Quadratic residues and related permutations
Number Theory
2025-03-04 v4
Abstract
Let be an odd prime. For any -adic integer we let denote the unique integer with and divisible by . In this paper we study some permutations involving quadratic residues modulo . For instance, we consider the following three sequences. \begin{align*} &A_0: \overline{1^2},\ \overline{2^2},\ \cdots,\ \overline{((p-1)/2)^2},\\ &A_1: \overline{a_1},\ \overline{a_2},\ \cdots,\ \overline{a_{(p-1)/2}},\\ &A_2: \overline{g^2},\ \overline{g^4},\ \cdots,\ \overline{g^{p-1}}, \end{align*} where is a primitive root modulo and are all quadratic residues modulo . Obviously is a permutation of and we call this permutation . Sun obtained the sign of when . In this paper we give the sign of and determine the sign when .
Cite
@article{arxiv.1903.01098,
title = {Quadratic residues and related permutations},
author = {Hai-Liang Wu},
journal= {arXiv preprint arXiv:1903.01098},
year = {2025}
}