3. 设 f(x,,x,)-Zf;(xi,,xn),=1g(x,xn)=Zg(X,.,xn),i-1则积 h(x,",xn)= f(xi,",xn)g(xi,.",xn)的k次齐次成分为ht(xi,*xn)= E f,(xi,..,xn)g,(x,,xn)i+ j=k特别地,hm+(x1,..,xn)= fm(xj,"",xn)g(xi,.,xn).4：积的次数=因子的次数之和。81.10多元多项式R下§1.10 多元多项式 1 1 1 ( , , ) ( , , ) ( , , ) k n i n j n i j k h x x f x x g x x + = =  特别地， 1 1 1 ( , , ) ( , , ) ( , , ). h x x f x x g x x m l n m n l n + = 4 ．积的次数＝因子的次数之和． 3 ．设 1 1 1 ( , , ) ( , , ) , m n i n i f x x f x x = =  的 k 次齐次成分为 则积 1 1 1 ( , , ) ( , , ) ( , , ) h x x f x x g x x n n n = 1 1 1 ( , , ) ( , , ) , l n i n i g x x g x x = = 