An improved non-linear Roth-type theorem in finite fields

Fuente: arXiv
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Main Author: Lewko, Mark
Format: Preprint
Published: 2026
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author Lewko, Mark
author_facet Lewko, Mark
contents Let $F$ be a finite field of odd characteristic. We prove that any set $A\subset F$ with $|A|\geq C|F|^{5/6}$ contains a nontrivial quadratic progression $(x, x+y, x+y^2), y\neq 0.$ For prime fields, this improves the previous best-known exponent of $7/8$, due to Kavrut and Wu. Unlike some of the previous papers, which rely on Katz's deep multivariate exponential-sum estimates, our argument uses only one-variable Weil-type estimates. We also construct, over certain non-prime finite fields, progression-free sets of size $c|F|^{2/3}$. A key idea in the proof was suggested to the author by ChatGPT 5.5.
format Preprint
id arxiv_https___arxiv_org_abs_2604_27501
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle An improved non-linear Roth-type theorem in finite fields
Lewko, Mark
Number Theory
Combinatorics
Let $F$ be a finite field of odd characteristic. We prove that any set $A\subset F$ with $|A|\geq C|F|^{5/6}$ contains a nontrivial quadratic progression $(x, x+y, x+y^2), y\neq 0.$ For prime fields, this improves the previous best-known exponent of $7/8$, due to Kavrut and Wu. Unlike some of the previous papers, which rely on Katz's deep multivariate exponential-sum estimates, our argument uses only one-variable Weil-type estimates. We also construct, over certain non-prime finite fields, progression-free sets of size $c|F|^{2/3}$. A key idea in the proof was suggested to the author by ChatGPT 5.5.
title An improved non-linear Roth-type theorem in finite fields
topic Number Theory
Combinatorics
url https://arxiv.org/abs/2604.27501