An=(apTn=aBTaBTaBT…af =3-1A |A|=|3-A|=(3-1y川A =(3-1)y 21 3 =0An = ( αβT ) n = αβTαβTαβT … αβT = 3n-1A | An | = | 3n-1A | = (3n-1 ) n | A | 1 1 2 3 1 2 3 3 2 1 (3 ) 2 1 3 1 n n − = = 0