Berlin-Hamburg-Seminar am 24.4.2017
Steven Sivek (MPI Bonn) Khovanov homology detects the trefoil
Khovanov homology assigns to each knot in S3 a bigraded abelian group whose graded Euler characteristic is the Jones polynomial. While it is not known whether the Jones polynomial detects the unknot, Kronheimer and Mrowka proved in 2010 that the Khovanov homology of K has rank 1 if and only if K is the unknot. Building on their work, I will outline a proof that Khovanov homology also detects the left and right handed trefoils, with an emphasis on the crucial role played by contact geometry in this setting. This is joint work with John Baldwin.
Paolo Ghiggini (Nantes) The wrapped Fukaya category of a Weinstein manifold is generated by the cocores of the critical handles
A Weinstein manifold is an open symplectic manifold admitting a handle decomposition adapted to the symplectic structure. It turns out that the handles of such a decomposition have index at most half of the dimension. When the index is half the dimension, they are called critical handles and their cocores are Lagrangian discs.
In a joint work with Baptiste Chantraine, Georgios Dimitroglou Rizell and Roman Golovko, we decompose any object in the wrapped Fukaya category of a Weinstein manifold as a twisted complex built from the cocores of the critical handles in a Weinstein handle decomposition. The main tools used are the Floer homology theories of exact Lagrangian immersions, of exact Lagrangian cobordisms in the SFT sense (i.e. between Legendrians), as well as relations between these theories.