A 2 - (υ, k, 1) design D = (?,?, ?) is a system consisting of a finite set ? of υ points and a collection ? of ?-subsets of ?, called blocks, such that each 2-subset of ? is contained in precisely one block. Let G b...A 2 - (υ, k, 1) design D = (?,?, ?) is a system consisting of a finite set ? of υ points and a collection ? of ?-subsets of ?, called blocks, such that each 2-subset of ? is contained in precisely one block. Let G be an automorphism group of a 2-(υ, k, 1) design. Delandtsheer proved that if G is block-primitive and D is not a projective plane, then G is almost simple, that is, T ? G ? Aut(T), where T is a non-abelian simple group. In this paper, we prove that T is not isomorphic to 3 D 4(q). This paper is part of a project to classify groups and designs where the group acts primitively on the blocks of the design.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.10171089).
文摘A 2 - (υ, k, 1) design D = (?,?, ?) is a system consisting of a finite set ? of υ points and a collection ? of ?-subsets of ?, called blocks, such that each 2-subset of ? is contained in precisely one block. Let G be an automorphism group of a 2-(υ, k, 1) design. Delandtsheer proved that if G is block-primitive and D is not a projective plane, then G is almost simple, that is, T ? G ? Aut(T), where T is a non-abelian simple group. In this paper, we prove that T is not isomorphic to 3 D 4(q). This paper is part of a project to classify groups and designs where the group acts primitively on the blocks of the design.