Permutations from an arithmetic setting

Abstract

Let m,n be positive integers such that m>1 divides n. In this paper, we introduce a special class of piecewise-affine permutations of the finite set [1,n]≔{1,…,n} with the property that the reduction (modm) of m consecutive elements in any of its cycles is, up to a cyclic shift, a fixed permutation of [1,m]. Our main result provides the cycle decomposition of such permutations. We further show that such permutations give rise to permutations of finite fields. In particular, we explicitly obtain classes of permutation polynomials of finite fields whose cycle decomposition and its inverse are explicitly given.