Speaker: Roberto Fringuelli
Title: The Picard group of the universal moduli space of principal bundles on
Riemann surfaces.
Abstract: The Wess-Zumino-Witten model is a type of two dimensional conformal
field theory, which associates to a Riemann surface with marked points and
irreducible representations of a Lie algebra attached to the points, a finite
dimensional vector space satisfying certain axioms. Deforming the pointed
surface in a family, we get the sheaf of conformal blocks. This sheaf have a
geometric interpretation as the sheaf of generalized theta functions, which is
the push-forward of a line bundle over the universal moduli space of principal
bundles on Riemann surfaces. In this talk, we present a complete description of
the group of line bundles (Picard group) over the universal moduli space of
principal bundles on Riemann surfaces. It is a joint work with Filippo Viviani.