Speaker: Prof. Yu Zhao (Beijing Institute of Technology)

Title: Instantons on blow ups and affine vertex algebra

Time: 10:30-11:30  March 25, 2026 (Wednesday)

Place: MCM410

Abstract: Inspired by the Nakajima quiver variety and the test on the S duality, in 1994 Vafa and Witten observed that the blow up formula of Yoshioka on the Euler characterstic coincide with the character of WZW model at level 1, and raised the question for the corresponding conformal theory explanation. In this talk, we will explain our solution on this open problem by constructing the basic representation of affine Lie algebras on the various cohomology groups of the moduli space of coherent sheaves on the blown up surface. It is a joint work with Weiping Li and Qingyuan Jiang.