Speaker: Scot Adams Title: The Origins of Lattice Superrigidity and Dynamical Superrigidity Abstract: I will discuss G. Margulis' superrigidity theorem. I will indicate how it arose and how R. Zimmer adapted it to dynamics as part of a larger program initiated by G. Mackey. I will also attempt to explain how this dynamical reformulation found application to the study of Borel reducibility of equivalence relations. Work Address: School of Mathematics, Vincent Hall 206 Church St. SE University of Minnesota Minneapolis, MN 55455 Electronic Mail: adams@math.umn.edu