Results 51 to 60 of about 97 (90)

Left Derivable Maps at Non-Trivial Idempotents on Nest Algebras

Annales Mathematicae Silesianae, 2019
Let Alg 𝒩 be a nest algebra associated with the nest 𝒩 on a (real or complex) Banach space 𝕏. Suppose that there exists a non-trivial idempotent P ∈ Alg 𝒩 with range P (𝕏) ∈ 𝒩, and δ : Alg 𝒩 → Alg 𝒩 is a continuous linear mapping (generalized) left ...
Ghahramani Hoger, Sattari Saman
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

Combined system of additive functional equations in Banach algebras

Open Mathematics
In this study, we solve the system of additive functional equations: h(x+y)=h(x)+h(y),g(x+y)=f(x)+f(y),2fx+y2=g(x)+g(y),\left\{\begin{array}{l}h\left(x+y)=h\left(x)+h(y),\\ g\left(x+y)=f\left(x)+f(y),\\ 2f\left(\frac{x+y}{2}\right)=g\left(x)+g(y),\end ...
Donganont Siriluk, Park Choonkil
doaj   +1 more source

New aspects in polygroup theory

Analele Stiintifice ale Universitatii Ovidius Constanta: Seria Matematica, 2020
The aim of this paper is to compute the commutativity degree in polygroup’s theory, more exactly for the polygroup PG and for extension of polygroups by polygroups, obtaining boundaries for them.
Sonea Andromeda Cristina
doaj   +1 more source

Commutators of multilinear fractional maximal operators with Lipschitz functions on Morrey spaces

Open Mathematics
In this work, we present necessary and sufficient conditions for the boundedness of the commutators generated by multilinear fractional maximal operators on the products of Morrey spaces when the symbol belongs to Lipschitz spaces.
Zhang Pu, Ağcayazı Müjdat
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

Contractible Kothe Co-Echelon Algebras

, 2020
In this note we investigate contractibility properties in the class of the socalled DF-algebras. We also give a complete characterization of contractible  Kothe co-echelon algebras.
Piszczek, Krzysztof
core  

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  

Nilpotent perturbations of m-isometric and m-symmetric tensor products of commuting d-tuples of operators

Demonstratio Mathematica
If T1{{\mathbb{T}}}_{1} and T2{{\mathbb{T}}}_{2} are commuting dd-tuples of Hilbert space operators in B(ℋ)dB{\left({\mathcal{ {\mathcal H} }})}^{d} such that (T1*⊗I+I⊗T2*,T1⊗I+I⊗T2)\left({{\mathbb{T}}}_{1}^{* }\otimes I+I\otimes {{\mathbb{T}}}_{2}^{* },{
Duggal Bhagwati Prashad, Kim In Hyoun
doaj   +1 more source

Bloom-type two-weight inequalities for commutators of maximal functions

Analysis and Geometry in Metric Spaces
We study Bloom-type two-weight inequalities for commutators of the Hardy-Littlewood maximal function and sharp maximal function. Some necessary and sufficient conditions are given to characterize the two-weight inequalities for such commutators.
Zhang Pu, Fan Di
doaj   +1 more source