Reduction for flag-transitive symmetric designs with k > lambda(lambda-2)

作者：Chen, Jianfu; Shen, Jiaxin^*; Zhou, Shenglin

来源：Discrete Mathematics, 2023, 346(10): 113557.

DOI：10.1016/j.disc.2023.113557

• Available online xxxx
• Symmetric design
• Flag-transitive
• Automorphism group
• Primitive

Let G be a flag-transitive automorphism group of a symmetric (v, k, & lambda;) design D with k > & lambda;(& lambda; -2). O'Reilly Regueiro proved that if G is point-imprimitive, then D has parameters (v, k, & lambda;) = (& lambda;2(& lambda; + 2), & lambda;(& lambda; + 1), & lambda;). In the present paper, we consider the case that G is point-primitive. By applying the O'Nan-Scott Theorem, we prove that G must be of affine type or almost simple type.& COPY; 2023 Elsevier B.V.