报告人：杨文元教授（北京大学）

时间：11月19日（周三）19:30

地点：二教2306

题目：Counting Problems in Geometric Group Theory and Applications

摘要：In this talk, we shall study a class of groups with contracting elements and survey several counting results in this class of groups. We will explain a basic tool called extension lemma in obtaining those counting results. This tool could be thought of as an orbit closing lemma in group theory. Appilcations are given to the coarse marked length spectrum and Hausdorff dimension of limit sets.