English

Geometric Progression-Free Sequences with Small Gaps II

Number Theory 2015-03-25 v1 Combinatorics

Abstract

When kk is a constant at least 33, a sequence SS of positive integers is called kk-GP-free if it contains no nontrivial kk-term geometric progressions. Beiglb\"ok, Bergelson, Hindman and Strauss first studied the existence of a kk-GP-free sequence with bounded gaps. In a previous paper the author gave a partial answer to this question by constructing a 66-GP-free sequence SS with gaps of size O(exp(6logn/loglogn))O(\exp(6\log n/\log\log n)). We generalize this problem to allow the gap function kk to grow to infinity, and ask: for which pairs of functions (h,k)(h,k) do there exist kk-GP-free sequences with gaps of size O(h)O(h)? We show that whenever (k(n)3)logh(n)loglogh(n)4log2logn(k(n)-3)\log h(n)\log\log h(n)\ge4\log2\cdot\log n and h,kh,k satisfy mild growth conditions, such a sequence exists.

Keywords

Cite

@article{arxiv.1503.06906,
  title  = {Geometric Progression-Free Sequences with Small Gaps II},
  author = {Xiaoyu He},
  journal= {arXiv preprint arXiv:1503.06906},
  year   = {2015}
}
R2 v1 2026-06-22T09:00:19.142Z