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We study the von Neumann algebra generated by q--deformed Gaussian elements l_i+l_i^* where operators l_i fulfill the q--deformed canonical commutation relations l_i l_j^*-q l_j^* l_i=delta_{ij} for -1<q<1. We show that if the number of…

Operator Algebras · Mathematics 2009-11-10 Piotr Sniady

The paper studies a generalized von Neumann-Jordan constant of non-normable metrics on vector spaces. To the best of our knowledge, all existing results of the von Neumann-Jordan constant and its generalizations have been established only…

Functional Analysis · Mathematics 2026-05-20 Doan Huu Hieu , Nguyen Duy Cuong

Results of Haagerup and Schultz (2009) about existence of invariant subspaces that decompose the Brown measure are extended to a large class of unbounded operators affiliated to a tracial von Neumann algebra. These subspaces are used to…

Operator Algebras · Mathematics 2015-09-14 Ken Dykema , Fedor Sukochev , Dmitriy Zanin

We provide adaptive inference methods, based on $\ell_1$ regularization, for regular (semi-parametric) and non-regular (nonparametric) linear functionals of the conditional expectation function. Examples of regular functionals include…

Machine Learning · Statistics 2022-10-25 Victor Chernozhukov , Whitney Newey , Rahul Singh

We define a noncommutative algebra of four basic objects within a differential calculus on quantum groups: functions, 1-forms, Lie derivatives and inner derivations, as the cross-product algebra associated with Woronowicz's (differential)…

q-alg · Mathematics 2009-10-30 A. A. Vladimirov

For three standard models of commutative algebras generated by Toeplitz operators in the weighted analytic Bergman space on the unit disk, we find their representations as the algebras of bounded functions of certain unbounded self-adjoint…

Functional Analysis · Mathematics 2022-03-09 Grigori Rozenblum , Nikolai Vasilevski

Regular and higher regular graded algebras (in simplest case satisfying Von Neumann regularity $\Theta_{1}\Theta_{2}\Theta_{1}=\Theta_{1}$ instead of anticommutativity) are introduced and their properties are studied. They are described in…

Quantum Algebra · Mathematics 2007-05-23 Steven Duplij , Wladyslaw Marcinek

We study a class of matrices with noncommutative entries, which were first considered by Yu. I. Manin in 1988 in relation with quantum group theory. They are defined as "noncommutative endomorphisms" of a polynomial algebra. More explicitly…

Quantum Algebra · Mathematics 2009-01-05 A. Chervov , G. Falqui , V. Rubtsov

Let $A$ be a commutative unital $\mathbb{R}$-algebra and let $\rho$ be a seminorm on $A$ which satisfies $\rho(ab)\leq\rho(a)\rho(b)$. We apply T. Jacobi's representation theorem to determine the closure of a $\sum A^{2d}$-module $S$ of $A$…

Functional Analysis · Mathematics 2013-12-16 Mehdi Ghasemi , Salma Kuhlmann , Murray Marshall

We give a description of operator algebras of free wreath products in terms of fundamental algebras of graphs of operator algebras as well as an explicit formula for the Haar state. This allows us to deduce stability properties for certain…

Operator Algebras · Mathematics 2024-02-22 Pierre Fima , Arthur Troupel

We study a semi-/nonparametric regression model with a general form of nonclassical measurement error in the outcome variable. We show equivalence of this model to a generalized regression model. Our main identifying assumptions are a…

Econometrics · Economics 2021-06-01 Christoph Breunig , Stephan Martin

Relativizing an idea from multiplicity theory, we say that an element x of a von Neumann algebra M is n-divisible if (W*(x)' cap M) unitally contains a factor of type I_n. We decide the density of the n-divisible operators, for various n,…

Operator Algebras · Mathematics 2008-06-09 David Sherman

Given a unital inclusion of simple $C^*$-algebras equipped with a conditional expectation of index-finite type, we study Fourier transforms and rotation operators and introduce the reflection operators on the relative commutants. We prove…

Operator Algebras · Mathematics 2026-01-19 Keshab Chandra Bakshi , Satyajit Guin , Biplab Pal , Sruthymurali

We study (von Neumann) regular $^*$-subalgebras of $B(H)$, which we call R$^*$-algebras. The class of R$^*$-algebras coincides with that of "E$^*$-algebras that are pre-C$^*$-algebras" in the sense of Z. Sz\H{u}cs and B. Tak\'acs. We give…

Operator Algebras · Mathematics 2022-03-23 Michiya Mori

In the 1970s Alain Connes identified the appropriate notion of amenabilty for von Neumann algebras, and used it to obtain a deep internal finite dimensional approximation structure for these algebras. This structure is exactly what is…

Operator Algebras · Mathematics 2023-07-11 Stuart White

We study the von Neumann algebra, generated by the unitary representations of infinite-dimensional groups nilpotent group $B_0^{\mathbb N}$. The conditions of the irreducibility of the regular and quasiregular representations of…

Operator Algebras · Mathematics 2008-03-25 Alexandre Kosyak

The category of $C^*$-algebras is blessed with many different tensor products. In contrast, virtually the only tensor product ever used in the category of von Neumann algebras is the normal spatial tensor product. We propose a definition of…

Operator Algebras · Mathematics 2015-06-05 Matthew Wiersma

We study operator algebraic and function theoretic aspects of algebras of bounded nc functions on subvarieties of the nc domain determined by all levels of the unit ball of an operator space (nc operator balls). Our main result is the…

Operator Algebras · Mathematics 2025-04-15 Jeet Sampat , Orr Shalit

We characterise Exel's noncommutative Cartan subalgebras in several ways using uniqueness of conditional expectations, relative commutants, or purely outer inverse semigroup actions. We describe in which sense the crossed product…

Operator Algebras · Mathematics 2020-11-04 B. K. Kwasniewski , R. Meyer

In this paper, we show how a construction of an implicit complexity model can be implemented using concepts coming from the core of von Neumann algebras. Namely, our aim is to gain an understanding of classical computation in terms of the…

Computational Complexity · Computer Science 2009-12-31 Marco Pedicini , Mario Piazza