报告题目：Noncollapsed ancient Ricci flow with nonnegative Ricci curvature

报告人：张永甲长聘教轨副教授，上海交通大学

报告时间：2026年4月17日（周五）9:30-12:00

报告地点：20-306

报告摘要：Perelman proved that  every noncollapsed ancient Ricci flow with bounded and nonnegative curvature operator admits an asymptotic Ricci shrinker. However, asymptotic shrinker may not exist for general ancient solutions. With Bamler’s F-convergence theory, one may take a limit for any sequence of Ricci flow in the same dimension. The asymptotic F-limit of a noncollapsed ancient solution, called a tangent flow at infinity, is a metric soliton, which is almost everywhere smooth. By studying metric solitons with nonnegative Ricci curvature, we prove dichotomy theorems for noncollapsed ancient Ricci flows with nonnegative Ricci curvature. For instance, such a flow either has zero AVR, or every tangent flow at infinity is a Ricci flat cone. This is a joint work with Yuxing Deng and Ganqi Wang.

报告人简介：张永甲于2019年在加州大学圣地亚哥分校取得博士学位，2022年起在上海交通大学任职副教授。张永甲长期从事Ricci流研究，在Ricci流上的古代解与孤立子、带手术Ricci流均有多项成果。研究成果发表在Adv. Math., Crelle’s Journal, Peking Math J, Trans. Amer. Math. Soc., Annals of PDE, J. Funct. Anal., Cal. Var. PDE.等期刊上。

邀请人：倪磊