English

Borel Kernels in Borel Directed Graphs

Logic 2026-05-27 v2 Combinatorics

Abstract

We prove that there is a Borel quasi-kernel in any locally countable Borel directed graph with finite Borel chromatic number. We prove that the Borel chromatic number of a Borel directed graph with bounded out-degree nn is either infinite or less than or equal to (n+1)(n+2)2\frac{(n+1)(n+2)}{2}. This is an alternative proof of Palamourdas' theorem.

Cite

@article{arxiv.2509.01948,
  title  = {Borel Kernels in Borel Directed Graphs},
  author = {Ruijun Wang},
  journal= {arXiv preprint arXiv:2509.01948},
  year   = {2026}
}

Comments

7 pages

R2 v1 2026-07-01T05:16:38.307Z