Glasnik Matematicki, Vol. 37, No.2 (2002), 259-268.

STEINER 2-DESIGNS S(2,4,28) WITH NONTRIVIAL AUTOMORPHISMS

Vedran Krcadinac

Abstract.   In this article designs with parameters S(2,4,28) and nontrivial automorphism groups are classified. A total of 4466 designs were found. Together with some S(2,4,28)'s with trivial automorphism groups found by A.Betten, D.Betten and V.D.Tonchev this sums up to 4653 nonisomorphic S(2,4,28) designs.

2000 Mathematics Subject Classification.   05B05, 51E10.

Key words and phrases.   Block design, Steiner system, automorphism group.