Cycles and divergent trajectories for a class of permutation sequences

Abstract

Let $f$ be a permutation from ${\mathbb{N}}_0$ onto ${\mathbb{N}}_0$. Let $x\in {\mathbb{N}}_0$ and consider a (finite or infinite) sequence $s=(x,f(x),f^2(x),\cdots )$. We call $s$ a permutation sequence. Let $D$ be the set of elements of $s$. If $D$ is a finite set then the sequence $s$ is a cycle, and if $D$ is an infinite set the sequence $s$ is a divergent trajectory. We derive theoretical and computational bounds for cycles and divergent trajectories for a defined class of permutations.