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B\'ar\'any, Kalai, and Meshulam recently obtained a topological Tverberg-type theorem for matroids, which guarantees multiple coincidences for continuous maps from a matroid complex to d-dimensional Euclidean space, if the matroid has…

Combinatorics · Mathematics 2017-05-11 Pavle V. M. Blagojević , Albert Haase , Günter M. Ziegler

Let $\cX$ be a family of subsets of a finite set $E$. A matroid on $E$ is called an $\cX$-matroid if each set in $\cX$ is a circuit. We consider the problem of determining when there exists a unique maximal $\cX$-matroid in the weak order…

Combinatorics · Mathematics 2021-03-16 Bill Jackson , Shin-ichi Tanigawa

Seymour's decomposition theorem is a hallmark result in matroid theory presenting a structural characterization of the class of regular matroids. Formalization of matroid theory faces many challenges, most importantly that only a limited…

We prove that, if $B_1, \dots, B_n$ are disjoint bases of a rank-$n$ matroid, then there are at least $\lfloor{\frac{n}{6 \lceil{\log n}\rceil}}\rfloor$ disjoint transversals of $(B_1, \dots, B_n)$ that are also bases.

Combinatorics · Mathematics 2018-02-06 Sally Dong , Jim Geelen

Let ${\mathcal{M} = (M_i \colon i\in K)}$ be a finite or infinite family consisting of matroids on a common ground set $E$ each of which may be finitary or cofinitary. We prove the following Cantor-Bernstein-type result: If there is a…

Combinatorics · Mathematics 2024-05-27 Joshua Erde , Pascal Gollin , Attila Joó , Paul Knappe , Max Pitz

In this paper, we propose a new type of matroids, namely covering matroids, and investigate the connections with the second type of covering-based rough sets and some existing special matroids. Firstly, as an extension of partitions,…

Artificial Intelligence · Computer Science 2012-12-03 Yanfang Liu , William Zhu

White's conjecture asserts that any two tuples of matroid bases that have the same multi-set union can be transformed from one to another by symmetric exchanges; it also implies that the toric ideals of matroids are generated by the…

Combinatorics · Mathematics 2025-10-07 Yu-Chuan Yu , Chi Ho Yuen

The configuration of a matroid $M$ is the abstract lattice of cyclic flats (flats that are unions of circuits) where we record the size and rank of each cyclic flat, but not the set. One can compute the Tutte polynomial of $M$, and stronger…

Combinatorics · Mathematics 2025-12-18 Joseph E. Bonin , Anna de Mier

The present note is a strengthening of a recent paper by K. Takazawa and Y. Yokoi (A generalized-polymatroid approach to disjoint common independent sets in two matroids, Discrete Mathematics (2019)). For given two matroids on $E$, under…

Combinatorics · Mathematics 2019-10-01 Satoru Fujishige , Kenjiro Takazawa , Yu Yokoi

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

We consider three forms of composition of matroids, each of which extends the category of bimatroids to a rigid monoidal category. Many well-known constructions are functorial or defined by morphisms in these categories. Motivating examples…

Combinatorics · Mathematics 2024-03-07 Kevin Purbhoo

Primary Cyclic matrices were used (but not named) by Holt and Rees in their version of Parker's MEAT-AXE algorithm to test irreducibility of finite matrix groups and algebras. They are matrices $X$ with at least one cyclic component in the…

Combinatorics · Mathematics 2014-01-09 Brian P. Corr , Cheryl E. Praeger

The purpose of this paper is to investigate the properties of spectral and tiling subsets of cyclic groups, with an eye towards the spectral set conjecture in one dimension, which states that a bounded measurable subset of $\mathbb{R}$…

Classical Analysis and ODEs · Mathematics 2023-01-02 Romanos Diogenes Malikiosis

We generalize the 1/3-2/3 conjecture from partially ordered sets to antimatroids: we conjecture that any antimatroid has a pair of elements x,y such that x has probability between 1/3 and 2/3 of appearing earlier than y in a uniformly…

Combinatorics · Mathematics 2014-08-07 David Eppstein

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

Graphings serve as limit objects for bounded-degree graphs. We define the ``cycle matroid'' of a graphing as a submodular setfunction, with values in [0,1], which generalizes (up to normalization) the cycle matroid of finite graphs. We…

Combinatorics · Mathematics 2023-11-08 László Lovász

We use the Strong Splitter Theorem to decompose the excluded minor class of binary matroids with no $E_4$-minor. Using this theorem we can get the 3-decomposers and the extremal internally 4-connected matroids as well as any other important…

Combinatorics · Mathematics 2014-08-12 S. R. Kingan

Simple cycles on a digraph form a trace monoid under the rule that two such cycles commute if and only if they are vertex disjoint. This rule describes the spatial configuration of simple cycles on the digraph. Cartier and Foata have showed…

Combinatorics · Mathematics 2023-07-03 J. Fromentin , P. -L Giscard , T. Karaboghossian

This paper studies the unitary diagonalization of matrices over formal power series rings. Our main result shows that a normal matrix is unitarily diagonalizable if and only if its minimal polynomial completely splits over the ring and the…

Commutative Algebra · Mathematics 2026-02-10 Zihao Dai , Hao Liang , Jingyu Lu , Lihong Zhi

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
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