Arithmetic progressions in sets of small doubling
Combinatorics
2016-02-24 v2 Number Theory
Abstract
We show that if a finite, large enough subset A of an arbitrary abelian group satisfies the small doubling condition |A + A| < (log |A|)^{1 - epsilon} |A|, then A must contain a three-term arithmetic progression whose terms are not all equal, and A + A must contain an arithmetic progression or a coset of a subgroup, either of which of size at least exp^[ c (log |A|)^{delta} ]. This extends analogous results obtained by Sanders and, respectively, by Croot, Laba and Sisask in the case where the group is that of the integers or a finite field.
Cite
@article{arxiv.1308.5248,
title = {Arithmetic progressions in sets of small doubling},
author = {Kevin Henriot},
journal= {arXiv preprint arXiv:1308.5248},
year = {2016}
}
Comments
30 pages, improved exposition