A note on embracing exchange sequences in oriented matroids

Fuente: arXiv
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Autores principales: Bérczi, Kristóf, Nádor, Benedek
Formato: Preprint
Publicado: 2025
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author Bérczi, Kristóf
Nádor, Benedek
author_facet Bérczi, Kristóf
Nádor, Benedek
contents An open problem in convex geometry asks whether two simplices $A,B\subseteq\mathbb{R}^d$, both containing the origin in their convex hulls, admit a polynomial-length sequence of vertex exchanges transforming $A$ into $B$ while maintaining the origin in the convex hull throughout. We propose a matroidal generalization of the problem to oriented matroids, concerning exchange sequences between bases under sign constraints on elements appearing in certain fundamental circuits. We formulate a conjecture on the minimum length of such a sequence, and prove it for oriented graphic matroids of directed graphs. We also study connections between our conjecture and several long-standing open problems on exchange sequences between pairs of bases in unoriented matroids.
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id arxiv_https___arxiv_org_abs_2511_14526
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A note on embracing exchange sequences in oriented matroids
Bérczi, Kristóf
Nádor, Benedek
Combinatorics
Discrete Mathematics
An open problem in convex geometry asks whether two simplices $A,B\subseteq\mathbb{R}^d$, both containing the origin in their convex hulls, admit a polynomial-length sequence of vertex exchanges transforming $A$ into $B$ while maintaining the origin in the convex hull throughout. We propose a matroidal generalization of the problem to oriented matroids, concerning exchange sequences between bases under sign constraints on elements appearing in certain fundamental circuits. We formulate a conjecture on the minimum length of such a sequence, and prove it for oriented graphic matroids of directed graphs. We also study connections between our conjecture and several long-standing open problems on exchange sequences between pairs of bases in unoriented matroids.
title A note on embracing exchange sequences in oriented matroids
topic Combinatorics
Discrete Mathematics
url https://arxiv.org/abs/2511.14526