Texas A&M University, Department of Mathematics, 216 Milner Hall, 25th of February 2009, 3:00-3:50

Groups and Dynamics Seminar


The spread of a finite group

Simon Guest of Baylor University


Let G be a finite group. We say that G has spread at least k if for any k distinct non-trivial elements of G, x_1,...,x_k, there exists y in G such that x_i and y generate G for every i=1,...,k. If G does not have spread at least 1 then G is said to have spread 0. We say that G has spread n if it has spread at least n but it does not have spread at least n+1. Using elementary methods we can prove that if G has a non-trivial normal subgroup N such that G/N is non-cyclic then G must have spread 0. It has been conjectured by Guralnick and Kantor that the converse is true. They can prove that the converse holds in many cases. We will discuss some recent joint work with Guralnick and Burness involving the remaining cases.