10 research outputs found
Almost simple groups as flag-transitive automorphism groups of 2-designs with {\lambda} = 2
In this article, we study -designs with admitting a
flag-transitive almost simple automorphism group with socle a finite simple
exceptional group of Lie type, and we prove that such a -design does not
exist. In conclusion, we present a classification of -designs with
admitting flag-transitive and point-primitive automorphism groups
of almost simple type, which states that such a -design belongs to an
infinite family of -designs with parameter set and
for some , or it is isomorphic to the -design with
parameter set , , , , ,
, , , or
On flag-transitive 2-(k^2, k, λ) designs with λ | k
It is shown that, apart from the smallest Ree group, a flag-transitive
automorphism group G of a 2-(k^2, k, λ) design D, with λ | k, is either an affine
group or an almost simple classical group. Moreover, when G is the smallest Ree
group, D is isomorphic either to the 2-(6^2, 6, 2) design or to one of the three 2-
(6^2, 6, 6) designs constructed in this paper. All the four 2-designs have the 36
secants of a non-degenerate conic C of PG(2,8) as a point set and 6-sets of secants
in a remarkable configuration as a block set