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We construct the moduli space of finite dimensional representations of generalized quivers for arbitrary connected complex reductive groups using Geometric Invariant Theory as well as Symplectic reduction methods. We explicit characterize…

Algebraic Geometry · Mathematics 2017-03-31 Artur de Araujo

The Chow polynomial of a matroid is a fundamental invariant whose coefficients exhibit strong positivity properties, including $\gamma$-positivity. We interpret the normalized Chow coefficients as a probability distribution and establish…

Combinatorics · Mathematics 2026-04-30 Ronnie Cheng , Wangyang Lin

We introduce and develop the theory of UMEL-shellable posets. These are posets equipped with an edge-lexicographical labeling satisfying certain uniformity and monotonicity properties. This framework encompasses classical families of…

Combinatorics · Mathematics 2025-12-22 Basile Coron , Luis Ferroni , Shiyue Li

In the first part of the paper, we clarify the connections between several algebraic objects appearing in matroid theory: both partial fields and hyperfields are fuzzy rings, fuzzy rings are tracts, and these relations are compatible with…

Algebraic Geometry · Mathematics 2021-06-29 Matthew Baker , Oliver Lorscheid

After recalling several constructions of the moduli space of curves of genus zero by different people we give our alternative construction of the moduli space. This gives a simple description of the intersection ring of this space. We give…

Algebraic Geometry · Mathematics 2017-05-05 Mehdi Tavakol

Inside a product of projective spaces, we try to understand which Chow classes come from irreducible subvarieties. The answer is closely related to the theory of integer polymatroids. The support of a representable class can be (partially)…

Algebraic Geometry · Mathematics 2020-05-20 Federico Castillo , Binglin Li , Naizhen Zhang

We study an infinite class of sequences of sparse polynomials that have binomial coefficients both as exponents and as coefficients. This generalizes a sequence of sparse polynomials which arises in a natural way as graph theoretic…

Classical Analysis and ODEs · Mathematics 2020-08-05 Karl Dilcher , Maciej Ulas

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

We define tropical Psi-classes on the moduli space of rational tropical curves in R^2 and consider intersection products of Psi-classes and pull-backs of evaluations on this space. We show a certain WDVV equation which is sufficient to…

Algebraic Geometry · Mathematics 2009-11-29 Hannah Markwig , Johannes Rau

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

We introduce the minor-closed, dual-closed class of multi-path matroids. We give a polynomial-time algorithm for computing the Tutte polynomial of a multi-path matroid, we describe their basis activities, and we prove some basic structural…

Combinatorics · Mathematics 2024-08-07 Joseph E. Bonin , Omer Gimenez

We prove two dual recursive decompositions as a graded $\underline{\mathrm{CH}}(M)\otimes \underline{\mathrm{CH}}(N)$-module of the Chow ring $\underline{\mathrm{CH}}(M\oplus N)$ of the direct sum of matroids. We use this to obtain a…

Algebraic Geometry · Mathematics 2025-11-17 Paweł Pielasa

The Tamari lattice and the associahedron provide methods of measuring associativity on a line. The real moduli space of marked curves captures the space of such associativity. We consider a natural generalization by considering the moduli…

Algebraic Topology · Mathematics 2015-06-16 Satyan L. Devadoss , Benjamin Fehrman , Timothy Heath , Aditi Vashist

We introduce the Z-polynomial of a matroid, which we define in terms of the Kazhdan-Lusztig polynomial. We then exploit a symmetry of the Z-polynomial to derive a new recursion for Kazhdan-Lusztig coefficients. We solve this recursion,…

Combinatorics · Mathematics 2017-06-20 Nicholas Proudfoot , Ben Young , Yuan Xu

We introduce the intersection cohomology module of a matroid and prove that it satisfies Poincar\'e duality, the hard Lefschetz theorem, and the Hodge-Riemann relations. As applications, we obtain proofs of Dowling and Wilson's Top-Heavy…

Combinatorics · Mathematics 2023-04-11 Tom Braden , June Huh , Jacob P. Matherne , Nicholas Proudfoot , Botong Wang

In this paper, we study positroids and its overlap with two classes of matroids: transversal and paving matroids. We exhibit a new class of fundamental transversal matroids and classify the Le-diagram for rank two transversal positroids. We…

Combinatorics · Mathematics 2024-07-29 John Machacek , George D. Nasr

We describe the point class and Todd class in the Chow ring of a quiver moduli space, building on a result of Ellingsrud-Str{\o}mme. This, together with the presentation of the Chow ring by the second author, makes it possible to compute…

Algebraic Geometry · Mathematics 2023-08-22 Pieter Belmans , Hans Franzen

The Chow class of the closure of the torus orbit of a point in a Grassmannian only depends on the matroid associated to the point. The Chow class can be extended to a matroid invariant of arbitrary matroids. We call the coefficients…

Combinatorics · Mathematics 2025-04-08 Jon Pål Hamre

Moduli spaces of algebraic curves and closely related to them Hurwitz spaces, that is, spaces of meromorphic functions on the curves, arise naturally in numerous problems of algebraic geometry and mathematical physics, especially in…

Algebraic Geometry · Mathematics 2015-06-26 M. E. Kazaryan , S. K. Lando

Motivated by the $Z$-polynomials of matroids, Ferroni, Matherne, Stevens, and Vecchi introduced the inverse $Z$-polynomial of a matroid. In this paper, we prove several fundamental properties of the inverse $Z$-polynomial, including…

Combinatorics · Mathematics 2025-07-03 Alice L. L. Gao , Xuan Ruan , Matthew H. Y. Xie