引理1:若f=gq+r,则f,g)=(r,g) poof:由(f,g)f,(f,g)g,知(f,g) 故(f,g)(,g);同理(r,g)(f,g) f=8q1+,deg≤degg deg r2 degr q3+ rs-2=rs-19s+rs degrs degrs s-1=rs95+ (f,g)=(g,1)=…=(-1,r)=C6 , , [ ] 1 , ( , ) ( , ). f g r F X f gq r f g r g  引理 ：若 = + 则 = ( , )( , ); ( , )( , ). : ( , ) , ( , ) , ( , ) , f g r g r g f g proof f g f f g g f g r 故 同理 由 知     ,   , deg deg , deg deg 1 2 3 3 1 2 2 2 1 1 1 1 r r q r g r q r r r f gq r r g = + = +  = +  s s s s s s s s s s s s f g g r r r cr r r q r r q r r r  = = = = =  = +  − − + − − − ( , ) ( , ) ( , ) deg deg 1 1 1 1 2 1 1 