Speaker: Alessandro Portaluri, Professor, Università degli Studi di Torino

Date: March 15, 2018

Time: 3:30 p.m.-4:30 p.m.

Location: 924 Lecture Hall, Block B, Zhixin Building, Central Campus

Sponsor: the School of Mathematics

Abstract:

A celebrated result due to Poincaré asserts that a closed minimizing geodesic on a orientable surface is linearly unstable when considered as orbit of the co-geodesic flow.

In this talk, starting from this classical theorem, we discuss some recently new results on the instability and hyperbolicity of closed (maybe not minimizing) geodesics of any causal character on higher dimensional (even not orientable) semi-Riemannian manifolds. Dropping the non-positivity assumption of the metric tensor is a quite challenging task since the Morse index is truly infinite.

For more information, please visit:

http://www.maths.sdu.edu.cn/index-and-stability-of-closed-semi-riemannian-geodesics.html

Edited by: Xing Chenyang, Song Yijun