I'm looking for a package where is defined the symbol for polynomial-time reduction that looks like the infinity symbol.
Thanks!
[Tex/LaTex] How to display polynomial-time “reduction” symbol
symbols
Related Solutions
You could, of course, use TikZ for this:
The symbol will scale with your font size, since it uses ex to define the path.
\documentclass{article}
\usepackage{tikz}
\begin{document}
\newcommand\shield{%
\tikz [baseline] \draw (0,1.75ex) -- (0,0.75ex) arc [radius=0.75ex, start angle=-180, end angle=0] -- (1.5ex,1.75ex) -- cycle;%
}
A shield: \shield
\end{document}
If you're feeling fancy, you could parametrise it a bit:
\documentclass[border=3mm]{standalone}
\usepackage{tikz}
\begin{document}
\newcommand\shield[1][]{%
\tikzset{
shield width/.store in=\shieldwidth,
shield width=1.5ex,
shield height/.store in=\shieldheight,
shield height=1.75ex
}%
\tikz [baseline,#1] \draw (0,\shieldheight) -- (0,\shieldwidth/2) arc [radius=\shieldwidth/2, start angle=-180, end angle=0] -- (\shieldwidth,\shieldheight) -- cycle;%
}
A shield: \shield
A wide shield: \shield[shield width=2ex]
A tall shield: \shield[shield height=3ex]
\end{document}
It is good practice to wrap your wrap the \vdash into a command. That way you can change the command once in the preamble (say you suddenly need it bold, or larger, or whatever) and it will be changed everywhere in the document. E.g.,
\documentclass{article}
\newcommand{\concl}{\ensuremath{\vdash}}
\begin{document}
\begin{itemize}
\item [P1] first premise
\item [P2] second premise
\item [\concl] conclusion
\end{itemize}
\end{document}
Best Answer
Do you mean
\propto? I think I've seen that for polynomial-time reduction before...This answer was brought to you by Detexify.