Three seminar talks in symplectic and contact geometry, in Orsay on 30/11/23

location: at the Institut de Mathématique d’Orsay, bldg 307



10h45 Joan Licata (Australian National University)
Heegaard splittings and the tight Giroux Correspondence
Room 3L15 - Exceptional symplectic and contact geometry seminar

Abstract: The Giroux Correspondence famously characterises the open books supporting a fixed isotopy class of contact structures.   In this talk I’ll sketch a new proof of the Giroux Correspondence for tight contact three-manifolds.  Our approach relies on convex surface theory and the close relationship between open books and Heegaard splittings. This is joint work with V Vertesi.


14h Patricia Dietzsch (ETH Zurich)
Lagrangian Hofer metric and barcodes
Room 2L8 - Weekly seminar of the team of Topology and Dynamics at LMO

Abstract: A major tool in symplectic topology to study Lagrangian submanifolds are Lagrangian Floer homology groups. A richer algebraic invariant can be obtained using filtered Lagrangian Floer theory. The resulting object is a persistence module, giving rise to a barcode, whose bar lengths are invariants for pairs of Lagrangians. It is well-known that these numbers are lower bounds of the Lagrangian Hofer distance between the two Lagrangians.
In this talk we will discuss a reverse inequality: We will show an upper bound of the Lagrangian Hofer distance between equators in the cylinder in terms of a weighted sum of the lengths of the finite bars and the spectral distance.


15h45 Guillem Cazassus (University of Oxford)
Hamiltonian actions on Fukaya categories
Room 2L8 - Exceptional symplectic and contact geometry seminar

Abstract: We will talk about algebraic structures arising in Lagrangian Floer homology in the presence of a Hamiltonian action of a compact Lie group. First, we will show how the Lagrangian Floer complex can be equipped with an A-infinity module structure over the Morse complex of the group, and how this action permits to define equivariant versions of Floer homology. We will then explain how this structure interacts with the structure of the Fukaya category: both can be packaged into (our version of) an A-infinity bialgebra action, giving an alternative answer to a conjecture of Teleman. This should enable one to build an extended topological field theory corresponding to Donaldson-Floer theory. This is based on two joint work in progress, one with Paul Kirk, Mike Miller-Eismeier and Wai-Kit Yeung, and another with Alex Hock and Thibaut Mazuir.