A similar-to symbol is a logical-mathematical symbol denoted by ∼. Latex stores more than one command and package that represents a similar-to symbol.
\documentclass{article}
\begin{document}
\[ a \sim b \]
\[ p \sim q \]
\end{document}Output :
The best practice is to use the direct \sim command without installing any packages.
Multiple logical symbols are used with the similar-to symbol. Such as equal, gatearthan, lessthen etc.
\documentclass{article}
\usepackage{amssymb,amsmath}
\begin{document}
\[ \begin{matrix}
\lesssim & \gtrsim & \succsim\\[6pt]
\backsim & \simeq & \backsimeq\\[6pt]
\nsim & \lnsim & \gnsim
\end{matrix}\]
\end{document}Output :
