Nico Spronk, Department of Pure Mathematics, University of Waterloo
"On projections in group and measure algebras"
Let G be a locally compact group and L^1(G) and M(G) denote its group and measure algebras, each of which admits an involution naturally extending inversion of G. A famous theorem of P.J. Cohen characterizes the idempotents of these algebras when G is abelian, and are all automatically self-adjoint, i.e. projections. For which classes of groups can we classify all the idempotents/projections in these algebras? I wish to survey this topic and highlight some results in a recent paper of mine, and also a recent paper authored by M. Alaghmandan (Chalmers U.), M. Ghandehari (U. Delaware) and K. F. Taylor (Dalhousie U.) and me.
MC 5417