学术报告（王彬 2024.9.27）

Abstract: We will talk about moduli spaces of Higgs pairs on surfaces where Vafa-Witten invariants are derived from. We will focus on the associated Hitchin maps and their generic fibers. We first work out Picard groups of spectral varieties, which also holds in positive characteristics under mild conditions. Then we give a necessary and sufficient conditions on the non-emptyness of generic fibers and apply this to obtain a vanishing result of Vafa-Witten invariants. This is a joint work with Xiaoyu Su.