EVENT DETAILS AND ABSTRACT

Title: "Almost homomorphisms", "almost linear" functionals and "almost measures" in symplectic topology
Speaker: Professor Michael Entov
Speaker Info: Technion-Isreal Institute of Technology
Brief Description:
Special Note: Special time and location
Abstract:

I will discuss how objects of the following sorts appear in symplectic topology as a convenient package for a certain information contained in the Hamiltonian Floer theory and how they can be used to prove various rigidity results, including non-displaceability by a Hamiltonian isotopy of fibers in (singular) Lagrangian fibrations:

- real-valued "almost homomorphisms" of groups of symplectomorphisms (quasi-morphisms and their generalizations);

- an "almost linear" positive functional on C(M) for a symplectic manifold M, with the "almost linearity" being sensitive to the Poisson brackets;

- an "almost measure" on M corresponding to such an "almost linear" positive functional by a generalization (due to Johan Aarnes) of the classical Riesz representation theorem.

The talk is based on joint works with P.Biran, L.Polterovich and F.Zapolsky.