Title: Orbifolds, K-theory and Deligne cohomology
Speaker: Professor Ernesto Lupercio
Speaker Info: University of Wisconsin -- Madison
Since their inception in mathematics by Satake under the name of V- manifolds, the category of orbifolds has proved to be a very rich source of ideas and examples for geometry, topology and physics. For example recently Dixon, Harvey, Vafa and Witten introduced orbifold string theory models. Motivated by these Chen and Ruan have discovered a remarkable cohomology theory whose full nature is yet to be elucidated. Adem and Ruan have studied a corresponding K-theory.Date: Tuesday, February 5, 2002
In this talk I will survey recent work of Uribe and myself concerning orbifolds seen as Deligne-Mumford stacks, gerbes over them, twisted K-theories and Deligne Cohomologies as related to Type II superstring theories, D-branes, B-fields and discrete torsion. I will also briefly mention the relation of this work to work of Poddar and myself (and independently T. Yasuda) regarding orbifold resolutions and a conjecture of Ruan.