Generalised Semiplanes and Certain Divisible Partial Designs.
Generalization of one Baer's theorem for nets
Geometric hyperquasigroups and line spaces
Geometrie und Kombinatorik.
Géométries combinatoires finies
Going down in (semi)lattices of finite Moore families and convex geometries
In this paper we first study what changes occur in the posets of irreducible elements when one goes from an arbitrary Moore family (respectively, a convex geometry) to one of its lower covers in the lattice of all Moore families (respectively, in the semilattice of all convex geometries) defined on a finite set. Then we study the set of all convex geometries which have the same poset of join-irreducible elements. We show that this set—ordered by set inclusion—is a ranked join-semilattice and we...