# triple \approx and triple \approx with a straight middle line

I'm trying to create a symbol \diffeo for "diffeomorphic" and \isomet for "isometric".

I'd like it to look exactly like \approx $\approx$, but with three lines for the first one; and three lines with the middle being straight for the second one:

where approx is the symbol

.

The first of the following macros is in the Comprehensive List of LaTeX Symbols (texdoc symbols, with TeX Live), where it is called \threesim; the second one has been built similarly.

\newcommand*{\diffeo}{%
\mathrel{\vcenter{\offinterlineskip
\hbox{$\sim$}\vskip-.35ex\hbox{$\sim$}\vskip-.35ex\hbox{$\sim$}}}}

\newcommand*{\isomet}{%
\mathrel{\vcenter{\offinterlineskip
\hbox{$\sim$}\vskip-.85ex\hbox{$-$}\vskip-.55ex\hbox{$\sim$}}}}

• I've searched Latex comprehensive symbol list before, but never found those two symbols. Don't know why they didn't add them as a built-in control and add a picture of it. I also checked Detexify (detexify.kirelabs.org/classify.html), but never got any suggestions. Thank you very much.
– Leo
Jul 2 '11 at 20:15
• It's on page 104, but I admit that I know where to look even without remembering the command's name. ;-) I built the second one just now. Jul 2 '11 at 20:21
• 10 years later it's on page 261 :) is it correct that this symbol is not part of LaTeX itself or any package, so the definition needs to be copied in order to use the symbol? Maybe a package can be found that is willing to "host" it? Sep 24 at 12:44
• @Marijn The code is free for use by anybody. Sep 24 at 13:30