Results 1 to 10 of about 11,357 (198)

Pseudodifferential operators with homogeneous symbols.

open access: yesMichigan Mathematical Journal, 1999
The authors define homogeneous symbols as symbols \(a(x,\xi)\) in \(C^\infty(\mathbb{R}^n\times (\mathbb{R}^n/0))\) satisfying \[ |D^\alpha_x D^\beta_\xi a(x,\xi)|\leq C_{\alpha\beta}|\xi|^{m- |\beta|+|\alpha|} \] for all \(\alpha\), \(\beta\), with constants \(C_{\alpha\beta}\) independent of \(x\in\mathbb{R}^n\), \(\xi\in \mathbb{R}^n/0\).
Grafakos, Loukas, Torres, Rodolfo H.
openaire   +2 more sources

Almost Diagonalization of Pseudodifferential Operators [PDF]

open access: yes, 2019
In this review we focus on the almost diagonalization of pseudodifferential operators and highlight the advantages that time-frequency techniques provide here. In particular, we retrace the steps of an insightful paper by Gr chenig, who succeeded in characterizing a class of symbols previously investigated by Se strand by noticing that Gabor frames ...
openaire   +2 more sources

Fundamental Results for Pseudo-Differential Operators of Type 1, 1

open access: yesAxioms, 2016
This paper develops some deeper consequences of an extended definition, proposed previously by the author, of pseudo-differential operators that are of type 1 , 1 in Hörmander’s sense. Thus, it contributes to the long-standing problem of creating
Jon Johnsen
doaj   +1 more source

The Friedrichs Extension of Elliptic Operators with Conditions on Submanifolds of Arbitrary Dimension

open access: yesMathematics
We describe the Friedrichs extension of elliptic symmetric pseudodifferential operators on a closed smooth manifold with the domain consisting of functions vanishing on a given submanifold.
Anton Savin
doaj   +1 more source

Families Index for Pseudodifferential Operators on Manifolds with Boundary

open access: yes, 2003
An analytic index is defined for a family of cusp pseudodifferential operators, $P_b,$ on a fibration with fibres which are compact manifolds with boundaries, provided the family is elliptic and has invertible indicial family at the boundary.
Melrose, Richard, Rochon, Frederic
core   +1 more source

$L^{p}$ estimates for joint quasimodes of semiclassical pseudodifferential operators

open access: yes, 2018
We develop a set of $L^{p}$ estimates for functions $u$ that are a joint quasimode (approximate eigenfunction) of $r$ pseudodifferential operators $p_{1}(x,hD),\dots,p_{r}(x,hD)$. This work extends Sarnak and Marshall's work on symmetric space to cover a
Tacy, Melissa
core  

Boundedness of a Class of Sublinear Operators and Their Commutators on Generalized Morrey Spaces

open access: yesAbstract and Applied Analysis, 2011
The authors study the boundedness for a large class of sublinear operator T generated by Calderón-Zygmund operator on generalized Morrey spaces Mp,φ.
Vagif S. Guliyev   +2 more
doaj   +1 more source

On a Class of h-Fourier Integral Operators

open access: yesDemonstratio Mathematica, 2014
In this paper, we study the L2-boundedness and L2-compactness of a class of h-Fourier integral operators. These operators are bounded (respectively compact) if the weight of the amplitude is bounded (respectively tends to 0).
Harrat Chahrazed   +1 more
doaj   +1 more source

The perturbed Maxwell operator as pseudodifferential operator

open access: yesDocumenta Mathematica, 2014
As a first step to deriving effective dynamics and ray optics, we prove that the perturbed periodic Maxwell operator in d = 3 can be seen as a pseudo­differential operator. This necessitates a better understanding of the periodic Maxwell operator
De Nittis, Giuseppe, Lein, Max
openaire   +2 more sources

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