Some generalizations of Littlewood-Paley inequality in the polydisc
K. L. Avetisyan and R. F. Shamoyan
Abstract
The paper generalizes the well-known inequality of Littlewood-Paley in the polydisc.
We establish a family of inequalities which are analogues and extensions of Littlewood-Paley
type inequalities proved by Sh.\ Yamashita and D. Luecking in the unit disk.
Some other generalizations of the Littlewood-Paley inequality are stated
in terms of anisotropic Triebel-Lizorkin spaces.
With the help of an extension of Hardy-Stein identity, we also obtain area inequalities and representations
for quasi-norms in weighted spaces of holomorphic functions in the polydisc.