Results 1 to 10 of about 46 (46)
Fractional Cesàro Matrix and its Associated Sequence Space
Concrete Operators, 2021 In this research, we introduce a new fractional Cesàro matrix and investigate the topological properties of the sequence space associated with this matrix.We also introduce a fractional Gamma matrix aswell and obtain some factorizations for the Hilbert ...
Roopaei H., İlkhan M.
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On linear chaos in function spaces
Demonstratio Mathematica, 2022 We show that, in Lp(0,∞){L}_{p}\left(0,\infty ) (1 ...
Jimenez John M., Markin Marat V.
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Concrete Operators, 2022 Let (X, 𝒜, μ) be a σ−finite measure space. A transformation ϕ : X → X is non-singular if μ ∘ ϕ−1 is absolutely continuous with respect with μ. For this non-singular transformation, the composition operator Cϕ: 𝒟(Cϕ) → L2(μ) is defined by Cϕf = f ∘ ϕ, f ∈
Zhou Hang
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The invariant subspaces of S ⊕ S*
Concrete Operators, 2020 Using the tools of Sz.-Nagy–Foias theory of contractions, we describe in detail the invariant subspaces of the operator S ⊕ S*, where S is the unilateral shift on a Hilbert space. This answers a question of Câmara and Ross.
Timotin Dan
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Bounds of operators on the Hilbert sequence space
Concrete Operators, 2020 The author has computed the bounds of the Hilbert operator on some sequence spaces [18, 19]. Through this study the author has investigated the bounds of operators on the Hilbert sequence space and the present study is a complement of those previous ...
Roopaei Hadi
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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.
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Characterizations of compact operators on ℓp−type fractional sets of sequences
Demonstratio Mathematica, 2019 Among the sets of sequences studied, difference sets of sequences are probably the most common type of sets. This paper considers some ℓp−type fractional difference sets via the gamma function.
Özger Faruk
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Bounded holomorphic projections for exponentially decreasing weights
Journal of Function Spaces, Volume 6, Issue 1, Page 59-70, 2008., 2008 We construct generalized Bergman projections on a large class of weighted L∞–spaces. The examples include exponentially decreasing weights on the unit disc and complex plane.
Wolfgang Lusky +2 more
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Operators commuting with the shift on sequence spaces
International Journal of Mathematics and Mathematical Sciences, Volume 2004, Issue 43, Page 2273-2278, 2004., 2004 A complete characterization of shift‐invariant operators that are isomorphisms is given in certain sequence spaces. Also given is a sufficient condition for an operator commuting with a shift‐invariant operator to be shift invariant.
J. Prada
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On cyclicity in weighted Dirichlet spaces
International Journal of Mathematics and Mathematical Sciences, Volume 22, Issue 4, Page 739-744, 1999., 1999 We extend some results of Brown and Shields on cyclicity to weighted Dirichlet spaces 0 < α < 1. We prove a comparison theorem for cyclicity in these spaces and provide a result on the geometry of the family of cyclic vectors in general functional Hilbert spaces.
F. Jafari, R. Raposa
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