# Definition:Permutation on n Letters/Set of Permutations

## Definition

Let $\N_k$ be used to denote the (one-based) initial segment of natural numbers:

$\N_k = \closedint 1 k = \set {1, 2, 3, \ldots, k}$

The set of permutations of $\N_n$ is denoted $S_n$.

## Also denoted as

Some sources use $\map S n$ for $S_n$.