| Speaker: Anthony Henderson Affiliation: University of Sydney Time: 10am Tuesday, 14 May, 2019 Location: 303e.257 |
| Let G be a connected complex reductive group. For reasons related to our work on nilpotent orbits, Pramod Achar and I were led to study a certain involution of an open subset of the affine Grassmannian of G. In this talk I will explain a moduli-space interpretation of this involution: it corresponds to the action of the nontrivial Weyl group element of SL(2) on the framed moduli space of G_m-equivariant principal G-bundles on CP^2. As a result, the fixed-point set of the involution can be partitioned into strata indexed by conjugacy classes of homomorphisms from N to G, where N is the normalizer of G_m in SL(2). In the case where G= GL(r), these strata are isomorphic to quiver varieties of type D. |