English

Counterexamples regarding linked and lean tree-decompositions of infinite graphs

Combinatorics 2025-07-17 v2

Abstract

Kriz and Thomas showed that every (finite or infinite) graph of tree-width kNk \in \mathbb{N} admits a lean tree-decomposition of width kk. We discuss a number of counterexamples demonstrating the limits of possible generalisations of their result to arbitrary infinite tree-width. In particular, we construct a locally finite, planar, connected graph that has no lean tree-decomposition.

Keywords

Cite

@article{arxiv.2405.06755,
  title  = {Counterexamples regarding linked and lean tree-decompositions of infinite graphs},
  author = {Sandra Albrechtsen and Raphael W. Jacobs and Paul Knappe and Max Pitz},
  journal= {arXiv preprint arXiv:2405.06755},
  year   = {2025}
}

Comments

Revision based on referee comments

R2 v1 2026-06-28T16:23:42.084Z