Members Seminar | |

Topic: | How to Construct Topological Invariants via Decompositions and the Symplectic Category |

Speaker: | Katrin Wehrheim |

Affiliation: | Massachusetts Institute of Technology; Member, School of Mathematics |

Date: | Monday, October 17 |

Time/Room: | 2:00pm - 3:00pm/S-101 |

Video Link: | https://video.ias.edu/members/wehrheim |

A Lagrangian correspondence is a Lagrangian submanifold in the product of two symplectic manifolds. This generalizes the notion of a symplectomorphism and was introduced by Weinstein in an attempt to build a symplectic category. In joint work with Chris Woodward we define such a category in which all Lagrangian correspondences are composable morphisms. We extend it to a 2-category by extending Floer homology to cyclic sequences of Lagrangian correspondences. This is based on counts of 'holomorphic quilts' - a collection of holomorphic curves in different manifolds with 'seam values' in the Lagrangian correspondences. A fundamental isomorphism of Floer homologies ensures that our constructions are compatible with the geometric composition of Lagrangian correspondences. This provides a general prescription for constructing topological invariants by decomposition into simple pieces and a partial functor into the symplectic category (which need only be defined on simple pieces; with moves corresponding to geometric composition).