English

Separating polynomial $\chi$-boundedness from $\chi$-boundedness

Combinatorics 2023-08-17 v2 Discrete Mathematics

Abstract

Extending the idea from the recent paper by Carbonero, Hompe, Moore, and Spirkl, for every function f ⁣:NN{}f\colon\mathbb{N}\to\mathbb{N}\cup\{\infty\} with f(1)=1f(1)=1 and f(n)(3n+13)f(n)\geq\binom{3n+1}{3}, we construct a hereditary class of graphs G\mathcal{G} such that the maximum chromatic number of a graph in G\mathcal{G} with clique number nn is equal to f(n)f(n) for every nNn\in\mathbb{N}. In particular, we prove that there exist hereditary classes of graphs that are χ\chi-bounded but not polynomially χ\chi-bounded.

Keywords

Cite

@article{arxiv.2201.08814,
  title  = {Separating polynomial $\chi$-boundedness from $\chi$-boundedness},
  author = {Marcin Briański and James Davies and Bartosz Walczak},
  journal= {arXiv preprint arXiv:2201.08814},
  year   = {2023}
}

Comments

v2: new proof with improved results

R2 v1 2026-06-24T08:58:01.552Z