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In this paper we give a necessary and sufficient criterion for representability of a matroid over an algebraic closed field. This leads to an algorithm, based on an extension of Groebner Bases, in order to decide if a given matroid is…

Combinatorics · Mathematics 2007-05-23 Massimiliano Lunelli , Antonio Laface

We provide a complete axiomatization of modal inclusion logic - team-based modal logic extended with inclusion atoms. We review and refine an expressive completeness and normal form theorem for the logic, define a natural deduction proof…

Logic · Mathematics 2025-03-13 Aleksi Anttila , Matilda Häggblom , Fan Yang

In this paper we extend the theory of oriented matroids to Lagrangian orthogonal matroids and their representations, and give a completely natural transformation from a representation of a classical oriented matroid to a representation of…

Combinatorics · Mathematics 2007-05-23 Richard F. Booth

We study rank-three matroids, known as point-line configurations, and their associated matroid varieties, defined as the Zariski closures of their realization spaces. Our focus is on determining finite generating sets of defining equations…

Combinatorics · Mathematics 2025-06-10 Emiliano Liwski , Fatemeh Mohammadi , Lisa Vandebrouck

We characterize a rich class of valuated matroids, called R-minor valuated matroids that includes the indicator functions of matroids, and is closed under operations such as taking minors, duality, and induction by network. We exhibit a…

Combinatorics · Mathematics 2024-11-27 Edin Husić , Georg Loho , Ben Smith , László A. Végh

We consider structural properties of $\mathcal{L}$-polymatroids, especially those defined on a finite complemented modular lattice $\mathcal{L}$. We introduce a set of cover-weight axioms and establish a cryptomorphism between these axioms…

Combinatorics · Mathematics 2025-12-30 Eimear Byrne , Andrew Fulcher

We show that each algebraic representation of a matroid $M$ in positive characteristic determines a matroid valuation of $M$, which we have named the {\em Lindstr\"om valuation}. If this valuation is trivial, then a linear representation of…

Combinatorics · Mathematics 2017-11-23 Guus Bollen , Jan Draisma , Rudi Pendavingh

We present a simple combinatorial model for the characters of the irreducible integrable highest weight modules for complex symmetrizable Kac-Moody algebras. This model can be viewed as a discrete counterpart to the Littelmann path model.…

Representation Theory · Mathematics 2007-05-23 Cristian Lenart , Alexander Postnikov

In this paper we introduce valuated $\Delta$-matroids, a natural generalization of two objects of study in matroid theory: valuated matroids and $\Delta$-matroids. We show that these objects exhibit nice properties analogous to ordinary…

Combinatorics · Mathematics 2025-07-23 Nathan Cheung , Tracy Chin , Gaku Liu , Cynthia Vinzant

We introduce a noncommutative binary operation on matroids, called free product. We show that this operation respects matroid duality, and has the property that, given only the cardinalities, an ordered pair of matroids may be recovered, up…

Combinatorics · Mathematics 2007-05-23 Henry Crapo , William Schmitt

We provide a deletion formula for the inverse Kazhdan--Lusztig polynomial and the inverse $Z$-polynomial of a matroid. Our formulas provide analogues to the deletion formulas of Braden--Vysogorets for Kazhdan--Lusztig and $Z$-polynomials.…

Combinatorics · Mathematics 2025-10-02 Tom Braden , Luis Ferroni , Jacob P. Matherne , Nutan Nepal

We introduce a connectivity function for infinite matroids with properties similar to the connectivity function of a finite matroid, such as submodularity and invariance under duality. As an application we use it to extend Tutte's linking…

Combinatorics · Mathematics 2011-01-31 Henning Bruhn , Paul Wollan

Using a new technique, we prove a rich family of special cases of the matroid intersection conjecture. Roughly, we prove the conjecture for pairs of tame matroids which have a common decomposition by 2-separations into finite parts.

Combinatorics · Mathematics 2014-04-25 Nathan Bowler , Johannes Carmesin

We prove that if M is a vertically 4-connected matroid with a modular flat X of rank at least three, then every representation of M | X over a finite field F extends to a unique F-representation of M. A corollary is that when F has order q,…

Combinatorics · Mathematics 2013-04-25 Jim Geelen , Rohan Kapadia

The classical theory of elliptic curves with complex multiplication is a fundamental tool for studying the arithmetic of abelian extensions of imaginary quadratic fields. While no direct analogue is available for real quadratic fields, a…

Number Theory · Mathematics 2023-09-22 Paulina Fust , Judith Ludwig , Alice Pozzi , Mafalda Santos , Hanneke Wiersema

We characterize 2-dimensional complexes associated canonically with basis graphs of matroids as simply connected triangle-square complexes satisfying some local conditions. This proves a version of a (disproved) conjecture by Stephen Maurer…

Combinatorics · Mathematics 2018-12-10 Jérémie Chalopin , Victor Chepoi , Damian Osajda

The foundation of a matroid is a canonical algebraic invariant which classifies representations of the matroid up to rescaling equivalence. Foundations of matroids are pastures, a simultaneous generalization of partial fields and…

Combinatorics · Mathematics 2020-08-04 Matthew Baker , Oliver Lorscheid

Generalizing a well known theorem for finite matroids, we prove that for every (infinite) connected matroid M there is a unique tree T such that the nodes of T correspond to minors of M that are either 3-connected or circuits or cocircuits,…

Combinatorics · Mathematics 2015-06-08 Elad Aigner-Horev , Reinhard Diestel , Luke Postle

We provide a natural definition of an elliptic arrangement, extending the classical framework to an elliptic curve E with complex multiplication. We analyse the intersections of elements of the arrangement and their connected components as…

Combinatorics · Mathematics 2026-05-13 Luca Moci , Roberto Pagaria , Maddalena Pismataro , Alejandro Vargas

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