Title: Commutators and weighted norm inequalities

Abstract: We will review the theory of commutators and BMO functions.  As an application of the theory of weighted norm inequalities we will show that the commutator of an operator that satisfies certain weighted norm inequalities is bounded on L^p.  We also show show a converse to this result.  This is joint work with Arpad Benyi, Jose Maria Martell, Eric Stachura, and Rodolfo Torres.