FIN#DEF. Finite and Infinite Set.
$X$ is finite if there is a bijection from $X$ to a natural number, i.e. for some $n\in\N$,
\[\lvert X\rvert = n.\]$X$ is infinite if it is not finite.
FIN#DEF. Finite and Infinite Set.
$X$ is finite if there is a bijection from $X$ to a natural number, i.e. for some $n\in\N$,
\[\lvert X\rvert = n.\]$X$ is infinite if it is not finite.