Entropy and links in 3D flows
数学专题报告
报告题目(Title)：Entropy and links in 3D flows
报告人(Speaker)：Matthias Meiwes (特拉维夫大学)
地点(Place)：后主楼1220
时间(Time)：2025年9月4日 （周四） 10：00-11：00
邀请人(Inviter)：龚文敏
报告摘要
Given a flow on a 3-dimensional closed manifold and a link of periodic orbits, we may consider all periodic orbits of the flow that are unique in their homotopy class in the link complement. In my talk, I will explain a result that says that for a $C^{1+\epsilon}$ flow, a sequence of such links can be found for which the exponential growth rates of the orbits with the above uniqueness property approximate the topological entropy of the flow. This result has some applications in the context of the dynamics of Hamiltonian diffeomorphisms and the dynamics of Reeb flows\geodesic flows. In particular, it is an important ingredient in the proof of a result (jointly obtained with M. Alves, L. Dahinden, and A. Pirnapasov) that generically the topological entropy of 3D Reeb flows is lower semi-continuous with respect to the $C^0$ distance on contact forms.
