Delandtsheer–Doyen parameters for block-transitive point-imprimitive 2-designs

Research output: Contribution to journalArticlepeer-review


Delandtsheer and Doyen bounded, in terms of the block size, the number of points of a point-imprimitive, block-transitive 2-design. To do this they introduced two integer parameters m, n, now called Delandtsheer–Doyen parameters, linking the block size with the parameters of an associated imprimitivity system on points. We show that the Delandtsheer–Doyen parameters provide upper bounds on the permutation ranks of the groups induced on the imprimitivity system and on a class of the system. We explore extreme cases where these bounds are attained, give a new construction for a family of designs achieving these bounds, and pose several open questions concerning the Delandtsheer–Doyen parameters.

Original languageEnglish
JournalDesigns, Codes, and Cryptography
Publication statusE-pub ahead of print - 2 Mar 2022


Dive into the research topics of 'Delandtsheer–Doyen parameters for block-transitive point-imprimitive 2-designs'. Together they form a unique fingerprint.

Cite this