Cycle Matroids of Graphings: From Convergence to Duality

Fuente: arXiv
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Autores principales: Bérczi, Kristóf, Borbényi, Márton, Lovász, László, Tóth, László Márton
Formato: Preprint
Publicado: 2024
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author Bérczi, Kristóf
Borbényi, Márton
Lovász, László
Tóth, László Márton
author_facet Bérczi, Kristóf
Borbényi, Márton
Lovász, László
Tóth, László Márton
contents A recent line of research has concentrated on exploring the links between analytic and combinatorial theories of submodularity, uncovering several key connections between them. In this context, Lovász initiated the study of matroids from an analytic point of view and introduced the cycle matroid of a graphing. Motivated by the limit theory of graphs, the authors introduced a form of right-convergence, called quotient-convergence, for a sequence of submodular setfunctions, leading to a notion of convergence for matroids through their rank functions. In this paper, we study the connection between local-global convergence of graphs and quotient-convergence of their cycle matroids. We characterize the exposed points of associated convex sets, forming an analytic counterpart of matroid independence- and base-polytopes. Finally, we consider dual planar graphings and show that the cycle matroid of one is the cocycle matroid of its dual if and only if the underlying graphings are hyperfinite.
format Preprint
id arxiv_https___arxiv_org_abs_2406_08945
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Cycle Matroids of Graphings: From Convergence to Duality
Bérczi, Kristóf
Borbényi, Márton
Lovász, László
Tóth, László Márton
Combinatorics
A recent line of research has concentrated on exploring the links between analytic and combinatorial theories of submodularity, uncovering several key connections between them. In this context, Lovász initiated the study of matroids from an analytic point of view and introduced the cycle matroid of a graphing. Motivated by the limit theory of graphs, the authors introduced a form of right-convergence, called quotient-convergence, for a sequence of submodular setfunctions, leading to a notion of convergence for matroids through their rank functions. In this paper, we study the connection between local-global convergence of graphs and quotient-convergence of their cycle matroids. We characterize the exposed points of associated convex sets, forming an analytic counterpart of matroid independence- and base-polytopes. Finally, we consider dual planar graphings and show that the cycle matroid of one is the cocycle matroid of its dual if and only if the underlying graphings are hyperfinite.
title Cycle Matroids of Graphings: From Convergence to Duality
topic Combinatorics
url https://arxiv.org/abs/2406.08945