English

Strongly complete sets and a conjecture of Erdős

Number Theory 2026-07-15 v1 Combinatorics

Abstract

A set ANA\subseteq\mathbb{N} is called complete\textit{complete} if every sufficiently large integer can be written as a sum of distinct elements of AA. It is strongly complete\textit{strongly complete} if it remains complete after one deletes finitely many elements from it. We show that ANA\subseteq\mathbb{N} is strongly complete whenever A(2k,2k+1]6 \big|A\cap(2^k,2^{k+1}]\big|\ge6 for every sufficiently large kNk\in\mathbb{N}, and aAaθ=,θRZ. \sum_{a\in A}\|a\theta\|=\infty, \quad\forall\theta\in\mathbb{R}\setminus\mathbb{Z}. In particular, this resolves a 1961 conjecture of Erd\H{o}s. The proof builds on previous work of Bergelson and Simmons. Our approach also allows us to establish a more general strong-completeness criterion with suitable ordered blocks in place of dyadic intervals.

Keywords

Cite

@article{arxiv.2607.14071,
  title  = {Strongly complete sets and a conjecture of Erdős},
  author = {Steve Fan},
  journal= {arXiv preprint arXiv:2607.14071},
  year   = {2026}
}

Comments

15 pages