Calderón-Zygmund operators are generalizations of the singular integral operators introduced by Calderón and Zygmund in the fifties [CZ]. These singular integrals are principal value convolutions of the formTf(x) = límε→0 ∫|x-y|>ε K(x-y) f(y) dy = p.v.K * f(x),where f belongs to some class of test functions.
The aim of this paper is to characterize the boundedness of two classes of integral operators from to in terms of the parameters , , , , and , , where is the Siegel upper half-space. The results in the presented paper generalize a corresponding result given in C. Liu, Y. Liu, P. Hu, L. Zhou (2019).
We first show that a linear operator which is bounded on with w ∈ A₁ can be extended to a bounded operator on the weighted local Hardy space if and only if this operator is uniformly bounded on all -atoms. As an application, we show that every pseudo-differential operator of order zero has a bounded extension to .
In this paper, it is proved that the Fourier integral operators of order , with , are bounded from three kinds of Hardy spaces associated with Herz spaces to their corresponding Herz spaces.
We describe a microlocal normal form for a symmetric system of pseudo-differential equations whose principal symbol is a real symmetric matrix with a generic crossing of eigenvalues. We use it in order to give a precise description of the microlocal solutions.
This article is concerned with the question of whether Marcinkiewicz multipliers on give rise to bilinear multipliers on ℝⁿ × ℝⁿ. We show that this is not always the case. Moreover, we find necessary and sufficient conditions for such bilinear multipliers to be bounded. These conditions in particular imply that a slight logarithmic modification of the Marcinkiewicz condition gives multipliers for which the corresponding bilinear operators are bounded on products of Lebesgue and Hardy spaces.
The spectral problem (s²I - ϕ(V)*ϕ(V))f = 0 for an arbitrary complex polynomial ϕ of the classical Volterra operator V in L₂(0,1) is considered. An equivalent boundary value problem for a differential equation of order 2n, n = deg(ϕ), is constructed. In the case ϕ(z) = 1 + az the singular numbers are explicitly described in terms of roots of a transcendental equation, their localization and asymptotic behavior is investigated, and an explicit formula for the ||I + aV||₂ is given. For all a ≠ 0 this...