Counterexample to the conjectured coarse grid theorem
Combinatorics
2026-02-25 v2 Metric Geometry
Abstract
We show that for every there exists a graph that does not contain the -grid as a -fat minor and is not -quasi-isometric to a graph with no minor. This refutes the conjectured coarse grid theorem by Georgakopoulos and Papasoglu and the weak fat minor conjecture of Davies, Hickingbotham, Illingworth, and McCarty. Our construction is a slight modification of the recent counterexample to the weak coarse Menger conjecture from Nguyen, Scott and Seymour. We further modify the construction to show that there are planar graphs that do not have the coarse Erd\H{o}s-P\'{o}sa property.
Keywords
Cite
@article{arxiv.2508.15342,
title = {Counterexample to the conjectured coarse grid theorem},
author = {Sandra Albrechtsen and James Davies},
journal= {arXiv preprint arXiv:2508.15342},
year = {2026}
}
Comments
Added a counterexample showing that not every planar graph has the coarse Erd\H{o}s-P\'{o}sa property