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Free independence is an important tool for studying the structure of operator algebras. It is natural to ask from the model-theoretic standpoint whether free independence is captured well in first-order model theory via the notion of a…

Operator Algebras · Mathematics 2026-02-25 William Boulanger , Jakub Curda , Emma Harvey , Yizhi Li , Jennifer Pi

We prove that the normalizer of any diffuse amenable subalgebra of a free group factor $L(\Bbb F_r)$ generates an amenable von Neumann subalgebra. Moreover, any II$_1$ factor of the form $Q \vt L(\Bbb F_r) $, with $Q$ an arbitrary subfactor…

Operator Algebras · Mathematics 2007-10-30 Narutaka Ozawa , Sorin Popa

These notes provide an explanation of the type classification of von Neumann algebras, which has made many appearances in recent work on entanglement in quantum field theory and quantum gravity. The goal is to bridge a gap in the literature…

High Energy Physics - Theory · Physics 2025-09-30 Jonathan Sorce

We investigate Cartan subalgebras in nontracial amalgamated free product von Neumann algebras $M_1 \ast_B M_2$ over an amenable von Neumann subalgebra $B$. First, we settle the problem of the absence of Cartan subalgebra in arbitrary free…

Operator Algebras · Mathematics 2019-02-20 Rémi Boutonnet , Cyril Houdayer , Sven Raum

In this paper, we exhibit strongly singular maximal abelian subalgebras living inside certain k-folded tensors of von Neumann group factors. The two classes of groups under consideration are the free groups of rank greater than 2 and the…

Operator Algebras · Mathematics 2007-05-23 Teodor Stefan Bildea

This paper establishes a necessary and sufficient condition for the coincidence of non-commutative $\log$-algebras constructed from different exact normal semifinite traces. Consequently, we provide a criterion for the isomorphism of…

Functional Analysis · Mathematics 2024-08-27 Rustam Abdullaev , Azizkhon Azizov

A reduction formula for compressions of von Neumann algebras arising as free products is proved. This shows that the fundamental group is all of the positive reals for some such algebras. Additionally, by taking a sort of free product with…

Operator Algebras · Mathematics 2007-05-23 Ken Dykema , Florin Radulescu

The weak Jacobi forms of integral weight and integral index associated to an even positive definite lattice form a bigraded algebra. In this paper we prove a criterion for this type of algebra being free. As an application, we give an…

Number Theory · Mathematics 2021-06-29 Haowu Wang

We study relatively free associative algebras $F^{(n)}_r$ of ranks $r=2,3$ with the identity $[x_1,\dots, x_n]=0$ of Lie nilpotency of step $n\geqslant 3$ over a field $K$ of characteristic $\neq 2,3$. First we prove a Theorem on the…

Rings and Algebras · Mathematics 2019-03-01 Sergey Pchelintsev

Any variety of classical algebras has a so-called conformal counterpart. For example one can consider Lie conformal or associative conformal algebras. Lie conformal algebras are closely related to vertex algebras. We define free objects in…

Quantum Algebra · Mathematics 2007-05-23 Michael Roitman

A free semigroupoid algebra is the closure of the algebra generated by a TCK family of a graph in the weak operator topology. We obtain a structure theory for these algebras analogous to that of free semigroup algebra. We clarify the role…

Operator Algebras · Mathematics 2019-06-14 Kenneth R. Davidson , Adam Dor-On , Boyu Li

We prove an inequality between the free entropy and the mutual free Fisher information for two projections, regarded as a free analog of the logarithmic Sobolev inequality. The proof is based on the random matrix approximation procedure via…

Operator Algebras · Mathematics 2019-05-21 Fumio Hiai , Yoshimichi Ueda

Five-valued Nelson algebras are those satisfying the condition: $((x\to z)\to y)\to(((y \to x)\to y)\to y)=1$. We give alternative equations defining these algebras, and determine the structure and number of elements of the free five-valued…

We prove that for a countable discrete group $\Gamma$ containing a copy of the free group $\F_n$, for some $2\leq n\leq\infty$, as a normal subgroup, the equivalence relations of conjugacy, orbit equivalence and von Neumann equivalence of…

Dynamical Systems · Mathematics 2012-05-22 Inessa Epstein , Asger Tornquist

We prove that if $A$ is a non-separable abelian tracial von Neuman algebra then its free powers $A^{*n}, 2\leq n \leq \infty$, are mutually non-isomorphic and with trivial fundamental group, $\mathcal F(A^{*n})=1$, whenever $2\leq…

Operator Algebras · Mathematics 2023-08-11 Rémi Boutonnet , Daniel Drimbe , Adrian Ioana , Sorin Popa

We first prove that a graded, connected, free and cofree Hopf algebra is always self-dual; then that two graded, connected, free and cofree Hopf algebras are isomorphic if, and only if, they have the same Poincar\'e-Hilbert formal series.…

Rings and Algebras · Mathematics 2011-06-23 Loïc Foissy

We consider cones in a Hilbert space associated to two von Neumann algebras and determine when one algebra is included in the other. If a cone is assocated to a von Neumann algebra, the Jordan structure is naturally recovered from it and we…

Operator Algebras · Mathematics 2011-02-01 Yoh Tanimoto

We define a canonical relative commutant planar algebra from a strongly Markov inclusion of finite von Neumann algebras. In the case of a connected unital inclusion of finite dimensional C*-algebras with the Markov trace, we show this…

Operator Algebras · Mathematics 2010-07-20 Vaughan F. R. Jones , David Penneys

We study classes of countable graphs where every member does not contain a given finite graph as an induced subgraph -- denoted by $\mathsf{Free}(\mathcal{G})$ for a given finite graph $\mathcal{G}$. Our main results establish a structural…

As an instance of a linear action of a Hopf algebra on a free associative algebra, we consider finite group gradings of a free algebra induced by gradings on the space spanned by the free generators. The homogeneous component corresponding…

Rings and Algebras · Mathematics 2008-11-12 Vitor O. Ferreira , Lucia S. I. Murakami