Symmetric (36,15,6) design having U(3,3) as an automorphism group

Glasnik Matematicki, Vol. 34, No.1 (1999), 1-3.

SYMMETRIC (36,15,6) DESIGN HAVING U(3,3) AS AN AUTOMORPHISM GROUP

Dean Crnković

Odsjek za matematiku, Filozofski fakultet u Rijeci, Omladinska 14, 51000 Rijeka, Croatia

Abstract. Up to isomorphism there are four symmetric (36,15,6) designs with automorphisms of order 7. Full automorphism group of one of them is the Chevalley group G(2,2) U(3,3) : Z₂ of order 12096. Unitary group U(3,3) acts transitively on that design.

1991 Mathematics Subject Classification. 05B05.

Key words and phrases. Symmetric design, automorphism group, orbit structure.

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