报告人：于立（南京大学）

邀请人：曾昊智

报告时间：2022年7月28日（星期四）14:00-16:00

报告地点：数学-欣苑2栋216会议室

报告题目：On Riemannian polyhedra with non-obtuse dihedral angles in

3-manifolds with positive scalar curvature（第二讲）

报告摘要：A Riemannian polyhedron is a smooth n-manifold with corners embedded as a polyhedral domain in a Riemannian n-manifold with the induced Riemannian metric. In this talk, we will discuss all possible 3-dimensional simple convex polytopes that can be realized as mean curvature convex (or totally geodesic) Riemannian polyhedra with non-obtuse dihedral angles in 3-manifolds with positive scalar curvature. This result can be considered as an analogue of the famous Andreev's theorem on 3-dimensional hyperbolic polyhedra with non-obtuse dihedral angles.Besides, we will introduce the notion of real moment-angle mani-fold associated to a simple convex polytope in a Euclidean space and discuss the existence of various geometric structures on such manifolds.

报告人简介：于立，副教授，硕士生导师，现任职于南京大学数学系。他主要从事代数拓扑学与几何拓扑学的研究，三项国家自然科学基金项目的主持人。他的数学工作发表在Advances in Mathematics, International Mathematics Research Notices, Mathematical Research Letters, Algebraic and Geometric Topology等国际著名期刊上。他近几年的主要研究方向：带环面群作用的空间的拓扑与几何性质。