# Dehn twists exact sequences through Lagrangian cobordism

 Princeton/IAS Symplectic Geometry Seminar Topic: Dehn twists exact sequences through Lagrangian cobordism Speaker: Weiwei Wu Affiliation: University of Montreal Date: Friday, October 23 Time/Room: 2:00pm - 3:00pm/S-101 Video Link: https://video.ias.edu/puiassgs/2015/1023-WeiweiWu

In this talk we first introduce a new "singularity-free" approach to the proof of Seidel's long exact sequence, including the fixed-point version. This conveniently generalizes to Dehn twists along Lagrangian submanifolds which are rank one symmetric spaces and their covers, including $\mathbb{RP}^n$ and $\mathbb{CP}^n$, matching a mirror prediction due to Huybrechts and Thomas. The idea of the proof can be interpreted as a "mirror" of the construction in algebraic geometry, realized by a new surgery and cobordism construction. This is a joint work with Cheuk-Yu Mak.