Find a p-Sylow subgroup for each of the given groups, and prime
p:
a. In Z24 a 2-sylow subgroup
b. In S4 a 2-sylow subgroup
c. In A4 a 3-sylow subgroup
(a) Let G and G′ be finite groups whose orders have no common
factors. Show that the only homomorphism φ:G→G′ is the trivial
one.
(b) Give an example of a nontrivial homomorphism φ for the given
groups, if an example exists. If no such homomorphism exists,
explain why.
i.φ: Z16→Z7
ii.φ: S4→S5
Let N be a normal subgroup of the group G.
(a) Show that every inner automorphism of G defines an
automorphism of N.
(b) Give an example of a group G with a normal subgroup N and an
automorphism of N that is not defined by an inner automorphism of
G
Let G be a nonabelian group of order 253=23(11), let P<G be a
Sylow 23-subgroup and Q<G a Sylow 11-subgroup.
a. What are the orders of P and Q. (Explain and include any
theorems used).
b. How many distinct conjugates of P and Q are there in G? n23?
n11? (Explain, include any theorems used).
c. Prove that G is isomorphic to the semidirect product of P and
Q.
1. Let N be a normal subgroup of G and let H be any subgroup
of G. Let HN = {hn|h ∈ H,n ∈
N}. Show that HN is a subgroup of G, and is the smallest
subgroup containing both N and H.
G
is a group and H is a normal subgroup of G. List the elements of
G/H and then write the table of G/H.
1. G=Z10, H= {0,5}. (Explain why G/H is congruent to Z5)
2. G=S4 and H= {e, (12)(34), (13)(24), (14)(23)
Let G be a group and K ⊂ G be a normal subgroup. Let H ⊂ G be a
subgroup of G such that K ⊂ H Suppose that H is also a normal
subgroup of G. (a) Show that H/K ⊂ G/K is a normal subgroup. (b)
Show that G/H is isomorphic to (G/K)/(H/K).