学术报告

【online】Localization of eta invariants and differential K-theory

发布人：发布时间： 2020-07-03

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**题目：**Localization of eta invariants and differential K-theory

**报告人：**刘博 教授 （华东师范大学）

**时间：**2020年7月10日 14:30-16:30

**摘要: **In 1968, Atiyah and Segal established a localization formula for the equivariant index which computes the equivariant index via the contribution of the fixed point sets of the group action using the topological K-theory. It is natural to ask if the localization property holds for the more complex spectral invariants, e.g., eta-invariant.

The eta-invariant was introduced in the 1970's as the boundary contribution of index theorem for compact manifolds with boundary. It is formally equal to the number of positive eigenvalues of the Dirac operator minus the number of its negative eigenvalues and has many applications in geometry, topology, number theory and theoretical physics. It is not computable in a local way and not a topological invariant.

In this talk, we will establish a version of localization formula for equivariant eta invariants by using differential K-theory, a new research field in this century. The differential K-theory is the differential extension of the topological K-theory and is the real analogue of the Gillet-Soulé’s Arithmetic K-theory, which extends the Grothendieck’s K-theory to the arithmetic setting in Arakelov geometry. In this talk, I’ll also compare these four K-theories and show the motivation of our proof.

This is a joint work with Xiaonan Ma.

**报告方式：**腾讯会议在线直播

点击链接入会，或添加至会议列表：

https://meeting.tencent.com/s/mIqDhIZWi0Bc

**会议 ID：**531 714 555

**邀请人：**胡昊宇