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It is unknown whether every polycube (polyhedron constructed by gluing cubes face-to-face) has an edge unfolding, that is, cuts along edges of the cubes that unfolds the polycube to a single nonoverlapping polygon in the plane. Here we…

Computational Geometry · Computer Science 2022-05-24 Erik D. Demaine , Martin L. Demaine , David Eppstein , Joseph O'Rourke

We briefly introduce several problems: (1) a generalization of the convex fair partition conjecture, (2) on non-trivial invariants among polyhedrons that can be formed from the same set of face polygons, (3) two questions on assembling…

Metric Geometry · Mathematics 2015-02-16 R. Nandakumar

We extend the notion of a star unfolding to be based on a simple quasigeodesic loop Q rather than on a point. This gives a new general method to unfold the surface of any convex polyhedron P to a simple, planar polygon: shortest paths from…

Computational Geometry · Computer Science 2008-12-15 Jin-ichi Itoh , Joseph O'Rourke , Costin Vîlcu

We study polyiamonds (polygons arising from the triangular grid) that fold into the smallest yet unstudied platonic solid -- the octahedron. We show a number of results. Firstly, we characterize foldable polyiamonds containing a hole of…

Computational Geometry · Computer Science 2022-07-29 Eva Stehr , Linda Kleist

We show that every orthogonal polyhedron homeomorphic to a sphere can be unfolded without overlap while using only polynomially many (orthogonal) cuts. By contrast, the best previous such result used exponentially many cuts. More precisely,…

Computational Geometry · Computer Science 2011-12-21 Mirela Damian , Erik Demaine , Robin Flatland

In the study of monostatic polyhedra, initiated by John H. Conway in 1966, the main question is to construct such an object with the minimal number of faces and vertices. By distinguishing between various material distributions and…

Metric Geometry · Mathematics 2023-04-17 Dávid Papp , Krisztina Regős , Gábor Domokos , Sándor Bozóki

A pseudo-edge graph of a convex polyhedron K is a 3-connected embedded graph in K whose vertices coincide with those of K, whose edges are distance minimizing geodesics, and whose faces are convex. We construct a convex polyhedron K in…

Metric Geometry · Mathematics 2019-03-01 Nicholas Barvinok , Mohammad Ghomi

Given a set of radii measured from a fixed point, the existence of a convex configuration with respect to the set of distinct radii in the two-dimensional case is proved when radii are distinct or repeated at most four points. However, we…

Computational Geometry · Computer Science 2025-08-22 Supanut Chaidee , Kokichi Sugihara

Problems with localized nonhomogeneous material properties arise frequently in many applications and are a well-known source of difficulty in numerical simulations. In certain applications (including additive manufacturing), the physics of…

Numerical Analysis · Mathematics 2020-04-22 Alex Viguerie , Silvia Bertoluzza , Ferdinando Auricchio

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 examine a computational geometric problem concerning the structure of polymers. We model a polymer as a polygonal chain in three dimensions. Each edge splits the polymer into two subchains, and a dihedral rotation rotates one of these…

Computational Geometry · Computer Science 2007-05-23 Michael Soss , Jeff Erickson , Mark Overmars

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

We present new examples of topologically convex edge-ununfoldable polyhedra, i.e., polyhedra that are combinatorially equivalent to convex polyhedra, yet cannot be cut along their edges and unfolded into one planar piece without overlap.…

Computational Geometry · Computer Science 2020-07-30 Erik D. Demaine , Martin L. Demaine , David Eppstein

Our main result is that every n-dimensional polytope can be described by at most (2n-1) polynomial inequalities and, moreover, these polynomials can explicitly be constructed. For an n-dimensional pointed polyhedral cone we prove the bound…

Metric Geometry · Mathematics 2007-05-23 Hartwig Bosse , Martin Groetschel , Martin Henk

Let us consider the set of all joint probabilities generated by local binary measurements on two separated quantum systems of a given local dimension d. We address the question of whether the shape of this quantum body is convex or not. We…

Quantum Physics · Physics 2015-05-13 K. F. Pál , T. Vértesi

Polytopes are the basic finite data structures for convex sets: they appear as feasible regions in linear optimization, as geometric summaries in algorithms, and as random objects in stochastic geometry. A natural geometric question is…

Metric Geometry · Mathematics 2026-03-10 Steven Hoehner

Constructing well-behaved Laplacian and mass matrices is essential for tetrahedral mesh processing. Unfortunately, the \emph{de facto} standard linear finite elements exhibit bias on tetrahedralized regular grids, motivating the development…

Graphics · Computer Science 2024-06-14 Alec Jacobson

Compact polyhedra of cubic point symmetry Oh, exhibit surfaces of planar sections (facets) characterized by normal vector families {abc} with up to 48 members each, compatible with Oh symmetry. We focus first on polyhedra confined by facets…

Atomic and Molecular Clusters · Physics 2022-09-20 KLaus E. Hermann

Given a set $\Sigma$ of spheres in $\mathbb{E}^d$, with $d\ge{}3$ and $d$ odd, having a fixed number of $m$ distinct radii $\rho_1,\rho_2,...,\rho_m$, we show that the worst-case combinatorial complexity of the convex hull $CH_d(\Sigma)$ of…

Computational Geometry · Computer Science 2011-06-14 Menelaos I. Karavelas , Eleni Tzanaki

Given a convex polyhedron $P$ of $n$ vertices inside a sphere $Q$, we give an $O(n^3)$-time algorithm that cuts $P$ out of $Q$ by using guillotine cuts and has cutting cost $O((\log n)^2)$ times the optimal.

Computational Geometry · Computer Science 2010-03-10 Syed Ishtiaque Ahmed , Masud Hasan , Md. Ariful Islam