Results 61 to 70 of about 9,965 (190)

Semiclassical quantization and spectral limits of h-pseudodifferential and Berezin-Toeplitz operators

open access: yes, 2013
We introduce a minimalistic notion of semiclassical quantization and use it to prove that the convex hull of the semiclassical spectrum of a quantum system given by a collection of commuting operators converges to the convex hull of the spectrum of the ...
Ngoc, San Vũ   +2 more
core   +3 more sources

Pseudodifferential Operators with Rough Symbols [PDF]

open access: yesJournal of Fourier Analysis and Applications, 2009
In this work, we develop $L^p$ boundedness theory for pseudodifferential operators with rough (not even continuous in general) symbols in the $x$ variable. Moreover, the $B(L^p)$ operator norms are estimated explicitly in terms of scale invariant quantities involving the symbols.
openaire   +2 more sources

The Metivier inequality and ultradifferentiable hypoellipticity

open access: yesMathematische Nachrichten, Volume 297, Issue 7, Page 2517-2531, July 2024.
Abstract In 1980, Métivier characterized the analytic (and Gevrey) hypoellipticity of L2$L^2$‐solvable partial linear differential operators by a priori estimates. In this note, we extend this characterization to ultradifferentiable hypoellipticity with respect to Denjoy–Carleman classes given by suitable weight sequences. We also discuss the case when
Paulo D. Cordaro, Stefan Fürdös
wiley   +1 more source

Invariant distributions and the transport twistor space of closed surfaces

open access: yesJournal of the London Mathematical Society, Volume 109, Issue 5, May 2024.
Abstract We study transport equations on the unit tangent bundle of a closed oriented Riemannian surface and their links to the transport twistor space of the surface (a complex surface naturally tailored to the geodesic vector field). We show that fibrewise holomorphic distributions invariant under the geodesic flow — which play an important role in ...
Jan Bohr   +2 more
wiley   +1 more source

Spectral Riesz-Cesaro means: How the square root function helps us to see around the world

open access: yesElectronic Journal of Differential Equations, 2000
The heat-kernel expansion for a nonanalytic function of a differential operator, and the integrated (Cesàro-smoothed) spectral densities associated with the corresponding nonanalytic function of the spectral parameter, exhibit a certain nonlocal ...
S. A. Fulling   +2 more
doaj  

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

Korteweg–de Vries waves in peridynamical media

open access: yesStudies in Applied Mathematics, Volume 152, Issue 1, Page 376-403, January 2024.
Abstract We consider a one‐dimensional peridynamical medium and show the existence of solitary waves with small amplitudes and long wavelength. Our proof uses nonlinear Bochner integral operators and characterizes their asymptotic properties in a singular scaling limit.
Michael Herrmann, Katia Kleine
wiley   +1 more source

Prediction Method of Maximum Propagation Angle in Parabolic Equation Model over Irregular Terrain

open access: yesInternational Journal of Antennas and Propagation, Volume 2024, Issue 1, 2024.
The parabolic equation (PE) model is effective for predicting signal propagation over irregular terrains. The shift map method of the PE model is highly accurate and widely used for terrain propagation predictions. The maximum propagation angle is a crucial parameter of the shift map model.
Rui Zhang   +5 more
wiley   +1 more source

A Note on the Regularity of the Solutions to Two Variational Inequalities Involving a Pseudodifferential Operator

open access: yesInternational Journal of Mathematics and Mathematical Sciences, 2007
The regularity of solutions to variational inequalities involving local operators has been studied extensively. Less attention has been paid to those involving nonlocal pseudodifferential operators. We present two regularity results for such problems.
Randolph G. Cooper
doaj   +1 more source

Home - About - Disclaimer - Privacy