Non-probabilistic proof of the A_2 theorem, and sharp weighted bounds for the q-variation of singular integrals

Tuomas P. Hytönen, Michael T. Lacey, Carlos Pérez

Published 2012-02-10Version 1

Any Calderon-Zygmund operator T is pointwise dominated by a convergent sum of positive dyadic operators. We give an elementary self-contained proof of this fact, which is simpler than the probabilistic arguments used for all previous results in this direction. Our argument also applies to the q-variation of certain Calderon-Zygmund operators, a stronger nonlinearity than the maximal truncations. As an application, we obtain new sharp weighted inequalities.