西安毛子科技大学XIDIANUNIVERSITY于是(m,n)=(2cnex,cge,) =2(8n08)eucgk=11-1k=1 [=122aneuc =C,AC,k=1 [-1: B=(n;,n;))=(C(AC)).A(Ci.C...,C.) = C'ACC,§9.1 定义与基本性质 1 1 ( , ) ( , ) n n i j ki k lj l k l     c c = = =   1 1 ( , ) n n k l ki lj k l   c c = = =   1 1 n n kl ki lj k l a c c = = =   C AC i j =  于是 B C AC (( , )  i j i j ) ( )  = =  ( ) 1 2 1 2 , , , n n C C A C C C C AC C     = =       