题目  Multiple Borel-Cantelli Lemma in Mixing Systems
报告人：刘思序 （清华大学) 
时间  2019年12月18日 10：00-11：00
地点   精正楼307
摘要   The classical Borel-Cantelli Lemma is a standard tool for deciding when an infinite number of rare events occur with probability one. It is a classical subject in probability and have many extensions in dynamical systems. A generalization of Borel-Cantelli Lemma is Multiple Borel-Cantell Lemma, which can decide when several events happen in the same time scale. In this talk, we will discuss multiple Borel-Cantell Lemma and its applications in some mixing systems. The talk is based on the joint work with Dmitry Dolgopyat and Bassam Fayad.

题目  Multiple Logarithm Law and Poisson Law for geodesic excursion
报告人：刘思序 （清华大学) 
时间  2019年12月18日 11：00-12：00
地点   精正楼307
摘要   We will show multiple Logarithm Law and Poisson Law for geodesic flows on non compact manifold of negative curvature with finite volume. This generalizes the result of Sullivan that gives Logarithm Law for geodesic excursion. I will also discuss Multiple Khintchine-Groshev Theorem for homogeneous and inhomogeneous cases.