Results 51 to 60 of about 446 (70)

Some inequalities for $(\alpha, \beta)$-normal operators in Hilbert spaces

open access: yes, 2008
An operator $T$ acting on a Hilbert space is called $(\alpha ,\beta)$-normal ($0\leq \alpha \leq 1\leq \beta $) if \begin{equation*} \alpha ^{2}T^{\ast }T\leq TT^{\ast}\leq \beta ^{2}T^{\ast}T.
Dragomir, Sever S.   +1 more
core  

Hyponormality of finite rank perturbations of normal operators

open access: yes, 2018
Let T be an arbitrary finite rank perturbation of a normal operator N acting on a separable, infinite dimensional, complex Hilbert space H . It is proved that the hyponormality and normality of T are equivalent.
I. Jung, Eun-young Lee, M. Seo
semanticscholar   +1 more source

Jointly hyponormal block Toeplitz pairs with rational symbols

open access: yes, 2018
In this paper, we are concerned with joint hyponormality of pairs of block Toeplitz operators acting on the vector-valued Hardy space H2 Cn of the unit circle.
I. Hwang, An-Hyun Kim
semanticscholar   +1 more source

Hyponormality of Toeplitz operators with polynomial symbols on the vector valued Bergman space

open access: yes, 2018
We arrive at a necessary condition and a sufficient condition for the hyponormal block Toeplitz operator TF+G∗ on the vector valued Bergman space La(D,C n) , where F and G are matrix valued analytic polynomials.
P. Cui, Yufeng Lu, Yanyue Shi
semanticscholar   +1 more source

NOTE ON SOME OPERATOR EQUATIONS AND LOCAL SPECTRAL PROPERTIES

open access: yes, 2016
In this paper we define Sk, j by the set of solutions (A,B) of the operator equations AkBj+1Ak = A2k+ j and BkAj+1Bk = B2k+ j . Then we observe the set Sk, j is increasing for all integers k 1 and j 0 .
I. An, Eungil Ko
semanticscholar   +1 more source

Spectral properties of k-quasi-*-n-paranormal operators

open access: yes, 2016
For positive integers n and k , an operator T is said to be k -quasi-∗ -n -paranormal if ||T 1+n+kx|| 1 1+n ||T kx|| n 1+n ||T ∗T kx|| for all x ∈ H , which is a generalization of ∗ -paranormal operator.
Junliang Shen, Alatancang Chen
semanticscholar   +1 more source

Synthesis of active distributed RC networks [PDF]

open access: yes
Open-circuit transfer function of two-port network expressed as rational function with real ...
Fu, J. S., Fu, Y.
core   +1 more source

A subnormal Toeplitz completion

open access: yes, 2016
In this paper we deal with a subnormal Toeplitz completion problem: Complete the unspecified Toeplitz operators of the partial block Toeplitz matrix G := [ U∗p ? ? U∗q ] (p,q = 1,2, · · ·) to make G subnormal, where U is the shift on the Hardy space H2(T)
I. Hwang, An-Hyun Kim, Jongrak Lee
semanticscholar   +1 more source

Evolution and history of grapevine (Vitis vinifera) under domestication: new morphometric perspectives to understand seed domestication syndrome and reveal origins of ancient European cultivars. [PDF]

open access: yesAnn Bot, 2010
Terral JF   +14 more
europepmc   +1 more source

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