2007 – present: Hagey Family Professor of Mathematics, Williams College
1984 – 2007: Assistant Professor, Associate Professor, Professor of Mathematics, Williams College
2010 – 2012: Chair, Department of Mathematics and Statistics, Williams College
2009 – 2010: On leave, Williams College
2008 – 2009: Chair, Department of Mathematics and Statistics, Williams College
Fall 94: Acting Chair, Department of Mathematics, Williams College
Visiting Postions:
2019 – 2021: Program Director, National Science Foundation (On leave from Williams)
Fall 95: SUNY at Albany
May 92: Université Paris Sud, France
Spring 92: University of Toronto
Fall 91: Swarthmore College
1987 – 1988: University of Maryland, College Park