Back to Algebraic Geometry Seminar: Fall 2008
Algebraic Geometry Seminar
Date: Monday, Nov 10, 2008
Time: 3:30PM - 4:30PM
Location: LCB 222
3:00pm, LCB 225
Hsian-Hua Tseng
University of Wisconsin-Madison
Title |
Extensions of finite groups, group algebras, and decomposition of étale gerbes |
Abstract |
Let G be a finite group. A G-gerbe over a space X may be intuitively thought of as a fiber bundle over X with fibers being the classifying space (stack) BG. In particular BG itself is the G-gerbe over a point. A more interesting class of examples consist of G-gerbes over BQ, which are equivalent to extensions of the finite group Q by G. Considerations from physics have led to conjectures asserting that the geometry of a G-gerbe Y over X is equivalent to certain “twisted” geometry of a “dual” space Y’. A lot of progresses have be made recently towards proving these conjectures in general. In this talk we’ll try to explain theses conjectures in the elementary concrete examples of G-gerbes over a point or BQ. |
Algebraic Geometry