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Now showing items 1-10 of 11

#### 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 ...

#### 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 ...

#### 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 ...

#### 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 ...

#### 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 ...

#### On optimality and construction of circular repeated-measurements designs

(2017-01) - Journal article,

The aim of this paper is to characterize and construct universally optimal designs among the class of circular repeated-measurements designs when the parameters do not permit balance for carry-over effects. It is shown ...

#### 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 ...

#### 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 ...