English
Related papers

Related papers: Describing Quasi-Graphic Matroids

200 papers

The ground set for all matroids in this paper is the set of all edges of a complete graph. The notion of a {\it maximum matroid for a graph} $G$ is introduced, and the existence and uniqueness of the maximum matroid for any graph $G$ is…

Combinatorics · Mathematics 2021-03-30 Meera Sitharam , Andrew Vince

In this thesis, we study nearly finitary matroids by introducing new definitions and prove various properties of nearly finitary matroids. In 2010, an axiom system for infinite matroids was proposed by Bruhn et al. We use this axiom system…

Combinatorics · Mathematics 2019-06-13 Patrick Tam

In this work we provide a decomposition theorem for the class of quaternary and non-binary signed-graphic matroids. This generalizes previous results for binary signed-graphic matroids and graphic matroids, and it provides the theoretical…

Combinatorics · Mathematics 2015-10-26 Leonidas Pitsoulis , Eleni-Maria Vretta

We characterize the shifted simple graphs and the $3$-uniform shifted hypergraphs whose inverse image under exterior shifting is the set of bases of a matroid: those are exactly the hypergraphs whose hyperedges form an initial lex-segment.…

Combinatorics · Mathematics 2025-12-04 Lazar Guterman , Eran Nevo

We specify what is meant for a polytope to be reconstructible from its graph or dual graph. And we introduce the problem of class reconstructibility, i.e., the face lattice of the polytope can be determined from the (dual) graph within a…

Combinatorics · Mathematics 2022-08-05 Guillermo Pineda-Villavicencio , Benjamin Schröter

Given a 3-connected biased graph $\Omega$ with a balancing vertex, and with frame matroid $F(\Omega)$ nongraphic and 3-connected, we determine all biased graphs $\Omega'$ with $F(\Omega') = F(\Omega)$. As a consequence, we show that if $M$…

Combinatorics · Mathematics 2017-11-17 Matt DeVos , Daryl Funk

Building on prior work that established Matrix Quasi-tree Theorems for special embedded graphs, in this paper, we develop a comprehensive theory applicable to all embedded graphs. We introduce symbolic skew-adjacency matrices and reduction…

Combinatorics · Mathematics 2025-12-02 Qingying Deng , Xian'an Jin , Qi Yan , Yexiang Yan

We introduce a new class of matroids, called graph curve matroids. A graph curve matroid is associated to a graph and defined on the vertices of the graph as a ground set. We prove that these matroids provide a combinatorial description of…

Combinatorics · Mathematics 2024-08-06 Alheydis Geiger , Kevin Kuehn , Raluca Vlad

In mathematics and computer science, connectivity is one of the basic concepts of matroid theory: it asks for the minimum number of elements which need to be removed to disconnect the remaining nodes from each other. It is closely related…

Artificial Intelligence · Computer Science 2013-11-06 Bin Yang , William Zhu

A {\em connectivity function} on a set $E$ is a function $\lambda:2^E\rightarrow \mathbb R$ such that $\lambda(\emptyset)=0$, that $\lambda(X)=\lambda(E-X)$ for all $X\subseteq E$, and that $\lambda(X\cap Y)+\lambda(X\cup Y)\leq…

Combinatorics · Mathematics 2020-07-10 Nathan Bowler , Susan Jowett

We consider three matroids defined by Kalai in 1985: the symmetric completion matroid $\mathcal{S}_d$ on the edge set of a looped complete graph; the hyperconnectivity matroid $\mathcal{H}_d$ on the edge set of a complete graph; and the…

Combinatorics · Mathematics 2026-03-17 Dániel Garamvölgyi , Bill Jackson , Tibor Jordán , Soma Villányi

Frame matroids and lifted-graphic matroids are two distinct minor-closed classes of matroids, each of which generalises the class of graphic matroids. The class of quasi-graphic matroids, recently introduced by Geelen, Gerards, and Whittle,…

Combinatorics · Mathematics 2017-06-21 Daryl Funk , Dillon Mayhew

A recent line of research has concentrated on exploring the links between analytic and combinatorial theories of submodularity, uncovering several key connections between them. In this context, Lov\'asz initiated the study of matroids from…

Combinatorics · Mathematics 2024-10-16 Kristóf Bérczi , Márton Borbényi , László Lovász , László Márton Tóth

Hypergraphics matroids were studied first by Lorea and later by Frank et al. They can be seen as generalizations of graphic matroids. Here we show that several algorithms developed for the graphic case can be extended to hypergraphic…

Combinatorics · Mathematics 2021-11-11 Mourad Baiou , Francisco Barahona

We introduce the notion of graphic cocircuits and show that a large class of regular matroids with graphic cocircuits belongs to the class of signed-graphic matroids. Moreover, we provide an algorithm which determines whether a cographic…

Discrete Mathematics · Computer Science 2009-09-29 Konstantinos Papalamprou , Leonidas Pitsoulis

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

An infinite matroid is graphic if all of its finite minors are graphic and the intersection of any circuit with any cocircuit is finite. We show that a matroid is graphic if and only if it can be represented by a graph-like topological…

Combinatorics · Mathematics 2013-09-17 Nathan Bowler , Johannes Carmesin , Robin Christian

The mutually enriching relationship between graphs and matroids has motivated discoveries in both fields. In this paper, we exploit the similar relationship between embedded graphs and delta-matroids. There are well-known connections…

Combinatorics · Mathematics 2019-03-04 Carolyn Chun , Iain Moffatt , Steven D. Noble , Ralf Rueckriemen

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

Motivated by work in graph theory, we define the fixing number for a matroid. We give upper and lower bounds for fixing numbers for a general matroid in terms of the size and maximum orbit size (under the action of the matroid automorphism…

Combinatorics · Mathematics 2014-05-27 Gary Gordon , Jennifer McNulty , Nancy Ann Neudauer