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Weighted parabolic Triebel spaces of product type. Fourier multipliers and pseudo-differential operators. (English) Zbl 0737.46021

The author considers the weighted Triebel spaces of product type related to the case when \(R^ n\) carries a structure \(R^ n=R_ 1^ n\times\dots\times R_ N^ n\) where each \(R_ 1^ n\) is provided with a distance function \(\rho_ i\) which is called parabolic. It is generated by a dilation group \(p_ t:=\exp(Q\ln t)\) with a real \(n\times n\) matrix \(Q\) (as in the known papers by Calderon and Torchinsky, Stein and Wainger, Dappa and others). Instead of a maximal technique the author uses a pointwise estimate developing his earlier results in the isotropic case. The author obtains sharp versions of Fourier multipliers theorems on weighted and unweighted Triebel spaces, \(L^ p\)-spaces and vector- valued \(L^ p\)-spaces. He also studies some generalizations of the Hörmander class \(S_{1,\delta}^ m\), \(0\leq \delta\leq 1\), gives an estimation of pseudo-differential operators \((PDOs)\) on the basic of the same pointwise estimate and considers \(PDOs\) with symbols in the Besov space \(B_{\infty,q}^ r\) in the \(x\)-variable on weighted Triebel spaces of product type.

MSC:

46E35 Sobolev spaces and other spaces of “smooth” functions, embedding theorems, trace theorems
47G30 Pseudodifferential operators
35S05 Pseudodifferential operators as generalizations of partial differential operators
42B15 Multipliers for harmonic analysis in several variables