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We utilize the coherent-constructible correspondence to construct full strongly exceptional collections of nef line bundles in the derived category of a toric variety through the combinatorics of constructible sheaves built from polytopes.…

Algebraic Geometry · Mathematics 2023-11-08 Mario Sanchez

We study an operation in matroid theory that allows one to transition a given matroid into another with more bases via relaxing a \emph{stressed subset}. This framework provides a new combinatorial characterization of the class of split…

Combinatorics · Mathematics 2024-09-12 Luis Ferroni , Benjamin Schröter

Extending work of Bielawski-Dancer and Konno, we develop a theory of toric hyperkahler varieties, which involves toric geometry, matroid theory and convex polyhedra. The framework is a detailed study of semi-projective toric varieties,…

Algebraic Geometry · Mathematics 2007-05-23 Tamas Hausel , Bernd Sturmfels

We introduce the notion of a categorical valuative invariant of polyhedra or matroids, in which alternating sums of numerical invariants are replaced by split exact sequences in an additive category. We provide categorical lifts of a number…

Combinatorics · Mathematics 2024-10-23 Ben Elias , Dane Miyata , Nicholas Proudfoot , Lorenzo Vecchi

The Chow ring of a matroid (or more generally, atomic latice) is an invariant whose importance was demonstrated by Adiprasito, Huh and Katz, who used it to resolve the long-standing Heron-Rota-Welsh conjecture. Here, we make a detailed…

Combinatorics · Mathematics 2023-11-16 Thomas Hameister , Sujit Rao , Connor Simpson

Each point $x$ in Gr$(r,n)$ corresponds to an $r \times n$ matrix $A_x$ which gives rise to a matroid $M_x$ on its columns. Gel'fand, Goresky, MacPherson, and Serganova showed that the sets $\{y \in \mathrm{Gr}(r,n) | M_y = M_x\}$ form a…

Algebraic Geometry · Mathematics 2020-07-03 Jessica Sidman , Will Traves , Ashley Wheeler

We use techniques from Gromov-Witten theory to construct new invariants of matroids taking value in the Chow groups of spaces of rational curves in the permutohedral toric variety. When the matroid is realizable by a complex hyperplane…

Algebraic Geometry · Mathematics 2022-05-03 Dhruv Ranganathan , Jeremy Usatine

We study paving matroids, their realization spaces, and their closures, along with matroid varieties and circuit varieties. Within this context, we introduce three distinct methods for generating polynomials within the associated ideals of…

Algebraic Geometry · Mathematics 2026-03-24 Emiliano Liwski , Fatemeh Mohammadi

We introduce and investigate multivariate Tutte polynomials, dichromatic polynomials, subset-corank polynomials, size-corank polynomials, and rank generating polynomials of semimatroids, which generalize the corresponding polynomial…

Combinatorics · Mathematics 2025-08-04 Houshan Fu

Schubert varieties of hyperplane arrangements, also known as matroid Schubert varieties, play an essential role in the proof of the Dowling-Wilson conjecture and in Kazhdan-Lusztig theory for matroids. We study these varieties as…

Algebraic Geometry · Mathematics 2023-06-30 Colin Crowley

We develop the theory of matroids over one-dimensional algebraic groups, with special emphasis on positive characteristic. In particular, we compute the Lindstr\"om valuations and Frobenius flocks of such matroids. Building on work by Evans…

Combinatorics · Mathematics 2023-01-10 Guus P. Bollen , Dustin Cartwright , Jan Draisma

Morphisms of matroids are combinatorial abstractions of linear maps and graph homomorphisms. We introduce the notion of basis for morphisms of matroids, and show that its generating function is strongly log-concave. As a consequence, we…

Combinatorics · Mathematics 2020-04-02 Christopher Eur , June Huh

Chow rings of toric varieties, which originate in intersection theory, feature a rich combinatorial structure of independent interest. We survey four different ways of computing in these rings, due to Billera, Brion, Fulton--Sturmfels, and…

Combinatorics · Mathematics 2024-01-17 Federico Ardila-Mantilla

Matroid varieties are the closures in the Grassmannian of sets of points defined by specifying which Pl\"ucker coordinates vanish and which don't --- the set of nonvanishing Pl\"ucker coordinates forms a well-studied object called a…

Algebraic Geometry · Mathematics 2015-08-11 Nicolas Ford

Polymatroids are combinatorial abstractions of subspace arrangements in the same way that matroids are combinatorial abstractions of hyperplane arrangements. By introducing augmented Chow rings of polymatroids, modeled after augmented…

Algebraic Geometry · Mathematics 2023-09-01 Christopher Eur , Matt Larson

We extend the notion of representation of a matroid to algebraic structures that we call skew partial fields. Our definition of such representations extends Tutte's definition, using chain groups. We show how such representations behave…

Combinatorics · Mathematics 2012-12-12 R. A. Pendavingh , S. H. M. van Zwam

We generalize the Tutte polynomial of a matroid to a morphism of matroids via the K-theory of flag varieties. We introduce two different generalizations, and demonstrate that each has its own merits, where the trade-off is between the ease…

Combinatorics · Mathematics 2021-01-19 Rodica Dinu , Christopher Eur , Tim Seynnaeve

For any matroid $M$, we compute the Tutte polynomial $T_M(x,y)$ using the mixed intersection numbers of certain classes in the combinatorial Chow ring $A^\bullet(M)$ arising from hypersimplices. Using the mixed Hodge-Riemann relations, we…

Algebraic Geometry · Mathematics 2023-03-27 Andrew Berget , Hunter Spink , Dennis Tseng

Lop\'ez de Medrano-Rin\'con-Shaw defined Chern-Schwartz-MacPherson cycles for an arbitrary matroid $M$ and proved by an inductive geometric argument that the unsigned degrees of these cycles agree with the coefficients of $T(M;x,0)$, where…

Combinatorics · Mathematics 2022-07-21 Ahmed Umer Ashraf , Spencer Backman

Matroids give rise to several natural constructions of polytopes. Inspired by this, we examine polytopes that arise from the signed circuits of an oriented matroid. We give the dimensions of these polytopes arising from graphical oriented…

Combinatorics · Mathematics 2025-01-03 Laura Escobar , Jodi McWhirter