How to write empty set in Latex ? Several possibilities using either the default math mode or the amssymb package. The empty set in mathematics represents a set that contains nothing.

How to write empty set in Latex ?

You can use the default math mode or the amssymb package:

\documentclass[12pt,a4paper]{article}
\usepackage[utf8]{inputenc}
\usepackage{amssymb}
\begin{document}
\noindent
$\emptyset$ $\Leftarrow$ no package \\
$\O$ $\Leftarrow$ no package \\
$\varnothing$ $\Leftarrow$ package amssymb \\
\end{document}

It gives: