Education and work experienceZimmer graduated from New York's Stuyvesant High School in 1964, and attended Brandeis University as an undergraduate, earning his B.A., summa cum laude, in 1968. He conducted his mathematics graduate study at Harvard University, receiving his master's degree in 1971 and his Ph.D. in 1975 under the supervision of George Mackey. Zimmer taught at the United States Naval Academy from 1975-1977, and moved to the mathematics department of the University of Chicago in 1977. He was on the mathematics faculty and held several administrative positions at the University of Chicago, including Chairman of the Department of Mathematics, Deputy Provost, and Vice President for Research and Argonne National Laboratory before he moved to Brown University as provost in 2002. He returned to the University of Chicago as president in 2006.
University of Chicago PresidencyAs president, Zimmer pushed for major academic initiatives at Chicago, including increased financial aid for students in the undergraduate College and the elimination of loans from financial aid packages for low income families; increased funding for doctoral students, particularly in humanities and social sciences; the University of Chicago’s first engineering program, the Institute for Molecular Engineering; new programs and facilities in the arts; and the establishment of the Becker-Friedman Institute for Research in Economics and the Neubauer Family Collegium for Culture and Society. During Zimmer's presidency, the University of Chicago expanded its presence locally with the launch of the Urban Education Institute and globally with the launch of the Center in Beijing and the Center in Delhi.
Under Zimmer's administration applications to the undergraduate College increased from under 10,000 in 2006 to over 30,000 in 2013.
During Zimmer’s tenure the University of Chicago received two of the largest gifts in its history: a $100 million donation to fund undergraduate scholarships, and a $300 million donation to endow the University of Chicago Booth School of Business.
An Associated Press report found Zimmer to be the highest-paid college president in the United States in 2011, with total compensation of $3.4 million in that year.
Mathematical workZimmer’s work centers around group actions on manifolds and more general spaces, with applications to topology and geometry. Much of his work is in the area now known as the "Zimmer Program" which aims to understand the actions of semisimple Lie groups and their discrete subgroups on differentiable manifolds.
Crucial to this program is “Zimmer’s cocycle superrigidity theorem”, a generalization of Grigory Margulis’s superrigidity theorem. Like Margulis’s work, which greatly influenced Zimmer, it uses ergodic theory as a central technique in the case of invariant measures. It led to many results within the Zimmer Program, although many of the main conjectures remain open. In addition to Margulis, Zimmer was greatly influenced by the work of Mikhail Gromov on rigid transformation groups and he extended and connected Gromov’s theory to the Zimmer Program.
Zimmer collaborated with a number of with mathematicians to apply the ideas from the Zimmer Program to other areas of mathematics. His collaboration with Alexander Lubotzky applied some of these ideas to arithmetic results on fundamental groups of manifolds. In collaboration with François Labourie and Shahar Mozes, cocycle superrigidity ideas were applied to the basic problem of the existence of compact locally homogeneous spaces of certain types. His collaboration with Amos Nevo concerned actions with stationary measure and provided certain basic structure theorems for such actions of higher rank semisimple groups. Zimmer’s earlier work provided a proof of a conjecture of Alain Connes on orbit equivalence of actions of semisimple groups, and introduced the basic notion of amenable group action.
Zimmer has an Erdős number of 3.