“…Operators of interest are the maximal function [S1, Moe, PzR, V], fractional and Poisson integrals [S2,Cr], the Hilbert transform [CS1,CS2,KP,NTV1,LSSU,L3] and general Calderón-Zygmund singular integral operators and their commutators [CrRV,CrMoe,CrMPz2,NRTV], the square functions [LLi1,LLi2,CLiX,HLi], paraproducts and their dyadic counterparts [M,HoLWic1,HoLWic2,IKP,Be3]. Necessary and sufficient conditions are only known for the maximal function, fractional and Poisson integrals [S1], square functions [LLi1] and the Hilbert transform [L3,LSSU], and among the dyadic operators for the martingale transform, the dyadic square functions, positive and well localized dyadic operators [Wil1,NTV1,NTV3,T,Ha,HaHLi,HL,LSU2,Ta,Vu1,Vu2]. If the weights u and v are assumed to be in A d 2 , then necessary and sufficient conditions for boundedness of dyadic paraproducts and commutators in terms of Bloom's BM O are known [HoLWic1,HoLWic2].…”