Results 21 to 30 of about 64 (56)
Factorization of k‐quasihyponormal operators
International Journal of Mathematics and Mathematical Sciences, Volume 14, Issue 3, Page 439-442, 1991., 1989 Let A be the class of all operators T on a Hilbert space H such that R(T*kT), the range space of T*KT, is contained in R(T*k+1), for a positive integer k. It has been shown that if T ϵ A, there exists a unique operator CT on H such that The main objective of this paper is to characterize k‐quasihyponormal; normal, and self‐adjoint operators T in A in ...
S. C. Arora, J. K. Thukral
wiley +1 more source
Cohyponormal operators with the single valued extension property
International Journal of Mathematics and Mathematical Sciences, Volume 9, Issue 4, Page 659-663, 1986., 1986 It is proved that in order to find a nontrivial hyperinvariant subspace for a cohyponormal operator it suffices to make the further assumption that the operator have the single‐valued extension property.
Ridgley Lange, Shengwang Wang
wiley +1 more source
On Quasi-similarity of a product of Quasi-similar operators in Hilbert Spaces. [PDF]
, 2015 In this paper we investigate the conditions under which two operators A and B are quasi-similar implies AB and BA are also quasi-similar. It is herein shown that if A and B satisfy the Putnam-Fuglede property and are quasi-similar with the intertwining ...
S.W., Luketero +3 more
core +1 more source
Absolute continuity and hyponormal operators
International Journal of Mathematics and Mathematical Sciences, Volume 4, Issue 2, Page 321-335, 1981., 1981 Let T be a completely hyponormal operator, with the rectangular representation T = A + iB, on a separable Hilbert space. If 0 is not an eigenvalue of T* then T also has a polar factorization T = UP, with U unitary. It is known that A, B and U are all absolutely continuous operators.
C. R. Putnam
wiley +1 more source
The Sobolev-type moment problem [PDF]
, 2000 9 pages, no figures.-- MSC2000 codes: Primary 44A99; Secondary 47B15, 47B20, 47B25.MR#: MR1694873 (2000k:44006)Zbl#: Zbl 0951.44002We propose necessary and sufficient conditions for a bisequence of complex numbers to be a moment one of Sobolev type over ...
Szafraniec, Franciszek H. +1 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. +2 more
core +1 more source
Hyponormality on a weighted Bergman space of an annulus with a general harmonic symbol
Open MathematicsIn this work we consider the hyponormality of Toeplitz operators on the Bergman space of the annulus with a logarithmic weight. We give necessary conditions when the symbol is of the form φ+ψ̄ $\varphi +\bar{\psi }$ where both φ and ψ are analytic on ...
Sadraoui Houcine, Halouani Borhen
doaj +1 more source
Generalized Derivations and Norm Equality in Normed Ideals [PDF]
, 2011 2000 Mathematics Subject Classification: 47A10, 47A12, 47A30, 47B10, 47B20, 47B37, 47B47, 47D50.We compare the norm of a generalized derivation on a Hilbert space with the norm of its restrictions to Schatten norm ...
Barraa, Mohamed
core
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. +2 more
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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. +2 more
core +1 more source