English

Fast winning strategies in a generalized van der Waerden game

Combinatorics 2026-01-28 v2

Abstract

Consider the following Maker-Breaker game. Fix a finite subset SNS\subset\mathbb{N} of the naturals. The players Maker and Breaker take turns choosing previously unclaimed natural numbers. Maker wins by eventually building a homothetic copy aS+baS+b of SS, where aN{0}a\in\mathbb{N}\setminus\{0\} and bZb\in\mathbb{Z}. This is a generalization of the van der Waerden game analyzed by Beck. By the Hales-Jewett theorem, there exists a constant cc depending only on S|S| such that Maker can win in cc or less moves. We show that Maker can win in S|S| moves if S3|S|\leq 3. When S=4|S|=4, we show that Maker can always win in 55 or less moves and describe all SS such that Maker can win in 44 moves. If S5|S|\geq 5, Maker has no winning strategy in S|S| moves.

Keywords

Cite

@article{arxiv.2309.11367,
  title  = {Fast winning strategies in a generalized van der Waerden game},
  author = {Hannah Alpert and Liam Barham and Brian Freidin and Ian Tan and Alexandra Weiner},
  journal= {arXiv preprint arXiv:2309.11367},
  year   = {2026}
}

Comments

17 pages, 6 figures, 2 tables