Abstract
In this lecture we will prove Oppenheim's trickling-down theorem, which says that local spectral expansion in the links implies global expansion of the underlying graph. This is a demonstration of Garland's local to global method.
In this lecture we will prove Oppenheim's trickling-down theorem, which says that local spectral expansion in the links implies global expansion of the underlying graph. This is a demonstration of Garland's local to global method.