English

Polynomial bounds for chromatic number. I. Excluding a biclique and an induced tree

Combinatorics 2021-07-27 v2

Abstract

Let H be a tree. It was proved by Rodl that graphs that do not contain H as an induced subgraph, and do not contain the complete bipartite graph Kt,tK_{t,t} as a subgraph, have bounded chromatic number. Kierstead and Penrice strengthened this, showing that such graphs have bounded degeneracy. Here we give a further strengthening, proving that for every tree H, the degeneracy is at most polynomial in t. This answers a question of Bonamy, Pilipczuk, Rzazewski, Thomasse and Walczak.

Keywords

Cite

@article{arxiv.2104.07927,
  title  = {Polynomial bounds for chromatic number. I. Excluding a biclique and an induced tree},
  author = {Alex Scott and Paul Seymour and Sophie Spirkl},
  journal= {arXiv preprint arXiv:2104.07927},
  year   = {2021}
}