Results 41 to 50 of about 446 (70)
Spectra of subnormal pairs [PDF]
, 2007 In this short note we present an example related to joint spectra of subnormal pairs of bounded operators. A counterexample to the equality between Taylor's spectrum and the closure of the defect spectrum is given. This example is related to the author's
Krzysztof Rudol
core
A NOTE ON P-SYMMETRIC OPERATORS
, 2016 Let L(H) denote the algebra of operators on a complex infinite dimensional Hilbert space H into itself. In this paper, we study the class of operators A ∈ L(H) which satisfy the following property, AT = TA implies AT ∗ = T ∗A for all T ∈ C1(H) (trace ...
S. Bouali +3 more
semanticscholar +1 more source
The compressions of the weighted conditional expectation operators
Operators and Matrices, 2019 A C-E type Toeplitz operator TE u is the compression of a weighted conditional expectation operator EMu to the Bergman space La . This study focuses on bounded C-E type Toeplitz operators. Several properties of such operators are obtained, in particular,
M. Jabbarzadeh, Z. Shakeri
semanticscholar +1 more source
Bishop's property (β) for paranormal operators
, 2009 For an operator T on a separable complex Hilbert space H , we say that T has Bishop’s property (β) if for any open subset D ⊂ C and any sequence of analytic functions fn : D →H such as ‖(T −z) fn(z)‖→ 0 as n→∞ uniformly on every compact subset K ⊂D ...
A. Uchiyama, K. Tanahashi
semanticscholar +1 more source
Propagation phenomena for mono-weakly hyponormal operator pairs
Operators and Matrices, 2019 In this note, we strengthen some of flatness results for mono-polynomially hyponormal and mono-weakly 2-hyponormal 2-variable weighted shifts in [15, 16, 17]. Mathematics subject classification (2010): 47B20, 47B37, 47A13.
Yongjiang Duan, Shichan Pang, S. Y. Wang
semanticscholar +1 more source
On quasi-∗-n-paranormal operators
, 2015 For a positive integer n , an operator T ∈ B(H) is called quasi-∗ -n -paranormal if ||T 2+nx|| 1 1+n ||Tx|| n 1+n ||T ∗Tx|| for every x∈H , which is a further generalization of hyponormal and a subclass of normaloid.
Fei Zuo
semanticscholar +1 more source
An Operator Inequality Which Implies Paranormality
, 1999 Let T be a bounded linear operator on a Hilbert space. Among other things, it is shown that (1) if |T2| |T|2 , then T is paranormal, (2) if T is w -hyponormal, then |T2| |T|2 and |T∗ | |T∗|2 , and (3) if T and T∗ are w -hyponormal, and either ker T ⊆ ker
Ariyadasa Aluthge, Derming Wang
semanticscholar +1 more source
A note on k-paranormal operators
, 2010 It is still unknown whether the inverse of an invertible k -paranormal operator is normaloid, and so whether a k -paranormal operator is totally hereditarily normaloid.
C. Kubrusly, B. Duggal
semanticscholar +1 more source
Weyl's Theorem for Class A Operators
, 2001 In this paper, we show that Weyl’s theorem holds for class A operators under a certain condition. We also show that a class A operator whose Weyl spectrum equals to the one-point set {0} is always compact and normal.
A. Uchiyama
semanticscholar +1 more source
Fuglede-Putnam's theorem for w-hyponormal operators
, 2012 An asymmetric Fuglede-Putnam’s Theorem for w -hyponormal operators and dominant operators is proved, as a consequence of this result, we obtain that the range of the generalized derivation induced by the above classes of operators is orthogonal to its ...
A. Bachir, F. Lombarkia
semanticscholar +1 more source