Kegelschnitte und steinersche Ovale in Fano-Ebenen

Projective Planes of ODD Orders Admitting Orthogonal Polarities

Das kleinste Ree-Unital

A class of unitals of order q which can be embedded in two different planes of order q2

By deriving the desarguesian plane of order q2 for every prime power q a unital of order q is constructed which can be embedded in both the Hall plane and the dual of the Hall plane of order q2 which are non-isomorphic projective planes. The representation of translation planes in the fourdimensional projective space of J. Andre and F. Buekenhouts construction of unitals in these planes are used. It is shown that the full automorphism groups of these unitals are just the collineation groups inherited from the classical unitals.