群同态第一定理 Let H be a normal subgroup of G. Define the natural or canonical homomorphism 般的正规子群尚不能让我 φ：G→G/H 们“看穿”同态映射给 我们带来的清晰结构 (g)=gH. Theorem11.3(First Isomorp ism Theorem)Ifψ：G→H is a group homomorphism with K =kerv,then K is normal in G.Let G-G/K be the canonical homomorphism.Then there exists a unique isomorphism n:G/K→(G)such thatψ=np.群同态第一定理 一般的正规子群尚不能让我 们“看穿”同态映射 给 我们带来的清晰结构