Power set - Aetherwisp

The power set (or powerset) $\mathcal{P}(S)$ of a set $S$ is the set of all of its possible subsets, including the empty set $\emptyset$ and $S$ itself.

For example, the power set of $\{ 1,2,3 \}$ is

\{ \emptyset, \{ 1 \}, \{ 2 \}, \{ 3 \}, \{ 1,2 \}, \{ 1,3 \}, \{ 2,3 \}, \{ 1,2,3 \} \}