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Related papers: Two-Variable Compressions of Shifts, Toeplitz Oper…

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We consider two-variable model spaces associated to rational inner functions $\Theta$ on the bidisk, which always possess canonical $z_2$-invariant subspaces $\mathcal{S}_2.$ A particularly interesting compression of the shift is the…

Complex Variables · Mathematics 2017-02-20 Kelly Bickel , Pamela Gorkin

The property of being shift invariant and being reflexive or transitive in the case of the space of (asymmetric) truncated Toeplitz operators, and the space of (asymmetric) dual truncated operators is investigated. Most of the results…

Functional Analysis · Mathematics 2022-03-18 M. Cristina Câmara , Kamila Kliś-Garlicka , Bartosz Łanucha , Marek Ptak

The numerical range of a bounded, linear operator on a Hilbert space is a set in $\mathbb{C}$ that encodes important information about the operator. In this survey paper, we first consider numerical ranges of matrices and discuss several…

Functional Analysis · Mathematics 2018-10-30 Kelly Bickel , Pamela Gorkin

We characterize matrix-valued asymmetric truncated Toeplitz operators (which are compressions of multiplication operators acting between two possibly different model spaces) by using compressed shifts, modified compressed shifts and shift…

Functional Analysis · Mathematics 2025-06-23 Rewayat Khan , Yagoub Ameur , Jamroz Khan

Truncated Toeplitz operators are compressions of Toeplitz operators on model spaces; they have received much attention in the last years. This survey article presents several recent results, which relate boundedness, compactness, and…

Functional Analysis · Mathematics 2016-01-08 Isabelle Chalendar , Emmanuel Fricain , Dan Timotin

In this paper we present some consequences of the description of matrix representations of asymmetric truncated Toeplitz operators acting between finite-dimensional model spaces. In particular, we prove that these operators can be…

Functional Analysis · Mathematics 2020-07-29 Bartosz Łanucha

Functions in backward shift invariant subspaces have nice analytic continuation properties outside the spectrum of the inner function defining the space. Inside the spectrum of the inner function, Ahern and Clark showed that under some…

Complex Variables · Mathematics 2010-12-21 Andreas Hartmann , William T. Ross

It was recently proved that in some special cases asymmetric truncated Toeplitz operators can be characterized in terms of compressed shifts and rank-two operators of special form. In this paper we show that such characterizations hold in…

Functional Analysis · Mathematics 2020-07-29 Bartosz Łanucha , Małgorzata Michalska

Unbounded (and bounded) Toeplitz operators (TO) with rational symbols are analysed in detail showing that they are densely defined closed and have finite dimensional kernels and deficiency spaces. The latter spaces as well as the domains,…

Functional Analysis · Mathematics 2021-10-22 Domenico P. L. Castrigiano

In this paper, we study closed densely defined unbounded truncated Toeplitz operators on model space, where u is an inner function, that commute with modified compressed shifts. The work also establishes properties related to their…

Functional Analysis · Mathematics 2026-04-09 Ali Chettih , Ameur Yagoub , Zohra Bendaoud

Following Beurling's theorem the natural compressions of the multiplication operator in the classical $L^2$ space are compressions to model spaces and to their orthogonal complements. Two possibly different model spaces are considered hence…

Functional Analysis · Mathematics 2020-12-29 M. Cristina Câmara , Kamila Kliś--Garlicka , Bartosz Łanucha , Marek Ptak

We relate dual-band general Toeplitz operators to block truncated Toeplitz operators and, via equivalence after extension, with Toeplitz operators with $4 \times 4$ matrix symbols. We discuss their norm, their kernel, Fredhomlness,…

Functional Analysis · Mathematics 2021-06-04 M. Cristina Câmara , Ryan O'Loughlin , Jonathan R. Partington

We study Clark measures associated with general two-variable rational inner functions (RIFs) on the bidisk, including those with singularities, and with general $d$-variable rational inner functions with no singularities. We give precise…

Functional Analysis · Mathematics 2024-10-29 John T. Anderson , Linus Bergqvist , Kelly Bickel , Joseph A. Cima , Alan A. Sola

In a recent paper [JFA, 278 (2020), 108401], Choe et al. obtained characterizations for bounded and compact differences of two weighted composition operators acting on standard weighted Bergman spaces over the unit disk in terms of Carleson…

Functional Analysis · Mathematics 2025-07-21 Cezhong Tong , Zicong Yang , Zehua Zhou

Compressions of Toeplitz operators to coinvariant subspaces of $H^2$ are called truncated Toeplitz operators. We study two questions related to these operators. The first, raised by Sarason, is whether boundedness of the operator implies…

Functional Analysis · Mathematics 2009-11-14 A. Baranov , Isabelle Chalendar , Emmanuel Fricain , Javad Mashreghi , Dan Timotin

In this paper we consider compressions of $k^{th}$--order slant Toeplitz operators to the backward shift invariant subspaces of the classical Hardy space $H^2$. In particular, we characterize these operators using compressed shifts and…

Functional Analysis · Mathematics 2019-11-12 Bartosz Łanucha , Małgorzata Michalska

We initiate the study of weighted multi-Toeplitz operators associated with noncommutative regular domains in B(H)^n. These operators are acting on the full Fock space with n generators and have as symbols free pluriharmonic functions.…

Functional Analysis · Mathematics 2018-12-18 Gelu Popescu

This tutorial paper presents a survey of results, both classical and new, linking inner functions and operator theory. Topics discussed include invariant subspaces, universal operators, Hankel and Toeplitz operators, model spaces, truncated…

Functional Analysis · Mathematics 2015-03-19 Isabelle Chalendar , Pamela Gorkin , Jonathan R. Partington

The aim of this paper is to investigate asymmetric truncated Toeplitz operators with $L^2$ symbols between two different model spaces given by inner functions such that one divides the other. Characterizations of these operators are given…

Functional Analysis · Mathematics 2017-10-18 Cristina Câmara , Joanna Jurasik , Kamila Kliś--Garlicka , Marek Ptak

We investigate the commutant problem for Toeplitz operators on the Bergman space of the unit disk whose symbols belong to a subclass of biharmonic functions. We obtain a complete characterization of when two such Toeplitz operators commute.…

Functional Analysis · Mathematics 2026-04-22 Aissa Bouhali , Issam Louhichi , Abdelrahman Yousef
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