(5)detA≤a1a2anm, fisher不等式 0 →A=LE,L=n“0 ∑l22 →LL= ∑|lm2 →ak=∑|l2l142=dtA= det Ldet"=I211 22 (5) det , A a a a fisher  nn 不等式 11 11 11 11 11 11 0 0 0 , H l l l A LL L l l l      = =         2 11 2 2 2 1 2 1 | | * * * | | * * * | | i H i n ni i l l LL A l = =          = =             2 2 1 | | | | k kk ki kk i a l l =  =   2 1 det det det | | n H ii i A L L l =  = = 