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Related papers: Flag enumerations of matroid base polytopes

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We present exponential and super factorial lower bounds on the number of Hamiltonian cycles passing through any edge of the basis graphs of a graphic, generalized Catalan and uniform matroids. All lower bounds were obtained by a common…

A (convex) polytope $P$ is said to be $2$-level if for every direction of hyperplanes which is facet-defining for $P$, the vertices of $P$ can be covered with two hyperplanes of that direction. The study of these polytopes is motivated by…

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

Efficient deterministic algorithms to construct representations of lattice path matroids over finite fields are presented. They are built on known constructions of hierarchical secret sharing schemes, a recent characterization of…

Combinatorics · Mathematics 2024-07-09 Carles Padró

A classification of discrete polymatroids whose independence polytopes are reflexive will be presented.

Combinatorics · Mathematics 2023-02-27 Jürgen Herzog , Takayuki Hibi

We produce the first regular unimodular triangulation of an arbitrary matroid base polytope. We then extend our triangulation to integral generalized permutahedra. Prior to this work it was unknown whether each matroid base polytope…

Combinatorics · Mathematics 2024-04-05 Spencer Backman , Gaku Liu

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 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

We show how to construct homology bases for certain CW complexes in terms of discrete Morse theory and cellular homology. We apply this technique to study certain subcomplexes of the half cube polytope studied in previous works. This…

Geometric Topology · Mathematics 2014-10-01 R. M. Green , Jacob T. Harper

In this paper we give a necessary and sufficient criterion for representability of a matroid over an algebraic closed field. This leads to an algorithm, based on an extension of Groebner Bases, in order to decide if a given matroid is…

Combinatorics · Mathematics 2007-05-23 Massimiliano Lunelli , Antonio Laface

For a matroid with an ordered (or "labelled") basis, a basis exchange step removes one element with label $l$ and replaces it by a new element that results in a new basis, and with the new element assigned label $l$. We prove that one…

Data Structures and Algorithms · Computer Science 2016-12-06 Anna Lubiw , Vinayak Pathak

Blind and Mani, and later Kalai, showed that the face lattice of a simple polytope is determined by its graph, namely its $1$-skeleton. Call a vertex of a $d$-polytope \emph{nonsimple} if the number of edges incident to it is more than $d$.…

Combinatorics · Mathematics 2018-03-16 Joseph Doolittle , Eran Nevo , Guillermo Pineda-Villavicencio , Julien Ugon , David Yost

We study the complexity of testing if two given matroids are isomorphic. The problem is easily seen to be in $\Sigma_2^p$. In the case of linear matroids, which are represented over polynomially growing fields, we note that the problem is…

Computational Complexity · Computer Science 2008-11-25 Raghavendra Rao B. V. , Jayalal M. N. Sarma

In this paper, we develop the theory of flag manifold over a semifield for any Kac-Moody root datum. We show that the flag manifold over a semifield admits a natural action of the monoid over that semifield associated with the Kac-Moody…

Representation Theory · Mathematics 2020-03-31 Huanchen Bao , Xuhua He

Given a group $G$ of automorphisms of a matroid $M$, we describe the representations of $G$ on the homology of the independence complex of the dual matroid $M^*$. These representations are related with the homology of the lattice of flats…

Representation Theory · Mathematics 2021-02-22 Luca Moci , Gian Marco Pezzoli

We study Dressians of matroids using the initial matroids of Dress and Wenzel. These correspond to cells in regular matroid subdivisions of matroid polytopes. An efficient algorithm for computing Dressians is presented, and its…

Combinatorics · Mathematics 2020-08-05 Madeline Brandt , David E Speyer

There is a well-established dictionary between zonotopes, hyperplane arrangements, and their (oriented) matroids. Arguably one of the most famous examples is the class of graphical zonotopes, also called acyclotopes, which encode…

Combinatorics · Mathematics 2024-09-24 Eleonore Bach , Matthias Beck , Sophie Rehberg

We investigate arithmetic, geometric and combinatorial properties of symmetric edge polytopes. We give a complete combinatorial description of their facets. By combining Gr\"obner basis techniques, half-open decompositions and methods for…

Combinatorics · Mathematics 2019-05-15 Akihiro Higashitani , Katharina Jochemko , Mateusz Michałek

We give an explicit description of the Mirkovic-Vilonen cycles on the affine Grassmannian for arbitrary complex reductive groups. We also give a combinatorial characterization of the MV polytopes. We prove that a polytope is an MV polytope…

Algebraic Geometry · Mathematics 2007-05-23 Joel Kamnitzer

The orbit graph of a k-orbit polytope is a graph on k nodes that shows how the flag orbits are related by flag adjacency. Using orbit graphs, we classify k-orbit polytopes and determine when a k-orbit polytope is i-transitive. We then…

Combinatorics · Mathematics 2013-06-10 Gabe Cunningham