度门六了 数学科学学院线性代数教学组 SITASAY (2)矩阵按行分块 2 21 22 n A m2 22 n 2 n（2）矩阵按行分块 11 12 1 21 22 2 1 2 n n m m mn a a a a a a A a a a     =           1 2 T T T m A          =         1 11 12 1  , , , , T n  = a a a  2 21 22 2  , , , , T n  = a a a  1 2 , , ,  T m m m mn  = a a a 1 2 , , , T T T    m