中国科学院数学与系统科学研究院

数学研究所

数学科学全国重点实验室

学术报告

代数几何研讨班

Speaker:  沈大立 助理研究员（北京雁栖湖应用数学研究院）

Inviter: 陈亦飞

Language: Chinese

Title：The MMP singularities of GIT versus Baily-Borel compactifications

Time&Venue：2025年11月27日（星期四）11：15-12：15 & 思源楼S315

Abstract:When the geometric invariant theory and the Baily-Borel theory both apply to a moduli space, the two resulting compactifications do not necessarily coincide. They usually differ by a birational transformation in terms of an arrangement. In this talk, I will compare the MMP singularities on both sides, specifically for the ball quotient case. It turns out that if the relevant arrangement is nonempty, the birational transformation from the GIT compactification to the Baily-Borel compactification turns non-log canonical singularities to log canonical singularities. This phenomenon can be illustrated by the moduli spaces of quartic curves, rational elliptic surfaces and cubic threefolds.