English

Various Diamond Properties in Combinatorial Game Theory

Combinatorics 2025-12-30 v2

Abstract

We investigate conditions under which positions in combinatorial games admit simple values. We introduce a unified diamond framework, the A\Diamond_A-property (A{Z,DA\in\{\mathbb{Z},\mathbb{D}), for sets of positions closed under options. Under certain conditions, this framework guarantees that all values are integers, dyadic rationals, or pairs {mn}\{m|n\} (on Z\mathbb{Z} or D\mathbb{D}). As an application, we establish that every position in \textsc{Yashima} game on bipartite graphs has an integer pair value.

Keywords

Cite

@article{arxiv.2509.21744,
  title  = {Various Diamond Properties in Combinatorial Game Theory},
  author = {Keiichirou Kusakari and Tomoaki Abuku},
  journal= {arXiv preprint arXiv:2509.21744},
  year   = {2025}
}
R2 v1 2026-07-01T05:57:32.739Z