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Constructing flag-transitive, point-imprimitive designs. (English) Zbl 1339.05043

Summary: We give a construction of a family of designs with a specified point-partition and determine the subgroup of automorphisms leaving invariant the point-partition. We give necessary and sufficient conditions for a design in the family to possess a flag-transitive group of automorphisms preserving the specified point-partition. We give examples of flag-transitive designs in the family, including a new symmetric 2-(1408,336,80) design with automorphism group \(2^{12}:((3\cdot \mathrm {M}_{22}):2)\) and a construction of one of the families of the symplectic designs (the designs \(S^-(n)\)) exhibiting a flag-transitive, point-imprimitive automorphism group.

MSC:

05B30 Other designs, configurations
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References:

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