Seminar: What is ... an Expander?

Michal Jan Adamaszek will talk about: What is an Expander?

Abstract: Expanders are gadgets in graph theory that draw on ideas from algebra, number theory and combinatorics and come in extremely handy in computer science and many areas of mathematics (and probably elsewhere, too). I will introduce expanders and give some motivating examples and applications. If there is time I will hint at what higher-dimensional expansion might be, and how Gromov  solved a problem in extremal combinatorics.

Familiarity with the notions of eigenvalue, metric space and manifold may be helpful at some points (but at most one at a time, so no worries...).

This lecture is part of the "What is...?" seminar.