Paper detail

A characterisation of the Besov-Lipschitz and Triebel-Lizorkin spaces using Poisson like kernels

We give a complete characterisation of the spaces $\dot{B}^α_{p,q}$ and $\dot{F}^α_{p,q}$ by using a non-smooth kernel satisfying near minimal conditions. The tools used include a Stromberg-Torchinsky type estimate for certain maximal functions and the concept of a distribution of finite growth, inspired by Stein. Moreover, our exposition also makes essential use of a number of refinements of the well-known Calderon reproducing formula. The results are then applied to obtain the characterisation of these spaces via a fractional derivative of the Poisson kernel.