Stefaan De Winter

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Let Π = (P,L, I) denote a rank two geometry. In this paper, we are interested in the largest value of |X||Y | where X ⊂ P and Y ⊂ L are sets such that (X×Y )∩I = ∅. Let α(Π) denote this value. We concentrate on the case where P is the point set of PG(n, q) and L is the set of k-spaces in PG(n, q). In the case that Π is the projective plane PG(2, q), Haemers(More)
In 1969, Denniston gave a construction of maximal arcs of degree d in Desarguesian projective planes of even order q, for all d dividing q. In 2002 Mathon gave a construction method generalizing the one of Denniston. We will give a new geometric approach to these maximal arcs. This will allow us to count the number of non-isomorphic Mathon maximal arcs of(More)
In this paper we introduce semi-pseudo-ovoids, as generalizations of the semi-ovals and semi-ovoids. Examples of these objects are particular classes of SPG-reguli and some classes of m-systems of polar spaces. As an application it is proved that the axioms of pseudo-ovoid O(n, 2n, q) in PG(4n − 1, q) can be considerably weakened and further a useful and(More)
All known finite generalized quadrangles that admit an automorphism group acting sharply transitively on their point set arise by Payne derivation from thick elation generalized quadrangles of order s with a regular point. In these examples only two groups occur: elementary abelian groups of even order and odd order Heisenberg groups of dimension 3. In [2](More)