推 jacky7987 :1. Given s_1 s_2 in S. Since f is onto 07/15 13:00
→ jacky7987 :there exist r_1 r_2 such that f(r_i)=s_i,i=1,2 07/15 13:01
→ jacky7987 :第二題也差不多!? 07/15 13:01
(1) if f:(R,+.*) -> (S,⊕,⊙) is a ring homomorphism and onto, where |S|>1
show that if R is commutative, then S is commutative
(2) suppose that f: G->H is a group homomorphism and f is onto
prove that if G is a abelian, then H is abelian
請問這兩題應該怎麼證呢?
謝謝
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