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Let $E$ be a $W^{\ast}$-correspondence over a von Neumann algebra $M$ and let $H^{\infty}(E)$ be the associated Hardy algebra. If $\sigma$ is a faithful normal representation of $M$ on a Hilbert space $H$, then one may form the dual…

Operator Algebras · Mathematics 2007-06-13 Paul S. Muhly , Baruch Solel

We study the relation between Pick bodies on Carath\'eodory hyperbolic domains and contractions on finite dimensional Hilbert spaces. We give a condition sufficient to realize Pick bodies on Carath\'eodory hyperbolic domains as a Pick body…

Complex Variables · Mathematics 2026-02-03 Anindya Biswas

The operator-valued Schur-class is defined to be the set of holomorphic functions $S$ mapping the unit disk into the space of contraction operators between two Hilbert spaces. There are a number of alternate characterizations: the operator…

Classical Analysis and ODEs · Mathematics 2011-11-09 Joseph A. Ball , Animikh Biswas , Quanlei Fang , Sanne ter Horst

We study a reproducing kernel Hilbert space of functions defined on the positive integers and associated to the binomial coefficients. We introduce two transforms, which allow us to develop a related harmonic analysis in this Hilbert space.…

Complex Variables · Mathematics 2014-12-19 Daniel Alpay , Palle Jorgensen

Let $G/H$ be a semisimple symmetric space. Then the space $L^2(G/H)$ can be decomposed into a finite sum of series representations induced from parabolic subgroups of $G$. The most continuous part of the spectrum of $L^2(G/H)$ is the part…

Representation Theory · Mathematics 2007-05-23 Simon Gindikin , Bernhard Kroetz , Gestur Olafsson

In view of recent developments of the study of reproducing kernel Hilbert spaces, in particular with the context the Hardy spaces on tubes, aspects of rational approximation for functions of finite energy in several complex and several real…

Complex Variables · Mathematics 2020-02-26 Weixiong Mai , Tao Qian

We investigate the structure of subspaces of a Hilbert space that are invariant under unitary representations of a discrete group. We work with square integrable representations, and we show that they are those for which we can construct an…

Functional Analysis · Mathematics 2020-07-09 Davide Barbieri , Eugenio Hernández , Victoria Paternostro

We prove a conjecture of Brevig, Ortega-Cerd\`a, Seip and Zhao about contractive inequalities between Dirichlet and Hardy spaces and discuss its consequent connection with the Riesz projection.

Complex Variables · Mathematics 2024-02-19 Adrián Llinares

We investigate an extended version of Hilbert space of analytic functions called Hilbert space of complex-valued harmonic functions. It is found that functions in Hilbert space of complex-valued harmonic functions exhibit many properties…

Complex Variables · Mathematics 2024-10-30 Tseganesh Getachew Gebrehana , Hunduma Legesse Geleta

This note characterizes multiplicative linear functionals on reproducing kernel Hilbert spaces of functions on the Euclidean unit ball in complex d-dimensional space, in terms of their action on kernel functions. The kernels considered are…

Functional Analysis · Mathematics 2026-05-22 Tirthankar Bhattacharyya , Jaikishan , Poornendu Kumar

The existence of a rigged Hilbert space whose extreme spaces are, respectively, the projective and the inductive limit of a directed contractive family of Hilbert spaces is investigated. It is proved that, when it exists, this rigged…

Functional Analysis · Mathematics 2013-12-06 Giorgia Bellomonte , Camillo Trapani

We give properties of strict pseudocontractions and demicontractions defined on a Hilbert space, which constitute wide classes of operators that arise in iterative methods for solving fixed point problems. In particular, we give necessary…

Optimization and Control · Mathematics 2023-07-17 Andrzej Cegielski

This paper considers model spaces in an $H_p$ setting. The existence of unbounded functions and the characterisation of maximal functions in a model space are studied, and decomposition results for Toeplitz kernels, in terms of model…

Functional Analysis · Mathematics 2015-07-22 M. C. Câmara , M. T. Malheiro , J. R. Partington

Parallel to the study of finite dimensional Banach spaces, there is a growing interest in the corresponding local theory of operator spaces. We define a family of Hilbertian operator spaces H_n^k,0< k < n+1, generalizing the row and column…

Operator Algebras · Mathematics 2007-05-23 Matthew Neal , Bernard Russo

In this paper, we present a constructive generalization of metric and uniform spaces by introducing a new class of spaces, called cover spaces. These spaces form a topological concrete category with a full reflective subcategory of complete…

General Topology · Mathematics 2024-12-31 Valery Isaev

Given a holomorphic self-map $\varphi$ of $\D$ (the open unit disc in $\mathbb{C}$), the composition operator $C_{\varphi} f = f \circ \varphi$, $f \in H^2(\mathbb{\D})$, defines a bounded linear operator on the Hardy space…

Functional Analysis · Mathematics 2021-08-13 P. Muthukumar , Jaydeb Sarkar

In this article, we characterize the Beurling and Model subspaces of the Hardy-Hilbert space $H^2(\mathbb{D})$ invariant under the composition operator $C_{\phi_a}f=f\circ\phi_a$, where $\phi_a(z) = az + 1 - a$ for $a \in (0,1)$ is an…

Functional Analysis · Mathematics 2024-06-17 Ben Hur Eidt , S. Waleed Noor

We develop a structural classification of multipliers between generalized Toeplitz kernels, extending the work of Fricain and Rupam. Our results establish new equivalences between multiplier space and Carleson-type embeddings, linking them…

Functional Analysis · Mathematics 2025-07-15 Anjali , R. K. Srivastava

In this paper, we establish a Bloch-type growth theorem for generalized Bloch-type spaces and discuss relationships between Dirichlet-type spaces and Hardy-type spaces on certain classes of complex-valued functions. Then we present some…

Complex Variables · Mathematics 2013-12-12 Shaolin Chen , Saminathan Ponnusamy , Antti Rasila

We present results about spaces of holomorphic functions associated to the classical Dirichlet space. The spaces we consider have roles similar to the roles of $H^{1}$ and $BMO$ in the Hardy space theory and we emphasize those analogies.

Complex Variables · Mathematics 2011-09-13 Nicola Arcozzi , Richard Rochberg , Eric Sawyer , Brett D. Wick