- Boston University; Boston, Massachusetts, U.S.A.
- Professor; 9/2009 - present
- Associate Professor; 9/2001 - 8/2009
- Assistant Professor; 9/95 - 8/2001
- Institut des Hautes Études Scientifiques in Bures-sur-Yvette,
France
- Visiting Professor, 7/5-8/5/06
- Visiting Professor, 6/15-8/15/04
- Visiting Professor, 7/1-8/31/03
- Visiting Professor, 6/96 - 8/96
- Institute for Advanced Study in Princeton, New Jersey, U.S.A.
- Université de Bourgogne in Dijon, France
- Visiting Professor, 6/1-7/1/00
- Max Planck Institut für Mathematik in Bonn, Germany
- Visiting Professor, (on leave from Boston University), 9/1/1996 - 9/1/97
- University of North Carolina; Chapel Hill, North Carolina, U.S.A.
- National Science Foundation Postdoctoral Fellow; 9/93 - 8/95
- University of Pennsylvania; Philadelphia, Pennsylvania, U.S.A.
- National Science Foundation Postdoctoral Fellow; 9/92 -
8/93
- University of Texas; Austin, Texas, U.S.A.