主讲人：史逸 北京大学 研究员
内容先容：The Cr-closing lemma is one well-known problem in the theory of dynamical systems. The problem is to perturb the original dynamical system so as to obtain a Cr-close system that has a periodic orbit passing through a given point. And this point is called Cr-closable. In this talk, we prove the Cr-closing lemma (r = 2,3,···,∞) for partially hyperbolic diffeomorphisms on 3-manifolds: every non-wandering point of these diffeomorphisms is Cr-closable. Moreover, we will show that Cr-generic conservative partially hyperbolic diffeomorphisms on 3-manifolds have dense periodic points.This is a joint work with Shaobo Gan.