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Consider an orthogonal polyhedron, i.e., a polyhedron where (at least after a suitable rotation) all faces are perpendicular to a coordinate axis, and hence all edges are parallel to a coordinate axis. Clearly, any facial angle and any…

Computational Geometry · Computer Science 2013-12-25 Therese Biedl , Martin Derka , Stephen Kiazyk , Anna Lubiw , Hamide Vosoughpour

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

Recently, cutting planes derived from maximal lattice-free convex sets have been studied intensively by the integer programming community. An important question in this research area has been to decide whether the closures associated with…

Optimization and Control · Mathematics 2013-01-10 Amitabh Basu , Robert Hildebrand , Matthias Köppe

A simple graph is called triangular if every edge of it belongs to a triangle. We conjecture that any graphical degree sequence all terms of which are greater than or equal to 4 has a triangular realisation, and establish this conjecture…

Combinatorics · Mathematics 2023-04-03 Benjamin Egan , Yuri Nikolayevsky

A polyiamond is a polygon composed of unit equilateral triangles, and a generalized deltahedron is a convex polyhedron whose every face is a convex polyiamond. We study a variant where one face may be an exception. For a convex polygon P,…

A polygonal complex in euclidean 3-space is a discrete polyhedron-like structure with finite or infinite polygons as faces and finite graphs as vertex-figures, such that a fixed number r of faces surround each edge. It is said to be regular…

Metric Geometry · Mathematics 2009-06-08 Daniel Pellicer , Egon Schulte

We consider facet-Hamiltonian cycles of polytopes, defined as cycles in their skeleton such that every facet is visited exactly once. These cycles can be understood as optimal watchman routes that guard the facets of a polytope. We consider…

Combinatorics · Mathematics 2024-11-05 Hugo Akitaya , Jean Cardinal , Stefan Felsner , Linda Kleist , Robert Lauff

Given a graph G, we construct a convex polytope whose face poset is based on marked subgraphs of G. Dubbed the graph multiplihedron, we provide a realization using integer coordinates. Not only does this yield a natural generalization of…

Quantum Algebra · Mathematics 2015-06-16 Satyan L. Devadoss , Stefan Forcey

This paper deals with triangulations of the 2-torus with the vertex labeled general octahedral graph $O_4$ which is isomorphic to the complete four-partite graph $K_{2,2,2,2}$; it is known that there exist precisely twelve such…

Combinatorics · Mathematics 2022-04-25 Serge Lawrencenko , Alex Lao

Every regular map on a closed surface gives rise to generally six regular maps, its "Petrie relatives", that are obtained through iteration of the duality and Petrie operations (taking duals and Petrie-duals). It is shown that the skeletal…

Combinatorics · Mathematics 2012-10-09 Anthony M. Cutler , Egon Schulte , Jorg M. Wills

Mr. C. Stephanos posed the following question in the Interm\'ediaire des Math\'ematiciens: "Do there exist polyhedra with invariant facets that are susceptible to an infinite family of transformations that only alter solid angles and…

History and Overview · Mathematics 2012-03-07 Raoul Bricard

A fullerene graph is a cubic bridgeless plane graph with only pentagonal and hexagonal faces. We exhibit an infinite family of fullerene graphs of diameter $\sqrt{4n/3}$, where $n$ is the number of vertices. This disproves a conjecture of…

Combinatorics · Mathematics 2017-09-22 Diego Nicodemos , Matěj Stehlík

When the number of non-triangular faces adjacent to a vertex $v$ is less than or equal to three, the vertex $v$ will be called (\emph{combinatorially}) \emph{rigid}. We study the number of rigid vertices and suggest a conjecture on a…

Metric Geometry · Mathematics 2017-03-16 Seonhwa Kim , Yunhi Cho

A chiral polyhedron has a geometric symmetry group with two orbits on the flags, such that adjacent flags are in distinct orbits. Part I of the paper described the discrete chiral polyhedra in ordinary Euclidean 3-space with finite skew…

Metric Geometry · Mathematics 2007-05-23 Egon Schulte

A spherical polyhedron surface is a triangulated surface obtained by isometric gluing of spherical triangles. For instance, the boundary of a generic convex polytope in the 3-sphere is a spherical polyhedron surface. This paper investigates…

Geometric Topology · Mathematics 2016-09-07 Feng Luo

Skeletal polyhedra and polygonal complexes in ordinary Euclidean 3-space are finite or infinite 3-periodic structures with interesting geometric, combinatorial, and algebraic properties. They can be viewed as finite or infinite 3-periodic…

Metric Geometry · Mathematics 2014-03-04 Egon Schulte

For a finite planar graph, it associates with some metric spaces, called (regular) spherical polyhedral surfaces, by replacing faces with regular spherical polygons in the unit sphere and gluing them edge-to-edge. We consider the class of…

Metric Geometry · Mathematics 2018-05-01 Yohji Akama , Bobo Hua , Yanhui Su

We consider triangle faced convex polyhedra inscribed in the unit sphere $S^2$ in ${\Bbb{R}}^3$. One way of measuring their deviation from regular polyhedra with triangular faces is to consider the quotient of the lengths of the longest and…

Metric Geometry · Mathematics 2019-09-09 E. Makai,

Given a convex n-gon P in the Euclidean plane, it is well known that the simplicial complex \theta(P) with vertex set given by diagonals in P and facets given by triangulations of P is the boundary complex of a polytope of dimension n-3. We…

Combinatorics · Mathematics 2010-07-23 Benjamin Braun , Richard Ehrenborg

Considering regions in a map to be adjacent when they have nonempty intersection (as opposed to the traditional view requiring intersection in a linear segment) leads to the concept of a facially complete graph: a plane graph that becomes…

Combinatorics · Mathematics 2024-09-18 James Tilley , Stan Wagon , Eric Weisstein