Cocenters and representations of affine Hecke algebra
  In this paper, we study the relation between the cocenter and the representation theory of affine Hecke algebras. The approach is based on the interaction between the rigid cocenter, an important subspace of the cocenter, and the dual object in representation theory, the rigid quotient of the Grothendieck group of finite dimensional representations. 
Dan Ciubotaru and Xuhua He
math.RT