求和E等价的积和表达式 Algorithm 15.1:The input is a Boolean expression E.The output is a sum-of-products expression equivalent to E. Step I.Use DeMorgan's laws and involution to move the complement operation into any parenthesis until finally the complement operation only applies to variables.Then E will consist only of sums and products of literals. Step 2.Use the distributive operation to next transform E into a sum of products. Step 3.Use the commutative,idempotent,and complement laws to transform each product in E into 0 or a fundamental product. Step 4.Use the absorption and identity laws to finally transform E into a sum-of-products expression.求和E等价的积和表达式