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Generalized alcoved polytopes are polytopes whose facet normals are roots in a given root system. We call a set of points in an alcoved polytope a generating set if there does not exist a strictly smaller alcoved polytope containing it. The…

Combinatorics · Mathematics 2016-08-22 Annette Werner , Josephine Yu

We show the uniqueness and existence of the Euler form for a simply-laced generalized root system. This enables us to show that the Coxeter element for a simply-laced generalized root system is admissible in the sense of R.~W.~Carter. As an…

Algebraic Geometry · Mathematics 2016-03-28 Shunsuke Nakamura , Yuuki Shiraishi , Atsushi Takahashi

We show that the $f$-vector of Galashin's poset associahedron $\mathscr A(P)$ only depends on the comparability graph of $P$. In particular, this allows us to produce a family of polytopes with the same $f$-vectors as permutohedra, but that…

Combinatorics · Mathematics 2023-10-03 Son Nguyen , Andrew Sack

The paper considers systems of contraction similarities in $\mathbb R^d$ sending a given polyhedron $P$ to polyhedra $P_i\subset P$, whose non-empty intersections are singletons and contain the common vertices of those polyhedra, while the…

Metric Geometry · Mathematics 2017-07-11 Andrei Tetenov , Mary Samuel , Dmitry Vaulin

We identify a family of $O(|E(G)|^2)$ nontrivial facets of the connected matching polytope of a graph $G$, that is, the convex hull of incidence vectors of matchings in $G$ whose covered vertices induce a connected subgraph. Accompanying…

Combinatorics · Mathematics 2023-10-24 Phillippe Samer

We introduce topological notions of polytopes and simplexes, the latter being expected to play in p-adically closed fields the role played by real simplexes in the classical results of triangulation of semi-algebraic sets over real closed…

Logic · Mathematics 2016-11-15 Luck Darnière

Let $\Gamma$ be a Coxeter graph, let $W$ be its associated Coxeter group, and let $G$ be a group of symmetries of $\Gamma$.Recall that, by a theorem of H{\'e}e and M\"uhlherr, $W^G$ is a Coxeter group associated to some Coxeter graph $\hat…

Group Theory · Mathematics 2018-04-23 Olivier Geneste , Jean-Yves Hée , Luis Paris

Let $G$ be a finite graph allowing loops, having no multiple edge and no isolated vertex. We associate $G$ with the edge polytope ${\cal P}_G$ and the toric ideal $I_G$. By classifying graphs whose edge polytope is simple, it is proved that…

Commutative Algebra · Mathematics 2018-08-22 Hidefumi Ohsugi , Takayuki Hibi

We define $G$-symmetric polygonal systems of similarities and study the properties of symmetric dendrites, which appear as their attractors. This allows us to find the conditions under which the attractor of a zipper becomes a dendrite.

Metric Geometry · Mathematics 2018-02-13 Mary Samuel , Dmitry Mekhontsev , Andrey Tetenov

Symmetric edge polytopes $\mathcal{A}_G$ of type A are lattice polytopes arising from the root system $A_n$ and finite simple graphs $G$. There is a connection between $\mathcal{A}_G$ and the Kuramoto synchronization model in physics. In…

Combinatorics · Mathematics 2022-01-26 Hidefumi Ohsugi , Akiyoshi Tsuchiya

This paper examines a systematic method to construct a pair of (inter-related) root systems for arbitrary Coxeter groups from a class of non-standard geometric representations. This method can be employed to construct generalizations of…

Representation Theory · Mathematics 2013-03-18 Xiang Fu

Given two graphs G and H, we ask under which conditions there is a relation R that generates the edges of H given the structure of graph G. This construction can be seen as a form of multihomomorphism. It generalizes surjective…

Combinatorics · Mathematics 2012-10-18 Jan Hubicka , Jürgen Jost , Yangjing Long , Peter F. Stadler , Ling Yang

Steinitz's theorem states that a graph $G$ is the edge-graph of a $3$-dimensional convex polyhedron if and only if, $G$ is simple, plane and $3$-connected. We prove an analogue of this theorem for ball polyhedra, that is, for intersections…

Metric Geometry · Mathematics 2020-11-23 Sami Mezal Almohammad , Márton Naszódi , Zsolt Lángi

Given a graph G, we construct a convex polytope whose face poset is based on marked subgraphs of G. Dubbed the graph multiplihedron, we provide a realization using integer coordinates. Not only does this yield a natural generalization of…

Quantum Algebra · Mathematics 2015-06-16 Satyan L. Devadoss , Stefan Forcey

For simple graphs $G$ and $H$, the Hom complex $\mathrm{Hom}(G,H)$ is a polyhedral complex whose vertices are the graph homomorphisms $G\to H$ and whose edges connect the pairs of homomorphisms which differ in a single vertex of $G$. Hom…

Combinatorics · Mathematics 2025-09-08 Soichiro Fujii , Yuni Iwamasa , Kei Kimura , Yuta Nozaki , Akira Suzuki

To directed graphs with unique sink and source we associate a noncommutative associative alsgebra and a polynomial over this algebra. Edges of the graph correspond to pseudo-roots of the polynomial. We give a sufficient condition when…

Quantum Algebra · Mathematics 2009-11-11 Israel Gelfand , Sergei Gelfand , Vladimir Retakh , Robert Lee Wilson

We consider facet-Hamiltonian cycles of polytopes, defined as cycles in their skeleton such that every facet is visited exactly once. These cycles can be understood as optimal watchman routes that guard the facets of a polytope. We consider…

Combinatorics · Mathematics 2024-11-05 Hugo Akitaya , Jean Cardinal , Stefan Felsner , Linda Kleist , Robert Lauff

To any graph $G$ one can associate a toric variety $X(\mathcal{P}G)$, obtained as a blowup of projective space along coordinate subspaces corresponding to connected subgraphs of $G$. The polytope of this toric variety is the graph…

Algebraic Geometry · Mathematics 2017-06-06 Rodrigo Ferreira da Rosa , David Jensen , Dhruv Ranganathan

Starting from a finite simple graph $G$, for each eigenvalue $\theta$ of its adjacency matrix one can construct a convex polytope $P_G(\theta)$, the so called $\theta$-eigenpolytop of $G$. For some polytopes this technique can be used to…

Metric Geometry · Mathematics 2020-09-07 Martin Winter

Matroids give rise to several natural constructions of polytopes. Inspired by this, we examine polytopes that arise from the signed circuits of an oriented matroid. We give the dimensions of these polytopes arising from graphical oriented…

Combinatorics · Mathematics 2025-01-03 Laura Escobar , Jodi McWhirter