Referring to the definition before Exercise 11 and to Exercise 49, show that for S

Referring to the definition before Exercise 11 and to Exercise 49, show that for σ ∈ S_A, (σ) i

Data before Exercise 11

Let A be a set and let σ ∈ S_A· For a fixed a ∈ A, the set 

O_a.σ- = {σⁿ(a) |n ∈ Z}