Let m, n be natural numbers such that their greatest common
divisor gcd(m, n) = 1. Prove that there is a natural number k such
that n divides ((m^k) − 1).
Let G be a group of order p
am where p is a prime not dividing m. Show the following
1. Sylow p-subgroups of G exist; i.e. Sylp(G) 6= ∅.
2. If P ∈ Sylp(G) and Q is any p-subgroup of G, then there exists g
∈ G such that Q 6
gP g−1
; i.e. Q is contained in some conjugate of P. In particular, any
two Sylow p-
subgroups of G are conjugate in G.
3. np ≡...
Let A∈Mn(R)A∈Mn(R) such that I+AI+A is invertible. Suppose thatB=(I−A)(I+A)−1B=(I−A)(I+A)−1(a) Show that B=(I+A)−1(I−A)B=(I+A)−1(I−A) (b) Show that I+BI+B is invertible and express AA in terms of BB.
1. Let T : Mn×n(F) → Mn×n(F) be the transposition map, T(A) =
At. Compute the characteristic polynomial of T. You may wish to use
the basis of Mn×n(F) consisting of the matrices eij + eji, eij −eji
and eii.
2. Let A = (a b c d) (2 by 2 matrix) and let T :
M2×2(F) → M2×2(F) be defined asT (B) = AB. Represent T as a 4×4
matrix using the ordered basis {e11,e21,e12,e22}, and use this
matrix to...
Let a be an element of a finite group G. The order of a is the
least power k such that ak = e.
Find the orders of following elements in S5
a. (1 2 3 )
b. (1 3 2 4)
c. (2 3) (1 4)
d. (1 2) (3 5 4)
Let G be a group and let N ≤ G be a normal subgroup.
(i) Define the factor group G/N and show that G/N is a
group.
(ii) Let G = S4, N = K4 = h(1, 2)(3, 4),(1, 3)(2, 4)i ≤ S4. Show
that N is a normal subgroup of G and write out the set of cosets
G/N.