The Calabi invariant for some groups of homeomorphisms

Abstract

We show that the Calabi homomorphism extends to some groups of homeomorphisms on exact symplectic manifolds. The construction is based on the uniqueness of the generating Hamiltonian (proved by Viterbo) of continuous Hamiltonian isotopies (introduced by Mueller and Oh).

arXiv comment16 pages, proof of the main result simplified, "motivations" section improved