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Inspired by a recent result of Brakensiek et al. that symmetric tensor matroids and rigidity matroids are linked by matroid duality, we define abstract symmetric tensor matroids as a dual concept to abstract rigidity matroids and establish…

Combinatorics · Mathematics 2025-03-20 Bill Jackson , Shin-ichi Tanigawa

A matroid is sticky if any two of its extensions by disjoint sets can be glued together along the common restriction (that is, they have an amalgam). The sticky matroid conjecture asserts that a matroid is sticky if and only if it is…

Combinatorics · Mathematics 2024-08-07 Joseph E. Bonin

In the Inverse Matroid problem, we are given a matroid, a fixed basis $B$, and an initial weight function, and the goal is to minimally modify the weights -- measured by some function -- so that $B$ becomes a maximum-weight basis. The…

Data Structures and Algorithms · Computer Science 2025-07-03 Kristóf Bérczi , Lydia Mirabel Mendoza-Cadena , José Soto

In recent years, combinatorial reconfiguration problems have attracted great attention due to their connection to various topics such as optimization, counting, enumeration, or sampling. One of the most intriguing open questions concerns…

Combinatorics · Mathematics 2023-11-14 Kristóf Bérczi , Bence Mátravölgyi , Tamás Schwarcz

In the matroid secretary problem we are given a stream of elements and asked to choose a set of elements that maximizes the total value of the set, subject to being an independent set of a matroid given in advance. The difficulty comes from…

Data Structures and Algorithms · Computer Science 2012-07-24 Michael Dinitz , Guy Kortsarz

In this paper, we investigate the classes of matroid intersection admitting a solution for the problem of partitioning the ground set $E$ into $k$ common independent sets, where $E$ can be partitioned into $k$ independent sets in each of…

Combinatorics · Mathematics 2019-01-29 Kenjiro Takazawa , Yu Yokoi

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 class of 2-regular matroids is a natural generalisation of regular and near-regular matroids. We prove an excluded-minor characterisation for the class of 2-regular matroids. The class of 3-regular matroids coincides with the class of…

Combinatorics · Mathematics 2023-09-07 Nick Brettell , James Oxley , Charles Semple , Geoff Whittle

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

We study the prophet inequality when the gambler has an access only to a single sample from each distribution. Rubinstein, Wang and Weinberg showed that an optimal guarantee of 1/2 can be achieved when the underlying matroid has rank 1,…

Computer Science and Game Theory · Computer Science 2023-07-03 Kanstantsin Pashkovich , Alice Sayutina

This is a revised version of our original paper (arXiv:1808.00489v2) incorporating the corrections published in a corrigendum (arXiv:1808.00489v3). Our main theorem as originally stated was missing the required assumption that matroids…

Combinatorics · Mathematics 2025-05-28 Nathan Bowler , Daryl Funk , Daniel Slilaty

The Adwords and Online Bipartite Matching problems have enjoyed a renewed attention over the past decade due to their connection to Internet advertising. Our community has contributed, among other things, new models (notably stochastic) and…

Data Structures and Algorithms · Computer Science 2016-06-28 Yajun Wang , Sam Chiu-wai Wong

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

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

The famous Braess paradox describes the following phenomenon: It might happen that the improvement of resources, like building a new street within a congested network, may in fact lead to larger costs for the players in an equilibrium. In…

Computer Science and Game Theory · Computer Science 2017-01-11 Satoru Fujishige , Michel X. Goemans , Tobias Harks , Britta Peis , Rico Zenklusen

We introduce combinatorial objects named matricubes that provide a generalization of the theory of matroids. As matroids provide a combinatorial axiomatization of hyperplane arrangements, matricubes provide a combinatorial axiomatization of…

Combinatorics · Mathematics 2024-04-03 Omid Amini , Lucas Gierczak

We study some properties of a serial (i.e. one-by-one) symmetric exchange of elements of two disjoint bases of a matroid. We show that any two elements of one base have a serial symmetric exchange with some two elements of the other base.…

Combinatorics · Mathematics 2013-04-19 Daniel Kotlar , Ran Ziv

This paper studies the properties of two kinds of matroids: (a) algebraic matroids and (b) finite and infinite matroids whose ground set have some canonical symmetry, for example row and column symmetry and transposition symmetry. For (a)…

Combinatorics · Mathematics 2013-12-16 Franz J. Király , Zvi Rosen , Louis Theran

We call a matroid element "loose" if it is contained in no circuits of size less than the rank of the matroid. A matroid in which all elements are loose is a paving matroid. Acketa determined all binary paving matroids, while Oxley…

Combinatorics · Mathematics 2025-01-15 Jagdeep Singh , Thomas Zaslavsky

Matroid is a generalization of many fundamental objects in combinatorial mathematics , and matroid intersection problem is a classical subject in combinatorial optimization . However , only the intersection of two matroids are well…

Combinatorics · Mathematics 2023-01-10 Tianyu Liu