On projective planes of type (4, m)

If a group G acts on a finite projective plane to make it a plane of type (4, m) and if G/K is the related 2-transitive representation of G then either G/K has a normal regular subgroup or PSL(2, q)G/KPL(2, q) for some prime power q.     

Some new results on sets of type (m,n) in projective planes

All possible sets of type (l,n) in a finite projective plane are completely characterized from the arithmetical point of view. Furthermore, necessary existence conditions are proved for sets of type (m,n) which are stronger then the previously known ones and provide the unique possible arithmetical solutions whenever they are satisfied.     

On n2 -sets of type (0,1,n) in projective planes

In this paper n²-sets of type (0,1,n), in projective planes of order greater than 3, are completely characterized.This paper was written while the author was studying at the University of Rome, under the direction of Prof. G. Tallini, supported by a grant from the Institute for Italian Hungarian Cultural Exchange.     

Sets of type (m,n) in the affine and projective planes of order nine

In this paper we give the results of exhaustive computer searches for sets of points of type (m, n) in the projective and affine planes of order nine. In particular, as the list of planes of order nine is known to be complete, our results are also complete. We also examine all known constructions of sets of type (m, n) that apply to the planes of order nine, in an attempt to summarise and extend all existing knowledge about such sets. The contrast between known constructions and our computer results leads us to conclude that sets of type (m, n) are far more numerous than was previously thought.     

Self-dual sets of type (m, n) in projective spaces

In this paper we introduce and analyze the notion of self-dual k-sets of type (m, n). We show that in a non-square order projective space such sets exist only if the dimension is odd. We prove that, in a projective space of odd dimension and order q, self-dual k-sets of type (m, n), with , are of elliptic and hyperbolic type, respectively. As a corollary we obtain a new characterization of the non-singular elliptic and hyperbolic quadrics.     

On multiple-valued ordered projective planes

We codify the notion of compatibility between multiple-valued orderings and epimorphisms of projective planes and investigate its algebraic counterpart. Using the machinery of lifting orderings via places, we construct a wide variety of proper, multiple-valued ordered projective planes.Herrn Professor W. Benz zum 60. Geburtstag gewidmet     

On tangentially transitive projective planes

The existence of Baer collineations in a projective plane is related to the existence of desargues-like configurations. The plane of order four is characterized as the only finite plane that possesses a Baer subplane partition into tangentially transitive Baer subplanes which is preserved by each of the tangentially transitive groups. It is shown that a finite projective plane has either no or one tangentially transitive Baer subplane or is partially transitive of Hughes type (4, m), (5, m) or (6, m) for some m. The Lenz-Barlotti classes which contain a finite plane which is not a translation plane nor its dual and which possesses a tangentially transitive Baer subplane are shown to be classes I.1 and II.1.     

On automatic presentations of projective planes

We study automatic presentations of projective planes and prove that no freely generated projective plane has any automatic presentations. Every desarguesian (pappian) projective plane is shown to be automatically presentable if and only if it is finite.     

On homologies of finite projective planes

Study of finite projective planes which have a polarity preserved by many homologies. This research was supported in part by NSF Grant GP-33223.     

Sets of type (0,n) in Steiner systems and in finite projective planes

In this paper we study the sets of type (0,n)₁ in a finite projective plane and the inclusion relations between them.     

On hyperovals in small projective planes

In this paper we collate the results of three computer searches for hyperovals in small projective planes, each of which resulted in new hyperovals. The three searches involve finding all hyperovals with non-trivial automorphisms in PG(2,64), all hyperovals with GF(2) o-polynomials in PG(2, 128) and PG(2, 256) and hyperovals stabilised by a particular group in PG(2, 256).