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2-31 COMMUTATIVE LAW the order in which terms are written does not affect their value (AB = BA, A+B = B+A). ASSOCIATIVE LAW a simple equality statement A(BC) = ABC or A+(B+C) = A+B+C. IDEMPOTENT LAW a term ANDed with itself or ORed with itself is equal to that term (AA = A, A+A = A). DOUBLE NEGATIVE LAW a term that is inverted twice is equal to the term  = A. COMPLEMENTARY LAW a term ANDed with its complement equals 0, and a term ORed with its complement equals 1 (A  = 0, A+  = 1). LAW OF INTERSECTION a term ANDed with 1 equals that term and a term ANDed with 0 equals 0 (A·1 = A, A·0 = 0). LAW OF UNION a term ORed with 1 equals 1 and a term ORed with 0 equals that term (A+1 = 1, A+0 = A). DeMORGAN’S THEOREM this theorem consists of two parts: (1)  AB  =   +   and (2) B + =   ·   (Look at the fourth and eighth sets of gates in table 2-4). DISTRIBUTIVE LAW (1) a term (A) ANDed with an parenthetical expression (B+C) equals that term ANDed with each term within the parenthesis: A·(B+C) = AB+AC; (2) a term (A) ORed with a parenthetical expression ( B ·C) equals that term ORed with each term within the parenthesis: A+(BC) = (A+B) · (A+C). LAW OF ABSORPTION this law is the result of the application of several other laws: A·(A+B) = A or A+(AB) = A. LAW OF COMMON IDENTITIES the two statements A·( +B) = AB and A+ B = A+B are based on the complementary law.