Results 11 to 20 of about 46 (46)

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
wiley   +1 more source

Generalized bilateral shifts of higher multiplicity [PDF]

Arab Journal of Mathematical Sciences
PurposeSince 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
doaj   +1 more source

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
wiley   +1 more source

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
wiley   +1 more source

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
wiley   +1 more source

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
doaj   +1 more source

Cohyponormality of Unbounded Product of Composition Operators in L2 Spaces

Journal of Function Spaces, Volume 2025, Issue 1, 2025.
Let X,A,μ be a σ‐finite measure space. The composition operators Cϕ:DCϕ⟶L2μ are defined by Cϕf=f∘ϕ,f∈DCϕ, where ϕ are nonsingular transformations and DCϕ=f∈L2μ: f∘ϕ∈L2μ. Suppose that ϕ1, ϕ2, ⋯, ϕn are nonsingular transformations of X, where n ∈ ℕ and n ≥ 2.
Hang Zhou, Qing Su, Nikhil Khanna
wiley   +1 more source

The Cauchy problem of the one dimensional Schrödinger equation with non‐local potentials

, 1993
International Journal of Mathematics and Mathematical Sciences, Volume 16, Issue 4, Page 791-794, 1993.
I. E. Kougias
wiley   +1 more source

Compact diagonal linear operators on Banach spaces with unconditional bases

, 1992
International Journal of Mathematics and Mathematical Sciences, Volume 16, Issue 4, Page 823-824, 1993.
Yun Sung Choi, Sung Guen Kim
wiley   +1 more source

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
doaj