Results 51 to 60 of about 147 (142)

Joint numerical ranges: recent advances and applications minicourse by V. Müller and Yu. Tomilov

Concrete Operators, 2020
We present a survey of some recent results concerning joint numerical ranges of n-tuples of Hilbert space operators, accompanied with several new observations and remarks.
Müller V., Tomilov Yu.
doaj   +1 more source

A self adjoint expansion of a symmetric differential operator with operator coefficient

, 2007
In this work, we prove that the closure of a symmetric operator L0which is formed by differential expression(L0y)(x) = −(p(x)y(x)) − Q(x)y(x)and with the boundary conditioncos α.y(0) + sinα.y(0) = 0is self adjoint where α ∈ (−∞,∞) in the space L2(0,∞; H )
Adıgüzelov, Ehliman, Karayel, Serpil
core   +1 more source

On the completely indeterminate case for block Jacobi matrices

Concrete Operators, 2017
We consider the infinite Jacobi block matrices in the completely indeterminate case, i. e. such that the deficiency indices of the corresponding Jacobi operators are maximal.
Osipov Andrey
doaj   +1 more source

The invertibility of 2x2 operator matrices [PDF]

, 2014
In this paper the properties of right invertible row operators, i.e., of 1x2 surjective operator matrices are studied. This investigation is based on a specific space decomposition.
Trunk, Carsten, Huang, Junjie, Sun, Junfeng, Chen, Alatancang   +3 more
core  

Finite-dimensional approximations of the resolvent of an infinite band matrix and continued fractions [PDF]

, 1999
19 pages, no figures.-- MSC1991 codes: Primary 47B99, 47A10, 40A15; Secondary 30B70.-- Originally published in Russian language by the Russian Academy of Mathematics in: Matematicheskii Sbornik 190(4): 23–42 (1999).MR#: MR1702505 (2000e:47052)Zbl#: Zbl ...
López Lagomasino, Guillermo, Martínez-Finkelshtein, Andrei, Torrano, Emilio, Barrios, Dolores, A Martinez-Finkelshtein, Guillermo L López, Dolores Barrios, Emilio Torrano   +7 more
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Fixed  Point in Non-Archimedeant T -Banach Spaces [PDF]

In this paper, we introduce the concept of T -normed space in a non-Archimedean space, which is called a non-Archimedean T -normed space and give some properties.
TALLAB , ABDELHAMID, PARK, CHOONKIL, AMMAR, AYMEN   +2 more
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Ultrametric Fredholm operators and approximate pseudospectrum [PDF]

Arab Journal of Mathematical Sciences
PurposeThe paper deals with ultrametric bounded Fredholm operators and approximate pseudospectra of closed and densely defined (resp. bounded) linear operators on ultrametric Banach spaces.Design/methodology/approachThe author used the notions of ...
Jawad Ettayb
doaj   +1 more source

Compact Jacobi matrices: from Stieltjes to Krein and M(a,b) [PDF]

, 1996
. --- In a note at the end of his paper Recherches sur les fractions continues, Stieltjes gave a necessary and sufficient condition when a continued fraction is represented by a meromorphic function. This result is related to the study of compact Jacobi
Walter Van Assche, Van Assche, Walter
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The Resolvent of Impulsive Singular Hahn–Sturm–Liouville Operators

Annales Mathematicae Silesianae
In this study, the resolvent of the impulsive singular Hahn–Sturm– Liouville operator is considered. An integral representation for the resolvent of this operator is obtained.
Allahverdiev Bilender P., Tuna Hüseyin, Isayev Hamlet A.   +2 more
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Local spectral theory of endomorphisms of the disk algebra

Demonstratio Mathematica, 2016
Let A(𝔻) denote the disk algebra. Every endomorphism of A(𝔻) is induced by some ϕ ∈ A(𝔻) with ‖ϕ‖ ≤ 1. In this paper, it is shown that if ϕ is not an automorphism of 𝔻 and ϕ has a fixed point in the open unit disk then the endomorphism induced by ϕ is ...
Trivedi Shailesh, Chandra Harish
doaj   +1 more source