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Main Author: Houdayer, Cyril
Format: Preprint
Published: 2008
Subjects:
Online Access:https://arxiv.org/abs/0812.1325
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author Houdayer, Cyril
author_facet Houdayer, Cyril
contents We show that for any type ${\rm III_1}$ free Araki-Woods factor $\mathcal{M} = Γ(H_\R, U_t)"$ associated with an orthogonal representation $(U_t)$ of $\R$ on a separable real Hilbert space $H_\R$, the continuous core $M = \mathcal{M} \rtimes_σ\R$ is a semisolid ${\rm II_\infty}$ factor, i.e. for any non-zero finite projection $q \in M$, the ${\rm II_1}$ factor $qMq$ is semisolid. If the representation $(U_t)$ is moreover assumed to be mixing, then we prove that the core $M$ is solid. As an application, we construct an example of a non-amenable solid ${\rm II_1}$ factor $N$ with full fundamental group, i.e. $\mathcal{F}(N) = \R^*_+$, which is not isomorphic to any interpolated free group factor $L(\F_t)$, for $1 < t \leq +\infty$.
format Preprint
id arxiv_https___arxiv_org_abs_0812_1325
institution arXiv
publishDate 2008
record_format arxiv
spellingShingle Structural results for free Araki-Woods factors and their continuous cores
Houdayer, Cyril
Operator Algebras
46L10, 46L54
We show that for any type ${\rm III_1}$ free Araki-Woods factor $\mathcal{M} = Γ(H_\R, U_t)"$ associated with an orthogonal representation $(U_t)$ of $\R$ on a separable real Hilbert space $H_\R$, the continuous core $M = \mathcal{M} \rtimes_σ\R$ is a semisolid ${\rm II_\infty}$ factor, i.e. for any non-zero finite projection $q \in M$, the ${\rm II_1}$ factor $qMq$ is semisolid. If the representation $(U_t)$ is moreover assumed to be mixing, then we prove that the core $M$ is solid. As an application, we construct an example of a non-amenable solid ${\rm II_1}$ factor $N$ with full fundamental group, i.e. $\mathcal{F}(N) = \R^*_+$, which is not isomorphic to any interpolated free group factor $L(\F_t)$, for $1 < t \leq +\infty$.
title Structural results for free Araki-Woods factors and their continuous cores
topic Operator Algebras
46L10, 46L54
url https://arxiv.org/abs/0812.1325