Geometry and Topology Seminar —— On the Dax invariants of S^2-bundles over surfaces
报告人：尤淇正（色控
）
时间：2026-09-16 15:10-17:00
地点：智华楼四元厅
【摘要】
This talk concerns the isotopy problems for embedded surfaces in nontrivial orientable sphere bundles over surfaces. We begin with a survey of the four-dimensional light bulb theorem, the Dax invariants for disks, and the barbell diffeomorphisms. We then outline the construction of the Dax invariants for closed surfaces and explain their applications to the isotopy classification problem and the structure of the mapping class groups.
