Ch3-10 对于任意a<b,c<d F(b, d)-F(6, c-F(a, d)+ F(a, c20 事实上 F(b, d)-F(b,c) F(a, d)+ F(a, c) b =P(a<X≤b,c<Y≤d)≥0Ch3-10 F (b,d) – F (b,c) – F (a,d) + F (a,c)  0 事实上 ④ 对于任意 a < b , c < d – F (b,c) – F (a,d) + F (a,c) =      P a X b c Y d ( , 0 ) F (b,d) a b c d