A Characterization of the Lüneburg Planes.
A Construction of a Skewaffine Structure in Laguerre Geometry
J. Andre constructed a skewaffine structure as a group space of a normally transitive group. In this paper his construction is used to describe the structure of the set of circles not passing through a point of a Laguerre plane. Sufficient conditions to ensure that this structure is a skewaffine plane are given.
Affine regular decagons in GS-quasigroup.
Alcuni risultati nello studio degli spazi affini generalizzati di Sperner
Angeordnete affine lokale Ternärringe und angeordnete affine Klingenbergsche Ebenen
Anti-nets. I. (Basic notation and properties - closure conditions)
Anti-nets. II. (Collineations of anti-nets)
Central Automorphisms of Veblenian Nearaffine Planes
The paper deals with nearaffine planes described by H. A. Wilbrink. We consider their central automorphisms, i.e. automorphisms satisfying the Veblen condition, which become central collineations in connected projective planes. Moreover, a concept of central pseudo-automorphism is considered, i.e. some bijections in a nearaffine plane are not automorphisms but they become central collineations in the related projective planes.
Configuration conditions of small point rank in 3-nets
Extending Nearaffine Planes to Hyperbola Structures
H. A. Wilbrink [Geom. Dedicata 12 (1982)] considered a class of Minkowski planes whose restrictions, called residual planes, are nearaffine planes. Our study goes in the opposite direction: what conditions on a nearaffine plane are necessary and sufficient to get an extension which is a hyperbola structure.
GS-quasigroups
On a generalization of nets
On a special class of Frobenius groups admitting planar partitions.
On orthogonality in nets
Produktbildung von Inzedenzenräumen mit Parallelismus.
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.
Strutture di André con gruppi di traslazioni transitivi non normali
We give some examples of André-structures admitting translation groups which are transitive on the set of points but which are not normal in the dilatation group. André structures with this property seem to be new in the literature.
The classification of subplane covered nets.
The orthogonality in affine parallel structure
Transversal designs and partitions associated with Frobenius groups.