演讲者：夏志宏（美国西北大学）
时间：2023-10-18 15:00-16:00
地点：理学院大楼M1001
Abstract
Consider a symplectic diffeomorphism on a compact symplectic manifold. There are two notable invariants, the area and volume flux and mean rotation yector. We show that the volume flux (which is defined as a cohomology element) is exactly the Poincare dual of the rotation vector (a homology element). We also establish the relationships between the area flux and the volume flux, and show that a symplectic diffeomorphism is Hamiltonian if and only if the rotation yector is zero.
