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There are two chiral Archimedean polyhedra, the snub cube and snub dodecahedron together with their duals the Catalan solids, pentagonal icositetrahedron and pentagonal hexacontahedron. In this paper we construct the chiral polyhedra and…

Mathematical Physics · Physics 2016-12-20 Mehmet Koca , Nazife Ozdes Koca , Muna Al-Shu'eili

A convex polygon is defined as a sequence (V_0,...,V_{n-1}) of points on a plane such that the union of the edges [V_0,V_1],..., [V_{n-2},V_{n-1}], [V_{n-1},V_0] coincides with the boundary of the convex hull of the set of vertices…

General Mathematics · Mathematics 2007-05-23 Iosif Pinelis

In this paper, we establish that the non-zero dihedral angles of hyperbolic Coxeter polyhedra of large dimensions are not arbitrarily small. Namely, for dimensions $n\geq 32$, they are of the form $\frac{\pi}{m}$ with $m\leq 6$. Moreover,…

Combinatorics · Mathematics 2025-07-08 Naomi Bredon

Abstract polytopes generalize the classical notion of convex polytopes to more general combinatorial structures. The most studied ones are regular and chiral polytopes, as it is well-known, they can be constructed as coset geometries from…

Combinatorics · Mathematics 2023-04-06 Isabel Hubard , Elías Mochán

Given a set of disjoint simple polygons $\sigma_1, \ldots, \sigma_n$, of total complexity $N$, consider a convexification process that repeatedly replaces a polygon by its convex hull, and any two (by now convex) polygons that intersect by…

Computational Geometry · Computer Science 2019-12-11 Elias Dahlhaus , Sariel Har-Peled , Alan L. Hu

Sometimes, it is possible to represent a complicated polytope as a projection of a much simpler polytope. To quantify this phenomenon, the extension complexity of a polytope $P$ is defined to be the minimum number of facets of a (possibly…

Combinatorics · Mathematics 2022-03-24 Matthew Kwan , Lisa Sauermann , Yufei Zhao

This work presents the tessellations and polytopes from the perspective of both n-dimensional geometry and abstract symmetry groups. It starts with a brief introduction to the terminology and a short motivation. In the first part, it…

Group Theory · Mathematics 2023-01-06 Plamen Dimitrov

Orthogonal surfaces are nice mathematical objects which have interesting connections to various fields, e.g., integer programming, monomial ideals and order dimension. While orthogonal surfaces in one or two dimensions are rather trivial…

Combinatorics · Mathematics 2007-05-23 Stefan Felsner , Sarah Kappes

The exact complexity of geometric cuts and bisections is the longstanding open problem including even the dimension one. In this paper, we resolve this problem for dimension one (the real line) by designing an exact polynomial time…

Data Structures and Algorithms · Computer Science 2012-07-05 Marek Karpinski , Andrzej Lingas , Dzmitry Sledneu

Classical results of Cauchy and Dehn imply that the 1-skeleton of a convex polyhedron $P$ is rigid i.e. every continuous motion of the vertices of $P$ in $\mathbb R^3$ which preserves its edge lengths results in a polyhedron which is…

Combinatorics · Mathematics 2025-03-04 James Cruickshank , Bill Jackson , Shin-ichi Tanigawa

Let $P$ be an orthogonal polygon of $n$ vertices, without holes. The Orthogonal Polygon Covering with Squares (OPCS) problem takes as input such an orthogonal polygon $P$ with integral vertex coordinates, and asks to find the minimum number…

Computational Geometry · Computer Science 2024-11-19 Anubhav Dhar , Subham Ghosh , Sudeshna Kolay

A completely well-centered tetrahedral mesh is a triangulation of a three dimensional domain in which every tetrahedron and every triangle contains its circumcenter in its interior. Such meshes have applications in scientific computing and…

Computational Geometry · Computer Science 2008-08-06 Evan VanderZee , Anil N. Hirani , Damrong Guoy

In this paper we describe a procedure for calculating the number of regular octahedrons that have vertices with coordinates in the set {0,1,...,n}. As a result, we introduce a new sequence in ``The Online Encyclopedia of Integer Sequences"…

Number Theory · Mathematics 2010-07-12 Eugen J. Ionascu

A spherical polyhedron surface is a triangulated surface obtained by isometric gluing of spherical triangles. For instance, the boundary of a generic convex polytope in the 3-sphere is a spherical polyhedron surface. This paper investigates…

Geometric Topology · Mathematics 2016-09-07 Feng Luo

The Euclidean projection onto a convex set is an important problem that arises in numerous constrained optimization tasks. Unfortunately, in many cases, computing projections is computationally demanding. In this work, we focus on…

Optimization and Control · Mathematics 2021-09-22 Ilnura Usmanova , Maryam Kamgarpour , Andreas Krause , Kfir Yehuda Levy

An $S$-hypersimplex for $S \subseteq \{0,1, \dots,d\}$ is the convex hull of all $0/1$-vectors of length $d$ with coordinate sum in $S$. These polytopes generalize the classical hypersimplices as well as cubes, crosspolytopes, and…

Combinatorics · Mathematics 2019-12-02 Sebastian Manecke , Raman Sanyal , Jeonghoon So

It is shown that there exists a dihedral acute triangulation of the three-dimensional cube. The method of constructing the acute triangulation is described, and symmetries of the triangulation are discussed.

Computational Geometry · Computer Science 2009-09-30 Evan VanderZee , Anil N. Hirani , Vadim Zharnitsky , Damrong Guoy

Algorithms that decompose a manifold into simple pieces reveal the geometric and topological structure of the manifold, showing how complicated structures are constructed from simple building blocks. This note describes a way to…

Geometric Topology · Mathematics 2022-06-08 Mark Bell , Joel Hass , J. Hyam Rubinstein , Stephan Tillmann

Polypolyhedra are edge-transitive compounds of polyhedra. In this paper we use group theory to determine the number of distinct polypolyhedra whose symmetry group is any given finite irreducible Coxeter group. We apply this result in order…

Across various scientific and engineering domains, a growing interest in flexible and deployable structures is becoming evident. These structures facilitate seamless transitions between distinct states of shape and find broad applicability…

Rings and Algebras · Mathematics 2024-01-26 Yang Liu , Yi Ouyang , Dominik L. Michels