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Related papers: Reducing subspaces of $C_{00}$ contractions

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The problems considered in this paper come as a natural continuation of our program to develop a free analogue of Sz.-Nagy-Foias theory, for row contractions. The paper is structured as follows: Introduction Part I. Unitary invariants for…

Operator Algebras · Mathematics 2009-11-29 Gelu Popescu

The explicit constructions of minimal isometric, and minimal unitary dilations of an arbitrary linear pencil of operators $T(\lambda)=T_0+\lambda T_1$ consisting of contractions on a separable Hilbert space for $|\lambda |=1$, which…

Functional Analysis · Mathematics 2007-05-23 Dmitriy S. Kalyuzhniy

For $b\in H^\infty_1$, the closed unit ball of $H^\infty$, the de Branges-Rovnyak spaces $\mathcal{H}(b)$ is a Hilbert space contractively contained in the Hardy space $H^2$ that is invariant by the backward shift operator $S^*$. We…

Functional Analysis · Mathematics 2018-10-03 Cheng Chu

Truncated Toeplitz operators and their asymmetric versions are studied in the context of the Hardy space $H^p$ of the half-plane for $1<p<\infty$. It is shown that they are equivalent after extension to $2 \times 2$ matricial Toeplitz…

Functional Analysis · Mathematics 2015-04-27 M. Cristina Câmara , Jonathan R. Partington

We prove that in the setting of operator spaces the result of Davis, Figiel, Johnson and Pelczynski on factoring weakly compact operators holds accordingly. Though not related directly to the main theorem we add a remark on the description…

Functional Analysis · Mathematics 2016-09-07 Hermann Pfitzner , Georg Schluechtermann

Let $A$ be a unital, simple and Z-stable C$^*$-algebra. We show that the set of positive elements in $A$ (resp. $A \otimes K$) belonging to a fixed non-compact Cuntz class is contractible as a topological subspace of $A$ (resp. $A \otimes…

Operator Algebras · Mathematics 2024-12-18 Chrisil Ouseph , Andrew S. Toms

This paper is a survey on the emerging theory of truncated Toeplitz operators. We begin with a brief introduction to the subject and then highlight the many recent developments in the field since Sarason's seminal paper in 2007.

Complex Variables · Mathematics 2012-06-25 Stephan Ramon Garcia , William T. Ross

For a very general class of weighted Fock spaces on $\mathbb{C}^n$, we give necessary and sufficient conditions for a Toeplitz operator with a (not necessarily positive) measure symbol to be compact. Furthermore, we show that all compact…

Functional Analysis · Mathematics 2013-06-04 Joshua Isralowitz

We describe the $C^*$-algebra associated with the finite sections discretization of truncated Toeplitz operators on the model space $K^2_u$ where $u$ is an infinite Blaschke product. As consequences, we get a stability criterion for the…

Operator Algebras · Mathematics 2014-01-22 Steffen Roch

This paper introduces a new subtraction operation for convex sets, which defines their difference as a collection of inclusion-minimal convex sets with appropriate definitions of linear operations on them. With these operations the set of…

Optimization and Control · Mathematics 2018-06-18 Evgeni Nurminski , Stan Uryasev

In this article, we establish that any uniformly local Mizoguchi-Takahashi contraction is actually a set-valued contraction due to Feng and Liu on a metrically convex complete metric space. Through an example, we demonstrate that this…

Functional Analysis · Mathematics 2023-01-24 Pallab Maiti , Asrifa Sultana

We prove a fixpoint theorem for contractions on Cauchy-complete quantale-enriched categories. It holds for any quantale whose underlying lattice is continuous, and applies to contractions whose control function is sequentially…

Category Theory · Mathematics 2022-11-04 Arij Benkhadra , Isar Stubbe

We establish the following result, confirming a conjecture of Jean Esterle. For each closed subset $E$ of the unit circle of Lebesgue measure zero, there exists a positive sequence $u_n\to\infty$ with the following property: if $T$ is a…

Functional Analysis · Mathematics 2026-05-18 Thomas Ransford

We explicitly establish a unitary correspondence between spherical irreducible tensor operators and cartesian tensor operators of any rank. That unitary relation is implemented by means of a basis of integer-spin wave functions that…

Quantum Physics · Physics 2020-08-11 Antonio O. Bouzas

We prove several results concerning the theory of Toeplitz algebras over $p$-Fock spaces using a correspondence theory of translation invariant symbol and operator spaces. The most notable results are: The full Toeplitz algebra is the norm…

Functional Analysis · Mathematics 2020-06-03 Robert Fulsche

We prove several lower bounds for the norm of a truncated Toeplitz operator and obtain a curious relationship between the $H^2$ and $H^{\infty}$ norms of functions in model spaces.

Functional Analysis · Mathematics 2009-07-20 Stephan Ramon Garcia , William T. Ross

In seven dimensions any spin manifold admits an SU(2) structure and therefore very general M-theory compactifications have the potential to allow for a reduction to N=4 gauged supergravity. We perform this general SU(2) reduction and give…

High Energy Physics - Theory · Physics 2015-11-05 Hagen Triendl

We establish connections between Schur parameters of the Schur class operator-valued functions, the corresponding simple conservative realizations, lower triangular Toeplitz matrices, and Kre\u\i n shorted operators. By means of Schur…

Functional Analysis · Mathematics 2011-09-20 Yury Arlinskii

The purpose of this paper is to systematically study compactness and essential norm properties of operators on a very general class of weighted Fock spaces over $\C$. In particular, we obtain rather strong necessary and sufficient…

Functional Analysis · Mathematics 2014-04-09 Joshua Isralowitz

A truncated Toeplitz operator is the compression of a classical Toeplitz operator on the Hardy space to a model space. A truncated Hankel operator is the compression of a Hankel operator on the Hardy space to the orthogonal complement of a…

Functional Analysis · Mathematics 2020-04-07 Cheng Chu
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