Control of the Bilinear Indicator Cube Testing property
Abstract
We show that the {\alpha}-fractional Bilinear Indicator/Cube Testing Constant
arising in arXiv:1906.05602 is controlled by the classical fractional
Muckenhoupt constant, provided the product measure {\sigma} x {\omega} is
diagonally reverse doubling (in particular if it is reverse doubling) with
exponent exceeding 2(n-{\alpha}). Moreover, this control is sharp within the
class of diagonally reverse doubling product measures. When combined with the
main results in arXiv:1906.05602, 1907.07571 and 1907.10734, the above control
of BICT_{T^{{\alpha}}} for {\alpha}>0 yields a two weight T1 theorem for
doubling weights with appropriate diagonal reverse doubling, i.e. the norm
inequality for T^{{\alpha}} is controlled by cube testing constants and the
{\alpha}-fractional one-tailed Muckenhoupt constants (without any energy
assumptions), and also yields a corresponding cancellation condition theorem
for the kernel of T^{{\alpha}}, both of which hold for arbitrary
{\alpha}-fractional Calderón-Zygmund operators T^{{\alpha}}. We do not know
if the analogous result for BICT_{H}({\sigma},{\omega}) holds for the Hilbert
transform H in case {\alpha}=0, but we show that
BICT_{H^{dy}}({\sigma},{\omega}) is not controlled by the Muckenhoupt condition
for the dyadic Hilbert transform H^{dy} and doubling weights {\sigma},{\omega}.