David Fisher is the Distinguished Professor Emeritus of Mathematics at Indiana University Bloomington, where he held the Ruth N. Halls Professorship in the Department of Mathematics from approximately 2005 to 2023. He earned his B.S. from Columbia University and his Ph.D. from the University of Chicago in 1999 under the supervision of Robert J. Zimmer. Throughout his tenure at Indiana University, Fisher received continuous funding from the National Science Foundation since 1999 and advanced the fields of pure mathematics through groundbreaking research.

Fisher's research specializations include rigidity in geometry and dynamics, analytic and geometric group theory, ergodic theory, Lie groups, their discrete subgroups, and generalizations. His major contributions encompass quasi-isometric rigidity of polycyclic groups, arithmeticity of hyperbolic manifolds, and the collaborative solution to Zimmer's conjecture with Aaron Brown and Sebastian Hurtado Salazar, resolving a question open since the early 1980s. Key publications include "Coarse differentiation of quasi-isometries I: Spaces not quasi-isometric to Cayley graphs" (2012, with Alex Eskin and Kevin Whyte), "Quasi-isometric rigidity of solvable groups" (2010, with Alex Eskin), "Groups acting on manifolds: around the Zimmer program" (2011), "Almost isometric actions, property (T), and local rigidity" (2005, with Gregory Margulis), and editorship of "Dynamics, Geometry, Number Theory: The Impact of Margulis on Modern Mathematics" (University of Chicago Press). Fisher serves as an editor for the Journal of Topology and Analysis, Geometriae Dedicata, Indiana University Mathematics Journal, and Geometry and Topology. His influence is evident in international workshops dedicated to his work, coverage in Quanta Magazine, and an invited lecture at the 2022 International Congress of Mathematicians.

Among his honors are election as a Fellow of the American Mathematical Society, Radcliffe Fellowship, Simons Fellowship in the Mathematical Sciences, NSF Postdoctoral Fellowship, and designation as Distinguished Professor in 2021.

Professional Email: fisherdm@iu.edu