Calabi quasimorphisms for the symplectic ball
Loading...
Date
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Description
We prove that the group of compactly supported symplectomorphisms of the standard symplectic ball admits a continuum of linearly independent real-valued homogeneous quasimorphisms. In addition these quasimorphisms are Lipschitz in the Hofer metric and have the following property: the value of each such quasimorphism on any symplectomorphism supported in any "sufficiently small" open subset of the ball equals the Calabi invariant of the symplectomorphism. By a "sufficiently small" open subset we mean that it can be displaced from itself by a symplectomorphism of the ball. As a byproduct we show that the (Lagrangian) Clifford torus in the complex projective space cannot be displaced from itself by a Hamiltonian isotopy.
Minor errors corrected. To appear in Communications in Contemporary Mathematics
Minor errors corrected. To appear in Communications in Contemporary Mathematics