Séance du 5 février 2016

Lieu: IHP, salle 201


11:00  Janko Latchev (Hamburg)
Knot contact homology, string topology, and the cord algebra.
Abstract: I will discuss recently completed joint work with K.Cieliebak, T.Ekholm and L.Ng which provides a new proof of the isomorphism between (the degree zero part of) Legendrian contact homology for the unit conormal bundle of a smooth knot K in R^3 (known as knot contact homology) and the cord algebra, a combinatorially defined invariant of such knots introduced in work of L.Ng.
One of the important ingredients is a string topology version of the cord algebra, which serves as an intermediary between the two objects we ultimately want to relate.

14:15  Gilberto Spano (Budapest)
A categorification of the Alexander polynomial in ECH.
Abstract: In 2010 Colin, Ghiggini, Honda and Hutchings defined a "hat" version  of an embedded contact homology ECK for knots in 3-manifolds. We will  describe this homology, a "full" version of ECK and also generalizations to links with more then one component; we will then  prove that for any link L in a homology 3-sphere, the graded Euler  characteristic of ECK coincides with the (multivariable) Alexander  polynomial of L. 

16:00  Michael Khanevsky (Bruxelles)
Lagrangian displacement energy and Hofer's norm of commutators.
Abstract: Chekanov proved that the displacement energy of a Lagrangian L is bounded from below by the minimal area of holomorphic spheres and disks in (M;L). We discuss a similar bound by M. Usher for the energy needed to separate a pair of Lagrangian submanifolds in M. An application of this estimate shows that certain manifolds admit Hamiltonian commutators with large Hofer's norm..

Prochaine séance: 1/04 (pas de séance en mars).
Autre activité symplectique à Paris: groupe de travail faisceaux.