Results 21 to 30 of about 109 (35)

Compact $AC(\sigma)$ operators

, 2008
All compact $AC(\sigma)$ operators have a representation analogous to that for compact normal operators. As a partial converse we obtain conditions which allow one to construct a large number of such operators. Using the results in the paper, we answer a
Ashton, Brenden, Doust, Ian
core   +1 more source

Unitary groups and spectral sets

, 2014
We study spectral theory for bounded Borel subsets of $\br$ and in particular finite unions of intervals. For Hilbert space, we take $L^2$ of the union of the intervals. This yields a boundary value problem arising from the minimal operator $\Ds = \frac1{
Dutkay, Dorin Ervin, Jorgensen, Palle E. T.   +1 more
core   +1 more source

New forms of bilateral inequalities for K-g-frames

Demonstratio Mathematica
In this work, several bilateral inequalities for KK-gg-frames in subspaces are established, drawing support from two kinds of operators induced, respectively, by the KK-gg-frame itself and the KK-dual pair, which, compared with previous ones concerning ...
Xiang Zhong-Qi
doaj   +1 more source

Spectral multiplier theorems and averaged R-boundedness [PDF]

, 2016
Let $A$ be a $0$-sectorial operator with a bounded $H^\infty(\Sigma\_\sigma)$-calculus for some $\sigma \in (0,\pi),$ e.g. a Laplace type operator on $L^p(\Omega),\: 1 < p < \infty,$ where $\Omega$ is a manifold or a graph.
Kriegler, Christoph, Weis, Lutz
core  

Generalized TKNN-equations

, 2011
We derive generalized TKNN-equations via bundle representations of the noncommutative torus with rational deformation parameter, the bundle coming from spectral projections in the torus algebra.
De Nittis, Giuseppe, Landi, Giovanni
core   +2 more sources

PC-Asymptotically almost automorphic mild solutions for impulsive integro-differential equations with nonlocal conditions [PDF]

In this article, we study the existence of PC-asymptotically almost automorphic mild solutions of integro-differential equations with nonlocal conditions via resolvent operators in Banach space. Further, we give sufficient conditions for the solutions to
BENCHOHRA, Mouffak, BENSALEM, Abdelhamid, IKHLEF, Nadia, LITIMEIN, Sara, SALIM, Abdelkrim   +4 more
core   +2 more sources

Existence and attractivity results on semi-infinite intervals for integrodifferential equations with non-instantaneous impulsions in Banach spaces

Analele Stiintifice ale Universitatii Ovidius Constanta: Seria Matematica
In this article, we study the existence of mild solutions of a non-instantaneous integrodi erential equations on unbounded domain via resolvent operators in Banach space. For our proofs, we employ the semigroups theory and Schauder’s fixed point theorem.
Bensalem Abdelhamid, Salim Abdelkrim, Benchohra Mouffak, Karapinar Erdal   +3 more
doaj   +1 more source

The Muckenhoupt $A_\infty$ class as a metric space and continuity of weighted estimates

, 2011
We show how the $A_\infty$ class of weights can be considered as a metric space. As far as we know this is the first time that a metric d is considered on this set. We use this metric to generalize the results obtained in [9].
Pattakos, Nikolaos, Volberg, Alexander
core   +1 more source

On the differentiability of weak solutions of an abstract evolution equation with a scalar type spectral operator on the real axis

, 2018
Given the abstract evolution equation \[ y'(t)=Ay(t),\ t\in \mathbb{R}, \] with scalar type spectral operator $A$ in a complex Banach space, found are conditions necessary and sufficient for all weak solutions of the equation, which a priori need not be ...
Markin, Marat V.
core   +1 more source

HOLOMORPHIC FUNCTIONAL CALCULUS APPROACH TO THE CHARACTERISTIC FUNCTION OF QUANTUM OBSERVABLES [PDF]

We show how Cauchy's Integral Formula and the ideas of Dunford's Holomorphic Functional Calculus (for unbounded operators) can be used to compute the Vacuum Characteristic Function (Quantum Fourier Transform) of quantum random variables defined as self ...
Boukas, Andreas
core   +3 more sources