唯一性:设A=U1R1=U2R2→R1=U1U2R2 R J为酉矩阵 ku k2 0 k 0 设R1 kn2 r2 22 2 00 00 nn 21 21 (1)k1n=v141 2 nn唯一性： 设A = U1 R1 = U2 R2 2 2 1 R1 U1 U R − = =VR2 V为酉矩阵 11 11 11 (1) k = v l             =             = n n n n n n n n l l l l l l R k k k k k k R               0 0 0 0 0 0 22 2 11 21 1 2 22 2 11 21 1 设 1             = n n nn n n v v v v v v v v v V        1 2 21 22 2 11 21 1