- 1985-90, researcher at l'Institut pour le Problèmes de l'Information et des Transmissions, Moscou
- December 1988, Centre de Physique Théorique, Marseille-Luminy, visitor
- March-June 1990, Max-Planck-Institut für Mathematik, Bonn, visitor
- January - November 1991, Max-Planck-Institut für Mathematik, Bonn
- November 1991- January 1992, Harvard University, USA, visitor
- February - September 1992, Max-Planck-Institut für Mathematik, Bonn, visitor
- October 1992 - March 1993, Institute for Advanced Study, Princeton, visitor
- April 1993 - August 1994, Max-Planck-Institut für Mathematik, Bonn, visitor
- July 1993 - August 1995, University of California at Berkeley, Professor
- Since 1 September 1995, permanent professor at l'Institut des Hautes Études Scientifiques, holder of the AXA Chair for mathematics
- Since November 1997, Chair holder at Rutgers University, one month per year
