## Department Colloquium

### Friday, March 12th, 2021

**Time:** 2:30 p.m. **Place:** Online (via Zoom)

**Speaker:** Boris Hasselblatt (Tufts University)

**Title:** Symmetries of dynamical systems.

**Abstract: ** Examples of dynamical systems with symmetries are not particularly rare, but it is often clear that perturbations can break such symmetry. Thus, it is natural to expect that the presence of symmetries is exceptional. We describe some results about continuous, discrete, and trivial symmetry groups of flows (continuous-time dynamical systems) in the categories of smooth flows and of continuous flows.

**Boris Hasselblatt** is a professor of mathematics as well as former department chair and Associate Provost at Tufts University. He obtained his PhD from Caltech, before moving to Tufts in 1989. His research centers on smooth, geometrically motivated, and topological dynamical systems with hyperbolic behavior. He has coauthored the book Introduction to the Modern Theory of Dynamical Systems, which is the reference in dynamics, and one of the top 100 most cited books in mathematics. He is a Fellow of the American Mathematical Society, held the Chaire Jean Morlet at CIRM in Marseille, as well as many visiting positions, including at the ETH Z\"{u}rich, the University of Tokyo and the IHES. He cofounded the Journal of Modern Dynamics, Electronic Research Announcements - Mathematical Sciences, and Mathematics Research Reports, and he currently serves as the eleventh Secretary of the American Mathematical Society.