English

Primitive pairs of rational functions with prescribed traces over finite fields

Number Theory 2024-11-26 v1

Abstract

Let qq be a positive integral power of some prime pp and Fqm\mathbb{F}_{q^m} be a finite field with qmq^m elements for some mNm \in \mathbb{N}. Here we establish a sufficient condition for the existence of a non-zero element ϵFqm\epsilon \in \mathbb{F}_{q^m}, such that (f(ϵ),g(ϵ))(f(\epsilon), g(\epsilon)) is a primitive pair in Fqm\mathbb{F}_{q^m} with two prescribed traces, \TrFqm/Fq(ϵ)=a\Tr_{{\mathbb{F}_{q^m}}/{\mathbb{F}_q}}(\epsilon)=a and \TrFqm/Fq(ϵ1)=b\Tr_{{\mathbb{F}_{q^m}}/{\mathbb{F}_q}}(\epsilon^{-1})=b, where f(x),g(x)Fqm(x)f(x), g(x) \in \mathbb{F}_{q^m}(x) are rational functions with some restrictions and a,bFqa, b \in \mathbb{F}_q. Also, we show that there exists an element ϵFqm\epsilon \in \mathbb{F}_{q^m} satisfying our desired properties in all but finitely many fields Fqm\mathbb{F}_{q^m} over Fq\mathbb{F}_q. We also calculate possible exceptional pairs explicitly for m9m\geq 9, when degree sums of both the rational functions are taken to be 3.

Keywords

Cite

@article{arxiv.2411.15568,
  title  = {Primitive pairs of rational functions with prescribed traces over finite fields},
  author = {Shikhamoni Nath and Dhiren Kumar Basnet},
  journal= {arXiv preprint arXiv:2411.15568},
  year   = {2024}
}

Comments

arXiv admin note: text overlap with arXiv:2405.19068