Algebraic Geometry Seminar: On the decomposition of etale gerbes

  • Date: 01/11/2010
Hsian-Hua Tseng (Ohio State University)

University of British Columbia


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 these conjectures in the elementary concrete examples of G-gerbes over a point or BQ.


3:10pm-4:30pm, WMAX 110