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We examine certain maps from root systems to vector spaces over finite fields. By choosing appropriate bases, the images of these maps can turn out to have nice combinatorial properties, which reflect the structure of the underlying root…

Combinatorics · Mathematics 2007-05-23 Kevin Purbhoo

We investigate the collapsibility of systolic finite simplicial complexes of arbitrary dimension. The main tool we use in the proof is discrete Morse theory. We shall consider a convex subcomplex of the complex and project any simplex of…

Combinatorics · Mathematics 2014-03-19 Djordje Baralic , Ioana-Claudia Lazar

Each convex combination of extreme points of a compact convex set represents a certain point of the convex set. Barycentric coordinates provide solutions to the inverse problem of expressing an element of a compact convex set as a convex…

Metric Geometry · Mathematics 2026-03-10 A. B. Romanowska , J. D. H. Smith , A. Zamojska-Dzienio

Ghomi proved that every convex polyhedron could be stretched via an affine transformation so that it has an edge-unfolding to a net [Gho14]. A net is a simple planar polygon; in particular, it does not self-overlap. One can view his result…

Computational Geometry · Computer Science 2023-02-17 Joseph O'Rourke

We prove that a conformal mapping defined on the unit disk belongs to a weighted Bergman space if and only if certain integrals involving the harmonic measure converge. With the aid of this theorem, we give a geometric characterization of…

Complex Variables · Mathematics 2021-09-23 Christina Karafyllia , Nikolaos Karamanlis

We develop a combinatorial framework to study certain polyhedral maps which are higher-dimensional analogues of tropical covers between metric graphs. Under a mild combinatorial assumption, we show that a map satisfies the so-called…

Combinatorics · Mathematics 2023-05-08 Alejandro Vargas

We define the notion of colocally weakly differentiable maps from a manifold $M$ to a manifold $N$. If $p \ge 1$ and $M$ and $N$ are endowed with a Riemannian metric, this allows us to define intrinsically the homogeneous Sobolev space…

Functional Analysis · Mathematics 2017-07-04 Alexandra Convent , Jean Van Schaftingen

Given a tree $T$, its path polytope is the convex hull of the edge indicator vectors for the paths between any two distinct leaves in $T$. These polytopes arise naturally in polyhedral geometry and applications, such as phylogenetics,…

Combinatorics · Mathematics 2025-03-03 Amer Goel , Aida Maraj , Alvaro Ribot

We study the harmonic polytope, which arose in Ardila, Denham, and Huh's work on the Lagrangian geometry of matroids. We describe its combinatorial structure, showing that it is a $(2n-2)$-dimensional polytope with…

Combinatorics · Mathematics 2021-07-05 Federico Ardila , Laura Escobar

The goal of this paper is to establish certain inequalities between the numbers of convex polytopes in the d-dimensional space "containing" and "avoiding" zero provided that their vertex sets are subsets of a given finite set of points in…

Combinatorics · Mathematics 2013-12-24 Alexander Kelmans , Anatoliy Rubinov

The convex shape contained in a disk having prescribed area and maximal perimeter is completely characterized in terms of the area fraction. The solution is always a polygon having all but one sides equal. The lengths of the sides are…

Metric Geometry · Mathematics 2024-02-09 Beniamin Bogosel

Bisztriczky defines a multiplex as a generalization of a simplex, and an ordinary polytope as a generalization of a cyclic polytope. This paper presents results concerning the combinatorics of multiplexes and ordinary polytopes. The flag…

Combinatorics · Mathematics 2007-05-23 Margaret M. Bayer , Aaron M. Bruening , Joshua Stewart

Abstractly, tropical hyperelliptic curves are metric graphs that admit a two-to-one harmonic morphism to a tree. They also appear as embedded tropical curves in the plane arising from triangulations of polygons with all interior lattice…

Algebraic Geometry · Mathematics 2019-12-17 Ralph Morrison

Irregular pyramids are made of a stack of successively reduced graphs embedded in the plane. Such pyramids are used within the segmentation framework to encode a hierarchy of partitions. The different graph models used within the irregular…

Computer Vision and Pattern Recognition · Computer Science 2007-05-23 Luc Brun , Walter G. Kropatsch

Convex polytopes are convex hulls of point sets in the $n$-dimensional space $\E^n$ that generalize 2-dimensional convex polygons and 3-dimensional convex polyhedra. We concentrate on the class of $n$-dimensional polytopes in $\E^n$ called…

Quantum Physics · Physics 2010-12-15 Colin Wilmott , Hermann Kampermann , Dagmar Bruss

We present a method of constructing discrete integrable systems with crystallographic reflection group (Weyl) symmetries, thus clarifying the relationship between different discrete integrable systems in terms of their symmetry groups.…

Exactly Solvable and Integrable Systems · Physics 2016-05-05 Nalini Joshi , Nobutaka Nakazono , Yang Shi

One of the basic problems in discrete geometry is to determine the most efficient packing of congruent replicas of a given convex set $K$ in the plane or in space. The most commonly used measure of efficiency is density. Several types of…

Metric Geometry · Mathematics 2016-08-14 András Bezdek , Włodzimierz Kuperberg

Discrete forms of the mean and directed curvature are constructed on piecewise flat manifolds, providing local curvature approximations for smooth manifolds embedded in both Euclidean and non-Euclidean spaces. The resulting expressions take…

Differential Geometry · Mathematics 2023-04-04 Rory Conboye

Magnitude homology is an $\mathbf{R}^+$-graded homology theory of metric spaces that captures information on the complexity of geodesics. Here we address the question: when are two metric spaces magnitude homology equivalent, in the sense…

Metric Geometry · Mathematics 2026-02-25 Adrián Doña Mateo , Tom Leinster

This paper develops a uniformly valid and asymptotically nonconservative test based on projection for a class of shape restrictions. The key insight we exploit is that these restrictions form convex cones, a simple and yet elegant structure…

Econometrics · Economics 2021-09-21 Zheng Fang , Juwon Seo