1、报告题目：连通性问题进展

报告人： 纪友清教授（吉林大学数学学院）

报告摘要：套代数的可逆元群是否为道路连通的？这个问题已经公开几十年，至今仍然没有完全解决。我们这里介绍一下这个问题的进展情况和最新相关结果。

报告时间：2020年6月5日下午2:30--3:10

报告地点：腾讯会议 会议 ID： 228 258 955

2、报告题目：Dilation of oblique dual pairs of frame sequences

报告人： 李鹏同教授（南京航空航天大学理学院）

报告摘要： In this talk, I shall introduce the dilation of oblique dual pairs for frame sequences. The main result says that any oblique dual pair of frame sequences in a Hilbert space can be dilated to an oblique dual pair of Riesz sequences in a larger Hilbert space, which essentially extends the well known dilation result for dual frames. Also, similar results for frame vectors associated with group representations are considered.

报告时间：2020年6月5日下午3:15--3:55

报告地点：腾讯会议 会议 ID： 228 258 955

3、报告题目： Linear combinations of composition operators on Bergman  spaces.                    

报告人：王茂发教授（武汉大学数学科学学院）

报告摘要：Motivated by the question of Shapiro and Sundberg raised in 1990, study on linear combinations of composition operators has been a topic of growing interest. In this talk, we completely characterize the compactness of any linear combination of composition operators with general symbols on the weighted Bergman spaces in terms of three different point views: one is a function theoretic characterization of Julia-Caratheodory type, the second is a measure theoretic characterization of Carleson type, and the other is of power type characterization. Our approach is completely different from what have been known so far.    

报告时间：2020年6月5日下午4:00-4:40

报告地点：腾讯会议 会议 ID： 228 258 955

4、报告题目：Topology on Universal Coefficient Theorems of C*-Algebras

报告人： 魏常果教授（中国海洋大学数学科学学院）

报告摘要： In this talk, I will recall topological structures on Ext-groups of C*-algebra Extensions and introduce our recent work on topologizing UCTs of C*-algebras. It is proved that the stable strong Ext-group and the stable weak Ext-group for unital extensions are pseudopolish groups if A is a unital C*-algebra in the bootstrap class N and B is a stable separable C*-algebra. Furthermore, we topologize certain UCTs and prove that these UCTs are exact sequences as topological groups.

报告时间：2020年6月5日下午4:45--5:25

报告地点：腾讯会议 会议 ID： 228 258 955