时间：2026年10月30日（周五）14:00-15:00
地点：E14-301
主讲人：张子宇，上海科技大学
主讲人简介：Professor Ziyu Zhang received his PhD in Mathematics from Stanford University in 2009 under the supervision of Professor Jun Li. He subsequently held postdoctoral positions at the universities of Bonn, Mainz, Bath, and Hannover. Since 2019, he has been an Associate Professor of Mathematics at ShanghaiTech University.
Professor Zhang's primary research interests lie in algebraic geometry, with a particular focus on the interaction between moduli spaces of sheaves and holomorphic symplectic manifolds.
讲座主题：Explicit Degenerations of Hyperkähler Manifolds
讲座摘要：The degeneration theory of K3 surfaces is well understood, thanks to the seminal work of Kulikov and Persson–Pinkham. Hyperkähler manifolds are natural higher-dimensional analogues of K3 surfaces, and important aspects of their degeneration theory have been developed by Kollár, Laza, Saccà, and Voisin.
While the general theory provides a powerful framework, constructing explicit degenerations and understanding their geometry remain important challenges. In this talk, after a brief review of the background, we will explain how Jun Li's technique of expanded degenerations can be used to construct explicit Type II degenerations of Hilbert schemes of points on K3 surfaces and generalized Kummer varieties. We will discuss the geometric and moduli-theoretic interpretations of these constructions, and describe the dual complexes of their central fibers, which capture how the components intersect.
The talk is based on joint work with M. Gulbrandsen, L. H. Halle, and K. Hulek.
