Betti numbers of quiver varieties, revisited
Hiraku Nakajima (Kyoto University)
MSRI: Simons Auditorium
Generating functions of Betti numbers of quiver varieties are q-deformation of Weyl-Kac character formulas, and have been computed various ways. Recently Chari and Ion showed that, when quiver varieties are of finite type, they are given by a specialization of Macdonald polynomials at t=0 in the context of the representation theory of the current algebra. I would like to explain a geometric approach to this result, hoping that it can be generalized to quiver varieties of affine types.