Date: Monday, September 24, 2018
Location: 4096 East Hall (4:00 PM to 6:00 PM)
Title: VafaWitten invariants for surface DeligneMumford stacks
Abstract: Motivated by the Sduality conjecture, TanakaThomas have defined the VafaWitten invariants for projective surfaces by constructing a perfect obstruction theory on the moduli space of stable Higgs sheaves on a smooth surface. They proved that the generating function of the invariants satisfies modularity properties. The study of the Higgs sheaves on a surface implies that there exists threefold contributions to the VafaWitten invariants. In this talk I will talk about the VafaWitten invariants via surface DeligneMumford stacks. There are many interesting surface DeligneMumford stacks which are pretty useful in mirror symmetry. We will define the VafaWitten invariants for surface DeligneMumford stacks and calculate some examples.
In the second part of the talk, I will explain one special case of root stacks, and how the VafaWitten invariants are related to the geometric Eisenstein series over functional field of curves.
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Speaker: Yunfeng Jiang
Institution: University of Kansas
Event Organizer:
