Faithful universal graphs for minor-closed classes

Fuente: arXiv
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Main Authors: Bastide, Paul, Esperet, Louis, Groenland, Carla, Hilaire, Claire, Rambaud, Clément, Wesolek, Alexandra
Format: Preprint
Published: 2025
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author Bastide, Paul
Esperet, Louis
Groenland, Carla
Hilaire, Claire
Rambaud, Clément
Wesolek, Alexandra
author_facet Bastide, Paul
Esperet, Louis
Groenland, Carla
Hilaire, Claire
Rambaud, Clément
Wesolek, Alexandra
contents It was proved by Huynh, Mohar, Šámal, Thomassen and Wood in 2021 that any countable graph containing every countable planar graph as a subgraph has an infinite clique minor. We prove a finite, quantitative version of this result: for fixed $t$, if a graph $G$ is $K_t$-minor-free and contains every $n$-vertex planar graph as a subgraph, then $G$ has $2^{Ω(n)}$ vertices. On the other hand, we construct a polynomial size $K_4$-minor-free graph containing every $n$-vertex tree as an induced subgraph, and a polynomial size $K_7$-minor-free graph containing every $n$-vertex $K_4$-minor-free graph as induced subgraph. This answers several problems raised recently by Bergold, Iršič, Lauff, Orthaber, Scheucher and Wesolek. We study more generally the order of universal graphs for various classes (of graphs of bounded degree, treedepth, pathwidth, or treewidth), if the universal graphs retain some of the structure of the original class.
format Preprint
id arxiv_https___arxiv_org_abs_2504_19582
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Faithful universal graphs for minor-closed classes
Bastide, Paul
Esperet, Louis
Groenland, Carla
Hilaire, Claire
Rambaud, Clément
Wesolek, Alexandra
Combinatorics
Data Structures and Algorithms
It was proved by Huynh, Mohar, Šámal, Thomassen and Wood in 2021 that any countable graph containing every countable planar graph as a subgraph has an infinite clique minor. We prove a finite, quantitative version of this result: for fixed $t$, if a graph $G$ is $K_t$-minor-free and contains every $n$-vertex planar graph as a subgraph, then $G$ has $2^{Ω(n)}$ vertices. On the other hand, we construct a polynomial size $K_4$-minor-free graph containing every $n$-vertex tree as an induced subgraph, and a polynomial size $K_7$-minor-free graph containing every $n$-vertex $K_4$-minor-free graph as induced subgraph. This answers several problems raised recently by Bergold, Iršič, Lauff, Orthaber, Scheucher and Wesolek. We study more generally the order of universal graphs for various classes (of graphs of bounded degree, treedepth, pathwidth, or treewidth), if the universal graphs retain some of the structure of the original class.
title Faithful universal graphs for minor-closed classes
topic Combinatorics
Data Structures and Algorithms
url https://arxiv.org/abs/2504.19582