Signed permutohedra, delta‐matroids, and beyond

We establish a connection between the algebraic geometry of the type B$B$ permutohedral toric variety and the combinatorics of delta‐matroids. Using this connection, we compute the volume and lattice point counts of type B$B$ generalized permutohedra. Applying tropical Hodge theory to a new framewor...

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Bibliographic Details
Published in:Proceedings of the London Mathematical Society Vol. 128; no. 3
Main Authors: Eur, Christopher, Fink, Alex, Larson, Matt, Spink, Hunter
Format: Journal Article
Language:English
Published: 01-03-2024
Online Access:Get full text
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Summary:We establish a connection between the algebraic geometry of the type B$B$ permutohedral toric variety and the combinatorics of delta‐matroids. Using this connection, we compute the volume and lattice point counts of type B$B$ generalized permutohedra. Applying tropical Hodge theory to a new framework of “tautological classes of delta‐matroids,” modeled after certain vector bundles associated to realizable delta‐matroids, we establish the log‐concavity of a Tutte‐like invariant for a broad family of delta‐matroids that includes all realizable delta‐matroids. Our results include new log‐concavity statements for all (ordinary) matroids as special cases.
ISSN:0024-6115
1460-244X
DOI:10.1112/plms.12592