Full Idea
The 'power set' of A is all the subsets of A. P(A) = {B : B ⊆ A}.
Gist of Idea
The 'power set' of A is all the subsets of A
Source
A.George / D.J.Velleman (Philosophies of Mathematics [2002], Ch.3)
Book Reference
George,A/Velleman D.J.: 'Philosophies of Mathematics' [Blackwell 2002], p.50