Speaker: Pablo Solis (UC Berkeley)
2012.09.20 |
Date | Fri 14 Sep |
Time | 13:15 — 14:15 |
Location | Aud. D4 (1531-219) |
Abstract
I describe the wonderful compactification of loop groups. These compactifications are obtained by adding normal-crossing boundary divisors to the group LG of loops in a reductive group (or more accurately, to the semi-direct product ) in a manner equivariant for the left and right -actions. The analogue for a torus group is the theory of toric varieties; for an adjoint group , this is the wonderful compactications of De Concini and Procesi. The loop group analogue is suggested by work of Faltings in relation to the compacti cation of moduli of -bundles over nodal curves. Using the loop analogue one can construct a 'wonderful' completion of the moduli stack of -bundles over nodal curves which parametrizes Parahoric bundles.