Set Identities A,B are sets; U=Universal Set; u is union; n is intersection; ' is complement ------------------------------------------------------------------------------- A u {} = A Identity Laws A n U = A ------------------------------------------------------------------------------- A u U = U Domination Laws A n {} = {} ------------------------------------------------------------------------------- A u A = A Idempotent Laws A n A = A ------------------------------------------------------------------------------- A'' = A Complementation Law ------------------------------------------------------------------------------- A u B = B u A Commutative Laws A n B = B n A ------------------------------------------------------------------------------- (A u B) u C = A u (B u C) Associativity Laws A n (B n C) = (A n B) n C ------------------------------------------------------------------------------- A u (B n C) = (A u B) n (A u C) Distributive Laws A n (B u C) = (A n B) u (A n C) ------------------------------------------------------------------------------- (A u B)' = A' n B' De Morgan's Laws (A n B)' = A' u B' ------------------------------------------------------------------------------- A u A' = U Complement Laws A n A' = {}