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In this work, we introduce the concept of the direct integral of locally Hilbert spaces. This notion is formulated such that the direct integral of locally Hilbert spaces forms a locally Hilbert space. We then define two classes of locally…

Functional Analysis · Mathematics 2025-08-06 Chaitanya J. Kulkarni , Santhosh Kumar Pamula

It is shown that the *-algebra of all (closed densely defined linear) operators affiliated with a finite type I von Neumann algebra admits a unique center-valued trace, which turns out to be, in a sense, normal. It is also demonstrated that…

Operator Algebras · Mathematics 2017-05-26 Piotr Niemiec , Adam Wegert

Investigating the direct integral decomposition of von Neumann algebras of bounded module operators on self-dual Hilbert W*-moduli an equivalence principle is obtained which connects the theory of direct disintegration of von Neumann…

funct-an · Mathematics 2008-02-03 Michael Frank

In this work, we introduce the concept of the direct integral of locally Hilbert spaces by generalizing the classical notion of a measure space to that of a locally measure space. We establish that the direct integral of a family of locally…

Functional Analysis · Mathematics 2025-08-07 Chaitanya J. Kulkarni , Santhosh Kumar Pamula

We obtain a functional model for an arbitrary Abelian locally von Neumann algebra acting on a representing locally Hilbert space under the assumption that the index directed set is countable, in terms of locally essentially bounded…

Functional Analysis · Mathematics 2026-05-13 Aurelian Gheondea , Chaitanya J. Kulkarni , Santhosh Kumar Pamula

Every unital nonselfadjoint operator algebra possesses canonical and functorial classes of faithful (even completely isometric) Hilbert space representations satisfying a double commutant theorem generalizing von Neumann's classical result.…

Operator Algebras · Mathematics 2007-05-23 David P. Blecher , Baruch Solel

An \textit{ideal} of $N$-tuples of operators is a class invariant with respect to unitary equivalence which contains direct sums of arbitrary collections of its members as well as their (reduced) parts. New decomposition theorems (with…

Operator Algebras · Mathematics 2014-11-03 Piotr Niemiec

This paper is concerned with derivations in algebras of (unbounded) operators affiliated with a von Neumann algebra $\mathcal{M}$. Let $\mathcal{% A}$ be one of the algebras of measurable operators, locally measurable operators or, $\tau…

Operator Algebras · Mathematics 2009-07-08 A. F. Ber , B. de Pagter , F. A. Sukochev

We characterize injectivity of von Neumann algebras in terms of factoring bilinear maps as products of linear maps.

Operator Algebras · Mathematics 2007-05-23 Allan M. Sinclair , Roger R. Smith

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

An $n$-tuple of operators $(V_1,...,V_n)$ acting on a Hilbert space $H$ is said to be isometric if the operator $[V_1\...\ V_n]:H^n\to H$ is an isometry. We prove a decomposition for an isometric tuple of operators that generalizes the…

Operator Algebras · Mathematics 2015-09-15 Matthew Kennedy

Given a von Neumann algebra $M$ we introduce so called central extension $mix(M)$ of $M$. We show that $mix(M)$ is a *-subalgebra in the algebra $LS(M)$ of all locally measurable operators with respect to $M,$ and this algebra coincides…

Operator Algebras · Mathematics 2009-08-11 Shavkat A. Ayupov , Karimbergen K. Kudaybergenov

A certain class of matrix-valued Borel matrix functions is introduced and it is shown that all functions of that class naturally operate on any operator T in a finite type I von Neumann algebra M in a way such that uniformly bounded…

Operator Algebras · Mathematics 2017-05-26 Piotr Niemiec

Let $M$ be a type I von Neumann algebra with the center $Z,$ and let $LS(M)$ be the algebra of all locally measurable operators affiliated with $M.$ We prove that every $Z$-linear derivation on $LS(M)$ is inner. In particular all $Z$-linear…

Operator Algebras · Mathematics 2008-08-07 S. Albeverio , Sh. A. Ayupov , K. K. Kudaybergenov

We characterize in terms of inequalities the possible generalized singular numbers of a product AB of operators A and B having given generalized singular numbers, in an arbitrary finite von Neumann algebra. We also solve the analogous…

Operator Algebras · Mathematics 2016-01-26 Hari Bercovici , Benoit Collins , Ken Dykema , Wing Suet Li

We extend some inequalities for normal matrices and positive linear maps related to the Russo-Dye theorem. The results cover the case of some positive linear maps on a von Neumann algebra mapping any nonzero operator to an unbounded…

Operator Algebras · Mathematics 2020-04-24 Jean-Christophe Bourin , Jingjing Shao

We give a generalization of the Jordan canonical form theorem for a class of bounded linear operators on complex separable Hilbert spaces in terms of direct integrals. Precisely, we study the uniqueness of strongly irreducible…

Functional Analysis · Mathematics 2011-09-28 Rui Shi

We develop a natural generalization of vector-valued frame theory, we term operator-valued frame theory, using operator-algebraic methods. This extends work of the second author and D. Han which can be viewed as the multiplicity one case…

Functional Analysis · Mathematics 2007-07-24 Victor Kaftal , David Larson , Shuang Zhang

We study regular inclusions of finite-dimensional von Neumann algebras from a matrix-theoretic perspective. To this end, we introduce a new combinatorial invariant of an inclusion, called the normalizer matrix, which encodes the structure…

Operator Algebras · Mathematics 2026-02-18 Keshab Chandra Bakshi , Silambarasan C

Strongly irreducible operators can be considered as building blocks for bounded linear operators on complex separable Hilbert spaces. Many bounded linear operators can be written as direct sums of at most countably many strongly irreducible…

Functional Analysis · Mathematics 2012-11-28 Chunlan Jiang , Rui Shi
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