We provide lower and upper bounds for the maximal number of facets of a d-dimensional 0/1-polytope, and for the maximal number of vertices that can appear in a two-dimensional projection (“shadow”)… (More)

Dynamic or interactive Geometry software (DGS) is the mathematical version of vector based drawing software: the objects (points, lines, circles, conics, polygons, etc.) are both graphical and… (More)

This article deals with the intrinsic complexity of tracing and reachability questions in the context of elementary geometric constructions. We consider constructions from elementary geometry as… (More)

In this overview article we describe the manifold achievements and challenges of Intergeo, a project co-funded within the eContentplus programme of the European Union. THE INTERGEO PROJECT The… (More)

Java has been proven useful as middleware solution, for ebusiness applications and intranet applications. We present another project, The Interactive Geometry Software Cinderella, where the… (More)

Interactive Geometry is a major tool in modern geometry education and various software tools are available. We discuss the requirements of such tools and how they can be fulfilled. We also explain… (More)

This article gives my very personal view of the development of (mathematical) software in the past and in the future. It is based both on my experiences as a user and as an author of math software… (More)

The Intergeo project started in October 2007 and will be funded until September 2010. Its main concern is the propagation of Interactive or Dynamic Geometry Software throughout Europe. Interactive… (More)

In this article we survey the theoretical background that is required to build a consistent and continuous setup of dynamic elementary geometry. Unlike in static elementary geometry in dynamic… (More)