汇报标题（中英文） (Title)：高Kazhdan投影和非部门化l2贝蒂数（Higher Kazhdan projections and delocalised ?2-Betti numbers）
汇报人 (Speaker)：王航 教授（华东师范大学）
汇报功夫（Time）：2023年9月14日（周四）14：00
汇报地址 (Place)：校本部C110
约请人(Inviter)：陈旦旦、孟沆洋
主办部门：理学院数学系
汇报提要：We explicitly describe the K-theory class of higher Kazhdan projections for certain free product groups and Cartesian products. Employing the explicit description, we obtain new calculations of Lott’s delocalised ?2-Betti numbers. In particular, we establish the first non-vanishing results for infinite groups.
