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We consider the expected value for the total curvature of a random closed polygon. Numerical experiments have suggested that as the number of edges becomes large, the difference between the expected total curvature of a random closed…

Differential Geometry · Mathematics 2019-10-23 Jason Cantarella , Alexander Y Grosberg , Robert B. Kusner , Clayton Shonkwiler

In this work, we show the geometric properties of a family of polyhedra obtained by folding a regular tetrahedron along regular triangular grids. Each polyhedron is identified by a pair of nonnegative integers. The polyhedron can be cut…

Computational Geometry · Computer Science 2019-12-04 Seri Nishimoto , Takashi Horiyama , Tomohiro Tachi

We compute the analytic torsion of a cone over a sphere of dimension 1, 2, and 3, and we conjecture a general formula for the cone over an odd dimensional sphere.

Differential Geometry · Mathematics 2012-10-12 L. Hartmann , M. Spreafico

We define a new family of valuations on polyhedral cones valued in the space of bounded polyhedra.

Metric Geometry · Mathematics 2019-01-24 Hailun Zheng , Michał Zydor

Regular decompositions are necessary for most superpixel-based object recognition or tracking applications. So far in the literature, the regularity or compactness of a superpixel shape is mainly measured by its circularity. In this work,…

Computer Vision and Pattern Recognition · Computer Science 2025-09-19 Rémi Giraud , Vinh-Thong Ta , Nicolas Papadakis

Let $M$ be a compact oriented 3-manifold with non-empty boundary consisting of surfaces of genii $>1$ such that the interior of $M$ is hyperbolizable. We show that for each spherical cone-metric $d$ on $\partial M$ such that all cone-angles…

Metric Geometry · Mathematics 2025-01-08 Roman Prosanov

DeepAngle is a machine learning-based method to determine the contact angles of different phases in the tomography images of porous materials. Measurement of angles in 3--D needs to be done within the surface perpendicular to the angle…

Computer Vision and Pattern Recognition · Computer Science 2022-11-29 Arash Rabbani , Chenhao Sun , Masoud Babaei , Vahid J. Niasar , Ryan T. Armstrong , Peyman Mostaghimi

A very fast heuristic iterative method of projection on simplicial cones is presented. It consists in solving two linear systems at each step of the iteration. The extensive experiments indicate that the method furnishes the exact solution…

Optimization and Control · Mathematics 2010-01-19 A. Ekárt , A. B. Németh , S. Z. Németh

We investigate the rigidity of hyperbolic cone metrics on $3$-manifolds which are isometric gluing of ideal and hyper-ideal tetrahedra in hyperbolic spaces. These metrics will be called ideal and hyper-ideal hyperbolic polyhedral metrics.…

Geometric Topology · Mathematics 2014-04-29 Feng Luo , Tian Yang

An unfolding of a polyhedron is produced by cutting the surface and flattening to a single, connected, planar piece without overlap (except possibly at boundary points). It is a long unsolved problem to determine whether every polyhedron…

Computational Geometry · Computer Science 2007-05-23 Mirela Damian , Robin Flatland , Joseph O'Rourke

A convex polyhedron, that is, a compact convex subset of $\mathbb{R}^3$ which is the intersection of finitely many closed half-spaces, can be rectified by taking the convex hull of the midpoints of the edges of the polyhedron. We derive…

Metric Geometry · Mathematics 2016-04-05 Samuel Reid

Here we analyze three dimensional analogues of the classical Crofton's formula for planar compact convex sets. In this formula a fundamental role is played by the visual angle of the convex set from an exterior point. A generalization of…

Metric Geometry · Mathematics 2023-03-09 J. Bruna , J. Cufí E. Gallego , A. Reventós

Motivated by applications in geomorphology, the aim of this paper is to extend Morse-Smale theory from smooth functions to the radial distance function (measured from an internal point), defining a convex polyhedron in 3-dimensional…

Computational Geometry · Computer Science 2023-06-16 Balázs Ludmány , Zsolt Lángi , Gábor Domokos

Hyperbolic polynomials elegantly encode a rich class of convex cones that includes polyhedral and spectrahedral cones. Hyperbolic polynomials are closed under taking polars and the corresponding cones, the derivative cones, yield…

Optimization and Control · Mathematics 2011-11-11 Raman Sanyal

We investigate the folding problem that asks if a polygon P can be folded to a polyhedron Q for given P and Q. Recently, an efficient algorithm for this problem has been developed when Q is a box. We extend this idea to regular polyhedra,…

Computational Geometry · Computer Science 2021-06-01 Tonan Kamata , Akira Kadoguchi , Takashi Horiyama , Ryuhei Uehara

A solvency cone is a polyhedral convex cone which is used in Mathematical Finance to model proportional transaction costs. It consists of those portfolios which can be traded into nonnegative positions. In this note, we provide a…

Optimization and Control · Mathematics 2024-01-26 Andreas Löhne , Birgit Rudloff

The mean width is a measure on three-dimensional convex bodies that enjoys equal status with volume and surface area [Rota]. As the phrase suggests, it is the mean of a probability density f. We verify formulas for mean widths of the…

Metric Geometry · Mathematics 2016-03-15 Steven R. Finch

Hyperbolicity cones are convex algebraic cones arising from hyperbolic polynomials. A well-understood subclass of hyperbolicity cones is that of spectrahedral cones and it is conjectured that every hyperbolicity cone is spectrahedral. In…

Optimization and Control · Mathematics 2012-08-03 Tim Netzer , Raman Sanyal

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 convex and metric structures underlying probabilistic physical theories are generally described in terms of base normed vector spaces. According to a recent proposal, the purely geometrical features of these spaces are appropriately…

Mathematical Physics · Physics 2011-01-04 P. Busch