报告人简介：

吴健超，复旦大学上海数学中心青年研究员，研究领域为非交换几何与算子代数，入选国家级青年人才计划，主持科技部国家重点研发青年项目，在Geom. Funct. Anal., Adv. Math., Comm. Math. Phys., Trans. Amer. Math. Soc.等知名数学期刊发表多篇论文，其中与Sherry Gong和郁国樑的合作文章获得2025年国际基础科学大会Frontiers of Science Awards。

报告简介：

Generalizing the intriguing phenomenon of Voiculescu's almost commuting unitary matrices is the notion of a quasi-representation of a (discrete) group. As demonstrated by the work of Exel and Loring on Voiculescu's example, there may be topological obstructions to perturbing quasi-representations into genuine representations---this is where (topological or operator) K-theory enters the picture. Previous studies have mostly focused on fundamental groups of finite CW complexes. In this talk, which is based on joint work with Shmuel Weinberger and Guoliang Yu, we introduce the notion of a character as a more general and refined invariant for quasi-representations.