English

Existence of primitive normal pairs over finite fields with prescribed subtrace

Number Theory 2025-04-22 v3

Abstract

Given positive integers q,n,mq,n,m and aFqa\in\mathbb{F}_{q}, where qq is an odd prime power and n5n\geq 5, we investigate the existence of a primitive normal pair (ϵ,f(ϵ))(\epsilon,f(\epsilon)) in Fqn\mathbb{F}_{q^{n}} over Fq\mathbb{F}_{q} such that STrqn/q(ϵ)=a\mathrm{STr}_{q^n/q}(\epsilon)=a, where f(x)=f1(x)f2(x)Fqn(x)f(x)=\frac{f_{1}(x)}{f_{2}(x)}\in\mathbb{F}_{q^n}(x) is a rational function together with deg(f1)+(f_{1})+deg(f2)=m(f_{2})=m and STrqn/q(ϵ)=0i<jn1ϵqi+qj\mathrm{STr}_{q^n/q}(\epsilon) = \sum_{0\leq i<j\leq n-1}^{}\epsilon^{q^i+q^j}. Finally, we conclude that for m=2m=2, n6n\geq 6 and q=7kq=7^k; kNk\in\mathbb{N}, such a pair will exist certainly for all (q,n)(q,n) except at most 1111 choices.

Keywords

Cite

@article{arxiv.2405.11463,
  title  = {Existence of primitive normal pairs over finite fields with prescribed subtrace},
  author = {K. Chatterjee and G. Kapetanakis and H. Sharma and S. K. Tiwari},
  journal= {arXiv preprint arXiv:2405.11463},
  year   = {2025}
}