According to the Handbook of Combinatorial Designs, the only known example of a (27, 6, 5) design was given by Hanani. Even though a census of the designs with these parameters appears to be unfeasible, in this paper we show how some algebraic methods and the aid of a computer allow us to say that their number is at least 459. We show, in particular, that two of them are doubly point-transitive with their full automorphism groups being AΓL(1, 27) and AGL(1, 27). These two special designs are both flag-transitive and additive.

(27, 6, 5) designs with a nice automorphism group / Buratti, M.; Martinovic, F.; Nakic, A.. - In: THE AUSTRALASIAN JOURNAL OF COMBINATORICS. - ISSN 2202-3518. - 92:(2025), pp. 80-95.

(27, 6, 5) designs with a nice automorphism group

Buratti M.
Primo
Writing – Original Draft Preparation
;
Nakic A.
Writing – Original Draft Preparation
2025

Abstract

According to the Handbook of Combinatorial Designs, the only known example of a (27, 6, 5) design was given by Hanani. Even though a census of the designs with these parameters appears to be unfeasible, in this paper we show how some algebraic methods and the aid of a computer allow us to say that their number is at least 459. We show, in particular, that two of them are doubly point-transitive with their full automorphism groups being AΓL(1, 27) and AGL(1, 27). These two special designs are both flag-transitive and additive.
2025
2-design; automorphism group; group action
01 Pubblicazione su rivista::01a Articolo in rivista
(27, 6, 5) designs with a nice automorphism group / Buratti, M.; Martinovic, F.; Nakic, A.. - In: THE AUSTRALASIAN JOURNAL OF COMBINATORICS. - ISSN 2202-3518. - 92:(2025), pp. 80-95.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1747447
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