The set {1,1 / 2,1 / 3,1 / 4} is represented by description,

The set {1,1 / 2,1 / 3,1 / 4} is represented by description,

Set {1,1 / 2,1 / 3,1 / 4}
={x|x=1/n,n=1,2,3,4}
={x | x = 1 / N, n ∈ n * and N ≤ 4}