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Now showing items 1-10 of 11

#### 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 ...

#### Guessing games on triangle-free graphs

(2016) - Journal article,

The guessing game introduced by Riis is a variant of the "guessing your own hats" game and can be played on any simple directed graph G on n vertices. For each digraph G, it is proved that there exists a unique guessing ...

#### 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 ...

#### 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 ...

#### 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 ...

#### The classification of partition homogeneous groups with applications to semigroup theory

(2016-04-15) - Journal article,

Let λ=(λ1,λ2,...) be a partition of n, a sequence of positive integers in non-increasing order with sum n. Let Ω:={1,...,n}. An ordered partition P=(A1,A2,...) of Ω has type λ if |Ai|=λi.Following Martin and Sagan, we say ...

#### Sesqui-arrays, a generalisation of triple arrays

(2018-02-13) - 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 ...

#### Computing in permutation groups without memory

(2014-11-02) - Journal article,

Memoryless computation is a new technique to compute any function of a set of registers by updating one register at a time while using no memory. Its aim is to emulate how computations are performed in modern cores, since ...

#### Computing in matrix groups without memory

(2014-11-02) - Journal article,

Memoryless computation is a novel means of computing any function of a set of registers by updating one register at a time while using no memory. We aim to emulate how computations are performed on modern cores, since they ...

#### 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 ...