2.
problem 3.
Let H be a normal subgroup of a group G and let K be any subgroup of G. Prove that the subset HK of G defined by is a subgroup of G Let G S, H ), (12) (34), (13) (24), (1 4) (23)J, and K ((13)). We know that H is a normal subgroup of S, so HK is a subgroup of S4 by Problem 2. (a) Calculate HK (b) To which familiar group is HK...
question for 10.
(16M) Let H and K be subgroups of G. Define HK = {hk |h E H,kE K}. Suppose K is normal in G. Prove (a) HK is a subgroup of G. (b) HnK is a normal subgroup of H; K is a normal subgroup of the subgroup H K. HK K H (c) HnK
(16M) Let H and K be subgroups of G. Define HK = {hk |h E H,kE K}. Suppose K is normal in G....
(a) Show that if H and K are subgroups of an abelian group G, then HK = {hk|he H, k E K} is a subgroup of G (b) Show that if H and K are normal subgroups of a group G, then H N K is a normal subgroup of G
(4)(20 points) (a) Show that if H and K are subgroups of an abelian group G, then HK = {hk|he H, KE K} is a subgroup of G. (b) Show that if H and K are normal subgroups of a group G, then HK is a normal subgroup of G
Problem 3. Subgroups of quotient groups. Let G be a group and let H<G be a normal subgroup. Let K be a subgroup of G that contains H. (1) Show that there is a well-defined injective homomorphism i: K/ H G /H given by i(kH) = kH. By abuse of notation, we regard K/H as being the subgroup Imi < G/H consisting of all cosets of the form KH with k EK. (2) Show that every subgroup of G/H is...
(4)(20 points) (a) Show that if H and K are subgroups of an abelian group G, then HK = {hk|he H, ke K}is a subgroup of G (b) Show that if Hand K are normal subgroups of a group G, then H N K is a normal subgroup of G
Let G be a group and let H,K be normal subgroups of G such that H∩K = {e} and that G = {hk|h ∈ H,k ∈ K}. (1)Prove that for every h∈H, k∈K we have kh(k^-1)(h^−1) = e in G. (2) Prove that the group G is isomorphic to H × K. Hint: For (2), consider the map φ : H ×K → G, defined as φ(h,k) = hk, whereh ∈ H,k ∈ K.
proof please
51. Let H and K be subgroups of an abelian group G of orders n and m respectively. Show that if H K = {e}, then HK = {hkh e H and ke K} is a subgroup of G of order nm.
Let H be a subgroup of G. Define the normalizer of H in G to be the subset NG(H) {g € G |gHg= H}. (i) Prove that NG(H) is a subgroup of G that contains H (ii) Prove that Ha NG(H) (iii) Prove that if H < K < G, and H K, then KC NG(H)
Is this true,If HK is normal subgroup of finite group G ,then H and K is subgroups and normal of G????