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Related papers: Polypositroids

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We characterize the edges of two classes of $0/1$-polytopes. The first class corresponds to the stable set polytope of a graph $G$ and includes chain polytopes of posets, some instances of matroid independence polytopes, as well as…

Combinatorics · Mathematics 2021-10-27 Farid Aliniaeifard , Carolina Benedetti , Nantel Bergeron , Shu Xiao Li , Franco Saliola

Compact polyhedra of cubic point symmetry Oh, exhibit surfaces of planar sections (facets) characterized by normal vector families {abc} with up to 48 members each, compatible with Oh symmetry. We focus first on polyhedra confined by facets…

Atomic and Molecular Clusters · Physics 2022-09-20 KLaus E. Hermann

Plabic graphs are intimately connected to the positroid stratification of the positive Grassmannian. The duals to these graphs are quivers, and it is possible to associate to them cluster algebras. For the top-cell graph of $Gr_{+}(k,n)$,…

High Energy Physics - Theory · Physics 2015-06-22 Miguel F. Paulos , Burkhard U. W. Schwab

A plabic graph is a planar bicolored graph embedded in a disk, which satisfies some combinatorial conditions. Postnikov's boundary measurement map takes the space of positive edge weights of a plabic graph $G$ to a positroid cell in some…

Combinatorics · Mathematics 2017-03-21 Rachel Karpman , Yi Su

We study symplectic forms on hypersurface algebroids. These are a broad generalization of the $b^{k}$-Poisson structures studied extensively by Miranda, Scott, and collaborators, and their geometry is intimately related to the group of…

Differential Geometry · Mathematics 2026-02-17 Francis Bischoff , Aldo Witte

A permutation polytope is the convex hull of a group of permutation matrices. In this paper we investigate the combinatorics of permutation polytopes and their faces. As applications we completely classify permutation polytopes in…

Combinatorics · Mathematics 2010-02-14 Barbara Baumeister , Christian Haase , Benjamin Nill , Andreas Paffenholz

It is known that every lattice polytope is unimodularly equivalent to a face of some reflexive polytope. A stronger question is to ask whether every $(0,1)$-polytope is unimodularly equivalent to a facet of some reflexive polytope. A large…

Combinatorics · Mathematics 2020-09-08 Takahiro Nagaoka , Akiyoshi Tsuchiya

The cosmohedron was recently proposed as a polytope underlying the cosmological wavefunction for $\text{Tr}(\Phi^3)$ theory. Its faces were conjectured to be in bijection with Matryoshkas, which are obtained from a subdivision of a polygon…

Combinatorics · Mathematics 2026-03-23 Federico Ardila-Mantilla , Nima Arkani-Hamed , Carolina Figueiredo , Francisco Vazão

This is the second introductory paper concerning structures called rootoids and protorootoids, the definition of which is abstracted from formal properties of Coxeter groups with their root systems and weak orders. The ubiquity of…

Group Theory · Mathematics 2011-10-18 Matthew Dyer

We give an elementary introduction to some recent polyhedral techniques for understanding and solving systems of multivariate polynomial equations. We provide numerous concrete examples and illustrations, and assume no background in…

Algebraic Geometry · Mathematics 2025-10-20 J. Maurice Rojas

The aim of the paper is to calculate face numbers of simple generalized permutohedra, and study their f-, h- and gamma-vectors. These polytopes include permutohedra, associahedra, graph-associahedra, simple graphic zonotopes, nestohedra,…

Combinatorics · Mathematics 2007-05-23 Alexander Postnikov , Victor Reiner , Lauren Williams

Given two tropical polynomials $f, g$ on $\mathbb{R}^n$, we provide a characterization for the existence of a factorization $f= h \odot g$ and the construction of $h$. As a ramification of this result we obtain a parallel result for the…

Combinatorics · Mathematics 2019-08-02 Robert Alexander Crowell

We show the existence of families of periodic polyhedra in spaces of constant curvature whose fundamental domains can be obtained by attaching prisms and antiprisms to Archimedean solids. These polyhedra have constant discrete curvature and…

Differential Geometry · Mathematics 2024-01-09 Christina Duffield , Daniel Freese , William Holt , Matthias Weber , Ramazan Yol

In this paper we use toric geometry to investigate the topology of the totally non-negative part of the Grassmannian (Gr_{kn})_{\geq 0}. This is a cell complex whose cells Delta_G can be parameterized in terms of the combinatorics of…

Algebraic Geometry · Mathematics 2008-10-15 Alexander Postnikov , David Speyer , Lauren Williams

We tackle the problem of a combinatorial classification of finite metric spaces via their fundamental polytopes, as suggested by Vershik in 2010. In this paper we consider a hyperplane arrangement associated to every split pseudometric and,…

Combinatorics · Mathematics 2022-03-28 Emanuele Delucchi , Linard Hoessly

This memoir constitutes the author's PhD thesis at Cornell University. It serves both as an expository work and as a description of new research. At the heart of the memoir, we introduce and study a poset $NC^{(k)}(W)$ for each finite…

Combinatorics · Mathematics 2007-10-19 Drew Armstrong

A dimer model is a quiver with faces embedded into a disk. A consistent dimer model gives rise to a strand diagram, and hence to a positroid. The Gorenstein-projective module category over the completed boundary algebra of a dimer model was…

Representation Theory · Mathematics 2024-04-04 Jonah Berggren , Khrystyna Serhiyenko

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 enumerate factorizations of a Coxeter element in a well generated complex reflection group into arbitrary factors, keeping track of the fixed space dimension of each factor. In the infinite families of generalized permutations, our…

Combinatorics · Mathematics 2024-02-07 Joel Brewster Lewis , Alejandro H. Morales

In this paper, we continue our study of blade arrangements and the positroidal subdivisions which are induced by them on $\Delta_{k,n}$. A blade is a tropical hypersurface which is generated by a system of $n$ affine simple roots of type…

Combinatorics · Mathematics 2022-10-14 Nick Early