Results 31 to 40 of about 1,449 (134)
General numerical radius inequalities for matrices of operators
Open Mathematics, 2016 Let Ai ∈ B(H), (i = 1, 2, ..., n), and T=[0⋯0A1⋮⋰A200⋰⋰⋮An0⋯0] $ T = \left[ {\matrix{ 0 & \cdots & 0 & {A_1 } \cr \vdots & {\mathinner{\mkern2mu\raise1pt\hbox{.}\mkern2mu \raise4pt\hbox{.}\mkern2mu\raise7pt\hbox{.}\mkern1mu}} & {A_2 } & 0
Al-Dolat Mohammed +3 more
doaj +1 more source
The Spectrum and fine spectrum of generalized Rhaly-Cesàro matrices on c_0 and c
, 2018 The generalized Rhaly Cesàro matrices Aα are the triangular matrix with nonzero entries ank = αn−k/(n+1) with α ∈ [0,1] . In [Proc. Amer. Math. Soc. 86 (1982), 405409], Rhaly determined boundedness, compactness of generalized Rhaly Cesàro matrices on 2 ...
M. Yıldırım +2 more
semanticscholar +1 more source
Discrete Dynamics in Nature and Society, Volume 2004, Issue 1, Page 221-249, 2004., 2004 We present state of the art, the new results, and discuss open problems in the field of spectral analysis for a class of integral‐difference operators appearing in some nonequilibrium statistical physics models as collision operators. The author dedicates this work to the memory of Professor Ilya Prigogine, who initiated this activity in 1997 and ...
Yuri B. Melnikov
wiley +1 more source
Dynamical localization of Dirac particles in electromagnetic fields with dominating magnetic potentials [PDF]
, 2015 We consider two-dimensional massless Dirac operators in a radially symmetric electromagnetic field. In this case the fields may be described by one-dimensional electric and magnetic potentials $V$ and $A$.
Barbaroux, Jean-Marie +3 more
core +2 more sources
Generalized lower characteristic involving measures of non-strict singularity
Topological Algebra and its Applications, 2023 This work establishes a connection between the class of generalized lower characteristic operators and [⋅]a{\left[\cdot ]}_{a} acting on a Banach space involving measures of non-strict singularity.
Baraket Sami +2 more
doaj +1 more source
Essential 𝒰cκ‐type maps and Birkhoff‐Kellogg theorems
International Journal of Stochastic Analysis, Volume 2004, Issue 1, Page 1-8, 2004., 2004 We present a new continuation theorem for 𝒰cκ‐type maps. The analysis is elementary and relies on properties of retractions and fixed point theory for self‐maps. Also we present some Birkhoff‐Kellogg type theorems on invariant directions.
R. P. Agarwal, Donal O′Regan
wiley +1 more source
An Alternate Proof of De Branges Theorem on Canonical Systems [PDF]
, 2014 The aim of this paper is to show that, in the limit circle case, the defect index of a symmetric relation induced by canonical systems, is constant on C. This provides an alternative proof of the De Branges theorem that the canonical systems with tr H(x)=
Acharya, Keshav Raj
core +4 more sources
On new strong versions of Browder type theorems
Open Mathematics, 2018 An operator T acting on a Banach space X satisfies the property (UWΠ) if σa(T)∖ σSF+−$\begin{array}{} \sigma_{SF_{+}^{-}} \end{array} $(T) = Π(T), where σa(T) is the approximate point spectrum of T, σSF+−$\begin{array}{} \sigma_{SF_{+}^{-}} \end{array} $
Sanabria José +4 more
doaj +1 more source
Local spectral theory for 2 × 2 operator matrices
International Journal of Mathematics and Mathematical Sciences, Volume 2003, Issue 42, Page 2667-2672, 2003., 2003 We discuss the spectral properties of the operator MC ∈ ℒ(X ⊕ Y) defined by MC:=(AC0B), where A ∈ ℒ(X), B ∈ ℒ(Y), C ∈ ℒ(Y, X), and X, Y are complex Banach spaces. We prove that (SA∗∩SB)∪σ(MC)=σ(A)∪σ(B) for all C ∈ ℒ(Y, X). This allows us to give a partial positive answer to Question 3 of Du and Jin (1994) and generalizations of some results of Houimdi ...
H. Elbjaoui, E. H. Zerouali
wiley +1 more source
A note on positive $\mathcal{AN}$ operators
, 2018 We show that positive absolutely norm attaining operators can be characterized by a simple property of their spectra. This result clarifies and simplifies a result of Ramesh. As an application we characterize weighted shift operators which are absolutely
Doust, Ian
core +1 more source