Generalized spikes with circuits and cocircuits of different cardinalities

Fuente: arXiv
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Auteurs principaux: Brettell, Nick, Grace, Kevin
Format: Preprint
Publié: 2022
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author Brettell, Nick
Grace, Kevin
author_facet Brettell, Nick
Grace, Kevin
contents We consider matroids with the property that every subset of the ground set of size $s$ is contained in a $2s$-element circuit and every subset of size $t$ is contained in a $2t$-element cocircuit. We say that such a matroid has the \emph{$(s,2s,t,2t)$-property}. A matroid is an \emph{$(s,t)$-spike} if there is a partition of the ground set into pairs such that the union of any $s$ pairs is a circuit and the union of any $t$ pairs is a cocircuit. Our main result is that all sufficiently large matroids with the $(s,2s,t,2t)$-property are $(s,t)$-spikes, generalizing a 2019 result that proved the case where $s=t$. We also present some properties of $(s,t)$-spikes.
format Preprint
id arxiv_https___arxiv_org_abs_2209_14524
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Generalized spikes with circuits and cocircuits of different cardinalities
Brettell, Nick
Grace, Kevin
Combinatorics
05B35
We consider matroids with the property that every subset of the ground set of size $s$ is contained in a $2s$-element circuit and every subset of size $t$ is contained in a $2t$-element cocircuit. We say that such a matroid has the \emph{$(s,2s,t,2t)$-property}. A matroid is an \emph{$(s,t)$-spike} if there is a partition of the ground set into pairs such that the union of any $s$ pairs is a circuit and the union of any $t$ pairs is a cocircuit. Our main result is that all sufficiently large matroids with the $(s,2s,t,2t)$-property are $(s,t)$-spikes, generalizing a 2019 result that proved the case where $s=t$. We also present some properties of $(s,t)$-spikes.
title Generalized spikes with circuits and cocircuits of different cardinalities
topic Combinatorics
05B35
url https://arxiv.org/abs/2209.14524