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Define a body A to be able to hide behind a body B if the orthogonal projection of B contains a translation of the corresponding orthogonal projection of A in every direction. In two dimensions, it is easy to observe that there exist two…

Metric Geometry · Mathematics 2015-03-20 Christina Chen

An equiangular hyperbolic Coxeter polyhedron is a hyperbolic polyhedron where all dihedral angles are equal to \pi/n for some fixed integer n at least 2. It is a consequence of Andreev's theorem that either n=3 and the polyhedron has all…

Geometric Topology · Mathematics 2014-10-01 Christopher K. Atkinson

Hyperideal tetrahedra are the fundamental building blocks of hyperbolic 3-manifolds with geodesic boundary. The study of their geometric properties (in particular, of their volume) has applications also in other areas of low-dimensional…

Geometric Topology · Mathematics 2019-04-12 Roberto Frigerio , Marco Moraschini

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

The dodecahedral conjecture states that the volume of the Voronoi polyhedron of a sphere in a packing of equal spheres is at least the volume of a regular dodecahedron with inradius 1. The authors prove the conjecture following the…

Metric Geometry · Mathematics 2008-08-09 Thomas C. Hales , Sean McLaughlin

We provide two algorithms for computing the volume of a convex polytope with half-space representation {x>=0; Ax <=b} for some (m,n) matrix A and some m-vector b. Both algorithms have a O(n^m) computational complexity which makes them…

Numerical Analysis · Mathematics 2025-10-20 J. B. Lasserre , E. S. Zeron

In this paper we give an affirmative answer to the following question posed by Daryl Cooper: If one lengthens the sides of a tetrahedron by one unit, is the result still a tetrahedron and (if so) does the volume increase? Our proof involves…

Metric Geometry · Mathematics 2014-08-06 Richard Evan Schwartz

In this paper, we are interested in flat metric structures with conical singularities on surfaces which are obtained by deforming translation surface structures. The moduli space of such flat metric structures can be viewed as some…

Differential Geometry · Mathematics 2010-02-18 Duc-Manh Nguyen

In this paper, we give a formula for the area of the triangle formed by the vertices that live on a given polynomial, and we generalize this formula to the volumes of $n$-simplices with vertices on a polynomial space curve. To prove these…

Combinatorics · Mathematics 2015-05-14 Zubeyir Cinkir

There is an elegant expression for the volume of hypercube $[0,1]^n$ clipped by a single hyperplane. In the article the formula is generalized to the case of more than one hyperplane. An important foundation for the result is Lawrence's…

Combinatorics · Mathematics 2022-05-11 Yunhi Cho , Seonhwa Kim

In this paper we obtain new upper bounds on volumes of right-angled polyhedra in hyperbolic space $\mathbb{H}^3$ in three different cases: for ideal polyhedra with all vertices on the ideal hyperbolic boundary, for compact polytopes with…

Geometric Topology · Mathematics 2022-01-06 Stepan Alexandrov , Nikolay Bogachev , Andrei Egorov , Andrei Vesnin

We prove that the answer to the question of the title is `as many times as you want.' More precisely, given any constant $c>0$, we construct two oblique triangular bipyramids, $P$ and $Q$, such that $P$ is convex, $Q$ is nonconvex and…

Metric Geometry · Mathematics 2017-08-08 Victor Alexandrov

The sample range of uniform random points $X_1, \dots , X_n$ chosen in a given convex set is the convex hull ${\rm conv}[X_1, \dots, X_n]$. It is shown that in dimension three the expected volume of the sample range is not monotone with…

Probability · Mathematics 2016-12-07 Stefan Kunis , Benjamin Reichenwallner , Matthias Reitzner

In this paper, we propose two methods of calculating theoretically maximal metamer mismatch volumes. Unlike prior art techniques, our methods do not make any assumptions on the shape of spectra on the boundary of the mismatch volumes. Both…

Computational Geometry · Computer Science 2019-01-25 Michal Mackiewicz , Hans Jakob Rivertz , Graham D. Finlayson

A calculation formula of volume of revolution with integration by parts of definite integral is derived based on monotone function, and extended to a general case that curved trapezoids is determined by continuous, piecewise strictly…

Classical Analysis and ODEs · Mathematics 2019-02-26 Yi Liu , Jingwei Liu

We formulate and give partial answers to several combinatorial problems on volumes of simplices determined by $n$ points in 3-space, and in general in $d$ dimensions. (i) The number of tetrahedra of minimum (nonzero) volume spanned by $n$…

Combinatorics · Mathematics 2013-12-17 Csaba D. Toth , Adrian Dumitrescu

We show that the volume of any Riemannian metric on a three sphere is bounded below by the length of the shortest closed curve that links its antipodal image. In particular, the volume is bounded below by the minimum of the length of the…

Differential Geometry · Mathematics 2007-05-23 Christopher B. Croke

In this paper an explicit formula for a lower bound on the volume of a hyperbolic orbifold, dependent on dimension and the maximal order of torsion in the orbifolds' fundamental group, is constructed.

Geometric Topology · Mathematics 2007-09-05 Ilesanmi Adeboye

We obtain an estimate for the volume of neighbourhoods of sets of large curvature in three-dimensional K\"ahler-Einstein manifolds.

Differential Geometry · Mathematics 2011-04-22 X-X. Chen , S. K. Donaldson

We derive an analytic formula for the dual Jacobian matrix of a generalised hyperbolic tetrahedron. Two cases are considered: a mildly truncated and a prism truncated tetrahedron. The Jacobian for the latter arises as an analytic…

Metric Geometry · Mathematics 2016-06-06 Alexander Kolpakov , Jun Murakami