Strongly regular graphs induced by polarities of symmetric designs

Graphs;mathematics

A new Euclidean tight 6-design

We give a new example of Euclidean tight 6-design in $\mathbb R^{22}$.Comment: 9 page

Some results on the Krein parameters of an association scheme

We consider association schemes with d classes and the underlying Bose- Mesner algebra, A. Then, by taking into account the relationship between the Hadamard and the Kronecker products of matrices and making use of some matrix techniques over the idempotents of the unique basis of minimal orthogonal idempotents of A , we prove some results over the Krein parameters of an association scheme

Strongly regular graphs with strongly regular decomposition

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28040/1/0000479.pd

On collineation groups of finite projective spaces

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46263/1/209_2005_Article_BF01122320.pd

Steiner t-designs for large t

One of the most central and long-standing open questions in combinatorial design theory concerns the existence of Steiner t-designs for large values of t. Although in his classical 1987 paper, L. Teirlinck has shown that non-trivial t-designs exist for all values of t, no non-trivial Steiner t-design with t > 5 has been constructed until now. Understandingly, the case t = 6 has received considerable attention. There has been recent progress concerning the existence of highly symmetric Steiner 6-designs: It is shown in [M. Huber, J. Algebr. Comb. 26 (2007), pp. 453-476] that no non-trivial flag-transitive Steiner 6-design can exist. In this paper, we announce that essentially also no block-transitive Steiner 6-design can exist.Comment: 9 pages; to appear in: Mathematical Methods in Computer Science 2008, ed. by J.Calmet, W.Geiselmann, J.Mueller-Quade, Springer Lecture Notes in Computer Scienc