Power set

[summary: The power set $~$\mathcal P (X)$~$ of a set $~$X$~$ is the set of all subsets of $~$X$~$. That is, if $~$Y \subseteq X$~$, then $~$Y \in \mathcal P (X)$~$. ]

The power set $~$\mathcal P (X)$~$ of a set $~$X$~$ is the set of all subsets of $~$X$~$. That is, if $~$Y \subseteq X$~$, then $~$Y \in \mathcal P (X)$~$.