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This note contributes to the structure theory of abstract rigidity matroids in general dimension. In the spirit of classical matroid theory, we prove several cryptomorphic characterizations of abstract rigidity matroids (in terms of…

Combinatorics · Mathematics 2015-03-13 Emanuele Delucchi , Tim Lindemann

We study Stanley-Reisner ideals of broken circuits complexes and characterize those ones admitting a linear resolution or being complete intersections. These results will then be used to characterize arrangements whose Orlik-Terao ideal has…

Commutative Algebra · Mathematics 2021-05-18 Le Van Dinh , Tim Roemer

A $q$-matroid is the analogue of a matroid which arises by replacing the finite ground set of a matroid with a finite-dimensional vector space over a finite field. These $q$-matroids are motivated by coding theory as the representable…

Combinatorics · Mathematics 2025-11-27 Sebastian Degen , Lukas Kühne

Oriented matroids (often called order types) are combinatorial structures that generalize point configurations, vector configurations, hyperplane arrangements, polyhedra, linear programs, and directed graphs. Oriented matroids have played a…

Combinatorics · Mathematics 2020-06-17 Ilan Adler , Jesús A. De Loera , Steven Klee , Zhenyang Zhang

One generalization of ordinary matroids is symplectic matroids. While symplectic matroids were initially defined by their collections of bases, there has been no cryptomorphic definition of symplectic matroids in terms of circuits. We give…

Combinatorics · Mathematics 2020-09-22 Zhexiu Tu

This paper introduces Dirichlet matroids, a generalization of graphic matroids arising from electrical networks. We present four main theorems. First, we exhibit a matroid quotient involving geometric duals of networks embedded in surfaces…

Combinatorics · Mathematics 2022-06-02 Bob Lutz

A matroid is a combinatorial structure that captures and generalizes the algebraic concept of linear independence under a broader and more abstract framework. Matroids are closely related with many other topics in discrete mathematics, such…

Combinatorics · Mathematics 2022-03-16 Gianira N. Alfarano , Karan Khathuria , Simran Tinani

We generalise the construction of infinite matroids from trees of matroids to allow the matroids at the nodes, as well as the field over which they are represented, to be infinite.

Combinatorics · Mathematics 2014-09-24 Nathan Bowler , Johannes Carmesin

While there are many parallels between matroid theory and $q$-matroid theory, most notably on the level of cryptomorphisms, there are substantial differences when it comes to the direct sum. The direct sum of $q$-matroids has been…

Combinatorics · Mathematics 2023-02-24 Heide Gluesing-Luerssen , Benjamin Jany

A transversal matroid whose dual is also transversal is called bi-transversal. Let $G$ be an undirected graph with vertex set $V$. In this paper, for every subset $W$ of $V$, we associate a bi-transversal matroid to the pair $(G,W)$. We…

Combinatorics · Mathematics 2024-03-01 Mahdi Ebrahimi

An excluded minor characterization for the class of binary signed-graphic matroids with graphic cocircuits is provided. In this report we present the necessary computations for the case analysis in the proof.

Combinatorics · Mathematics 2012-05-07 Konstantinos Papalamprou , Leonidas Pitsoulis

In this paper we employ Tutte's theory of bridges to derive a decomposition theorem for binary matroids arising from signed graphs. The proposed decomposition differs from previous decomposition results on matroids that have appeared in the…

Combinatorics · Mathematics 2015-03-17 Konstantinos Papalamprou , Leonidas Pitsoulis

We show that the fact that a political decision filtered through a finite tree of committees gives a determined answer generalises in some sense to infinite trees. This implies a new special case of the Matroid Intersection Conjecture.

Combinatorics · Mathematics 2014-04-02 Johannes Carmesin

In 1999 Merino and Welsh conjectured that evaluations of the Tutte polynomial of a graph satisfy an inequality. In this short article we show that the conjecture generalized to matroids holds for the large class of all split matroids by…

Combinatorics · Mathematics 2023-09-11 Luis Ferroni , Benjamin Schröter

Rough set theory is a useful tool to deal with uncertain, granular and incomplete knowledge in information systems. And it is based on equivalence relations or partitions. Matroid theory is a structure that generalizes linear independence…

Artificial Intelligence · Computer Science 2012-10-24 Yanfang Liu , William Zhu

In this paper, we construct an infinite series of line arrangements in characteristic two, each featuring only triple intersection points. This finding challenges the existing conjecture that suggests the existence of only a finite number…

Combinatorics · Mathematics 2025-05-21 Lukas Kühne , Tomasz Szemberg , Halszka Tutaj-Gasińska

Seymour's Decomposition Theorem for regular matroids states that any matroid representable over both GF(2) and GF(3) can be obtained from matroids that are graphic, cographic, or isomorphic to R10 by 1-, 2-, and 3-sums. It is hoped that…

Combinatorics · Mathematics 2015-03-13 Dillon Mayhew , Geoff Whittle , Stefan H. M. van Zwam

For a real affine hyperplane arrangement, we define an integer intersection matrix with a natural $q$-deformation related to the intersections of bounded chambers of the arrangement. By connecting the integer matrix to a bilinear form of…

Combinatorics · Mathematics 2024-07-09 Jens Niklas Eberhardt , Carl Mautner

We present an algebraic framework which simultaneously generalizes the notion of linear subspaces, matroids, valuated matroids, and oriented matroids. We call the resulting objects matroids over hyperfields. In fact, there are (at least)…

Combinatorics · Mathematics 2017-04-21 Matthew Baker , Nathan Bowler

For any minor-closed class of matroids over a fixed finite field, we state an exact structural characterization for the sufficiently connected matroids in the class. We also state a number of conjectures that might be approachable using the…

Combinatorics · Mathematics 2015-01-06 Jim Geelen , Bert Gerards , Geoff Whittle