报告题目：Lagrangian link quasimorphisms and the non-simplicity of Hameomorphism group of surfaces
报告人：Cheuk Yu Mak（南安普顿大学）
In this talk, we will explain the construction of a sequence of homogeneous quasi-morphisms of the area-preserving homeomorphism group of the sphere using Lagrangian Floer theory for links. This sequence of quasi-morphisms has asymptotically vanishing defects, so it is asymptotically a homomorphism. It enables us to show that the Hameomorphism group is not the smallest normal subgroup of the area-preserving homeomorphism group.If time permits, we will explain how to generalize it to all positive genus surfaces even though we no longer have quasi-morphisms.
The case of the sphere is joint work with Daniel Cristofaro-Gardiner, Vincent Humilière, Sobhan Seyfaddini, and Ivan Smith. The case of positive genus surfaces is joint work with Ibrahim Trifa.
Cheuk Yu Mak now is a Royal Society University Research Fellow of the University of Southampton who research fields including symplectic topology, Fukaya category and Homological mirror symmetry.
Mak obtained his PhD at the University of Minnesota in 2016. Then he became a research member at IAS from 2016-2017, a postdoc at the University of Cambridge during 2017-2020, and a research associate at the University of Edinburgh between 2020-2022. Mak is a young prominent mathematician who publishes many papers in the top journals such as Journal of the European Mathematical Society, Geometric And Functional Analysis, Forum of Mathematics Pi, etc.