Finite field extensions with the line or translate property for $r$-primitive elements

Abstract

Let $r,n>1$ be integers and $q$ be any prime power $q$ such that $r\mid q^n-1$. We say that the extension $\mathbb{F}_{q^n}/\mathbb{F}_q$ possesses the line property for $r$-primitive elements property if, for every $α,θ\in\mathbb{F}_{q^n}^*$, such that $\mathbb{F}_{q^n}=\mathbb{F}_q(θ)$, there exists some $x\in\mathbb{F}_q$, such that $α(θ+x)$ has multiplicative order $(q^n-1)/r$. We prove that, for sufficiently large prime powers $q$, $\mathbb{F}_{q^n}/\mathbb{F}_q$ possesses the line property for $r$-primitive elements. We also discuss the (weaker) translate property for extensions.