Publications

A point-line space is an abstract geometric object that consists of a set of points and a set of lines such that on each line there are at least two points. A large class of point-line spaces with high symmetry comes along with buildings, combinatorial objects that are introduced by Jacques Tits and help to study algebraic objects with geometric methods.To formulate quantum mechanics as abstract and general as possible, the physicist Pascual ...

In this paper, we consider a set L of lines of PG(5, q) with the properties that (1) every plane contains 0, 1 or q + 1 elements of L, (2) every solid contains no more than q(2) + q + 1 and no less than q + 1 elements of L, and (3) every point of PG(5, q) is on q + 1 members of L, and we show that, whenever (4) q not equal 2 (respectively, q = 2) and the lines of L through some point are contained in a solid (respectively, a plane), then L is ...

We introduce a rank 3 geometry for any Ree group over a not necessarily perfect field and show that its full collineation group is the automorphism group of the corresponding Ree group. A similar result holds for two rank 2 geometries obtained as a truncation of this rank 3 geometry. As an application, we show that a polarity in any Moufang generalized hexagon is unambiguously determined by its set of absolute points, or equivalently, its set of ...

In 1954 Segre proved the following celebrated theorem : In PG(2, q), with q odd, every oval is a nonsingular conic. Crucial for the proof is Segre's Lemma of Tangents, where a strong result is deduced from the simple fact that the product of the nonzero elements of GF(q) is -1. Relying on this Lemma of Tangents he was able to prove excellent theorems on certain point sets in PG(2,q). To this end he also generalized the classical theorem of ...

A geometrically simple flow cell is proposed to generate different types of stagnation flows, using a separation flow and small variations of the geometric parameters. Flows with high local deformation rates can be changed from purely rotational, over simple shear flow, to extensional flow in a region surrounding a stagnation point. Computational fluid dynamic calculations are used to analyse how variations of the geometrical parameters affect ...

Context. Recent high-resolution observations have shown that stellar winds harbour complexities that strongly deviate from spherical symmetry, which generally is assumed as standard wind model. One such morphology is the Archimedean spiral, which is generally believed to be formed by binary interactions, as has been directly observed in multiple sources. Aims: We seek to investigate the manifestation in the observables of spiral structures ...

© 2016 EDAA. In this paper, electrothermal field phenomena in electronic components are considered. This coupling is tackled by multiphysical field simulations using the Finite Integration Technique (FIT). In particular, the design of bonding wires with respect to thermal degradation is investigated. Instead of resolving the wires by the computational grid, lumped element representations are introduced as point-to-point connections in the ...

This book is the second edition of the third and last volume of a treatise on projective spaces over a finite field, also known as Galois geometries. This volume completes the trilogy comprised of plane case (first volume) and three dimensions (second volume). This revised edition includes much updating and new material. It is a mostly self-contained study of classical varieties over a finite field, related incidence structures and particular ...

We present noncommutative topology as a basis for noncommutative geometry phrased completely in terms of partially ordered sets with operations. In this note we introduce a noncommutative space-time starting from a dynamical system of noncommutative topologies based on the notion of temporal points. At every moment a commutative topological space is constructed and it is shown to approximate the noncommutative space in sheaf theoretical terms; ...