Schleiermachers Starrheitsbedingung für Projektivitäten in der Topologischen Geometric.
Schließungssätze und Projektivitäten in der Möbius- und Laguerregeometrie.
Semiclassical 4-dimensional Laguerre Planes.
Simple Groups and Möbius Planes of Even Order.
Some Characterizations of Finite Miquelian Möbius Planes.
Some Connections between Minkowski and Hyperbolic Planes
The model of the Minkowski plane in the projective plane with a fixed conic sheds a new light on the connection between the Minkowski and hyperbolic geometries. The construction of the Minkowski plane in a hyperbolic plane over a Euclidean field is given. It is also proved that the geometry in an orthogonal bundle of circles is hyperbolic in a natural way.
Some Generalization of Nearaffine Planes
There are three kinds of Benz planes: Möbius planes, Laguerre planes and Minkowski planes. A Minkowski plane satisfying an additional axiom is connected with some other structure called a nearaffine plane. We construct an analogous structure for a Laguerre plane. Moreover, our description is common for both cases.
Some Moebius-geometric theorems connected to Euclidean kinematics.
Some representations of affine conformal transformations of Minkowski space.
Sphärische Kreisebene mit dreidimensionaler nichteinfacher Automorphismengruppe.
Stereographische Projektion und quadratisches Spurenprinzip im R4
Strongly Ovoidal Möbius Planes.
Strongly Ovoidal Möbius Planes II.
Systeme halbkonzentrischer Kreise der euklidischen Ebene im komplexen Gebiet.