Affiliation: | Lefschetz Center for Dynamical Systems, Division of Applied Mathematics, Brown University, Providence, Rhode Island 02912, U.S.A.;Lefschetz Center for Dynamical Systems, Division of Applied Mathematics, Brown University, Providence, Rhode Island 02912, U.S.A.;Instituto de Ciências Mathemáticas de Saõ Carlos, USP 13.560, Saõ Carlos, SP, Brazil |