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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

We demonstrate the existence of four types of flexible prismatic polyhedra that can be derived or inferred from a consideration of Bricard octahedra and generalizations of Bricard octahedra. These flexible polyhedra are of genus 0 and 1,…

Metric Geometry · Mathematics 2014-07-09 Gerald D. Nelson

We provide an algorithm for unfolding the surface of any orthogonal polyhedron that falls into a particular shape class we call Manhattan Towers, to a nonoverlapping planar orthogonal polygon. The algorithm cuts along edges of a 4x5x1…

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

In this work we study inside-out dissections of polygons and polyhedra. We first show that an arbitrary polygon can be inside-out dissected with $2n+1$ pieces, thereby improving the best previous upper bound of $4(n-2)$ pieces.…

Computational Geometry · Computer Science 2024-11-12 Reymond Akpanya , Adi Rivkin , Frederick Stock

In this note we consider the problem of manufacturing a convex polyhedral object via casting. We consider a generalization of the sand casting process where the object is manufactured by gluing together two identical faces of parts cast…

Computational Geometry · Computer Science 2007-05-23 David Bremner , Alexander Golynski

It is shown that every orthogonal terrain, i.e., an orthogonal (right-angled) polyhedron based on a rectangle that meets every vertical line in a segment, has a grid unfolding: its surface may be unfolded to a single non-overlapping piece…

Computational Geometry · Computer Science 2007-07-12 Joseph O'Rourke

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

Given any finite set of nonnegative integers, there exists a closed convex set whose facial dimension signature coincides with this set of integers, that is, the dimensions of its nonempty faces comprise exactly this set of integers. In…

Optimization and Control · Mathematics 2024-08-26 Vera Roshchina , Levent Tunçel

We prove that every homogeneous convex polyhedron with only one unstable equilibrium (known as a mono-unstable convex polyhedron) has at least $7$ vertices. Although it has been long known that no mono-unstable tetrahedra exist, and…

Metric Geometry · Mathematics 2024-06-06 Sándor Bozóki , Gábor Domokos , Dávid Papp , Krisztina Regős

We consider whether any two triangulations of a polygon or a point set on a non-planar surface with a given metric can be transformed into each other by a sequence of edge flips. The answer is negative in general with some remarkable…

Metric Geometry · Mathematics 2010-08-02 C. Cortes , C. I. Grima , F. Hurtado , A. Marquez , F. Santos , J. Valenzuela

We study a polyhedron with $n$ vertices of fixed volume having minimum surface area. Completing the proof of Fejes Toth, we show that all faces of a minimum polyhedron are triangles, and further prove that a minimum polyhedron does not…

Metric Geometry · Mathematics 2020-12-21 Shigeki Akiyama

We study the problem of folding a polyomino $P$ into a polycube $Q$, allowing faces of $Q$ to be covered multiple times. First, we define a variety of folding models according to whether the folds (a) must be along grid lines of $P$ or can…

We construct the first two continuous bloomings of all convex polyhedra. First, the source unfolding can be continuously bloomed. Second, any unfolding of a convex polyhedron can be refined (further cut, by a linear number of cuts) to have…

Computational Geometry · Computer Science 2009-06-16 Erik D. Demaine , Martin L. Demaine , Vi Hart , John Iacono , Stefan Langerman , Joseph O'Rourke

Let $P$ be a (non necessarily convex) embedded polyhedron in $\R^3$, with its vertices on an ellipsoid. Suppose that the interior of $P$ can be decomposed into convex polytopes without adding any vertex. Then $P$ is infinitesimally rigid.…

Differential Geometry · Mathematics 2007-05-23 Jean-Marc Schlenker

Using the orthogonal connectedness, we introduce the notion of orthogonal decomposability of convex polytopes and study it in the case of Platonic and Archimedean solids. While doing so, we also encounter polytopes which are not…

Combinatorics · Mathematics 2026-03-10 Julia Q. Du , Xuemei He , Xiaotian Song , Daniela Stiller , Liping Yuan , Tudor Zamfirescu

It is well-known that the convex and concave envelope of a multilinear polynomial over a box are polyhedral functions. Exponential-sized extended and projected formulations for these envelopes are also known. We consider the convexification…

Optimization and Control · Mathematics 2021-06-14 Yibo Xu , Warren Adams , Akshay Gupte

We show that every convex polyhedron admits a simple edge unfolding after an affine transformation. In particular there exists no combinatorial obstruction to a positive resolution of Durer's unfoldability problem, which answers a question…

Metric Geometry · Mathematics 2016-01-20 Mohammad Ghomi

We characterise which simplicial surfaces can be folded onto a triangle. We define a notion of folding that incorporates the non-intersection-properties of real materials. All of the surfaces foldable onto a triangle admit a…

Combinatorics · Mathematics 2019-04-30 Markus Baumeister

Which polyominoes can be folded into a cube, using only creases along edges of the square lattice underlying the polyomino, with fold angles of $\pm 90^\circ$ and $\pm 180^\circ$, and allowing faces of the cube to be covered multiple times?…

Computational Geometry · Computer Science 2024-02-26 Oswin Aichholzer , Florian Lehner , Christian Lindorfer

In 1956, Tutte showed that every planar 4-connected graph is hamiltonian. In this article, we will generalize this result and prove that polyhedra with at most three 3-cuts are hamiltonian. In 2002 Jackson and Yu have shown this result for…

Combinatorics · Mathematics 2018-06-05 Gunnar Brinkmann , Carol T. Zamfirescu
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