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Hybrid logic extends modal logic with special propositions called nominals, each of which is true at only one state in a model. This enables us to describe some properties of binary relations, such as irreflexivity and anti-symmetry, which…

Logic · Mathematics 2026-03-17 Yuki Nishimura

Maximizing a monotone submodular function is a fundamental task in machine learning. In this paper, we study the deletion robust version of the problem under the classic matroids constraint. Here the goal is to extract a small size summary…

Data Structures and Algorithms · Computer Science 2024-02-20 Paul Dütting , Federico Fusco , Silvio Lattanzi , Ashkan Norouzi-Fard , Morteza Zadimoghaddam

One of the simplest axiomatizations of a matroid is in terms of independent sets. Curiously, no such independent set axiomatization is known for Gelfand and Serganova's WP-matroids (which are ``Coxeter group analogues'' of matroids). Here…

Combinatorics · Mathematics 2007-05-23 Timothy Y. Chow

In this paper we present a definition of oriented Lagrangian symplectic matroids and their representations. Classical concepts of orientation and this extension may both be thought of as stratifications of thin Schubert cells into unions of…

Combinatorics · Mathematics 2007-05-23 Richard F. Booth , Alexandre V. Borovik , Israel M. Gelfand , Neil White

We introduce a construction of oriented matroids from a triangulation of a product of two simplices. For this, we use the structure of such a triangulation in terms of polyhedral matching fields. The oriented matroid is composed of…

Combinatorics · Mathematics 2020-10-26 Marcel Celaya , Georg Loho , Chi Ho Yuen

We prove that all injective maps on positive complex matrices which preserve order and shrink spectrum are implemented by unitary or antiunitary conjugations. We show by counterexamples that all assumptions are indispensable. The result…

Functional Analysis · Mathematics 2022-04-26 Mateo Tomašević

We introduce dual matroids of 2-dimensional simplicial complexes. Under certain necessary conditions, duals matroids are used to characterise embeddability in 3-space in a way analogous to Whitney's planarity criterion. We further use dual…

Combinatorics · Mathematics 2017-09-15 Johannes Carmesin

In this work, we consider robust submodular maximization with matroid constraints. We give an efficient bi-criteria approximation algorithm that outputs a small family of feasible sets whose union has (nearly) optimal objective value. This…

Data Structures and Algorithms · Computer Science 2018-07-26 Sebastian Pokutta , Mohit Singh , Alfredo Torrico

Given two finite matroids on the same ground set, a celebrated result of Edmonds says that the ground set can be partitioned into two disjoint subsets in a manner that there is a common independent set in both matroids whose intersection…

Combinatorics · Mathematics 2025-01-27 Irfan Alam

We study determinantal varieties from conditional independence models with hidden variables, focusing on their irreducible decompositions, dimensions, degrees, and Gr\"obner bases. Each variety encodes a collection of matroids, whose flats…

Combinatorics · Mathematics 2026-01-22 Per Alexandersson , Yulia Alexandr , Emiliano Liwski , Fatemeh Mohammadi , Pardis Semnani

In this paper, we define generalized splitting and element splitting operations on $p$-matroids. $p$-matroids are the matroids representable over $GF(p).$ The circuits and the bases of the new matroid are characterized in terms of circuits…

Combinatorics · Mathematics 2023-03-06 Sachin Gunjal , Uday Jagadale , Prashant Malavadkar

The effect of replacing a basis element on the way the basis spans other elements is studied. This leads to a new characterization of binary matroids.

Combinatorics · Mathematics 2012-03-02 Daniel Kotlar

We prove that any element in a matroid can be removed, by either deletion or contraction, in such a way that no tangle "splits".

Combinatorics · Mathematics 2025-12-12 Jim Geelen

In a finite real reflection group, two factorizations of a Coxeter element into an arbitrary number of reflections are shown to lie in the same orbit under the Hurwitz action if and only if they use the same multiset of conjugacy classes.…

Combinatorics · Mathematics 2016-12-12 Joel Brewster Lewis , Victor Reiner

We introduce the notion of a matroid M over a commutative ring R, assigning to every subset of the ground set an R-module according to some axioms. When R is a field, we recover matroids. When R=$\mathbb{Z}$, and when R is a DVR, we get…

Combinatorics · Mathematics 2019-11-19 Alex Fink , Luca Moci

A minor-closed class of matroids is (strongly) fractal if the number of n-element matroids in the class is dominated by the number of n-element excluded minors. We conjecture that when K is an infinite field, the class of K-representable…

Combinatorics · Mathematics 2019-08-01 Dillon Mayhew , Mike Newman , Geoff Whittle

We construct a family of independent sets for finite, atomic, and graded lattices, extending the well-known cryptomorphism between geometric lattices and matroids. This construction leads to an embedding theorem into geometric lattices that…

Combinatorics · Mathematics 2026-01-08 Or Raz

Inspired by Kontsevich's graphic orbifold Euler characteristic we define a virtual Euler characteristic for any finite set of isomorphism classes of matroids of rank $r$. Our main result provides a simple formula for the virtual Euler…

Combinatorics · Mathematics 2026-02-05 Madeline Brandt , Juliette Bruce , Daniel Corey

Double circuits were introduced by Lov\'{a}sz in 1980 as a fundamental tool in his derivation of a min-max formula for the size of a maximum matching in linear matroids. This formula was extended to all matroids satisfying the so-called…

Combinatorics · Mathematics 2026-02-13 Bill Jackson , Anthony Nixon , Ben Smith

We introduce a new class of structured symmetric matrices by extending the notion of perfect elimination ordering from graphs to weighted graphs or matrices. This offers a common framework capturing common vertex elimination orderings of…

Combinatorics · Mathematics 2018-11-20 Monique Laurent , Shin-ichi Tanigawa