Existence of primitive pairs with two prescribed traces over finite fields

TL;DR

This paper establishes conditions under which primitive pairs with prescribed trace values exist over finite fields, providing explicit existence results for various degrees and identifying exceptions for small cases.

Contribution

It introduces new sufficient conditions on field parameters ensuring the existence of primitive pairs with prescribed traces, including explicit results for degrees 2 and 3.

Findings

Existence of primitive pairs with prescribed traces for large t

Explicit exceptions identified for degree 2 cases

Results extended to degree 3 cases

Abstract

Given $F= \mathbb{F}_{p^{t}}$, a field with $p^t$ elements, where $p $ is a prime power, $t\geq 7$, $n$ are positive integers and $f=f_1/f_2$ is a rational function, where $f_1, f_2$ are relatively prime, irreducible polynomials with $deg(f_1) + deg(f_2) = n $ in $F[x]$. We construct a sufficient condition on $(p,t)$ which guarantees primitive pairing $(\epsilon, f(\epsilon))$ exists in $F$ such that $Tr_{\mathbb{F}_{p^t}/\mathbb{F}_p}(\epsilon) = a$ and $Tr_{\mathbb{F}_{p^t}/\mathbb{F}_p}(f(\epsilon)) = b$ for any prescribed $a,b \in \mathbb{F}_{p}$. Further, we demonstrate for any positive integer $n$, such a pair definitely exists for large $t$. The scenario when $n = 2$ is handled separately and we verified that such a pair exists for all $(p,t)$ except from possible 71 values of $p$. A result for the case $n=3$ is given as well.