English

Chromatic Nim finds a game for your solution

Combinatorics 2016-02-26 v2

Abstract

We play a variation of Nim on stacks of tokens. Take your favorite increasing sequence of positive integers and color the tokens according to the following rule. Each token on a level that corresponds to a number in the sequence is colored red; if the level does not correspond to a number in the sequence, color it green. Now play Nim on a arbitrary number of stacks with the extra rule: if all top tokens are green, then you can make any move you like. On two stacks, we give explicit characterizations for winning the normal play version for some popular sequences, such as Beatty sequences and the evil numbers corresponding to the 0s in the famous Thue-Morse sequence. We also propose a more general solution which depends only on which of the colors `dominates' the sequence. Our construction resolves a problem posed by Fraenkel at the BIRS 2011 workshop in combinatorial games.

Keywords

Cite

@article{arxiv.1601.03034,
  title  = {Chromatic Nim finds a game for your solution},
  author = {Michael Fisher and Urban Larsson},
  journal= {arXiv preprint arXiv:1601.03034},
  year   = {2016}
}

Comments

18 pages, 2 figures

R2 v1 2026-06-22T12:28:10.173Z