In: Advanced Math
Let G be a group. The center of G is the set Z(G) = {g∈G |gh = hg ∀h∈G}. For a∈G, the centralizer of a is the set C(a) ={g∈G |ga =ag }
(a)Prove that Z(G) is an abelian subgroup of G.
(b)Compute the center of D4.
(c)Compute the center of the group G of the shuffles of three objects x1,x2,x3.
○n: no shuffling occurred
○s12: swap the first and second items
○s13: swap the first and third items
○s23: swap the second and third items
○m1: move the last item to the front
○m2: move the front item to the end
(d)Compute the center of GL2(R).
(e)Prove that Z(G) = ∩a∈GC(a).
please explain every subquestion