English
Related papers

Related papers: A note on the classification of Gamma factors

200 papers

In this paper, we prove a non-commutative version of the Weyl-von Neumann theorem for representations of unital, separable AH algebras into countably decomposable, semifinite, properly infinite, von Neumann factors, where an AH algebra…

Operator Algebras · Mathematics 2019-11-19 Junhao Shen , Rui Shi

We use continuous model theory to obtain several results concerning isomorphisms and embeddings between II_1 factors and their ultrapowers. Among other things, we show that for any II_1 factor M, there are continuum many nonisomorphic…

Operator Algebras · Mathematics 2017-05-17 Ilijas Farah , Bradd Hart , David Sherman

In 1960 Puk\'anszky introduced an invariant associating to every masa in a separable $\mathrm{II}_1$ factor a non-empty subset of $\mathbb N\cup\{\infty\}$. This invariant examines the multiplicity structure of the von Neumann algebra…

Operator Algebras · Mathematics 2008-04-08 Stuart White

For a countably decomposable finite von Neumann algebra $\mathscr{R}$, we show that any choice of a faithful normal tracial state on $\mathscr{R}$ engenders the same measure topology on $\mathscr{R}$ in the sense of Nelson (J. Func. Anal.,…

Operator Algebras · Mathematics 2022-12-16 Soumyashant Nayak

We consider various statements that characterize the hyperfinite II$_1$ factors amongst embeddable II$_1$ factors in the non-embeddable situation. In particular, we show that "generically" a II$_1$ factor has the Jung property (which states…

Operator Algebras · Mathematics 2021-01-27 Isaac Goldbring

We show that a free product of a II_1-factor and a finite von Neumann algebra with amalgamation over a finite dimensional subalgebra is always a II_1-factor, and provide an algorithm for describing it in terms of free products (with…

Operator Algebras · Mathematics 2010-02-10 Ken Dykema

A full set of (higher order) Casimir invariants for the Lie algebra $gl(\infty )$ is constructed and shown to be well defined in the category $O_{FS}$ generated by the highest weight (unitarizable) irreducible representations with only a…

Mathematical Physics · Physics 2009-10-30 M. D. Gould , N. I. Stoilova

Let $A$ be a separable, unital and exact $C^*$-algebra satisfying the universal coefficient theorem. We prove uniqueness theorems up to unitary conjugacy for unital, full and nuclear maps from $A$ into ultraproducts of finite von Neumann…

Operator Algebras · Mathematics 2026-05-15 Shanshan Hua , Stuart White

We construct countable groups $G$ with the following new degree of W*-superrigidity: if $L(G)$ is virtually isomorphic, in the sense of admitting a bifinite bimodule, with any other group von Neumann algebra $L(\Lambda)$, then the groups…

Operator Algebras · Mathematics 2025-03-14 Milan Donvil , Stefaan Vaes

Convergent infinite products, indexed by all natural numbers, in which each factor is a rational function of the index, can always be evaluated in terms of finite products of gamma functions. This goes back to Euler. A purpose of this note…

Number Theory · Mathematics 2013-09-16 Marc Chamberland , Armin Straub

We introduce a new invariant of Borel reducibility, namely the notion of thickness; this associates to every sentence $\Phi$ of $\mathcal{L}_{\omega_1 \omega}$ and to every cardinal $\lambda$, the thickness $\tau(\Phi, \lambda)$ of $\Phi$…

Logic · Mathematics 2024-07-16 Danielle Ulrich

Building on results of Haagerup and Schultz, we decompose an arbitrary operator in a diffuse, finite von Neumann algebra into the sum of a normal operator and an s.o.t.-quasinilpotent operator. We also prove an analogue of Weyl's inequality…

Operator Algebras · Mathematics 2013-06-17 K. Dykema , F. Sukochev , D. Zanin

The singularities of the $\Gamma$ function, a meromorphic function on the complex plane, are known to occur at the nonpositive integers. We show, using Euler and Gauss identities, that for all positive integers $n$ and $k$, $$…

General Mathematics · Mathematics 2010-08-16 Anirudh Prabhu

We show that a number of key structural properties transfer between sufficiently close II$_1$ factors, including solidity, strong solidity, uniqueness of Cartan masas and property $\Gamma$. We also examine II$_1$ factors close to tensor…

Operator Algebras · Mathematics 2016-06-01 Jan Cameron , Erik Christensen , Allan M. Sinclair , Roger R. Smith , Stuart White , Alan D. Wiggins

In our previous paper math.QA/0412192 the Cayley-Hamilton identity for the GL(m|n) type quantum matrix algebra was obtained. Here we continue investigation of that identity. We derive it in three alternative forms and, most importantly, we…

Quantum Algebra · Mathematics 2007-05-23 Dimitri Gurevich , Pavel Pyatov , Pavel Saponov

We provide an alternative proof for the extreme amenability of the unitary group of the hyperfinite II${}_1$-factor von Neumann algebra, endowed with the strong operator topology.

Operator Algebras · Mathematics 2015-07-02 Philip A. Dowerk , Andreas Thom

We observe how a classical model-theoretic fact proves the existence of many strong amalgamation bases for the class of R^\omega-embeddable von Neumann algebras, where R is the hyperfinite II_1 factor. In particular, we shows that R itself…

Operator Algebras · Mathematics 2013-01-30 Ilijas Farah , Isaac Goldbring , Bradd Hart

We show that a large class of i.c.c., countable, discrete groups satisfying a weak negative curvature condition are not inner amenable. By recent work of Hull and Osin, our result recovers that mapping class groups and Out(F_n) are not…

Operator Algebras · Mathematics 2019-02-20 Ionut Chifan , Thomas Sinclair , Bogdan Udrea

Theories of classification distinguish classes with some good structure theorem from those for which none is possible. Some classes (dense linear orders, for instance) are non-classifiable in general, but are classifiable when we consider…

Logic · Mathematics 2007-05-23 Wesley Calvert

It is known that the eigenvalues of selfadjoint elements a,b,c with a+b+c=0 in the factor R^omega (ultrapower of the hyperfinite II1 factor) are characterized by a system of inequalities analogous to the classical Horn inequalities of…

Operator Algebras · Mathematics 2019-02-27 H. Bercovici , B. Collins , K. Dykema , W. S. Li , D. Timotin