Jaroslaw Kedra: On the autonomous norm on the group of Hamiltonian diffeomorphisms of a surface

Every Hamiltonian diffeomorphism F is a product of autonomous ones. The smallest number of them is, by definition, the autonomous norm of F. I will sketch a proof the fact that the autonomous norm of Ham(M,w), where M is a surface, is unbounded. The main point of the argument is to construct a suitable Lipschitz function Ham(M,w) --> R. This will be done using braids and quasimorphisms.