English

Strong Ramsey game on two boards

Combinatorics 2025-01-28 v2

Abstract

The strong Ramsey game R(B,H)R(\mathcal{B}, H) is a two-player game played on a graph B\mathcal{B}, referred to as the board, with a target graph HH. In this game, two players, P1P_1 and P2P_2, alternately claim unclaimed edges of B\mathcal{B}, starting with P1P_1. The goal is to claim a subgraph isomorphic to HH, with the first player achieving this declared the winner. A fundamental open question, persisting for over three decades, asks whether there exists a graph HH such that in the game R(Kn,H)R(K_n, H), P1P_1 does not have a winning strategy in a bounded number of moves as nn \to \infty. In this paper, we shift the focus to the variant R(KnKn,H)R(K_n \sqcup K_n, H), introduced by David, Hartarsky, and Tiba, where the board KnKnK_n \sqcup K_n consists of two disjoint copies of KnK_n. We prove that there exist infinitely many graphs HH such that P1P_1 cannot win in R(KnKn,H)R(K_n \sqcup K_n, H) within a bounded number of moves through a concise proof. This perhaps provides evidence for the existence of examples to the above longstanding open problem.

Keywords

Cite

@article{arxiv.2501.06830,
  title  = {Strong Ramsey game on two boards},
  author = {Jiangdong Ai and Jun Gao and Zixiang Xu and Xin Yan},
  journal= {arXiv preprint arXiv:2501.06830},
  year   = {2025}
}

Comments

12 pages

R2 v1 2026-06-28T21:03:55.181Z