Strongly n-Uniform and Level n-Hjelmslev Planes.
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.
In this paper we prove that any incidence-preserving bijection between the line sets of Grassmann spaces is induced by either a collineation or a correlation.
In questa Nota diamo una caratterizzazione dell'insieme di tutti i flocks lineari della quadrica iperbolica assolutamente irriducibile in .