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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

Several matroids can be defined on the edge set of a graph. Although historically the cycle matroid has been the most studied, in recent times, the bicircular matroid has cropped up in several places. A theorem of Matthews from late 1970s…

Combinatorics · Mathematics 2014-04-18 Vaidy Sivaraman

In this article we disprove the conjectures asserting the positivity of the coefficients of the Ehrhart polynomial of matroid polytopes by De Loera, Haws and K\"oppe (2007) and of generalized permutohedra by Castillo and Liu (2015). We…

Combinatorics · Mathematics 2022-03-22 Luis Ferroni

We introduce a class of polytopes that we call chainlink polytopes and which allow us to construct infinite families of pairs of non isomorphic rational polytopes with the same Ehrhart quasi-polynomial. Our construction is based on circular…

Combinatorics · Mathematics 2025-04-08 Ezgi Kantarcı Oğuz , Cem Yalım Özel , Mohan Ravichandran

In this paper we investigate the Ehrhart Theory of the independence matroid polytope of uniform matroids. It is proved that these polytopes have an Ehrhart polynomial with positive coefficients. To do that, we prove that indeed all…

Combinatorics · Mathematics 2021-05-24 Luis Ferroni

A sweep of a point configuration is any ordered partition induced by a linear functional. Posets of sweeps of planar point configurations were formalized and abstracted by Goodman and Pollack under the theory of allowable sequences of…

Combinatorics · Mathematics 2023-10-26 Arnau Padrol , Eva Philippe

We introduce the minor-closed, dual-closed class of multi-path matroids. We give a polynomial-time algorithm for computing the Tutte polynomial of a multi-path matroid, we describe their basis activities, and we prove some basic structural…

Combinatorics · Mathematics 2024-08-07 Joseph E. Bonin , Omer Gimenez

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

We study paving matroids, their realization spaces, and their closures, along with matroid varieties and circuit varieties. Within this context, we introduce three distinct methods for generating polynomials within the associated ideals of…

Algebraic Geometry · Mathematics 2026-03-24 Emiliano Liwski , Fatemeh Mohammadi

For a lattice polytope $P$, the rank of $P$ is defined by $F-(\dim P+1)$, where $F$ is the number of facets of $P$. In this paper, we study matroid polytopes with small rank. More precisely, we characterize matroid independence polytopes…

Combinatorics · Mathematics 2025-03-31 Masato Konoike , Koji Matsushita

We study the equivariant Ehrhart theory of families of polytopes that are invariant under a non-trivial action of the group with order two. We study families of polytopes whose equivariant $H^*$-polynomial both succeed and fail to be…

Combinatorics · Mathematics 2023-02-15 Oliver Clarke , Akihiro Higashitani , Max Kölbl

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

Panhandle matroids are a specific family of lattice-path matroids corresponding to panhandle-shaped Ferrers diagrams. Their matroid polytopes are the subpolytopes carved from a hypersimplex to form matroid polytopes of paving matroids. It…

Combinatorics · Mathematics 2025-05-30 Danai Deligeorgaki , Daniel McGinnis , Andrés R. Vindas-Meléndez

We study a particular graded ring structure on the set of all loopfree matroids on a fixed labeled ground set, which occurs naturally in tropical geometry. The product is given by matroid intersection and the additive structure is defined…

Combinatorics · Mathematics 2016-09-05 Simon Hampe

We define and study a new family of polytopes which are formed as convex hulls of partial alternating sign matrices. We determine the inequality descriptions, number of facets, and face lattices of these polytopes. We also study partial…

Combinatorics · Mathematics 2022-03-09 Dylan Heuer , Jessica Striker

In this paper we generalise the even directed cycle problem, which asks whether a given digraph contains a directed cycle of even length, to orientations of regular matroids. We define non-even oriented matroids generalising non-even…

Combinatorics · Mathematics 2020-10-20 Karl Heuer , Raphael Steiner , Sebastian Wiederrecht

For a directed polytope, we construct a colored operad whose Poincare-Hilbert series encodes certain operations on the cellular complex of the polytope. We conjecture that for a class of short polytopes the constructed operads are Koszul…

K-Theory and Homology · Mathematics 2021-12-30 Sergey Arkhipov , Daria Poliakova

Graded Ehrhart theory is a new $q$-analogue of Ehrhart theory based on the orbit harmonics method. We study the graded Ehrhart theory of unimodular zonotopes from a matroid-theoretic perspective. Generalizing a result of Stanley (1991), we…

Combinatorics · Mathematics 2026-03-10 Colin Crowley , Ethan Partida

A biased graph is a graph with a class of selected circles ("cycles", "circuits"), called balanced, such that no theta subgraph contains exactly two balanced circles. A biased graph $\Omega$ has two natural matroids, the frame matroid…

Combinatorics · Mathematics 2021-06-16 Rigoberto Flórez , Thomas Zaslavsky

The natural matroid of an integer polymatroid was introduced to show that a simple construction of integer polymatroids from matroids yields all integer polymatroids. As we illustrate, the natural matroid can shed much more light on integer…

Combinatorics · Mathematics 2024-08-07 Joseph E. Bonin , Carolyn Chun , Tara Fife