Polynomial Gyárfás-Sumner conjecture for graphs of bounded boxicity
James Davies, Yelena Yuditsky
TL;DR
For every $d$ and forest $F$, the authors prove that the class of box-intersection graphs in $\mathbb{R}^d$ with no induced $F$ subgraph is polynomially $\chi$-bounded. The method combines a directed-graph framework with $(k,m)$-gradings and calm copies to find path-induced copies of rooted trees, together with a decomposition by intersection patterns $\mathcal{P}_d$ to control chromatic number. They derive an explicit bound $\chi(G)\le (2rk^d\omega(G)^2)^{4^{d}}$ for graphs avoiding an induced $T_{r,k}$, by showing large chi implies a path-induced tree that leads to a contradiction. This work extends the Gyárfás–Sumner program to high-dimensional geometric intersection graphs, connects to Erdős–Hajnal properties, and identifies several open problems and a Pollyanna-type phenomenon for box graphs.
Abstract
We prove that for every positive integer $d$ and forest $F$, the class of intersection graphs of axis-aligned boxes in $\mathbb{R}^d$ with no induced $F$ subgraph is (polynomially) $χ$-bounded.
