Laws of Boolean Algebra
# Boolean Postulates
According to Boolean Postulates of Boolean Algebra,
OR law | AND law | NOT law |
A + 0 = A | A.1 = A | 0' = 1 |
A + 1 = 1 | A.0 = 0 | 1' = 0 |
A + A= A | A.A = A | A'' = A |
A + A' = 1 | A.A' = 0 |
# Duality Principle
It states that, "dual expression of a Boolean expression can be obtained by replacing AND(.) with are OR(+) and vice versa, 1 with 0and vice versa keeping the variables and complements and variables unchanged.
Example; the duality of A.B' + C is A + B'.C
# Law of Boolean Algebra
◼ Identity Laws
➡ A + 0 = A, A.1 = A
◼ Complement Law
➡ A + A' = 1, A.A' = 0
◼ Idempotent Law
➡ A + A = A, A.A = A
◼ Boundedness Law
➡ A + 1 = 1, A.0 = 0
◼Absorption Law
➡ A + (A.B) = A, A.(A + B) = A
◼ Commutative Law
➡ A + B = B + A, A.B = B.A
◼ Associative Law
➡(A + B) + C = A + (B + C), (A.B).C = A.(B.C)
◼ Distributive Law
➡ A.(B + C) = A.B + A.C, A + (B.C) = (A + B) . (A + C)
◼ Involution Law
➡ (A')' = A
◼ De Morgan's Law
➡ i. (A + B)' = A'B' | ii. (A.B)' = A' + B'
● We prove only Identity Law, complement law, commutative law, associative law, distributive law and De Morgan's theorem as per the requirement of curriculum.