Note on a conjecture of Sárközy on special sequences

Fuente: arXiv
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Main Authors: Ding, Yuchen, Li, Huixi, Zhang, Zihan
Format: Preprint
Published: 2025
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author Ding, Yuchen
Li, Huixi
Zhang, Zihan
author_facet Ding, Yuchen
Li, Huixi
Zhang, Zihan
contents Let $α>1$ be an irrational number and $k\ge 2$ a positive integer. Let $f(x)$ be a polynomial with positive integer coefficients. Solving a 2001 problem of Sárközy on special sequences, Hegyvári proved in 2003 that there exists an infinite sequence $A$ with density $\frac{1}{k}-\frac{1}{kα}$ such that $$ \big\{f(a_1)+\ldots+f(a_k): a_i\in A, 1\le i\le k\big\}\cap \big\{\lfloor nα\rfloor: n\in \mathbb{N}\big\}=\emptyset. $$ Hegyvári also proved that the density given by him is optimal for $k=2$. In this article, we show that the density $\frac{1}{k}-\frac{1}{kα}$ given by Hegyvári is actually optimal for all $k\ge 2$.
format Preprint
id arxiv_https___arxiv_org_abs_2509_25025
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Note on a conjecture of Sárközy on special sequences
Ding, Yuchen
Li, Huixi
Zhang, Zihan
Number Theory
Let $α>1$ be an irrational number and $k\ge 2$ a positive integer. Let $f(x)$ be a polynomial with positive integer coefficients. Solving a 2001 problem of Sárközy on special sequences, Hegyvári proved in 2003 that there exists an infinite sequence $A$ with density $\frac{1}{k}-\frac{1}{kα}$ such that $$ \big\{f(a_1)+\ldots+f(a_k): a_i\in A, 1\le i\le k\big\}\cap \big\{\lfloor nα\rfloor: n\in \mathbb{N}\big\}=\emptyset. $$ Hegyvári also proved that the density given by him is optimal for $k=2$. In this article, we show that the density $\frac{1}{k}-\frac{1}{kα}$ given by Hegyvári is actually optimal for all $k\ge 2$.
title Note on a conjecture of Sárközy on special sequences
topic Number Theory
url https://arxiv.org/abs/2509.25025