amsmathmath-modemath-operatorssuperscriptssymbols
As the question states, I want a tilde over \equiv similar to \simeq and \cong commands. To be more specific, they tilde needs to be closer to the \equiv symbol.
I've tried using stackrel and DeclareMathOperator* but they place it way too high.
I've even tried to place it under empty space over \equiv as math operator as in
\DeclareMathOperator*{\eq}{\equiv}
\newcommand{\poly}{\eq^{\stackrel{\sim}{\hspace*{2em}}}}
yet still no luck.
Any suggestions? Thanks.
Adapting egreg's solution:
\documentclass{article}
\usepackage{graphicx}
\newcommand\subsetsim{\mathrel{%
\ooalign{\raise0.2ex\hbox{$\subset$}\cr\hidewidth\raise-0.8ex\hbox{\scalebox{0.9}{$\sim$}}\hidewidth\cr}}}
\begin{document}
\[
A \subsetsim B
\]
\end{document}
Adapt the parameters to your likings.
The following constructs the math symbol \isomorphism similar to \simeq, but with a longer line:
\documentclass{article}
\makeatletter
\newcommand*{\isomorphism}{%
\mathrel{%
\mathpalette\@isomorphism{}%
}%
}
\newcommand*{\@isomorphism}[2]{%
% Calculate the amount of moving \sim up as in \simeq
\sbox0{$#1\simeq$}%
\sbox2{$#1\sim$}%
\dimen@=\ht0 %
\advance\dimen@ by -\ht2 %
%
% Compose the two symbols
\sbox0{%
\lower1.9\dimen@\hbox{%
$\m@th#1\relbar\isomorphism@joinrel\relbar$%
}%
}%
\rlap{%
\hbox to \wd0{%
\hfill\raise\dimen@\hbox{$\m@th#1\sim$}\hfill
}%
}%
\copy0 %
}
\newcommand*{\isomorphism@joinrel}{%
\mathrel{%
\mkern-3.4mu %
\mkern-1mu %
\nonscript\mkern1mu %
}%
}
\makeatother
\begin{document}
\[ A \isomorphism B \simeq C = D \sim E \]
\[ A \isomorphism B^{C \isomorphism D^{E \isomorphism F}} \]
\end{document}
Remarks:
The line is constructed similar to \longrightarrow. There a line \relbar is joined a \rightarrow. The joining removes the side bearings, which means the glyphs can have white margins at the left and the right. LaTeX's \joinrel adds a negative space of 3mu to move the relational symbols together. The test file uses the symbol in smaller math styles, there -3mu leaves a gap, therefore \isomorphism@joinrel is defined with customized settings (-3.4mu for \displaystyle and \textstyle, -4.4mu for scriptstyle and \scriptscriptstyle).
The symbol \sim is horizontally centered and set in the same math style and size. It is raised to the same height as aymbol \simeq.
The vertical position of the line in \simeq is unhappily not available in TeX, therefore a guessed value is used (the shift of \sim multiplied by 1.9).
If you want the line a little higher, then you can decrease the factor.
\mathpalette is used to support the symbol in all math styles.
Then the internal macro \@isomorphism gets the math style (\displaystyle, \textstyle, \scriptstyle, \scriptscriptstyle) as first argument. The second argument is not used and left empty.
The measuring and glyph composing is done with many low level plain TeX macros for efficiency (and fun).
\m@th sets \mathsurround to 0pt. Usually the value is 0pt, but if set, then the space that should surround math expressions should not occur inside a formula or math symbol.
Best Answer
A straightforward modification of the code for
\conginfontmath.ltxHere is the new
\ccong(change the name to your liking):