codesymbols
How could I type the symbol as shown in the picture below?
I tried to use $\mathbb{R}_{(-)}$ instead, but the - inside can not touch the parenthesis on both sides.
I want to create a horizontal line that stops automatically when it touches the parenthesis.
One option is to define a command for this symbol taking it, for example, from the circuits.ee.IEC library (I wasn't sure if this symbol should be ord, rel, bin, so I opted for bin; also, there was no information about size or baseline position, but all these attributes can easily be adjusted):
\documentclass{article}
\usepackage{amsmath}
\usepackage{tikz}
\usetikzlibrary{circuits.ee.IEC}
\newcommand\Ground{%
\mathbin{\text{\begin{tikzpicture}[circuit ee IEC,yscale=0.6,xscale=0.5]
\draw (0,2ex) to (0,0) node[ground,rotate=-90,xshift=.65ex] {};
\end{tikzpicture}}}%
}
\begin{document}
$L\Ground {}$
\end{document}
Another option: this is listed as Unicode character 'EARTH GROUND' (U+23DA), so you could use XeLaTeX and a font supporting the symbol:
\documentclass{article}
\usepackage{fontspec}
\setmainfont{Symbola}
\begin{document}
The earth ground symbol $⏚$.
\end{document}
fileformat.info has a list of possible fonts supporting the symbol.
A simple solution is to declare another “math alphabet” with a different name:
% My standard header for TeX.SX answers:
\documentclass[a4paper]{article} % To avoid confusion, let us explicitly
% declare the paper format.
\usepackage[T1]{fontenc} % Not always necessary, but recommended.
% End of standard header. What follows pertains to the problem at hand.
\usepackage{amsfonts}
\DeclareMathAlphabet{\mathmybb}{U}{bbold}{m}{n}
\newcommand*{\R}{\mathbb{R}}
\newcommand*{\BOmega}{\mathmybb{\Omega}}
\begin{document}
The usual~$\R$.
The boldfaced omega: $\BOmega$
\end{document}
Best Answer
What about
\leftfree \mkern -12mu \rightfreefrom MnSymbol package?