复习几个概念： Literal？Fundamental product？Contained in? “惊艳”的吸收率： x'is not a literal of xy'z.Observe that if P is contained in P2,say P2 =P 2,then,by the absorption law, P1+P2=P1+P*Q=P1 Thus,for instance,x'+x'y=x'复习几个概念： Literal？Fundamental product？Contained in? “惊艳”的吸收率：