Flag-transitive symmetric $2$-designs]{The symmetric $2$-$(v,k,\lambda )$ designs, with $k>\lambda \left(\lambda-3 \right)/2$, admitting a flag-transitive, point imprimitive automorphism group are known
The symmetric 2-(v,k,λ) designs, with k>λ(λ−3)/2, admitting a flag-transitive, point-imprimitive automorphism group are completely classified: they are the known 2-designs with parameters (16,6,2),(45,12,3),(15,8,4) or (96,20,4).
@article{arxiv.2212.08893,
title = {Flag-transitive symmetric $2$-designs]{The symmetric $2$-$(v,k,\lambda )$ designs, with $k>\lambda \left(\lambda-3 \right)/2$, admitting a flag-transitive, point imprimitive automorphism group are known},
author = {Alessandro Montinaro},
journal= {arXiv preprint arXiv:2212.08893},
year = {2022}
}