Imprimitivity for $C^*$-Coactions of Non-Amenable Groups
Abstract
Description
We give a condition on a full coaction $(A,G,δ)$ of a (possibly) nonamenable group $G$ and a closed normal subgroup $N$ of $G$ which ensures that Mansfield imprimitivity works; i.e. that $A\times_{δ{\vert}} G/N$ is Morita equivalent to $A\times_δG\times_{\deltahat,r} N$. This condition obtains if $N$ is amenable or $δ$ is normal. It is preserved under Morita equivalence, inflation of coactions, the stabilization trick of Echterhoff and Raeburn, and on passing to twisted coactions.
23 pages, LaTeX 2e, requires amscd.sty and pb-diagram.sty. Revisions include deletion of false Lemma 2.3 and amendment of proofs of Proposition 2.4 and Theorem 4.1, which had relied on the false lemma or its proof
23 pages, LaTeX 2e, requires amscd.sty and pb-diagram.sty. Revisions include deletion of false Lemma 2.3 and amendment of proofs of Proposition 2.4 and Theorem 4.1, which had relied on the false lemma or its proof