Any sufficiently smooth one-dimensional Calderon-Zygmund convolution operator
is the average of Haar shift operators. The latter are dyadic operators which
can be efficiently expressed in terms of the Haar basis. This extends the
result of S. Petermichl on restoring Hilbert transform via Haar shift
operators, a technique that has become fundamental to the analysis of these
operators.
As a corollary to our main result we deduce sharp A_p$ inequalities for
The Small Ball Inequality is a conjectural lower bound on sums the L-infinity
norm of sums of Haar functions supported on dyadic rectangles of a fixed volume
in the unit cube. The conjecture is fundamental to questions in discrepancy
theory, approximation theory and probability theory. In this article, we
concentrate on a special case of the conjecture, and give the best known lower
bound in dimension 3, using a conditional expectation argument.
The Small Ball Inequality is a conjectural lower bound on sums the L-infinity
norm of sums of Haar functions supported on dyadic rectangles of a fixed volume
in the unit cube. The conjecture is fundamental to questions in discrepancy
theory, approximation theory and probability theory. In this article, we
concentrate on a special case of the conjecture, and give the best known lower
bound in dimension 3, using a conditional expectation argument.