 
Summary: COLLOQUIUM
University of Regina
Department of Mathematics and Statistics
Speaker: Karen Meagher (University of Regina)
Title: Extensions of the ErdosKoRado Theorem
Date: Friday, November 30, 2007
Time: 3:30
Place: Math & Stats Lounge (CW 307.20)
Abstract
The ErdosKoRado Theorem is a major result in extremal set theory. It
gives the exact size of the largest system of sets that has property that any
two sets in the system have nontrivial intersection. There have been many
extensions of this theorem to combinatorial objects other than set systems,
for example to systems of permutations, subspaces of a vector space and
chains in Boolean algebras. In this talk I will present two possible extensions
of this theorem to systems of partitions. The first of these is a more natural
extension and has a straightforward proof. The second extension seems to
be much more challenging  it has only been proven for a very limited number
of cases. While this extension is less natural, it is related to interesting
problems in algebraic graph theory, the theory of association schemes and
