Now showing items 1-6 of 6
Permutation groups and transformation semigroups : results and problems
(Cambridge University Press, 2015-10) - Book item
J.M. Howie, the influential St Andrews semigroupist, claimed that we value an area of pure mathematics to the extent that (a) it gives rise to arguments that are deep and elegant, and (b) it has interesting interconnections ...
String C-groups as transitive subgroups of Sn
(2016-02-01) - Journal article
If Γ is a string C-group which is isomorphic to a transitive subgroup of the symmetric group Sn (other than Sn and the alternating group An), then the rank of Γ is at most n/2+1, with finitely many exceptions (which are ...
Constructing flag-transitive, point-imprimitive designs
(2016-05-04) - Journal article
We give a construction of a family of designs with a specified point-partition and determine the subgroup of automorphisms leaving invariant the point-partition. We give necessary and sufficient conditions for a design in ...
Most primitive groups are full automorphism groups of edge-transitive hypergraphs
(2015-01-01) - Journal article
We prove that, for a primitive permutation group G acting on a set of size n, other than the alternating group, the probability that Aut(X,YG) = G for a random subset Y of X, tends to 1 as n tends to infinity. So the ...
Most switching classes with primitive automorphism groups contain graphs with trivial groups
(2015-06) - Journal article
The operation of switching a graph Gamma with respect to a subset X of the vertex set interchanges edges and non-edges between X and its complement, leaving the rest of the graph unchanged. This is an equivalence relation ...
Sesqui-arrays, a generalisation of triple arrays
(2018-06-01) - Journal article
A triple array is a rectangular array containing letters, each letter occurring equally often with no repeats in rows or columns, such that the number of letters common to two rows, two columns, or a row and a column are ...