# Definition:Non-Empty Set/Class Theory

(Redirected from Definition:Non-Empty Class)

## Theorem

Let $A$ be a class.

Then $A$ is non-empty if and only if $A$ has at least one element.

## Also known as

Some sources prefer to use nonempty, but $\mathsf{Pr} \infty \mathsf{fWiki}$, in striving for consistency, standardises on non-empty.