If K is a subgroup of G, then ϕ (K) = {ϕ(k) | k subgroup[ K} is a
subgroup of G (number 34 in the exercise chpt 6 Gallian ed 9) Modify this one by adding to the end of property 4 in Theorem 6.3: "... and ϕ carries K isomorphically to ϕ
(K)." (This means that ϕ, with a restricted domain of K and a restricted codomain of ϕ
(K), is an isomorphism from to ϕ(K).