This award supports cooperative research in the mathematics of dynamical systems to be conducted by Sheldon Newhouse of the University of North Carolina at Chapel Hill, Robert Williams of the University of Texas at Austin, Lai-sang Young of the University of Arizona and Dennis Sullivan at CUNY in cooperation with Jacob Palis and six others at the Institute for Pure and Applied Mathematics (IMPA) in Rio de Janeiro, Brazil. They will study dynamical systems including the specific areas of homoclinic bifurcations, rational mappings of the Riemann sphere, stability conjecture for maps of the interval and the dynamics and topology of the Lorentz attractor. In the last twenty or so years, significant progress has been made in this field with increasing impact on applications in biology, physics, chemistry and economics. This project will provide direct cooperation between groups doing frontier research of fundamental importance to both countries. It will also further strengthen the strong background of cooperation between two productive groups in the field of dynamical systems.