Pathographs and some (un)decidability results
Abstract
We introduce pathographs as a framework to study graph classes defined by forbidden structures, including forbidding induced subgraphs, minors, etc. Pathographs approximately generalize s-graphs of L\'ev\^eque--Lin--Maffray--Trotignon by the addition of two extra adjacency relations: one between subdivisible edges and vertices called spokes, and one between pairs of subdivisible edges called rungs. We consider the following decision problem: given a pathograph and a finite set of pathographs , is there an -free realization of ? This may be regarded as a generalization of the "graph class containment problem": given two graph classes and , is it the case that ? We prove the pathograph realization problem is undecidable in general, but it is decidable in the case that has no rungs (but may have spokes), or if is closed under adding edges, spokes, and rungs. We also discuss some potential applications to proving decomposition theorems.
Cite
@article{arxiv.2505.19871,
title = {Pathographs and some (un)decidability results},
author = {Daniel Carter and Nicolas Trotignon},
journal= {arXiv preprint arXiv:2505.19871},
year = {2025}
}
Comments
30 pages, 13 figures