English

Block-transitive $t$-($k^2,k,\lambda$) designs with $PSL(n,q)$ as socle

Group Theory 2025-11-14 v1

Abstract

Let D=(P,B)\mathcal{D}=(\mathcal{P},\mathcal{B}) be a non-trivial block-transitive tt-(k2,k,λ)(k^2,k,\lambda) design with G\Aut(D)G\leq \Aut(\mathcal{D}) and XG\Aut(X)X\unlhd G\leq \Aut(X), where X=PSL(n,q)(n3).X=PSL(n,q)(n\geq3). We prove that t=2t=2 and the parameters (n,q,v,k)(n,q,v,k) is (3,3,144,12),(4,7,400,20)(3,3,144,12),(4,7,400,20) or (5,3,121,11).(5,3,121,11). Moreover, D\mathcal{D} is a 22-(144,12,λ)(144,12,\lambda) design with λ{3,6,12}\lambda\in\{3,6,12\} if λk\lambda\mid k.

Keywords

Cite

@article{arxiv.2511.10095,
  title  = {Block-transitive $t$-($k^2,k,\lambda$) designs with $PSL(n,q)$ as socle},
  author = {Guoqiang Xiong and Haiyan Guan},
  journal= {arXiv preprint arXiv:2511.10095},
  year   = {2025}
}
R2 v1 2026-07-01T07:35:18.814Z