English

Towards the classification of scattered binomials

Combinatorics 2025-02-18 v1

Abstract

Let q q be a prime power and n n an integer. An Fq \mathbb{F}_q -linearized polynomial f f is said to be scattered if it satisfies the condition that for all x,yFqn{0} x, y \in \mathbb{F}_q^n \setminus \{ 0 \} , whenever f(x)x=f(y)y \frac{f(x)}{x} = \frac{f(y)}{y} , it follows that xyFq \frac{x}{y} \in \mathbb{F}_q . In this paper, we focus on scattered binomials. Two families of scattered binomials are currently known: the one from Lunardon and Polverino (LP), given by f(x)=δxqs+xqns,f(x) = \delta x^{q^s} + x^{q^{n-s}}, and the one from Csajb\'ok, Marino, Polverino, and Zanella (CMPZ), given by f(x)=δxqs+xqs+n/2,f(x) = \delta x^{q^s} + x^{q^{s + n/2}}, where n=6 n = 6 or n=8 n = 8 . Using algebraic varieties as a tool, we prove some necessary conditions for a binomial to be scattered. As a corollary, we obtain that when q q is sufficiently large and n n is prime, a binomial is scattered if and only if it is of the form (LP). Moreover we obtain a complete classification of scattered binomial in \Fn\Fn when n8n\leq8 and qq is large enough.

Keywords

Cite

@article{arxiv.2502.11666,
  title  = {Towards the classification of scattered binomials},
  author = {Daniele Bartoli and Francesco Ghiandoni and Alessandro Giannoni and Giuseppe Marino},
  journal= {arXiv preprint arXiv:2502.11666},
  year   = {2025}
}
R2 v1 2026-06-28T21:46:57.703Z