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Split matroids form a minor-closed class of matroids, and are defined by placing conditions on the system of split hyperplanes in the matroid base polytope. They can equivalently be defined in terms of structural properties involving cyclic…

Combinatorics · Mathematics 2021-01-07 Amanda Cameron , Dillon Mayhew

Let $\mathcal{N}$ be a set of matroids. A matroid $M$ is strictly $\mathcal{N}$-fragile if $M$ has a member of $\mathcal{N}$ as minor and, for all $e \in E(M)$, at least one of $M\backslash e$ and $M/e$ has no minor in $\mathcal{N}$. In…

Combinatorics · Mathematics 2015-11-10 Ben Clark , Dillon Mayhew , Stefan van Zwam , Geoff Whittle

We give two graph theoretical characterizations of tope graphs of (complexes of) oriented matroids. The first is in terms of excluded partial cube minors, the second is that all antipodal subgraphs are gated. A direct consequence is a third…

Combinatorics · Mathematics 2019-05-29 Kolja Knauer , Tilen Marc

We generalize the formalism of the dynamical vertex approximation (D$\Gamma$A) -- a diagrammatic extension of the dynamical mean-field theory (DMFT)-- to treat magnetically ordered phases. To this aim, we start by concisely illustrating the…

Strongly Correlated Electrons · Physics 2021-08-18 Lorenzo Del Re , Alessandro Toschi

The main result of this paper is a generalization of the classical blossom algorithm for finding perfect matchings. Our algorithm can efficiently solve Boolean CSPs where each variable appears in exactly two constraints (we call it edge…

Computational Complexity · Computer Science 2018-06-15 Alexandr Kazda , Vladimir Kolmogorov , Michal Rolínek

Inspired by a recent result of Brakensiek et al. that symmetric tensor matroids and rigidity matroids are linked by matroid duality, we define abstract symmetric tensor matroids as a dual concept to abstract rigidity matroids and establish…

Combinatorics · Mathematics 2025-03-20 Bill Jackson , Shin-ichi Tanigawa

Leclerc and Zelevinsky, motivated by the study of quasi-commuting quantum flag minors, introduced the notions of strongly separated and weakly separated collections. These notions are closely related to the theory of cluster algebras, to…

Combinatorics · Mathematics 2021-03-26 Pavel Galashin , Alexander Postnikov

The class of cographs or complement-reducible graphs is the class of graphs that can be generated from $K_1$ using the operations of disjoint union and complementation. By analogy, this paper introduces the class of binary comatroids as the…

Combinatorics · Mathematics 2021-10-20 James Oxley , Jagdeep Singh

We prove a splitter theorem for tight multimatroids, generalizing the corresponding result for matroids, obtained independently by Brylawski and Seymour. Further corollaries give splitter theorems for delta-matroids and ribbon graphs.

Combinatorics · Mathematics 2017-03-09 Carolyn Chun , Deborah Chun , Steven D. Noble

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

Gross, Mansour and Tucker introduced the partial-dual polynomial of a ribbon graph and asked under what conditions such a polynomial is even-interpolating, odd-interpolating, or both. In this paper, we provide an answer to this open…

Combinatorics · Mathematics 2026-05-08 Zhao Zhao , Qi Yan

The $es$-splitting operation on binary bridge-less matroids never produces an Eulerian matroid. But for matroids representable over $GF(p),(p>2),$ called $p$-matroids, the $es$-splitting operation may yield Eulerian matroids. In this work,…

Combinatorics · Mathematics 2022-11-29 Uday Jagadale , Prashant Malavadkar , Sachin Gunjal , M. M. Shikare

A $\{0,1\}$-matrix $\mathsf{A}$ is balanced if it does not contain a submatrix of odd order having exactly two 1's per row and per column. A graph is balanced if its clique-matrix is balanced. No characterization of minimally unbalanced…

Discrete Mathematics · Computer Science 2014-06-27 N. Apollonio , A. Galluccio

In general, the splitting operation on binary matroids does not preserve the graphicness and cographicness properties of binary matroids. In this paper, we obtain a characterization of the class of graphic matroids whose splitting with…

Combinatorics · Mathematics 2023-10-06 S. D. Solanki , Ganesh Mundhe , S. B. Dhotre

The Weighted $\mathcal{F}$-Vertex Deletion for a class ${\cal F}$ of graphs asks, weighted graph $G$, for a minimum weight vertex set $S$ such that $G-S\in{\cal F}.$ The case when ${\cal F}$ is minor-closed and excludes some graph as a…

Data Structures and Algorithms · Computer Science 2025-01-09 Eun Jung Kim , Euiwoong Lee , Dimitrios M. Thilikos

Seymour's Decomposition Theorem for regular matroids states that any matroid representable over both GF(2) and GF(3) can be obtained from matroids that are graphic, cographic, or isomorphic to R10 by 1-, 2-, and 3-sums. It is hoped that…

Combinatorics · Mathematics 2015-03-13 Dillon Mayhew , Geoff Whittle , Stefan H. M. van Zwam

Many real-world datasets can be represented in the form of a graph whose edge weights designate similarities between instances. A discrete Gaussian random field (GRF) model is a finite-dimensional Gaussian process (GP) whose prior…

Machine Learning · Computer Science 2012-09-18 Yifei Ma , Roman Garnett , Jeff Schneider

Using F-theory we construct 4D ${\cal N}=1$ SUGRA theories with the Standard Model gauge group, three chiral generations, and matter parity in order to forbid all dimension four baryon and lepton number violating operators. The underlying…

High Energy Physics - Theory · Physics 2018-10-17 Mirjam Cvetič , Ling Lin , Muyang Liu , Paul-Konstantin Oehlmann

Slater introduced the point-addition operation on graphs to classify 4-connected graphs. The $\Gamma$-extension operation on binary matroids is a generalization of the point-addition operation. In this paper, we obtain necessary and…

Combinatorics · Mathematics 2018-12-05 Y. M. Borse , Ganesh Mundhe

The singleton and doubleton minors of a polymatroid $\rho$ encode a surprising amount of information about the structural complexity of $\rho$. Given any polymatroid $\rho$, we can subtract from it a maximally-separated polymatroid,…

Combinatorics · Mathematics 2023-12-01 Fiona Young
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