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We present a comprehensive overview of Ardila and Develin's (generic) tropical oriented matroids, as well as many related objects and their axiomatics. Moreover, we use a unifying framework that elucidates the connections between these…

Combinatorics · Mathematics 2026-01-09 Yuan Yao

It is possible to write the indicator function of any matroid polytope as an integer combination of indicator functions of Schubert matroid polytopes. In this way, every matroid on $n$ elements of rank $r$ can be thought of as a lattice…

Combinatorics · Mathematics 2025-08-14 Luis Ferroni , Alex Fink

The spinor variety is cut out by the quadratic Wick relations among the principal Pfaffians of an n x n skew-symmetric matrix. Its points correspond to n-dimensional isotropic subspaces of a 2n-dimensional vector space. In this paper we…

Combinatorics · Mathematics 2013-03-07 Felipe Rincón

We compute the rational Borel-Moore homology groups for affine determinantal varieties in the spaces of general, symmetric, and skew-symmetric matrices, solving a problem suggested by the work of Pragacz and Ratajski. The main ingredient is…

Algebraic Geometry · Mathematics 2021-11-09 András C. Lőrincz , Claudiu Raicu

In this paper we address two of the major foundational questions in the theory of matroids over rings. First, we provide a cryptomorphic axiomatisation, by introducing an analogue of the base polytope for matroids. Second, we describe a…

Combinatorics · Mathematics 2017-08-02 Alex Fink , Luca Moci

We give a simple characterization of all perfectoid profinite \'{e}tale covers of abelian varieties in terms of the Hodge-Tate filtration on the $p$-adic Tate module. We also compute the geometric Sen morphism for all profinite $p$-adic Lie…

Number Theory · Mathematics 2025-01-08 Rebecca Bellovin , Hanlin Cai , Sean Howe , Tongmu He

A class of matroids is introduced which is very large as it strictly contains all paving matroids as special cases. As their key feature these split matroids can be studied via techniques from polyhedral geometry. It turns out that the…

Combinatorics · Mathematics 2018-07-02 Michael Joswig , Benjamin Schröter

We study a graded vector space of polynomials associated to a square matrix, defined by a finite difference condition along the rows. We show this space coincides with one defined by directional derivatives, and prove it is…

Combinatorics · Mathematics 2026-05-05 Tristram Bogart , Federico Castillo , Damián de la Fuente , David Plaza

We compute the cohomology ring of the complement of a toric arrangement with integer coefficients and investigate its dependency from the arrangement's combinatorial data. To this end, we study a morphism of spectral sequences associated to…

Algebraic Topology · Mathematics 2015-06-22 Filippo Callegaro , Emanuele Delucchi

We present an unexpected application of tropical convexity to the determination of invariants for linear systems of differential equations. We show that the classical G\'erard-Levelt lattice saturation procedure can be geometrically…

Classical Analysis and ODEs · Mathematics 2012-01-13 Eduardo Corel

We extend our generic rigidity theory for periodic frameworks in the plane to frameworks with a broader class of crystallographic symmetry. Along the way we introduce a new class of combinatorial matroids and associated linear…

Geometric Topology · Mathematics 2015-03-19 Justin Malestein , Louis Theran

We prove that the quantum DT invariants associated to quivers with genteel potential can be expressed in terms of certain refined counts of tropical disks. This is based on a quantum version of Bridgeland's description of cluster scattering…

Algebraic Geometry · Mathematics 2020-07-30 Man-Wai Cheung , Travis Mandel

We introduce and study the notion of the $G$-Tutte polynomial for a list $\mathcal{A}$ of elements in a finitely generated abelian group $\Gamma$ and an abelian group $G$, which is defined by counting the number of homomorphisms from…

Combinatorics · Mathematics 2021-09-03 Ye Liu , Tan Nhat Tran , Masahiko Yoshinaga

The Rota--Heron--Welsh conjecture (now a theorem of Adiprasito, Huh, and the author) asserts the log-concavity of the characteristic polynomial of matroids. We give an exposition of the Lorentzian polynomial proof following the work of…

Combinatorics · Mathematics 2025-08-13 Eric Katz

We define and study "semimatroids", a class of objects which abstracts the dependence properties of an affine hyperplane arrangement. We show that geometric semilattices are precisely the posets of flats of semimatroids. We define and…

Combinatorics · Mathematics 2007-05-23 Federico Ardila

We investigate the combinatorics and geometry of permutation polytopes associated to cyclic permutation groups, i.e., the convex hulls of cyclic groups of permutation matrices. We give formulas for their dimension and vertex degree. In the…

Combinatorics · Mathematics 2011-09-02 Barbara Baumeister , Christian Haase , Benjamin Nill , Andreas Paffenholz

The "2-variable general-$\lambda$-matrix polynomials (2VG$\lambda$MP)" is a new family of matrix polynomials, introduced and studied in this article. These matrix polynomials are constructed using umbral and symbolic methods. We delve into…

Classical Analysis and ODEs · Mathematics 2024-12-03 Ghazala Yasmin , Aditi Sharma

Many combinatorial and topological invariants of a hyperplane arrangement can be computed in terms of its Tutte polynomial. Similarly, many invariants of a hypertoric arrangement can be computed in terms of its arithmetic Tutte polynomial.…

Combinatorics · Mathematics 2013-05-30 Federico Ardila , Federico Castillo , Michael Henley

We show that the linear coefficient of the Ehrhart polynomial of a matroid base polytope evaluated at $t-1$ is equal to, up to normalization, the $\beta$-invariant of the matroid. This yields a lattice-point counting formula for the…

In this paper we study general tropical linear spaces locally: For any basis B of the matroid underlying a tropical linear space L, we define the local tropical linear space L_B to be the subcomplex of L consisting of all vectors v that…

Combinatorics · Mathematics 2013-10-14 Felipe Rincón