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Bibliographic Details
Main Authors: Campbell, Rutger, Davies, James, Hickingbotham, Robert
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2507.23182
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author Campbell, Rutger
Davies, James
Hickingbotham, Robert
author_facet Campbell, Rutger
Davies, James
Hickingbotham, Robert
contents We prove that for every bipartite graph $H$ and positive integer $s$, the class of $K_{s,s}$-subgraph-free graphs excluding $H$ as a pivot-minor has bounded average degree. Our proof relies on the announced binary matroid structure theorem of Geelen, Gerards, and Whittle. Along the way, we also prove that every $K_{s,t}$-free bipartite circle graph with $s\le t$ has a vertex of degree at most $\max\{2s-2, t-1\}$ and provide examples showing that this is tight.
format Preprint
id arxiv_https___arxiv_org_abs_2507_23182
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Binary matroids and degree-boundedness for pivot-minors
Campbell, Rutger
Davies, James
Hickingbotham, Robert
Combinatorics
We prove that for every bipartite graph $H$ and positive integer $s$, the class of $K_{s,s}$-subgraph-free graphs excluding $H$ as a pivot-minor has bounded average degree. Our proof relies on the announced binary matroid structure theorem of Geelen, Gerards, and Whittle. Along the way, we also prove that every $K_{s,t}$-free bipartite circle graph with $s\le t$ has a vertex of degree at most $\max\{2s-2, t-1\}$ and provide examples showing that this is tight.
title Binary matroids and degree-boundedness for pivot-minors
topic Combinatorics
url https://arxiv.org/abs/2507.23182