A general construction of regular complete permutation polynomials

TL;DR

This paper presents a comprehensive method for constructing regular complete permutation polynomials over finite fields, expanding the known classes and providing numerous new examples for various regularities.

Contribution

It introduces a general construction framework for r-regular permutation polynomials and complete permutation polynomials over finite fields, generalizing previous results.

Findings

Provides a general construction method for r-regular PPs and CPPs.

Generates many new examples of r-regular CPPs for various r.

Extends the class of known r-regular CPPs beyond previous work.

Abstract

Let $r\geq 3$ be a positive integer and $\mathbb{F}_q$ the finite field with $q$ elements. In this paper, we consider the $r$-regular complete permutation property of maps with the form $f=\tau\circ\sigma_M\circ\tau^{-1}$ where $\tau$ is a PP over an extension field $\mathbb{F}_{q^d}$ and $\sigma_M$ is an invertible linear map over $\mathbb{F}_{q^d}$. We give a general construction of $r$-regular PPs for any positive integer $r$. When $\tau$ is additive, we give a general construction of $r$-regular CPPs for any positive integer $r$. When $\tau$ is not additive, we give many examples of regular CPPs over the extension fields for $r=3,4,5,6,7$ and for arbitrary odd positive integer $r$. These examples are the generalization of the first class of $r$-regular CPPs constructed by Xu, Zeng and Zhang (Des. Codes Cryptogr. 90, 545-575 (2022)).