2013/06/22 by Mei-Lin Yau, Yau, Mei-Lin · 1 citation
Mathematics · #Geometric and Algebraic Topology #Homotopy and Cohomology in Algebraic Topology #Geometric Analysis and Curvature Flows
paper · pdf · doi:10.48550/arxiv.1306.5304
We considered a surgery, called Lagrangian attaching disk surgery, that can be applied to a Lagrangian surface L at the presence of a Lagrangian attaching disk D, to obtain a new Lagrangian surface L' which is always smoothly isotopic to L. We showed that this type of surgery includes all even generalized Dehn twists as constructed by Paul Seidel. We also constructed a new symplectic invariant, called y-index, for orientable closed Lagrangian surfaces immersed in a parallelizable symplectic 4-manifold W. With y-index we proved that L and L' are not Hamiltonian isotopic. We also obtained new examples of nullhomologous Lagrangian tori which are smooth isotopic but not Hamiltonian isotopic.