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...
11. Prove that a nonempty subset H of a group G is a subgroup of G if and only if whenever a, b E H, then ab-1 e H
Only for Question3
(2) Let H be a normal subgroup of a group G. Prove that the natural operation [x][y] = [xy] gives a well-defined group structure on G/H. (3 Consider the subgroup D3 C D9. Verify that the operation from (2) is not well-defined on D9/Ds
(2) Let H be a normal subgroup of a group G. Prove that the natural operation [x][y] = [xy] gives a well-defined group structure on G/H. (3 Consider the subgroup D3 C D9....
7. Let G be a group and let H be a subgroup of G. Prove that the relationon G given by ab if ab-i є H is an equivalence relation.
(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.
(8) Let G be a group and let H be a subgroup of G. Prove that the right cosets of H partition G, that is, G= U Hy HYEH\G and, if y, y' E G and Hyn Hy' + 0, then Hy= Hy'.
Exercise 2.23. Suppose H and K are subgroups of G. Prove that HK is a subgroup of G if and only if HK = KH a abaža Exercise 2.24. Suppose H is a subgroup of G. Prove that HZ(G) is a subgroup of G. Exercise 2.25. (a) Give an example of a group G with subgroups H and K such that HUK is not a subgroup of G. (b) Suppose H, H., H. ... is an infinite collection of subgroups...
4 (a) Let G be an abelian group with identity e and let H- gEGI8-e. Prove that H is a subgroup of G
4 (a) Let G be an abelian group with identity e and let H- gEGI8-e. Prove that H is a subgroup of G
I help help with 34-40
33. I H is a subgroup of G and g G, prove that gHg-1 is a subgroup of G. Also, prove that the intersection of gH for all g is a normal subgroup of G. 34. Prove that 123)(min-1n-)1) 35. Prove that (12) and (123 m) generate S 36. Prove Cayley's theorem, which is the followving: Any finite group is isomorphic to a subgroup of some S 37. Let Dn be the dihedral group of...
4. Let H be a subgroup of a group G and let a, b e H. Using the definition of cosets, prove that Ha= Hb if and only if ab-EH.