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Related papers: Shift invariant subspaces in the Bloch space

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We consider the shift operator $M_z$, defined on the Bloch space and the little Bloch space and we study the corresponding lattice of invariant subspaces. The index of a closed invariant subspace $E$ is defined as $\text{ind}(E) =…

Functional Analysis · Mathematics 2024-09-06 Nikiforos Biehler

This article consists of two connected parts. In the first part, we study the shift invariant subspaces in certain $\mathcal{P}^2(\mu)$-spaces, which are the closures of analytic polynomials in the Lebesgue spaces $\mathcal{L}^2(\mu)$…

Complex Variables · Mathematics 2023-11-28 Bartosz Malman

In this survey, we consider Banach spaces of analytic functions in one and several complex variables for which: (i) polynomials are dense, (ii) point-evaluations on the domain are bounded linear functionals, and (iii) the shift operator…

Functional Analysis · Mathematics 2025-04-23 Jeet Sampat

In this article, we characterize reducing and invariant subspaces of the space of square integrable functions defined in the unit circle and having values in some Hardy space with multiplicity. We consider subspaces that reduce the…

Functional Analysis · Mathematics 2023-09-28 Alejandra Aguilera , Carlos Cabrelli , Diana Carbajal , Victoria Paternostro

We study the invariant subspaces generated by inner functions for a class of $\mathcal{P}^t(\mu)$-spaces which can be identified as spaces of analytic functions in the unit disk $\mathbb{D}$, where $\mu$ is a measure supported in the closed…

Functional Analysis · Mathematics 2021-08-23 Adem Limani , Bartosz Malman

We obtain exhaustive results and treat in a unified way the question of boundedness, compactness, and weak compactness of composition operators from the Bloch space into any space from a large family of conformally invariant spaces that…

Functional Analysis · Mathematics 2016-11-07 Manuel D. Contreras , Santiago Diaz-Madrigal , Dragan Vukotic

We investigate certain classes of shift invariant subspaces in growth spaces on the unit disc of the complex plane determined by a majorant $w$, which include the classical Korenblum growth spaces. Our main result provides a complete…

Complex Variables · Mathematics 2023-08-08 Adem Limani

In this paper we characterize the closed invariant subspaces for the ($*$-)multiplier operator of the quaternionic space of slice $L^2$ functions. As a consequence, we obtain the inner-outer factorization theorem for the quaternionic Hardy…

Complex Variables · Mathematics 2018-06-13 Alessandro Monguzzi , Giulia Sarfatti

In a wide class of weighted Bergman spaces, we construct invertible non-cyclic elements. These are then used to produce z-invariant subspaces of index higher than one. In addition, these elements generate nontrivial bilaterally invariant…

Functional Analysis · Mathematics 2007-05-23 Alexander Borichev , Hakan Hedenmalm , Alexander Volberg

Let $\mathcal{W}$ be the corresponding wandering subspace of an invariant subspace of the Bergman shift. By identifying the Bergman space with $H^2(\mathbb{D}^2)\ominus[z-w]$, a sufficient and necessary conditions of a closed subspace of…

Functional Analysis · Mathematics 2022-09-21 Shunhua Sun , Anjian Xu

Let $\mathbb H$ be the finite direct sums of $H^2(\mathbb D)$. In this paper, we give a characterization of the closed subspaces of $\mathbb H$ which are invariant under the shift, thus obtaining a concrete Beurling-type theorem for the…

Functional Analysis · Mathematics 2026-02-17 Filippo Bracci , Eva A. Gallardo-Gutiérrez

A classical result of Norbert Wiener characterises doubly shift-invariant subspaces for square integrable functions on the unit circle with respect to a finite positive Borel measure $\mu$, as being the ranges of the multiplication maps…

Functional Analysis · Mathematics 2021-05-12 Amol Sasane

We use shift-invariant subspaces of the Hardy space on the bidisk to provide an elementary proof of the Agler Decomposition Theorem. We observe that these shift-invariant subspaces are specific cases of Hilbert spaces that can be defined…

Functional Analysis · Mathematics 2017-01-20 Kelly Bickel

Let $T$ be an absolutely continuous polynomially bounded operator, and let $\theta$ be a singular inner function. It is shown that if $\theta(T)$ is invertible and some additional conditions are fulfilled, then $T$ has nontrivial…

Functional Analysis · Mathematics 2019-12-17 Maria F. Gamal'

Bloch theorem for a periodic operator is being revisited here, and we notice extra orthogonality relationships. It is shown that solutions are bi-periodic, in the sense that eigenfunctions are periodic with respect to one argument, and…

Optics · Physics 2015-09-03 Sina Khorasani

It is well known that subspaces of the Hardy space over the unit disk which are invariant under the backward shift occur as the image of an observability operator associated with a discrete-time linear system with stable state-dynamics, as…

Classical Analysis and ODEs · Mathematics 2012-09-18 Joseph A. Ball , Vladimir Bolotnikov

The structure of subspaces of a Hilbert space that are invariant under unitary representations of a discrete group is related to a notion of Hilbert modules endowed with inner products taking values in spaces of unbounded operators. A…

Functional Analysis · Mathematics 2015-07-01 Davide Barbieri , Eugenio Hernández , Victoria Paternostro

Let $S_{E}$ be the shift operator on vector-valued Hardy space $H_{E}^{2}.$ Beurling-Lax-Halmos Theorem identifies the invariant subspaces of $S_{E}$ and hence also the invariant subspaces of the backward shift $S_{E}^{\ast}.$ In this…

Functional Analysis · Mathematics 2023-09-25 Caixing Gu , Shuaibing Luo

We show that any bounded operator $T$ on a separable, reflexive, infinite-dimensional Banach space $X$ admits a rank one perturbation which has an invariant subspace of infinite dimension and codimension. In the non-reflexive spaces, we…

Functional Analysis · Mathematics 2012-08-30 Alexey I. Popov , Adi Tcaciuc

A shift-invariant space is a space of functions that is invariant under integer translations. Such spaces are often used as models for spaces of signals and images in mathematical and engineering applications. This paper characterizes those…

Functional Analysis · Mathematics 2010-07-07 Akram Aldroubi , Carlos Cabrelli , Christopher Heil , Keri Kornelson , Ursula Molter
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