We survey the connection between two results from rather different areas: failure of the 3-space property for local convexity (and other properties) within the category of quasiBanach spaces, and the irreducibility (in the sense of Minkowski difference) of large families of finite dimensional polytopes. Mathematics subject classification (2010): 46A16, 46B03, 52B15..

A global visibility map is a spherical image built to describe the complete set of global visible view directions for a surface. In this paper, we consider the computation of global visibility maps for regions on the boundary of a polyhedron. Both the self-occlusions introduced by a region and the global occlusions introduced by the rest of the surfaces on the boundary of the polyhedron are con...

In a partially ordered semigroup with the duality (or polarity) transform, it is possible to define a generalisation of continued fractions. General sufficient conditions for convergence of continued fractions are provided. Two particular applications concern the cases of convex sets with the Minkowski addition and the polarity transform and the family of non-negative convex functions with the ...

Given a lattice polytope Q ⊆ IR, we define an affine scheme M̄ that reflects the possibilities of splitting Q into a Minkowski sum. On the other hand, Q induces a toric Gorenstein singularity Y , and we construct a flat family over M̄ with Y as special fiber. In case Y has an isolated singularity only, this family is versal.

In recent years, interspecific hybridization and introgression are increasingly recognized as significant events in the evolution of Saccharomyces yeasts. These mechanisms have probably been involved in the origin of novel yeast genotypes and phenotypes, which in due course were to colonize and predominate in the new fermentative environments created by human manipulation. The particular condit...

This paper discusses the visual algebraic speciication (vas) formalism and its supporting interactive environment (vase). The vas formalism is intended for the deenition of visual syntax and semantics and is aimed at generating language speciic environments. The collection construct of vas is emphasized in that it supports the convenient speciication of language constructs involving arbitrarily...

With the growth of its popularity, VoIP is increasingly popular nowadays. Similarly to other Internet applications, VoIP users may desire to be unlinkable with their participated VoIP session records for privacy issues. In this paper, we explore the Items of Interests (IOIs) from anonymisation aspects based on a simplified VoIP model and analyse the potential links between them. We address poss...

We consider the problem of listing faces of the Minkowski sum of several V-polytopes in R. An algorithm for listing all faces of dimension up to j is presented, for any given 0 ≤ j ≤ d − 1. It runs in time polynomial in the sizes of input and output.