We formulate general boundary conditions for a labelling to assure the existence of a balanced n-simplex in a triangulated polyhedron. Furthermore we prove a Knaster-Kuratowski-Mazurkiewicz type theorem for polyhedrons and generalize some theorems of Ichiishi and Idzik. We also formulate a necessary condition for a continuous function defined on a polyhedron to be an onto function.

We construct a flexible (non immersed) suspension with a hexagonal equator in Euclidean 3-space and study its properties related to the Strong Bellows Conjecture which reads as follows: if an immersed polyhedron P in Euclidean 3-space is obtained from another immersed polyhedron Q by a continuous flex then P and Q are scissors congruent. §

Given a polyhedron P in R with n vertices, a halfspace volume query asks for the volume of P ∩H for a given halfspace H. We show that, for d ≥ 3, such queries can require Ω(n) operations even if the polyhedron P is convex and can be preprocessed arbitrarily.

We present a new method for unfolding a convex polyhedron into one piece without overlap, based on shortest paths to a convex curve on the polyhedron. Our “sun unfoldings” encompass source unfolding from a point, source unfolding from an open geodesic curve, and a variant of a recent method of Itoh, O’Rourke, and Vı̂lcu.

Three open problems on folding/unfolding are discussed: (1) Can every convex polyhedron be cut along edges and unfolded at to a single nonoverlapping piece? (2) Given gluing instructions for a polygon, construct the unique 3D convex polyhedron to which it folds. (3) Can every planar polygonal chain be straightened?

It is proved that a triangulation of a polyhedron can always be transformed into any other triangulation of the polyhedron using only elementary moves. One consequence is that an additive function (valuation) defined only on simplices may always be extended to an additive function on all polyhedra. 2000 AMS subject classification: 52B45; 52A38; 57Q15;

A submodular polyhedron is a polyhedron associated with a submodular function. This paper presents a strongly polynomial time algorithm for line search in submodular polyhedra with the aid of a fully combinatorial algorithm for submodular function minimization as a subroutine. The algorithm is based on the parametric search method proposed by Megiddo.

Given a polyhedron, its diameter is defined as the maximum distance between two of its vertices, where the distance between two vertices u and v is the number of edges contained in the shortest u− v path in the skeleton of the polyhedron. Bounding the diameter of a polyhedron with respect to its dimension d and the number n of its facets is one of the most important open problems in convex geom...

Many applications of static analysis and verification compute on some abstract domain based on convex polyhedra. Traditionally, most of these applications are restricted to convex polyhedra that are topologically closed. When adopting the Double Description (DD) method [8], a closed convex polyhedron can be specified in two ways, using a constraint system or a generator system: the constraint s...

The first reference to the rigidity of frameworks in the mathematical literature occurs in a problem posed by Euler in 1776, see [8]. Consider a polyhedron P in 3-space. We view P as a ‘ panel-and-hinge framework’ in which the faces are 2-dimensional panels and the edges are 1-dimensional hinges. The panels are free to move continuously in 3-space, subject to the constraints that the shapes of ...