Results 41 to 50 of about 1,449 (134)

Left and right generalized Drazin invertible operators on Banach spaces and applications

open access: yesOperators and Matrices, 2019
In this paper, left and right generalized Drazin invertible operators on Banach spaces are defined and characterized by means of the generalized Kato decomposition. Then, new binary relations associated with these operators are presented and studied.
D. E. Ferreyra, F. Levis, N. Thome
semanticscholar   +1 more source

Spectral inclusions and stability results for strongly continuous semigroups

open access: yesInternational Journal of Mathematics and Mathematical Sciences, Volume 2003, Issue 37, Page 2379-2387, 2003., 2003
We prove some spectral inclusions for strongly continuous semigroups. Some stability results are also established.
Abdelkader Elkoutri, Mohamed Aziz Taoudi
wiley   +1 more source

Sequences of bounds for the spectral radius of a positive operator

open access: yes, 2019
In 1992, Szyld provided a sequence of lower bounds for the spectral radius of a nonnegative matrix $A$, based on the geometric symmetrization of powers of $A$.
Drnovšek, Roman
core   +1 more source

Approximate controllability of fractional differential equations via resolvent operators

open access: yesAdvances in Differential Equations, 2014
Of concern are the existence and approximate controllability of fractional differential equations governed by a linear closed operator which generates a resolvent.
Z. Fan
semanticscholar   +1 more source

The spectrum of a class of almost periodic operators

open access: yesInternational Journal of Mathematics and Mathematical Sciences, Volume 2003, Issue 36, Page 2277-2301, 2003., 2003
For almost Mathieu operators, it is shown that the occurrence of Cantor spectrum and the existence, for every point in the spectrum and suitable phase parameters, of at least one localized eigenfunction which decays exponentially are inconsistent properties.
Norbert Riedel
wiley   +1 more source

On the continuity of spectra for families of magnetic pseudodifferential operators

open access: yes, 2010
For families of magnetic pseudodifferential operators defined by symbols and magnetic fields depending continuously on a real parameter $\epsilon$, we show that the corresponding family of spectra also varies continuously with $\epsilon$.Comment: 22 ...
Blanchard E.   +5 more
core   +2 more sources

On the largest analytic set for cyclic operators

open access: yesInternational Journal of Mathematics and Mathematical Sciences, Volume 2003, Issue 30, Page 1899-1909, 2003., 2003
We describe the set of analytic bounded point evaluations for an arbitrary cyclic bounded linear operator T on a Hilbert space ℋ; some related consequences are discussed. Furthermore, we show that two densely similar cyclic Banach‐space operators possessing Bishop′s property (β) have equal approximate point spectra.
A. Bourhim
wiley   +1 more source

Existence conditions for periodic solutions of second-order neutral delay differential equations with piecewise constant arguments

open access: yesOpen Mathematics, 2020
In this paper, we describe a method to solve the problem of finding periodic solutions for second-order neutral delay-differential equations with piecewise constant arguments of the form x″(t) + px″(t − 1) = qx([t]) + f(t), where [⋅] denotes the greatest
I. Muminov Mukhiddin, H. M. Murid Ali
doaj   +1 more source

On the essential spectra of unbounded operator matrices with non diagonal domain and an application

open access: yesOperators and Matrices, 2019
This paper is devoted to the investigation of the spectral stability of unbounded operator matrices with non diagonal domain in product of Banach spaces.
Marwa Belghith, N. Moalla, I. Walha
semanticscholar   +1 more source

Common fixed point theorems for a pair of countably condensing mappings in ordered banach spaces

open access: yesInternational Journal of Stochastic Analysis, Volume 16, Issue 3, Page 243-248, 2003., 2003
In this paper some common fixed point theorems for a pair of multivalued weakly isotone mappings on an ordered Banach space are proved.
B. C. Dhage   +2 more
wiley   +1 more source

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