Results 11 to 20 of about 56 (50)
On the eleventh question of Allen Shields [PDF]
Fixed Point Theory and Applications, 2011 In this article, we will give sufficient conditions for the boundedness of the analytic projection on the set of multipliers of the formal Laurent series spaces. This answers a question that has been raised by A. L. Shields.
Kashkooly Ali, Yousefi Bahmann
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Weighted Sequence Spaces and Cyclicity
Journal of Mathematical Extension, 2006 In this paper we investigate the cyclicity of the multiplication operator Mz acting on the weighted Hardy spaces of formal Laurent series. AMS Subject Classification: Primary 47B37; Secondary 47A16.
J. Doroodgar, B. Yousefi
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Ascent, descent and additive preserving problems [PDF]
, 2019 Given an integer n ≥ 1, we provide a complete description of all additive surjective maps, on the algebra of all bounded linear operators acting on a complex separable infinite-dimensional Hilbert space, preserving in both directions the set of all ...
OUDGHIRI, Mourad, SOUILAH, Khalid
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Properties of absolute-∗-k-paranormal operators and contractions for ∗-A(k) operators [PDF]
, 2019 First, we see if T is absolute-∗-k-paranormal for k ≥ 1, then T is a normaloid operator. We also see some properties of absolute-∗-k-paranormal operator and ∗-A(k) operator.
BRAHA, Naim L., HOXHA, Ilmi, TATO, Agron
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Generalized bilateral shifts of higher multiplicity [PDF]
Arab Journal of Mathematical SciencesPurposeSince weighted shifts play a vital role in linear dynamics so in 2021 Chan & Sanders considered weighted shift operators on ℓp(Z) that are not hypercyclic and proved that under certain conditions they can be factorized as products of hypercyclic ...
Munmun Hazarika, Silpi Sikha Das
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Operators acting on certain Banach spaces of analytic functions
International Journal of Mathematics and Mathematical Sciences, Volume 18, Issue 1, Page 107-110, 1995., 1993 Let 𝒳 be reflexive Banach space of functions analytic plane domain Ω such that for every λ in Ω the functional of evaluation at λ is bounded. Assume further that 𝒳 contains the constants and Mz multiplication by the independent variable z, is bounded operator on 𝒳. We give sufficient conditions for Mz to be reflexive.
K. Seddighi, K. Hedayatiyan, B. Yousefi
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Certain invariant subspaces for operators with rich eigenvalues
International Journal of Mathematics and Mathematical Sciences, Volume 14, Issue 1, Page 69-76, 1991., 1988 For a connected open subset Ω of the plane and n a positive integer, let Bn(Ω) be the space introduced by Cowen and Douglas. In this article we study the spectrum of restrictions of T in order to obtain more information about the invariant subspaces of T.
Karim Seddighi
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Nontrivial isometries on sp(α)
International Journal of Mathematics and Mathematical Sciences, Volume 5, Issue 2, Page 257-261, 1982., 1982 sp(α) is a Banach space of sequences x with . For 1 < p < ∞, p ≠ 2, 0 < α < ∞, α ≠ 1, there are no nontrivial surjective isometries in sp(α). It has been conjectured that there are no nontrivial isometries. This note gives two distinct counterexamples to this conjecture and a partial affirmative answer for the case of isometries with finite codimension.
Stephen L. Campbell
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A singular functional‐differential equation
International Journal of Mathematics and Mathematical Sciences, Volume 5, Issue 3, Page 497-501, 1982., 1982 The representation of the Hardy‐Lebesque space by means of the shift operator is used to prove an existence theorem for a singular functional‐differential equation which yields, as a corollary, the well known theory of Frobenius for second order differential equations.
P. D. Siafarikas
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Numerical Range on Weighted Hardy Spaces as Semi Inner Product Spaces
Analele Stiintifice ale Universitatii Ovidius Constanta: Seria Matematica, 2017 The semi-inner product, in the sense of Lumer, on weighted Hardy space which generate the norm is unique. Also we will discuss some properties of the numerical range of bounded linear operators on weighted Hardy spaces.
Heydari Mohammad Taghi
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