Lecture: Thursday, September 27, 2018 – Gregory Margulis

Gregory Margulis: “On the early history of expanders”

The notion of an expander was introduced in early nineteen seventies by M.S.Pinsker in his work on the complexity of a concentrator. In recent decades the theory of expanders attracted a lot of attention and became a rather big industry. I will talk only about the development of this theory until approximately 1987-88.