Conjugacy classes of S n correspond to integer partitions of n : to the partition μ = (μ 1, μ 2,..., μ k) with n = ∑ ∑ i = 1 k μ μ i and μ 1 ≥ μ 2 ≥... ≥ μ k, is associated the set C μ of permutations with cycles of lengths μ 1, μ 2,..., μ k. Then C μ is a conjugacy class of S n, whose elements are said to be of cycle-type μ μ .