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Related papers: On Polyhedral Realization with Isosceles Triangles

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A closed quasigeodesic is a closed curve on the surface of a polyhedron with at most $180^\circ$ of surface on both sides at all points; such curves can be locally unfolded straight. In 1949, Pogorelov proved that every convex polyhedron…

Computational Geometry · Computer Science 2025-10-21 Erik D. Demaine , Adam C. Hesterberg , Jason S. Ku

This paper introduces a new method to solve the problem of the approximation of the diagonal for face-coherent families of polytopes. We recover the classical cases of the simplices and the cubes and we solve it for the associahedra, also…

Algebraic Topology · Mathematics 2019-02-22 Naruki Masuda , Hugh Thomas , Andy Tonks , Bruno Vallette

We present a constructive proof of Alexandrov's theorem regarding the existence of a convex polytope with a given metric on the boundary. The polytope is obtained as a result of a certain deformation in the class of generalized convex…

Differential Geometry · Mathematics 2017-08-25 Alexander I. Bobenko , Ivan Izmestiev

We introduce a recursive procedure for computing the number of realizations of a minimally rigid graph on the sphere up to rotations. We accomplish this by combining two ingredients. The first is a framework that allows us to think of such…

Combinatorics · Mathematics 2023-08-30 Matteo Gallet , Georg Grasegger , Niels Lubbes , Josef Schicho

Let C be a simple, closed, directed curve on the surface of a convex polyhedron P. We identify several classes of curves C that "live on a cone," in the sense that C and a neighborhood to one side may be isometrically embedded on the…

Discrete Mathematics · Computer Science 2011-02-15 Joseph O'Rourke , Costin Vilcu

We prove that each lower-dimensional face of a quasi-arithmetic Coxeter polytope, which happens to be itself a Coxeter polytope, is also quasi-arithmetic. We also provide a sufficient condition for a codimension $1$ face to be actually…

Geometric Topology · Mathematics 2020-11-03 Nikolay Bogachev , Alexander Kolpakov

The faces of a convex set owe their relevance to an interplay between convexity and topology that is systematically studied in the work of Rockafellar. Infinite-dimensional convex sets are excluded from this theory as their relative…

Metric Geometry · Mathematics 2026-01-01 Stephan Weis

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

If all tiles in a tiling are congruent, the tiling is called monohedral. Tiling by convex polygons is called edge-to-edge if any two convex polygons are either disjoint or share one vertex or one entire edge in common. In this paper, we…

Metric Geometry · Mathematics 2017-12-27 Teruhisa Sugimoto

We present structures comprised of identical convex polyhedra which are interlocked geometrically. These sets cannot be disassembled by removing individual polyhedra by translations and/or rotations. The shapes that permit interlocking…

Metric Geometry · Mathematics 2017-12-05 A. J. Kanel-Belov , A. V. Dyskin , Y. Estrin , E. Pasternak , I. A. Ivanov-Pogodaev

We prove that, for any two polyhedral manifolds $\mathcal P, \mathcal Q$, there is a polyhedral manifold $\mathcal I$ such that $\mathcal P, \mathcal I$ share a common unfolding and $\mathcal I,\mathcal Q$ share a common unfolding. In other…

Computational Geometry · Computer Science 2025-10-08 Lily Chung , Erik D. Demaine , Jenny Diomidova , Tonan Kamata , Jayson Lynch , Ryuhei Uehara , Hanyu Alice Zhang

We prove that every cusped hyperbolic 3-manifold has a finite cover admitting infinitely many geometric ideal triangulations. Furthermore, every long Dehn filling of one cusp in this cover admits infinitely many geometric ideal…

Geometric Topology · Mathematics 2022-11-22 David Futer , Emily Hamilton , Neil R. Hoffman

A platypus graph is a non-hamiltonian graph for which every vertex-deleted subgraph is traceable. They are closely related to families of graphs satisfying interesting conditions regarding longest paths and longest cycles, for instance…

Combinatorics · Mathematics 2017-12-15 Jan Goedgebeur , Addie Neyt , Carol T. Zamfirescu

A polyhedron is flexible if it can be continuously deformed preserving the shape and dimensions of every its face. In the late 1970's Klaus Steffen constructed a sphere-homeomorphic embedded flexible polyhedron with triangular faces and…

Metric Geometry · Mathematics 2025-09-23 Victor Alexandrov , Evgenii Volokitin

In this article we consider an open conjecture about coherently labelling a polyhedron in three dimensions. We exhibit all the forty eight possible coherent labellings of a tetrahedron. We also exhibit that some simplicial polyhedra like…

Combinatorics · Mathematics 2022-11-28 C. P. Anil Kumar

A~$k$-associahedron is a simplicial complex whose facets, called~$k$-triangulations, are the inclusion maximal sets of diagonals of a convex polygon where no~$k+1$ diagonals mutually cross. Such complexes are conjectured for about a decade…

Combinatorics · Mathematics 2017-06-16 Thibault Manneville

We study three families of polyhedral cones whose sections are regular simplices, cubes, and crosspolytopes. We compute solid angles and conic intrinsic volumes of these cones. We show that several quantities appearing in stochastic…

Probability · Mathematics 2021-01-01 Zakhar Kabluchko , Hauke Seidel

We prove that any finite polyhedral manifold in 3D can be continuously flattened into 2D while preserving intrinsic distances and avoiding crossings, answering a 19-year-old open problem, if we extend standard folding models to allow for…

Computational Geometry · Computer Science 2021-05-25 Zachary Abel , Erik D. Demaine , Martin L. Demaine , Jason S. Ku , Jayson Lynch , Jin-ichi Itoh , Chie Nara

We prove that any convex geometry $\mathcal{A}=(U,\mathcal{C})$ on $n$ points and any ideal $\mathcal{I}=(U',\mathcal{C}')$ of $\mathcal{A}$ can be realized as the intersection pattern of an open convex polyhedral cone $K\subseteq {\mathbb…

Combinatorics · Mathematics 2025-07-30 Jérémie Chalopin , Victor Chepoi , Kolja Knauer

We prove that any polyhedron of genus zero or genus one built out of rectangular faces must be an orthogonal polyhedron, but that there are nonorthogonal polyhedra of genus seven all of whose faces are rectangles. This leads to a resolution…

Computational Geometry · Computer Science 2007-05-23 Melody Donoso , Joseph O'Rourke
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