Geometry, Topology and Dynamics Seminar
Michael Entov
Technion, Haifa
Quasi-states and quasi-measures in symplectic topology
Abstract: The notion of a quasi-state, whose origins lie in quantum mechanics, was
introduced by an analyst Johan Aarnes. It can be roughly described as an
"almost linear" positive functional on C(X), where X is a compact metric
space. A quasi-measure is an "almost measure" on X corresponding to a
quasi-state according to Aarnes' extension of the classical Riesz
representation theorem.
I will discuss how quasi-states and quasi-measures appear in symplectic
topology in close connection to quasi-morphisms ("homomorphisms up to a
bounded error") of groups of symplectomorphisms and how these and similar
objects can be used to prove various symplectic rigidity results.
The talk is based on joint works with P.Biran, L.Polterovich and
F.Zapolsky.
Wednesday November 9, 2005 at 3:00 PM in SEO 427