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Consider the lattice of bounded linear operators on the space of Borel measures on a Polish space. We prove that the operators which are continuous with respect to the weak topology induced by the bounded measurable functions form a…

Functional Analysis · Mathematics 2015-11-05 Moritz Gerlach , Markus Kunze

In this paper we prove an invertibility criterion for certain operators which is given as a linear algebraic combination of Toeplitz operators and Fourier multipliers acting on the Hardy space of the unit disc. Very similar to the case of…

Functional Analysis · Mathematics 2017-09-25 Uğur Gül , Beyaz Başak Koca

For truncated Toeplitz operators, which are compressions of multiplication operators to model subspaces of the Hardy space $H^2$, we obtain criteria for commutation relations. The results show an analogy to the case of Toeplitz matrices,…

Functional Analysis · Mathematics 2013-05-30 Isabelle Chalendar , Dan Timotin

The rational Dunkl operators are commuting differential-reflection operators on the Euclidean space $R^d$ associated with a root system, that contain some non-local refection terms, and the associated Hardy space is defined by means of the…

Functional Analysis · Mathematics 2022-12-20 Jiaxi Jiu , Zhongkai Li

In this paper we provide a simple proof of the fact that for a system of two spin-1/2 particles, and for a choice of observables, there is a unique state which shows Hardy-type nonlocality. Moreover, an explicit expression for the…

Quantum Physics · Physics 2007-05-23 Jose L. Cereceda

We consider weak-star closed invariant subspaces of the shift operator in the classical Bloch space. We prove that any bounded analytic function decomposes into two factors, one which is cyclic and another one generating a proper shift…

Functional Analysis · Mathematics 2025-05-26 Adem Limani , Artur Nicolau

In a recent paper, M. Raghupathi has extended the famous theorem of Beurling to the context of subspaces that are invariant under the class of subalgebras of $H^\infty$ of the form $IH^\infty$, where $I$ is an inner function. In this paper,…

Functional Analysis · Mathematics 2016-02-19 Ajay Kumar , Niteesh Sahni , Dinesh Singh

We obtain a Halmos-Richter-type wandering subspace theorem for covariant representations of C*-correspondences. Further the notion of Cauchy dual and a version of Shimorin's Wold-type decomposition for covariant representations of…

Operator Algebras · Mathematics 2021-06-01 Harsh Trivedi , Shankar Veerabathiran

In this paper we give two complete characterizations of the Poletsky- Stessin- Hardy spaces in the complex plane: First in terms of their boundary values as a weighted subclass of the usual $L^p$ class with respect to the arclength measure…

Complex Variables · Mathematics 2012-10-08 Nihat Gokhan Gogus , Muhammed Ali Alan

We reconsider studies of Toeplitz operators on function spaces (the weighted Bergman space, the generalized derivative Hardy space) and the H-Toeplitz operators on the Bergman space. Past studies have considered the presence or absence of…

Functional Analysis · Mathematics 2024-09-20 Chafiq Benhida , George R. Exner , Ji Eun Lee , Jongrak Lee

By analytic perturbations, we refer to shifts that are finite rank perturbations of the form $M_z + F$, where $M_z$ is the unilateral shift and $F$ is a finite rank operator on the Hardy space over the open unit disc. Here shift refers to…

Functional Analysis · Mathematics 2021-07-13 Susmita Das , Jaydeb Sarkar

We prove a Beurling-Helson type theorem on modulation spaces. More precisely, we show that the only $\mathcal{C}^{1}$ changes of variables that leave invariant the modulation spaces $\M{p,q}(\rd)$ are affine functions on $\rd$. A special…

Classical Analysis and ODEs · Mathematics 2008-01-10 Kasso A Okoudjou

Operators of multiplication by independent variables on the space of square summable functions over the torus and its Hardy subspace are considered. Invariant subspaces where the operators are compatible are described.

Functional Analysis · Mathematics 2022-11-04 Zbigniew Burdak , Marek Kosiek , Patryk Pagacz , Marek Słociński

In this paper we develop a theory of curvature (resp. multiplicity) invariant for tensor products of full Fock spaces and also for tensor products of symmetric Fock spaces. This is an attempt to find a more general framework for these…

Functional Analysis · Mathematics 2015-03-16 Gelu Popescu

We extend the de Branges-Beurling theorem characterizing the shift-invariant spaces boundedly contained in the Hardy space of square-summable power series to the full Fock space over $\mathbb{C} ^d$. Here, the full Fock space is identified…

Functional Analysis · Mathematics 2020-07-21 Robert T. W. Martin , Eli Shamovich

It is known that invariant subspaces of classical Jordan blocks of the Hardy space over the open unit disc are described by factorizations of inner functions. In the polydisc setting, Jordan blocks are tensor products of one-variable Jordan…

Functional Analysis · Mathematics 2026-05-26 Sneha B , Jaydeb Sarkar , Michio Seto

This paper is concerned with polynomially generated multiplier invariant subspaces of the weighted Bergman space $A_{\boldsymbol{\beta}}^2$ in infinitely many variables. We completely classify these invariant subspaces under the unitary…

Functional Analysis · Mathematics 2021-03-23 Hui Dan , Kunyu Guo , Jiaqi Ni

We introduce and systematically study a class of operators that arise naturally due to the Beurling decomposition of the Hardy space $H^2=K_\theta \oplus \theta H^2$. While the compressions of classical Toeplitz and Hankel operators to the…

Functional Analysis · Mathematics 2026-04-02 Priyanka Aroda , Arup Chattopadhyay , Supratim Jana

We give a necessary and sufficient condition for an n-hypercontraction to be similar to the backward shift operator in a weighted Bergman space. This characterization serves as a generalization of the description given in the Hardy space…

Functional Analysis · Mathematics 2014-02-26 Ronald G. Douglas , Hyun-Kyoung Kwon , Sergei Treil

In the classical Hardy space $H^2(\mathbb{D})$, it is well-known that the kernel of the Hankel operator is invariant under the action of shift operator S and sometimes nearly invariant under the action of backward shift operator $S^{*}$. It…

Functional Analysis · Mathematics 2024-12-03 Arup Chattopadhyay , Supratim Jana
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