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For an integer $n>2$, a rank-$n$ matroid is called an $n$-spike if it consists of $n$ three-point lines through a common point such that, for all $k\in\{1, 2, ..., n - 1\}$, the union of every set of $k$ of these lines has rank $k+1$.…

Combinatorics · Mathematics 2007-05-23 Zhaoyang Wu , Zhi-Wei Sun

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

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

We consider the budgeted matroid independent set problem. The input is a ground set, where each element has a cost and a non-negative profit, along with a matroid over the elements and a budget. The goal is to select a subset of elements…

Data Structures and Algorithms · Computer Science 2022-09-13 Ilan Doron-Arad , Ariel Kulik , Hadas Shachnai

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 discuss several extension properties of matroids and polymatroids and their application as necessary conditions for the existence of different matroid representations, namely linear, folded linear, algebraic, and entropic…

Combinatorics · Mathematics 2025-02-24 Michael Bamiloshin , Oriol Farràs , Carles Padró

Given an $\Bbb{F}$-represented matroid $(M,\rho)$ with the ground set $[m]$, the representation $\rho$ naturally defines a hyperplane arrangement $\mathcal{A}_\rho$. We will study its parallel translates $\mathcal{A}_{\rho,{g}}$ of…

Combinatorics · Mathematics 2020-10-15 Beifang Chen , Houshan Fu , Suijie Wang

We consider the matrix completion problem with a deterministic pattern of observed entries. In this setting, we aim to answer the question: under what condition there will be (at least locally) unique solution to the matrix completion…

Machine Learning · Computer Science 2019-01-30 Alexander Shapiro , Yao Xie , Rui Zhang

We present a new direct proof of a topological representation theorem for oriented matroids in the general rank case. Our proof is based on an earlier rank 3 version. It uses hyperline sequences and the generalized Sch{\"o}nflies theorem.…

Combinatorics · Mathematics 2007-05-23 Juergen Bokowski , Simon King , Susanne Mock , Ileana Streinu

In this article, we investigate the multi-parametric matroid problem. The weights of the elements of the matroid's ground set depend linearly on an arbitrary but fixed number of parameters, each of which is taken from a real interval. The…

Combinatorics · Mathematics 2025-03-13 Nils Hausbrandt , Stefan Ruzika

The Topological Representation Theorem for (oriented) matroids states that every (oriented) matroid can be realized as the intersection lattice of an arrangement of codimension one homotopy spheres on a homotopy sphere. In this paper, we…

Combinatorics · Mathematics 2015-03-19 Matthew T. Stamps

Gordon introduced a class of matroids $M(n)$, for prime $n\ge 2$, such that $M(n)$ is algebraically representable, but only in characteristic $n$. Lindstr\"om proved that $M(n)$ for general $n\ge 2$ is not algebraically representable if…

Combinatorics · Mathematics 2022-02-22 Rigoberto Florez

We study tropical subrepresentations of the Boolean regular representation $\mathbb{B}[G]$ of a finite group $G$. These are equivalent to the matroids on ground set $G$ for which left-multiplication by each element of $G$ is a matroid…

Combinatorics · Mathematics 2025-02-14 Jaiung Jun , Kalina Mincheva , Jeffrey Tolliver

A new connection between two different necessary conditions for a polymatroid to be linearly representable is presented. Specifically, we prove that the existence of a tensor product with the uniform matroid of rank two on three elements…

Combinatorics · Mathematics 2025-02-20 Carles Padró

We study the problem of allocating indivisible goods among strategic agents. We focus on settings wherein monetary transfers are not available and each agent's private valuation is a submodular function with binary marginals, i.e., the…

Computer Science and Game Theory · Computer Science 2021-09-14 Siddharth Barman , Paritosh Verma

There is a one-to-one correspondence between geometric lattices and the intersection lattices of arrangements of homotopy spheres. When the arrangements are essential and fully partitioned, Zaslavsky's enumeration of the cells of the…

Combinatorics · Mathematics 2007-05-23 Edward Swartz

A laminar family is a collection $\mathscr{A}$ of subsets of a set $E$ such that, for any two intersecting sets, one is contained in the other. For a capacity function $c$ on $\mathscr{A}$, let $\mathscr{I}$ be $\{I:|I\cap A| \leq…

Combinatorics · Mathematics 2016-06-28 Tara Fife , James Oxley

Matroids are a fundamental object of study in combinatorial optimization. Three closely related and important problems involving matroids are maximizing the size of the union of $k$ independent sets (that is, $k$-fold matroid union),…

Data Structures and Algorithms · Computer Science 2023-03-03 Kent Quanrud

In this paper, the structural controllability of the systems over F(z) is studied using a new mathematical method-matroids. Firstly, a vector matroid is defined over F(z). Secondly, the full rank conditions of [sI-A|B] are derived in terms…

Systems and Control · Computer Science 2017-04-04 Yupeng Yuan , Zhixiong Li , Malekian Reza , Yongzhi Chen , Ying Chen

For each proper minor-closed subclass $\cM$ of the $\GF(q^2)$-representable matroids containing all simple $\GF(q)$-representable matroids, we give, for all large $r$, a tight upper bound on the number of points in a rank-$r$ matroid in…

Combinatorics · Mathematics 2011-05-23 Peter Nelson