E0EBu1则ABB22)EB21AlBu1EA +B,A,Bu + B21又 A,B + B21,)=-22/+1+B,4.5矩阵的分块§4.5 矩阵的分块 则             = 21 22 11 1 B B B E A E E O AB . 1 11 21 1 22 11       + + = A B B A B B E 又 A1B11 + B21       − −  +      −       − = 1 1 1 0 1 2 1 0 1 1 1 2       − −  +      − = 1 1 1 0 0 2 3 4 , 1 1 2 4       − − =        +      − + = 2 0 4 1 1 1 1 2 A1 B22 , 3 1 3 3       =