symbols
Does anyone know of the symbol used for the center of mass in physics? Typically it is a circle with two quadrants shaded in. Unfortunately I can't find this in the standard LaTeX symbols PDF or on Detexify.
Is there a predefined command for this symbol or some other way I could get it?
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.
Well here is one that looks kinda like cheating, it uses amsmath only, though adding calc will make the definition much simpler:
\documentclass{article}
\usepackage{amsmath}
\newlength{\crossl}
\settowidth{\crossl}{$\times$}
\newlength{\ceql}
\settowidth{\ceql}{$\times=$}
\addtolength{\ceql}{-\crossl}
\newcommand{\crosseq}{\mathrel{\makebox[\crossl][l]{$\times\hspace{-\ceql}=$}}}
\begin{document}
$f(x)\crosseq g(x)\crosseq h(x)$
\end{document}
Result:
One can also play around with the position and the symbols used:
\newcommand{\crosseq}{\mathrel{\makebox[7.7778pt][l]{$\neq$\hspace{-6.7778pt}\raisebox{-2.5pt}{$\backslash$}}}}
EDIT: Since this answer is chose I will add some more solution, this time using egreg's suggestion as poking around with boxes will likely create unexpected spacing issue:
\newcommand{\crosseq}{\mathrel{\ooalign{\hidewidth$/$\hidewidth\cr\ooalign{\hidewidth$\backslash$\hidewidth\cr$=$\cr}\cr}}}
or
\newcommand{\crosseq}{\mathrel{\ooalign{\hidewidth$/$\hidewidth\cr\ooalign{\hidewidth\raisebox{-2pt}{$\backslash$}\hidewidth\cr$=$\cr}\cr}}}
Result:
EDIT2: Add [l] option to \makebox in order to adjust alignment.
Best Answer
I don't think it's available as a proper symbol, but you could use TikZ to draw it. By using the units
emorex, the symbol will scale corresponding to the surrounding text.