Extensions and Deletions of matroid classes closed under flats

Fuente: arXiv
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Main Authors: Singh, Jagdeep, Sivaraman, Vaidy
Format: Preprint
Published: 2024
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author Singh, Jagdeep
Sivaraman, Vaidy
author_facet Singh, Jagdeep
Sivaraman, Vaidy
contents We call a class of matroids hereditary if it is closed under restriction to flats. For a hereditary class $\mathcal{M}$, its extension class consists of all matroids in $\mathcal{M}$ together with their single-element extensions. The deletion class consists of all matroids in $\mathcal{M}$ along with their single-element deletions. We prove that if $\mathcal{M}$ has finitely many forbidden flats, then the forbidden flats for its extension class have bounded rank. For $GF(q)$-representable matroids where $q$ is in $\{2,3\}$, we exploit correspondence with $2$-colorings of projective geometries to establish the analogous result for the deletion class. We also note the consequences for hereditary classes of graphs, discussing the interplay of graphs and matroids.
format Preprint
id arxiv_https___arxiv_org_abs_2403_15496
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Extensions and Deletions of matroid classes closed under flats
Singh, Jagdeep
Sivaraman, Vaidy
Combinatorics
05C75, 05B35
We call a class of matroids hereditary if it is closed under restriction to flats. For a hereditary class $\mathcal{M}$, its extension class consists of all matroids in $\mathcal{M}$ together with their single-element extensions. The deletion class consists of all matroids in $\mathcal{M}$ along with their single-element deletions. We prove that if $\mathcal{M}$ has finitely many forbidden flats, then the forbidden flats for its extension class have bounded rank. For $GF(q)$-representable matroids where $q$ is in $\{2,3\}$, we exploit correspondence with $2$-colorings of projective geometries to establish the analogous result for the deletion class. We also note the consequences for hereditary classes of graphs, discussing the interplay of graphs and matroids.
title Extensions and Deletions of matroid classes closed under flats
topic Combinatorics
05C75, 05B35
url https://arxiv.org/abs/2403.15496