如何去寻找（定义）最小（其实是极小） 的积和表达式？ 复习几个概念： E is simpler than F E is minimx'yz+xy'+xyz'+xyz= ession which is sin Prime Implx'y xyz+xy'+xyz+xyz'+xyz= yz+xz+XV Theorem 15.9:A minimal sum-of-products form for a Boolean expression E is a sum of prime implicants of E.如何去寻找（定义）最小（其实是极小） 的积和表达式？ 复习几个概念： E is simpler than F E is minimal if there is no equivalent sum-of-products expression which is simpler than E. Prime Implicant Theorem 15.9: A minimal sum-of-products form for a Boolean expression E is a sum of prime implicants of E. x’ yz+ xy’ z+ xyz’+ xyz= x’ yz+ xyz+ xy’ z+ xyz+ xyz’+ xyz = yz+xz+xy