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Approximation Properties for Non-commutative L_p-Spaces Associated with Discrete Groups

M. Junge·Z. -J. Ruan
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Abstract

Let $1 < p < \infty$. It is shown that if $G$ is a discrete group with the approximation property introduced by Haagerup and Kraus, then the non-commutative $L_p(VN(G))$ space has the operator space approximation property. If, in addition, the group von Neumann algebra $VN(G)$ has the QWEP, i.e. is a quotient of a $C^*$-algebra with Lance's weak expectation property, then $L_p(VN(G))$ actually has the completely contractive approximation property and the approximation maps can be chosen to be finite-rank completely contractive multipliers on $L_p(VN(G))$. Finally, we show that if $G$ is a countable discrete group having the approximation property and $VN(G)$ has the QWEP, then $L_p(VN(G))$ has a very nice local structure, i.e. it is a $\mathcal C\OL_p$ space and has a completely bounded Schauder basis.

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M. Junge, Z. -J. Ruan. 2002-06-06. Approximation Properties for Non-commutative L_p-Spaces Associated with Discrete Groups. https://arxiv.org/abs/math/0206060

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