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Related papers: On polyhedra inscribed in $S^2$, with approximatel…

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We analyze polyhedra composed of hexagons and triangles with three faces around each vertex, and their 3-regular planar graphs of edges and vertices, which we call "trihexes". Trihexes are analogous to fullerenes, which are 3-regular planar…

Combinatorics · Mathematics 2025-07-01 Linda Green , Stellen Li

Unfolding a convex polyhedron into a simple planar polygon is a well-studied problem. In this paper, we study the limits of unfoldability by studying nonconvex polyhedra with the same combinatorial structure as convex polyhedra. In…

Computational Geometry · Computer Science 2007-05-23 Marshall Bern , Erik D. Demaine , David Eppstein , Eric Kuo , Andrea Mantler , Jack Snoeyink

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

This article focuses on the problem of analytically determining the optimal placement of five points on the unit sphere $\mathbb{S}^2$ so that the surface area of the convex hull of the points is maximized. It is shown that the optimal…

Metric Geometry · Mathematics 2020-12-15 Jessica Donahue , Steven Hoehner , Ben Li

A 1957 conjecture by Zdzislaw Melzak, that the unit volume polyhedron with least edge length was a triangular right prism, with edge length $2^{2/3}3^{11/6}$. We present a variety of necessary local criteria for any minimizer. In the case…

Metric Geometry · Mathematics 2023-04-21 Ásgeir Valfells

For a finite planar graph, it associates with some metric spaces, called (regular) spherical polyhedral surfaces, by replacing faces with regular spherical polygons in the unit sphere and gluing them edge-to-edge. We consider the class of…

Metric Geometry · Mathematics 2018-05-01 Yohji Akama , Bobo Hua , Yanhui Su

It is a widely observed phenomenon in computer graphics that the size of the silhouette of a polyhedron is much smaller than the size of the whole polyhedron. This paper provides, for the first time, theoretical evidence supporting this for…

Computational Geometry · Computer Science 2009-09-29 Marc Glisse , Sylvain Lazard

Given n >= 4 positive real numbers, we prove in this note that they are the face areas of a convex polyhedron if and only if the largest number is not more than the sum of the others.

Discrete Mathematics · Computer Science 2011-01-06 Joseph O'Rourke

The diameter of the graph of a $d$-dimensional polyhedron with $n$ facets is at most $n^{\log d+2}$

Metric Geometry · Mathematics 2008-02-03 Gil Kalai , Daniel J. Kleitman

The space of shapes of a polyhedron with given total angles less than 2\pi at each of its n vertices has a Kaehler metric, locally isometric to complex hyperbolic space CH^{n-3}. The metric is not complete: collisions between vertices take…

Geometric Topology · Mathematics 2007-05-23 William P. Thurston

A polyiamond is a polygon composed of unit equilateral triangles, and a generalized deltahedron is a convex polyhedron whose every face is a convex polyiamond. We study a variant where one face may be an exception. For a convex polygon P,…

We study the combinatorial complexity of D-dimensional polyhedra defined as the intersection of n halfspaces, with the property that the highest dimension of any bounded face is much smaller than D. We show that, if d is the maximum…

Computational Geometry · Computer Science 2013-07-30 David Eppstein , Maarten Löffler

We prove that every three-dimensional polyhedron is uniquely determined by its dihedral angles and edge lengths, even if nonconvex or self-intersecting, under two plausible sufficient conditions: (i) the polyhedron has only convex faces and…

Geometric Topology · Mathematics 2023-07-28 Yunhi Cho , Seonhwa Kim

We study oriented connected closed polyhedral surfaces with non-degenerate triangular faces in three-dimensional Euclidean space, calling them polyhedra for short. A polyhedron is called flexible if its spatial shape can be changed…

Metric Geometry · Mathematics 2020-06-08 Victor Alexandrov

It is well known that to determine a triangle up to congruence requires three measurements: three sides, two sides and the included angle, or one side and two angles. We consider various generalizations of this fact to two and three…

Metric Geometry · Mathematics 2008-11-27 Alexander Borisov , Mark Dickinson , Stuart Hastings

This article is concerned with the problem of placing seven or eight points on the unit sphere $\mathbb{S}^2$ in $\mathbb{R}^3$ so that the surface area of the convex hull of the points is maximized. In each case, the solution is given for…

Metric Geometry · Mathematics 2024-05-22 Nicolas Freeman , Steven Hoehner , Jeff Ledford , David Pack , Brandon Walters

An example of the volume and boundary face area of a curved polyhedron for the case of regular spherical and hyperbolic tetrahedron is discussed. An exact formula is explicitly derived as a function of the scalar curvature and the edge…

General Physics · Physics 2018-04-17 Omar Nemoul , Noureddine Mebarki

If the four triangular facets of a tetrahedron can be partitioned into pairs having the same area, then the triangles in each pair must be congruent to one another. A Heron-style formula is then derived for the volume of a tetrahedron…

Metric Geometry · Mathematics 2022-11-01 Daniel A. Klain

Consider a random set of points on the unit sphere in $\mathbb{R}^d$, which can be either uniformly sampled or a Poisson point process. Its convex hull is a random inscribed polytope, whose boundary approximates the sphere. We focus on the…

Metric Geometry · Mathematics 2020-07-16 Arseniy Akopyan , Herbert Edelsbrunner , Anton Nikitenko

While there is extensive literature on approximation of convex bodies by inscribed or circumscribed polytopes, much less is known in the case of generally positioned polytopes. Here we give upper and lower bounds for approximation of convex…

Probability · Mathematics 2021-03-03 Steven D. Hoehner , Carsten Schuett , Elisabeth M. Werner
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