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In this paper we introduce discrete polymatroids satisfying the one-sided strong exchange property and show that they are sortable (as a consequence their base rings are Koszul) and that they satisfy White's conjecture. Since any pruned…

Commutative Algebra · Mathematics 2017-03-09 Dancheng Lu

In $1980$ White conjectured that every element of the toric ideal of a matroid is generated by quadratic binomials corresponding to symmetric exchanges. We prove White's conjecture for high degrees with respect to the rank. This extends our…

Combinatorics · Mathematics 2021-12-01 Michał Lasoń

Describing minimal generating set of a toric ideal is a well-studied and difficult problem. In 1980 White conjectured that the toric ideal associated to a matroid is equal to the ideal generated by quadratic binomials corresponding to…

Combinatorics · Mathematics 2014-04-01 Michał Lasoń , Mateusz Michałek

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

In 1980, White conjectured that the toric ideal associated to a matroid is generated by binomials corresponding to a symmetric exchange. In this paper, we prove that classes of matroids for which the toric ideal is generated by quadrics and…

Combinatorics · Mathematics 2019-07-22 Kazuki Shibata

It has been conjectured that the toric ideal of the base ring of a discrete polymatroid is generated by symmetric exchange binomials. In the present paper, we give several classes of discrete polymatroids which yield toric ideals generated…

Commutative Algebra · Mathematics 2025-07-17 Takayuki Hibi , Seyed Amin Seyed Fakhari

In 1980, White conjectured that the toric ideal of a matroid is generated by quadratic binomials corresponding to a symmetric exchange. In this paper, we compute Gr\"obner bases of toric ideals associated with matroids and show that, for…

Commutative Algebra · Mathematics 2020-04-28 Ken-ichi Hayase , Takayuki Hibi , Koyo Katsuno , Kazuki Shibata

We prove a new exchange property for bases of a matroid that generalizes the multiple symmetric exchange property. For every bases $B_1,\dots,B_k$ of a matroid and a subset $A_1\subset B_1$ there exist subsets $A_2\subset…

Combinatorics · Mathematics 2016-06-01 Michał Lasoń

Let $S=K[x_1, \ldots,x_n]$ denote the polynomial ring in $n$ variables over a field $K$ and $I \subset S$ a monomial ideal. Given a vector $\mathfrak{c}\in\mathbb{Z}_{>0}^n$, the ideal $I_{\mathfrak{c}}$ is the ideal generated by those…

Commutative Algebra · Mathematics 2025-06-05 Takayuki Hibi , Seyed Amin Seyed Fakhari

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

This is a survey article on the exchange properties characterizing M-natural-concave set functions and valuated matroids (M-concave set functions). The objective of this paper is to collect related results scattered in the literature and to…

Combinatorics · Mathematics 2021-06-01 Kazuo Murota

A toric variety is constructed from a lattice polytope. It is common in algebraic combinatorics to carry this way a notion of an algebraic property from the variety to the polytope. From the combinatorial point of view, one of the most…

Combinatorics · Mathematics 2020-05-19 Michał Lasoń , Mateusz Michałek

Describing minimal generating sets of toric ideals is a well-studied and difficult problem. Neil White conjectured in 1980 that the toric ideal associated to a matroid is generated by quadrics corresponding to single element symmetric…

Combinatorics · Mathematics 2007-05-23 Jonah Blasiak

Blasiak verified a conjecture of White for graphic matroids by showing that the toric ideal of a graphic matroid is generated by quadrics. In this paper, we extend this result to frame matroids satisfying a linearity condition. Such classes…

Combinatorics · Mathematics 2020-04-10 Sean McGuinness

The operational Chow cohomology classes of a complete toric variety are identified with certain functions, called Minkowski weights, on the corresponding fan. The natural product of Chow cohomology classes makes the Minkowski weights into a…

alg-geom · Mathematics 2008-02-03 William Fulton , Bernd Sturmfels

We study conic divisorial ideals from the viewpoint of matroid theory and apply the resulting framework to toric rings arising from signed posets. For a toric ring, we describe the polytope representing divisor classes corresponding to…

Commutative Algebra · Mathematics 2026-05-05 Koji Matsushita

Finite matroids are combinatorial structures that express the concept of linear independence. In 1964, G.-C. Rota conjectured that the coefficients of the "characteristic polynomial" of a matroid $M$, polynomial whose coefficients enumerate…

Algebraic Geometry · Mathematics 2023-03-03 Antoine Chambert-Loir

We prove the hard Lefschetz theorem and the Hodge-Riemann relations for a commutative ring associated to an arbitrary matroid M. We use the Hodge-Riemann relations to resolve a conjecture of Heron, Rota, and Welsh that postulates the…

Combinatorics · Mathematics 2018-05-02 Karim Adiprasito , June Huh , Eric Katz

In this thesis, we focus on the study of the base rings associated to some transversal polymatroids. A transversal polymatroid is a special kind of discrete polymatroid. Discrete polymatroids were introduced by Herzog and Hibi \cite{HH} in…

Commutative Algebra · Mathematics 2008-08-05 Alin Ştefan

Two pairs of disjoint bases $\mathbf{P}_1=(R_1,B_1)$ and $\mathbf{P}_2=(R_2,B_2)$ of a matroid $M$ are called equivalent if $\mathbf{P}_1$ can be transformed into $\mathbf{P}_2$ by a series of symmetric exchanges. In 1980, White conjectured…

Combinatorics · Mathematics 2022-11-24 Kristóf Bérczi , Bence Mátravölgyi , Tamás Schwarcz
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