(10) Let G be a finite group. Prove that if H is a proper subgroup of G, then |H| = |G|/2. (11) Let G be a group. Prove that if Hį and H2 are subgroups of G such that G= H1 U H2, then either H1 = G or H2 = G.
1. Give an example of a group, G, and a proper subgroup, H, where H has finite index in G and H has infinite order 2. Give an example of a group, G, and a proper subgroup, H, where H has infinite index in G and H has finite order. (Hint: you won't be able to find this with the groups that we work a lot with. Try looking in SO2(R)) 1. Give an example of a group, G, and...
Let G be a finite group, and let H be a subgroup of order n. Suppose that H is the only subgroup of order n. Show that H is normal in G. [consider the subgroup of G] aha а
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...
Let G be a finite group, and let H be a M be a subgroup of G such that H C M C G. What are the possible orders for M? Why? Let G possible orders of subgroups of S5 which contain D5? subgroup of G. Finally, let S5, and let H = D5. What are the _ Let G be a finite group, and let H be a M be a subgroup of G such that H C M...
(5) Let G be a group, and let H be a subgroup of G. Define a relation ~ on G as follows: X~ · y if x-ly E H. Prove that this is an equivalence relation, and that the equivalence classes of the relation are the left cosets of H.
(*) Let G be a group. Let G, G denote the smallest subgroup of G containing S = {xyr-ly-1: 2, YEG}. (The subgroup (G,G] is called the commutator subgroup of G.) (a) Show that u-zyr-?-?u= (u-cu)(u-yu)(u--xu)-1(u-yu)-1 for all 2, 4, U E G. Deduce that (G,G| 4G. (b) Show that the quotient group G/[G,G] is abelian. (c) If N 4G and G/N is abelian, show that (G,G] C N. (In other words, G/(G,G) is the largest abelian quotient of G.)...
Let G be a finite group with subgroup H. Define E = { g^{-1} H g : g \in G }. Prove that |E| divides |G/H|.
1. Let G - Z. Let H - {0,3,5,9) be a subgroup of (you do not need to prove this is a subgroup of G). Prove that G/l is a valid quotient group. Explain what the elements of G/H are and what the group operation is. 2. Let G be a group and H a normal subgroup in G. I E H for all IEG, then prove that G/H is abelian
abstract algebra show your work 3. Let H be a subgroup of G with |G|/\H = 2. Prove that H is normal in G. Hint: Let G. If Hthen explain why xH is the set of all elements in G not in H. Is the same true for H.C? Remark: The above problem shows that A, is a normal subgroup of the symmetric group S, since S/A, 1 = 2. It also shows that the subgroup Rot of all rotations...