美Vd1I(同前)或 Y=DZ,yldYr+1Zr+1D = diagLn= zn则 f(X)= Z'(D'C'ACD)Z=z+ .. +, -2-称之为实二次型f(X)的规范形85.3唯一性§5.3 唯一性 则 f X Z D C ACD Z ( ) '( ' ' ) = 2 2 2 2 1 1 p p r z z z z = + + − − − + 1 1 1 1 1 1 1 ( ) r r r r r n n y z d y z d y z y z + + = = = = , 或 Y = D Z , 同前 1 1 1 ( , , , 1 , ,1) r D diag d d = 称之为实二次型 f X( ) 的规范形