Inverse element: Let s be a binary operation on a set S with identity element e Let a ES. Then b is an inverse ofa a*b b*ka=e o Theorem 6.2: Let a be a binary operation on a set a with identity element e. ifthe operation is associative, then inverse element of a is unique when a has its inverse• Inverse element: Let  be a binary operation on a set S with identity element e. Let a S. Then b is an inverse of a if ab = ba = e. • Theorem 6.2: Let  be a binary operation on a set A with identity element e. If the operation is Associative, then inverse element of a is unique when a has its inverse