A collection of disjoint subsets of a given set. The union of the subsets must equal the entire original set. For example, one possible partition of {1, 2, 3, 4, 5, 6} is {1, 3}, {2}, {4, 5, 6}. Power Set of {a,b,c}:

P(S) = { {}, {a}, {b}, {c}, {a, b}, {a, c}, {b, c}, {a, b, c} }(DON'T FORGET TO INCLUDE EMPTY SET) ;