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Related papers: Exact Continuous frames in Hilbert C*-modules

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We study such Hilbert C*-modules over a C*-algebra $A$, that the Banach $A$-dual module carries a natural structure of Hilbert $A$-module. In this direction we prove that if $A$ is monotone complete, $M$ and $N$ are Hilbert $A$-modules, $M$…

Operator Algebras · Mathematics 2023-04-11 Vladimir Manuilov , Evgenij Troitsky

In the present paper we develop both ideas of D. Baki\'c and B. Gulja{\v{s}} and the categorical approach to multipliers from E.C. Lance's book and publications of the second author, for the introduction and study of left multipliers of…

Operator Algebras · Mathematics 2025-04-29 Michael Frank , Alexander A. Pavlov

We study completely positive module maps on $C^{*}$-algebras which are $C^*$-module over another $C^*$-algebra with compatible actions. We extend several well known dilation and extension results to this setup, including the Stinespring…

Operator Algebras · Mathematics 2016-10-04 Massoud Amini

In this paper we introduce concepts of disjoint, strongly disjoint and weakly disjoint continuous $g$-frames in Hilbert spaces and we get some equivalent conditions to these notions. We also construct a continuous g-frame by disjoint…

Functional Analysis · Mathematics 2018-02-13 Yavar Khedmati , Mohammad Reza Abdollahpour

Halmos' two projections theorem for Hilbert space operators is one of the fundamental results in operator theory. In this paper, we introduce the term of two harmonious projections in the context of adjointable operators on Hilbert…

Functional Analysis · Mathematics 2021-07-23 Wei Luo , Mohammad Sal Moslehian , Qingxiang Xu

A semiregular operator on a Hilbert C^*-module, or equivalently, on the C^*-algebra of `compact' operators on it, is a closable densely defined operator whose adjoint is also densely defined. It is shown that for operators on extensions of…

Operator Algebras · Mathematics 2016-09-07 Arupkumar Pal

We investigate the notion of conditionally positive definite in the context of Hilbert $C^*$-modules and present a characterization of the conditionally positive definiteness in terms of the usual positive definiteness. We give a Kolmogorov…

Operator Algebras · Mathematics 2017-09-26 Mohammad Sal Moslehian

Loosely speaking, a semi-frame is a generalized frame for which one of the frame bounds is absent. More precisely, given a total sequence in a Hilbert space, we speak of an upper (resp. lower) semi-frame if only the upper (resp. lower)…

Functional Analysis · Mathematics 2012-05-31 Jean-Pierre Antoine , Peter Balazs

In an attempt to propose more general conditions for decoherence to occur, we study spectral and ergodic properties of unital, completely positive maps on not necessarily unital $C^*$-algebras, with a particular focus on gapped maps for…

Operator Algebras · Mathematics 2021-10-14 Francesco Fidaleo , Federico Ottomano , Stefano Rossi

Fusion frames are valuable generalizations of discrete frames. Most concepts of fusion frames are shared by discrete frames. However, the dual setting is so complicated. In particular, unlike discrete frames, two fusion frames are not dual…

Functional Analysis · Mathematics 2016-05-06 Elnaz Osgooei , Ali Akbar Arefijamaal

The parallel sum for adjoinable operators on Hilbert $C^*$-modules is introduced and studied. Some results known for matrices and bounded linear operators on Hilbert spaces are generalized to the case of adjointable operators on Hilbert…

Operator Algebras · Mathematics 2018-07-16 Wei Luo , Chuanning Song , Qingxiang Xu

Let $A$ and $B$ be arbitrary $C^*$-algebras, we prove that the existence of a Hilbert $A$-$B$-bimodule of finite index ensures that the WEP, QWEP, and LLP along with other finite-dimensional approximation properties such as CBAP and (S)OAP…

Operator Algebras · Mathematics 2017-05-25 Marzieh Forough , Massoud Amini

This is a graduate-level introduction to C*-algebras, Hilbert C*-modules, vector bundles, and induced representations of groups and C*-algebras, with applications to quantization theory, phase space localization, and configuration space…

Mathematical Physics · Physics 2007-05-23 N. P. Landsman

We apply Hilbert module methods to show that normal completely positive maps admit weak tensor dilations. Appealing to a duality between weak tensor dilations and extensions of CP-maps, we get an existence proof for certain extensions. We…

Operator Algebras · Mathematics 2007-05-23 Rolf Gohm , Michael Skeide

Hilbert C*-modules are the analogues of Hilbert spaces where a C*-algebra plays the role of the scalar field. With the advent of Kasparov's celebrated KK-theory they became a standard tool in the theory of operator algebras. While the…

Operator Algebras · Mathematics 2016-12-23 Jens Kaad , Matthias Lesch

In this note, a general version of Bessel multipliers in Hilbert $C^*$-modules is presented and then, many results obtained for multipliers are extended. Also the conditions for invertibility of generalized multipliers are investigated in…

Operator Algebras · Mathematics 2018-02-07 Gholamreza Abbaspour Tabadkan , Hessam Hossein-nezhad

We introduce the notion of the separated pair of closed submodules in the setting of Hilbert $C^*$-modules. We demonstrate that even in the case of Hilbert spaces this concept has several nice characterizations enriching the theory of…

Operator Algebras · Mathematics 2024-05-09 R. Eskandari , W. Luo , M. S. Moslehian , Q. Xu , H. Zhang

A regular operator T on a Hilbert C^*-module is defined just like a closed operator on a Hilbert space, with the extra condition that the range of (I+T^*T) is dense. Semiregular operators are a slightly larger class of operators that may…

Operator Algebras · Mathematics 2007-05-23 Arupkumar Pal

Introduced by Duffin and Schaefer as a part of their work on nonhamonic fourrier series in 1952, the theory of frames has undergone a very interesting evolution in recent decades following the multiplicity of work carried out in this field.…

Functional Analysis · Mathematics 2023-01-19 Hatim Labrigui , Mohamed Rossafi , Abdeslam Touri , Nadia Assila

We examine Hilbert bimodules which possess a (generally unbounded) involution. Topics considered include a linking algebra representation, duality, locality, and the role of these bimodules in noncommutative differential geometry.

Operator Algebras · Mathematics 2007-05-23 Nik Weaver