A permutation, regarded as a function from the set {1,..., n} to itself, is one-to-one and onto.

Question:

A permutation, regarded as a function from the set {1,..., n} to itself, is one-to-one and onto. Therefore, each permutation has an inverse.
(a) Find the inverse of each 2-permutation.
(b) Find the inverse of each 3-permutation.
This summarizes our notation for the 2- and 3- permutations.