如题所述
怎么表达呢?
(1)R∩S=R-(R-S) 或 R∩S=S-(S-R)(2) = AθB(R×S) = A=B(R×S)R∞S=∏ ( R.B=S.B(R×S))(3)R÷S =∏X(R)-∏X(∏X(R)×∏Y(S)-R)