Assignment 7

Due Thursday, November 3, 2022

Problem 1

c.f. Exercise 3.4.5

Prove that subgroups and quotient groups of a solvable group are solvable.

Problem 2

c.f. Exercise 5.4.16

Prove that if \(K\) is a normal subgroup of \(G\) then \(K'\) is normal in \(G\).

Problem 3

c.f. Exercise 5.5.6

Assume that \(K\) is a cyclic group, \(H\) is an arbitrary group and \(\varphi_1\) and \(\varphi_2\) are homomorphisms from \(K\) into \(\operatorname{Aut}(H)\) such that \(\varphi_1(K)\) and \(\varphi_2(K)\) are conjugate subgroups of \(\operatorname{Aut}(H)\). If \(K\) is infinite assume \(\varphi_1\) and \(\varphi_2\) are injective. Prove that \(H \rtimes_{\varphi_1} K\) is isomorphic to \(H \rtimes_{\varphi_2} K\).

Problem 4

c.f. Exercise 5.5.8

Classify all groups of order \(75\) up to isomorphism.

Problem 5

c.f. Exercise 6.3.6

Establish a finite presentation for \(S_4\) using \(2\) generators.