let E be set ; :: thesis: for A, B being Subset of holds (A /\ B) + c= (A + ) /\ (B + )
let A, B be Subset of ; :: thesis: (A /\ B) + c= (A + ) /\ (B + )
A1: A + = A |^.. 1 by Th50;
A2: B + = B |^.. 1 by Th50;
(A /\ B) + = (A /\ B) |^.. 1 by Th50;
hence (A /\ B) + c= (A + ) /\ (B + ) by A1, A2, Th44; :: thesis: verum