报告题目：Length functions on Groups and applications

报告人：叶圣奎

单位：上海纽约大学

时间：2023年3月3日10:00

线下地点：二楼会议室

腾讯会议：112-610-876

密码：123456

摘要：A length function l on a group G is a (nonnegative) real-valued function that is conjugate invariant, homogenous, and subadditive for commuting pairs. Such length functions exist in many branches of mathematics, mainly as stable word lengths, stable norms, smooth measure-theoretic entropy, translation lengths on CAT(0) spaces and Gromov delta-hyperbolic spaces, stable norms of quasi-cocycles, rotation numbers of circle homeomorphisms, smooth entropy, dynamical degrees of birational maps and so on. We study length functions on Lie groups, Gromov hyperbolic groups, arithmetic subgroups, matrix groups over rings, and Cremona groups. As applications, we prove rigidity results on group homomorphisms.

简介：叶圣奎，上海纽约大学副教授，2012年获新加坡国立大学博士学位，牛津大学博士后。主要从事拓扑学、几何群论研究，在Journal of London Math. Soc., Israel Journal of Math.， Journal of Algebra, Algebraic and Geometric Topology 等国际著名杂志独立作者发表论文多篇。