The Perfect Local Theorem and Twisted Martingale Transforms
arXiv:1204.6526 · doi:10.1090/S0002-9939-2014-11930-7
Abstract
A local Tb Theorem provides a flexible framework for proving the boundedness of a Calderón-Zygmund operator T. One needs only boundedness of the operator T on systems of locally pseudo-accretive functions \{b_Q\}, indexed by cubes. We give a new proof of this Theorem in the setting of perfect (dyadic) models of Calderón-Zygmund operators, imposing integrability conditions on the b_Q functions that are the weakest possible. The proof is a simple direct argument, based upon a new inequality for transforms of so-called twisted martingale differences.
12 pages v2: typos corrected in section 5 v3: The twisted martingale transform inequalities appeared in Auscher Routin (arXiv:1011.1747), which is now reflected in the text