English

The continuous oriented chromatic number of directed Schreier graphs of \(\mathbb Z^2\)-shift actions

Logic 2026-07-01 v1 Combinatorics

Abstract

Let F(2Z2)\vec F(2^{\mathbb Z^2}) be the directed Schreier graph on the free part of the Bernoulli shift Z22Z2\mathbb Z^2\curvearrowright 2^{\mathbb Z^2}, with arcs in the two coordinate directions. We prove that the continuous oriented chromatic number of it is 7, that is, there is a tournament on 7 vertices receiving a continuous graph homomorphism from F(2Z2)\vec F(2^{\mathbb Z^2}) and there is no continuous graph homomorphism from F(2Z2)\vec F(2^{\mathbb Z^2}) to any tournament on 6 vertices.

Keywords

Cite

@article{arxiv.2607.00367,
  title  = {The continuous oriented chromatic number of directed Schreier graphs of \(\mathbb Z^2\)-shift actions},
  author = {Ruijun Wang},
  journal= {arXiv preprint arXiv:2607.00367},
  year   = {2026}
}

Comments

19 pages