西要毛子科技大学三XIDIAN UNIVERSITY(fi(a), gi(a))=1, 故 (d,(a),d,(a))=1.由于d,(2)d,(a)[ d(2)因而另一方面，由于d(a)lfi(a)gi(a),可令d(a) = f(a)g(a)其中f(a)lfi(a), g(a)lgi(a)又 ： (fi(a),g2(a))=1, : (f(a),g2(a))=1又得f(a)lf,(a).由 f(a)/ f,(a)gz(a),由于 ( f g 1 1 ( ), ( ) 1 ,   ) = 故 (d d 1 2 ( ), ( ) 1.   ) = 因而 1 2 d d d ( ) ( ) ( )    另一方面，由于 1 1 d f g ( ) ( ) ( ),    可令 d f g ( ) ( ) ( ),    = 其中 1 1 f f g g ( ) | ( ), ( ) | ( )     又 ( f g 1 2 ( ), ( ) 1,   ) = 由 2 2 f f g ( ) | ( ) ( ),    又得 2 f f ( ) | ( ).    = ( f g ( ), ( ) 1.  2 )