Non-representable hyperbolic matroids

The generalized Lax conjecture asserts that each hyperbolicity cone is a linear slice of the cone of positive semidefinite matrices. Hyperbolic polynomials give rise to a class of (hyperbolic) matroids which properly contains the class of matroids representable over the complex numbers. This connect...

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Main Authors: Nima Amini, Petter Branden
Format: Article
Language:English
Published: Discrete Mathematics & Theoretical Computer Science 2020-04-01
Series:Discrete Mathematics & Theoretical Computer Science
Subjects:
Online Access:https://dmtcs.episciences.org/6328/pdf
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author Nima Amini
Petter Branden
author_facet Nima Amini
Petter Branden
author_sort Nima Amini
collection DOAJ
description The generalized Lax conjecture asserts that each hyperbolicity cone is a linear slice of the cone of positive semidefinite matrices. Hyperbolic polynomials give rise to a class of (hyperbolic) matroids which properly contains the class of matroids representable over the complex numbers. This connection was used by the first author to construct counterexamples to algebraic (stronger) versions of the generalized Lax conjecture by considering a non- representable hyperbolic matroid. The Va ́mos matroid and a generalization of it are to this day the only known instances of non-representable hyperbolic matroids. We prove that the Non-Pappus and Non-Desargues matroids are non-representable hyperbolic matroids by exploiting a connection, due to Jordan, between Euclidean Jordan algebras and projective geometries. We further identify a large class of hyperbolic matroids that are parametrized by uniform hypergraphs and prove that many of them are non-representable. Finally we explore consequences to algebraic versions of the generalized Lax conjecture.
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spelling doaj.art-440d22e29abe4f3cb71143298a6fc6a92024-03-07T14:55:20ZengDiscrete Mathematics & Theoretical Computer ScienceDiscrete Mathematics & Theoretical Computer Science1365-80502020-04-01DMTCS Proceedings, 28th...10.46298/dmtcs.63286328Non-representable hyperbolic matroidsNima Amini0https://orcid.org/0000-0002-2305-9764Petter Branden1Department of MathematicsDepartment of MathematicsThe generalized Lax conjecture asserts that each hyperbolicity cone is a linear slice of the cone of positive semidefinite matrices. Hyperbolic polynomials give rise to a class of (hyperbolic) matroids which properly contains the class of matroids representable over the complex numbers. This connection was used by the first author to construct counterexamples to algebraic (stronger) versions of the generalized Lax conjecture by considering a non- representable hyperbolic matroid. The Va ́mos matroid and a generalization of it are to this day the only known instances of non-representable hyperbolic matroids. We prove that the Non-Pappus and Non-Desargues matroids are non-representable hyperbolic matroids by exploiting a connection, due to Jordan, between Euclidean Jordan algebras and projective geometries. We further identify a large class of hyperbolic matroids that are parametrized by uniform hypergraphs and prove that many of them are non-representable. Finally we explore consequences to algebraic versions of the generalized Lax conjecture.https://dmtcs.episciences.org/6328/pdf[math.math-co]mathematics [math]/combinatorics [math.co]
spellingShingle Nima Amini
Petter Branden
Non-representable hyperbolic matroids
Discrete Mathematics & Theoretical Computer Science
[math.math-co]mathematics [math]/combinatorics [math.co]
title Non-representable hyperbolic matroids
title_full Non-representable hyperbolic matroids
title_fullStr Non-representable hyperbolic matroids
title_full_unstemmed Non-representable hyperbolic matroids
title_short Non-representable hyperbolic matroids
title_sort non representable hyperbolic matroids
topic [math.math-co]mathematics [math]/combinatorics [math.co]
url https://dmtcs.episciences.org/6328/pdf
work_keys_str_mv AT nimaamini nonrepresentablehyperbolicmatroids
AT petterbranden nonrepresentablehyperbolicmatroids