**Reinhard Laue, Alfred Wassermann,
University of Bayreuth, Germany**

Orbits of on 6-element subsets of the projective line with
prescribed non-trivial stabilizer are described. A refinement of cross-ratio
computations to orbits allows to determine the orbits on
5-element subsets that they cover. Then Steiner - designs
are assembled from them. In particular, there is one isomorphism type
of - designs that consists of orbits of the same size,
each being a - design. There are 7 isomorphism types
of - designs of this type. Generally, Steiner - designs
with such an orbit partition may only exist if
.

- Introduction
- Basic Conditions
- Subgroups of order up to 6 in
- Invariants
- Bibliography
- About this document ...

N.N. 2002-02-25