|ANDREW TOMS, Fields Institute, University of Toronto, Toronto, Ontario, Canada|
|Perforated K0-groups of algebras|
Every weakly unperforated ordered abelian group arises as the K0-group of some simple, separable algebra. What of perforated abelian groups? In this talk we outline methods for constructing algebras having a maximal free cyclic subgroup of K0, say H, with the property that , k and l relatively prime positive integers. The methods used also provide many other such algebras with subgroups whose intersection with the positive cone of K0 further extend the preceding result, though these are less succinctly described.