Colloquium| Institute of Mathematical
Time：15:30-16:30, Friday, December 27
Location：Room S408, IMS
Speaker: Martinus Kool, Utrecht University
Abstract: In this talk I discuss (virtual) Euler characteristics of moduli spaces of stable sheaves on general type surfaces. These are part of so-called Vafa-Witten invariants, which were discovered in the context of N=4 supersymmetric Yang-Mills theory by Vafa-Witten in 1994 and mathematically defined by Tanaka-Thomas in 2017. The generating functions of these invariants have interesting modularity properties predicted by physics. Using virtual intersection theory, we can verify Vafa-Witten's original predictions in examples and generalize in several new directions. Joint work with Göttsche.