Results 41 to 50 of about 99 (90)

Berezin number inequalities for operators

Concrete Operators, 2019
The Berezin transform à of an operator A, acting on the reproducing kernel Hilbert space ℋ = ℋ (Ω) over some (non-empty) set Ω, is defined by Ã(λ) = 〉Aǩ λ, ǩ λ〈 (λ ∈ Ω), where k⌢λ=kλ‖kλ‖${\mathord{\buildrel{\lower3pt\hbox{$\scriptscriptstyle\frown ...
Bakherad Mojtaba, Garayev Mubariz T.
doaj   +1 more source

Boundedness properties of resolvents and semigroups of operators [PDF]

, 1997
. Let T: H → H be an operator in the complex Hilbert space H. Suppose that T is square bounded in average in the sense that there exists a constant M(T) with the property that, for all natural numbers n and for all x ∈ H, the inequality 1 n+ 1 n∑ j=0 ‖T ...
van Casteren, Johannes A., J. A. Van Casteren, J. van Casteren, van Casteren, J.   +3 more
core   +2 more sources

On Quasi-Similarity and Putnam- Fuglede Property of Operators In Hilbert Spaces [PDF]

, 2014
The problem of finding conditions under which two given operators say A and B have equal spectra has been considered by several authors. In this paper we show that quasi-similar operators  and  which satisfy the Putnam- Fuglede property have equal ...
LUKETERO, S.W., RUGIRI, P.G., KHALAGAI, J.M.   +2 more
core   +1 more source

A posteriori analysis of the spectral element discretization of heat equation

Analele Stiintifice ale Universitatii Ovidius Constanta: Seria Matematica, 2014
In this paper, we present a posteriori analysis of the discretization of the heat equation by spectral element method. We apply Euler’s implicit scheme in time and spectral method in space.
Chorfi Nejmeddine, Abdelwahed Mohamed, Ben Omrane Ines   +2 more
doaj   +1 more source

ON EQUALITY OF SPECTRA AND ESSENTIAL SPECRA OF OPERATORS IN HILBERT SPACES [PDF]

, 2015
It is a well known fact in operator theory that for any operator A, the essential spectrum of A is contained in the spectrum of A.  The task of finding conditions under which the two are equal has been the subject matter in a number of several research ...
LUKETERO, S.W., RUGIRI, P.G., KHALAGAI, J.M.   +2 more
core   +1 more source

On Berezin norm and Berezin number inequalities for sum of operators

Demonstratio Mathematica
The aim of this study is to obtain several inequalities involving the Berezin number and the Berezin norm for various combinations of operators acting on a reproducing kernel Hilbert space.
Altwaijry Najla, Feki Kais, Minculete Nicusor   +2 more
doaj   +1 more source

A simulation algorithm for a single server retrial queuing system with batch arrivals

Analele Stiintifice ale Universitatii Ovidius Constanta: Seria Matematica, 2015
Many systems of real word are modeled by retrial queuing system with batch arrivals. Analytical formulas for this class of systems are complicated and address only particular cases.
Florea Ion, Nǎnǎu Corina-Ştefania
doaj   +1 more source

Accretive partial transpose matrices and their connections to matrix means

Open Mathematics
Accretive partial transpose (APT) matrices have been recently defined, as a natural extension of positive partial transpose (PPT) matrices. In this paper, we discuss further properties of APT matrices in a way that extends some of those properties known ...
Aldabbas Eman, Sababheh Mohammad
doaj   +1 more source

ON QUASI-INVERTIBILITY AND QUASI-SIMILARITY OF OPERATORS IN HILBERT SPACES. [PDF]

, 2015
It is a well known fact in operator Theory that if A and B are operators with at least one of them invertible then AB and BA are similar operators.  In this paper we prove an analogous result about quasi-invertible operators A and B. We thus show that if
LUKETERO, S.W., RUGIRI, P.G., KHALAGAI, J.M.   +2 more
core   +1 more source

Generalized D-Symmetric Operators I [PDF]

, 2008
2000 Mathematics Subject Classification: Primary: 47B47, 47B10; secondary 47A30.Let H be an infinite-dimensional complex Hilbert space and let A, B ∈ L(H), where L(H) is the algebra of operators on H into itself.
Ech-chad, M., Bouali, S.
core