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Related papers: Universal multipliers for Sub-Hardy Hilbert spaces

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We study conditions for containment of a given space $X$ of analytic functions on the unit disk $\mathbb{D}$ in the de Branges-Rovnyak space $\mathcal{H}(b)$. We deal with the non-extreme case in which $b$ admits a Pythagorean mate $a$, and…

Complex Variables · Mathematics 2024-04-02 Bartosz Malman , Daniel Seco

We consider de Branges-Rovnyak spaces of a considerably large class of reproducing kernel Hilbert spaces and find a characterization for them to be complete Nevanlinna-Pick spaces. This extends as well as recovers earlier characterizations…

Functional Analysis · Mathematics 2025-08-08 Hamidul Ahmed , B. Krishna Das , Samir Panja

This work characterizes the multipliers on vector-valued Hardy spaces over the infinite polydisk and the infinite polytorus, as well as in the context of Dirichlet series. Unlike the scalar-valued setting, where these frameworks are…

Functional Analysis · Mathematics 2025-12-05 Jorge Antezana , Daniel Carando , Tomás Fernández Vidal , Melisa Scotti

For the class of de Branges-Rovnyak spaces $\mathcal{H}(b)$ of the unit disk $\mathbb{D}$ defined by extreme points $b$ of the unit ball of $H^\infty$, we study the problem of approximation of a general function in $\mathcal{H}(b)$ by a…

Functional Analysis · Mathematics 2021-08-20 Adem Limani , Bartosz Malman

We study the multiplier algebras $A(\mathcal{H})$ obtained as the closure of the polynomials on certain reproducing kernel Hilbert spaces $\mathcal{H}$ on the ball $\mathbb{B}_d$ of $\mathbb{C}^d$. Our results apply, in particular, to the…

Functional Analysis · Mathematics 2022-04-25 Kenneth R. Davidson , Michael Hartz

We characterize the space of multipliers from the Hardy space of Dirichlet series $\mathcal H_p$ into $\mathcal H_q$ for every $1 \leq p,q \leq \infty$. For a fixed Dirichlet series, we also investigate some structural properties of its…

Complex Variables · Mathematics 2022-05-18 Tomás Fernandez Vidal , Daniel Galicer , Pablo Sevilla-Peris

Using real-variable methods, we characterise multipliers for general classes of Hardy--Orlicz spaces, unifying and extending several classical results due to Hardy and Littlewood; Duren and Shields; Paley; and others. Applications of our…

Classical Analysis and ODEs · Mathematics 2025-06-23 Odysseas Bakas , Sandra Pott , Salvador Rodriguez-Lopez , Alan Sola

This paper deals with representing in concrete fashion those Hilbert spaces that are vector subspaces of the Hardy spaces $H^p(\bb D^n) \ (1\le p\le \infty)$ that remain invariant under the action of coordinate wise multiplication by an…

Functional Analysis · Mathematics 2022-01-19 Sneh Lata , Sushant Pokhriyal , Dinesh Singh

Multipliers of reproducing kernel Hilbert spaces can be characterized in terms of positivity of $n \times n$ matrices analogous to the classical Pick matrix. We study for which reproducing kernel Hilbert spaces it suffices to consider…

Functional Analysis · Mathematics 2022-06-13 Alexandru Aleman , Michael Hartz , John E. McCarthy , Stefan Richter

We consider a number of examples of multiplier algebras on Hilbert spaces associated to discs embedded into a complex ball in order to examine the isomorphism problem for multiplier algebras on complete Nevanlinna-Pick reproducing kernel…

Operator Algebras · Mathematics 2015-03-20 Kenneth R. Davidson , Michael Hartz , Orr Shalit

Let $\mathbb B_n$ be the open unit ball in $\mathbb C^n$. We characterize the spectra of pointwise multipliers $M_u$ acting on Banach spaces of analytic functions on $\mathbb B_n$ satisfying some general conditions. These spaces include…

Functional Analysis · Mathematics 2020-02-18 Mikael Lindström , Santeri Miihkinen , David Norrbo

The article is devoted to the problem of Hilbert-Schmidt type analytic extensions in Hardy spaces over the infinite-dimensional unitary matrix group endowed with an invariant probability measure. An orthogonal basis of Hilbert-Schmidt…

Functional Analysis · Mathematics 2017-11-21 Oleh Lopushansky

The full Fock space over $\mathbb C ^d$ can be identified with the free Hardy space, $H^2 (\mathbb B ^d _\mathbb N)$ - the unique non-commutative reproducing kernel Hilbert space corresponding to a non-commutative Szeg\"{o} kernel on the…

Operator Algebras · Mathematics 2019-06-19 Michael T. Jury , Robert T. W. Martin

Let $\mathcal{H}(b)$ be the de Branges-Rovnyak space associated to a non-extreme point $b$ of the unit ball of $H^\infty$, and let $\phi=b/a$, where $a$ is the Pythagorean mate of $b$. It is known that, if $f$ is a function holomorphic on a…

Complex Variables · Mathematics 2026-05-29 Thomas Ransford

A broader class of Hardy spaces and Lebesgue spaces have been introduced recently on the unit circle by considering continuous $\|.\|_1$-dominating normalized gauge norms instead of the classical norms on measurable functions and a Beurling…

Functional Analysis · Mathematics 2022-08-19 Apoorva Singh , Niteesh Sahni

Let $\mathcal{E}$ be a Hilbert space and $H^2_{\mathcal{E}}(\mathbb{D})$ be the $\mathcal{E}$-valued Hardy space over the unit disc $\mathbb{D}$ in $\mathbb{C}$. The well known Beurling-Lax-Halmos theorem states that every shift invariant…

Functional Analysis · Mathematics 2015-03-10 Arup Chattopadhyay , B. Krishna Das , Jaydeb Sarkar

The primary aim of this paper is to characterize the uniformly locally univalent harmonic mappings in the unit disk. Then, we obtain sharp distortion, growth and covering theorems for one parameter family ${\mathcal B}_{H}(\lambda)$ of…

Complex Variables · Mathematics 2016-01-07 S. Ponnusamy , J. Qiao , X. Wang

In this note it is shown that the class of all multipliers from the $d$-parameter Hardy space $H^1_{\mathrm{prod}} (\mathbb{T}^d)$ to $L^2 (\mathbb{T}^d)$ is properly contained in the class of all multipliers from $L \log^{d/2} L…

Classical Analysis and ODEs · Mathematics 2019-10-16 Odysseas Bakas

We give a new characterization of the so-called quasi-extreme multipliers of the Drury-Arveson space $H^2_d$, and show that every quasi-extreme multiplier is an extreme point of the unit ball of the multiplier algebra of $H^2_d$.

Functional Analysis · Mathematics 2016-08-16 Michael T. Jury , Robert T. W. Martin

In this article we examine Dirichlet type spaces in the unit polydisc, and multipliers between these spaces. These results extend the corresponding work of G. D. Taylor in the unit disc. In addition, we consider functions on the polydisc…

Functional Analysis · Mathematics 2007-05-23 Daniel Jupiter , David Redett
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