English

Finding a low-dimensional piece of a set of integers

Combinatorics 2016-06-06 v2 Number Theory

Abstract

We show that a finite set of integers AZA \subseteq \mathbb{Z} with A+AKA|A+A| \le K |A| contains a large piece XAX \subseteq A with Fre\u{i}man dimension O(logK)O(\log K), where large means A/Xexp(O(log2K))|A|/|X| \ll \exp(O(\log^2 K)). This can be thought of as a major quantitative improvement on Fre\u{i}man's dimension lemma, or as a "weak" Fre\u{i}man--Ruzsa theorem with almost polynomial bounds. The methods used, centered around an "additive energy increment strategy", differ from the usual tools in this area and may have further potential. Most of our argument takes place over F2n\mathbb{F}_2^n, which is itself curious. There is a possibility that the above bounds could be improved, assuming sufficiently strong results in the spirit of the Polynomial Fre\u{i}man--Ruzsa Conjecture over finite fields.

Keywords

Cite

@article{arxiv.1512.06272,
  title  = {Finding a low-dimensional piece of a set of integers},
  author = {Freddie Manners},
  journal= {arXiv preprint arXiv:1512.06272},
  year   = {2016}
}

Comments

24 pages