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In this paper we survey our recent work on C*-correspondences and their associated operator algebras; in particular, on adding tails, the Shift Equivalence Problem and Hilbert bimodules.

Operator Algebras · Mathematics 2014-04-08 Evgenios T. A. Kakariadis , Elias G. Katsoulis

We establish the full range of the Caffarelli-Kohn-Nirenberg inequalities for radial functions in the Sobolev and the fractional Sobolev spaces of order $0 < s \le 1$. In particular, we show that the range of the parameters for radial…

Analysis of PDEs · Mathematics 2022-11-10 Arka Mallick , Hoai-minh Nguyen

In this paper, we begin by showing a new generalization of the celebrated Cauchy-Schwarz inequality for the inner product. Then, this generalization is used to present some bounds for the Euclidean operator radius and the Euclidean operator…

Functional Analysis · Mathematics 2023-10-09 Mohammad Sababheh , Hamid Reza Moradi

Properties of the inverse along an element in rings with an involution, Banach algebras and $C^*$-alegbras will be studied unifying known expressions concerning generalized inverses.

Functional Analysis · Mathematics 2015-09-15 Julio Benitez , Enrico Boasso

In this paper we prove a version of Gruss integral inequality for mappings with values in Hilbert C*-modules. Some applications for such functions are also given.

Operator Algebras · Mathematics 2014-07-10 Amir Ghasem Ghazanfari

In the present paper the notion of continuous frames is introduced and some results of these frames are proved. Next, we give the concept of duals of continuous frames in Hilbert C*-modules and investigate some properties of them.

Functional Analysis · Mathematics 2023-01-24 Hadi Ghasemi , Tayebe Lal Shateri

In this work, I develop a new view of presentation theory for C*-algebras, both unital and non-unital, heavily grounded in classical notions from algebra. In particular, I introduce Tietze transformations for these presentations, which lead…

Operator Algebras · Mathematics 2017-06-06 Will Grilliette

We present a new approach to C*-algebras recently constructed in the context of modular index theory by Carey, Phillips, Putnam and Rennie. It turns out that their constructions can be identified with full corners of ideals in semigroup…

Operator Algebras · Mathematics 2014-08-19 Xin Li

We introduce the growth rank of a C*-algebra, a (N \cup {\infty})-valued invariant which measures how far an algebra is from absorbing the Jiang-Su algebra Z tensorially. We prove that its range is exhausted by simple nuclear C*-algebras,…

Operator Algebras · Mathematics 2007-05-23 Andrew S. Toms

We characterize $C^*$-algebras and $C^*$-modules such that every maximal right ideal (resp. right submodule) is algebraically finitely generated. In particular, $C^*$-algebras satisfy the Dales--\.Zelazko conjecture.

Operator Algebras · Mathematics 2014-11-26 David P. Blecher , Tomasz Kania

We present three versions of the Lax-Milgram theorem in the framework of Hilbert C*-modules, two for those over W*-algebras and one for those over C*-algebras of compact operators. It is remarkable that while the Riesz theorem is not valid…

Operator Algebras · Mathematics 2025-04-29 R. Eskandari , M. Frank , V. M. Manuilov , M. S. Moslehian

We show that the distance from an element of a C*-algebra to the set of regular elements is the infimum of the $\delta>0$ for which the $\delta$-cut-down of the element admits a polar decomposition within the algebra. This parallels results…

Operator Algebras · Mathematics 2025-11-27 Hannes Thiel

We study nonunital $C^*$-algebras such that for any element there exists a local unit and prove that in such algebras there are no frames. This fact was previously known only for commutative algebras. Among other results, we establish some…

Operator Algebras · Mathematics 2025-06-17 Denis Fufaev

We show that the following properties of unital ${\rm C^*}$-algebra in a class of $\Omega$ are preserved by unital simple ${\rm C^*}$-algebra in the class of $\rm WTA\Omega$: $(1)$ uniform property $\Gamma$, $(2)$ a certain type of tracial…

Operator Algebras · Mathematics 2024-04-08 Qingzhai Fan , Jiahui Wang

The theory of multiplier modules of Hilbert C*-modules is reconsidered to obtain more properties of these special Hilbert C*-modules. The property of a Hilbert C*-module to be a multiplier C*-module is shown to be an invariant with respect…

Operator Algebras · Mathematics 2026-03-26 Michael Frank

We introduce two new formulations for the notion of "quantum metric on noncommutative space". For a compact noncommutative space associated to a unital C*-algebra, our quantum metrics are elements of the spatial tensor product of the…

Operator Algebras · Mathematics 2016-06-15 Maysam Maysami Sadr

From a planar algebra, we give a functorial construction to produce numerous associated $C^*$-algebras. Our main construction is a Hilbert $C^*$-bimodule with a canonical real subspace which produces Pimsner-Toeplitz, Cuntz-Pimsner, and…

Operator Algebras · Mathematics 2014-01-14 Michael Hartglass , David Penneys

We investigate the deformation of involution and multiplication in a unital $C^*$-algebra when its norm is fixed. Our main result is to present all multiplications and involutions on a given $C^*$-algebra $\mathcal{A}$ under which…

Operator Algebras · Mathematics 2014-11-04 H. Najafi , M. S. Moslehian

We explore the recently introduced local-triviality dimensions by studying gauge actions on graph $C^*$-algebras, as well as the restrictions of the gauge action to finite cyclic subgroups. For $C^*$-algebras of finite acyclic graphs and…

Operator Algebras · Mathematics 2021-06-09 Alexandru Chirvasitu , Benjamin Passer , Mariusz Tobolski

Order unit property of a positive element in a $C^{*}$-algebra is defined. It is proved that precisely projections satisfy this order theoretic property. This way, unital hereditary $C^{*}$-subalgebras of a $C^{*}$-algebra are…

Operator Algebras · Mathematics 2007-05-23 Anil K. Karn