Math Department MINERVA MINI-COURSE Alex Lubotzky, Weizmann Institute, The Hebrew University, and Minerva Distinguished Visitor Expanders and Ramanujan graphs Wednesday, Sep 27 Fine Hall Common Room 12:15 PM – 1:15 PM [ https://www.math.princeton.edu/events/expanders-and-ramanujan-graphs-2023-09... | https://www.math.princeton.edu/events/expanders-and-ramanujan-graphs-2023-09... ] Expander graphs are of fundamental importance in computer science and in recent years, also in several areas of mathematics. A brilliant insight of Margulis showed their connection with representation theory (Kazhdan Property T) and paved the way to use the theory of automorphic forms to construct ``optimal" expanders (a.k.a. Ramanujan graphs) based on the work of Deligne and Drinfeld on the Ramanujan conjecture for GL(2)(2).