# Axiom:Axiom of Empty Set/Class Theory

## Axiom

Let $V$ be a basic universe.

The empty class $\O$ is a set, that is:

$\O \in V$

## Also known as

In the specific context of set theory, the axiom of the empty set is also known as the axiom of existence, but there exists another axiom with such a name, used in a different context.

Hence it is preferable not to use that name.

Some sources refer to this as the axiom of the null set.