ok, but it does not hold integration limits right.

Answer 1

I assume you're looking for a version of the Principal Value Integral symbol, but with the centered "dash" symbol replaced with a "tilde" or \sim. Building on some code given in an earlier answer, you could define a macro called \simint using the code given below.

\documentclass{article}
\def\Yint#1{\mathchoice
    {\YYint\displaystyle\textstyle{#1}}%
    {\YYint\textstyle\scriptstyle{#1}}%
    {\YYint\scriptstyle\scriptscriptstyle{#1}}%
    {\YYint\scriptscriptstyle\scriptscriptstyle{#1}}%
      \!\int}
\def\YYint#1#2#3{{\setbox0=\hbox{$#1{#2#3}{\int}$}
    \vcenter{\hbox{$#2#3$}}\kern-.52\wd0}}
\def\simint{\Yint\sim}
\begin{document}
$
 \displaystyle 
 \simint_a^b f \quad
 \simint\limits_a^b f \quad
 \textstyle 
 \simint_a^b f
$
\end{document}