Extensions by simple $C^*$-algebras -- Quasidiagonal extensions

dc.creatorLin, Huaxin
dc.date2004-01-19
dc.date.accessioned2026-07-07T05:04:40Z
dc.date.available2026-07-07T05:04:40Z
dc.descriptionLet $A$ be an amenable separable \CA and $B$ be a non-unital but $σ$-unital simple \CA with continuous scale. We show that two essential extensions $τ_1$ and $τ_2$ of $A$ by $B$ are approximately unitarily equivalent if and only if $$ [τ_1]=[τ_2] {\rm in} KL(A, M(B)/B). $$ If $A$ is assumed to satisfy the Universal Coefficient Theorem, there is a bijection from approximate unitary equivalence classes of the above mentioned extensions to $KL(A, M(B)/B).$ Using $KL(A, M(B)/B),$ we compute exactly when an essential extension is quasidiagonal. We show that quasidiagonal extensions may not be approximately trivial. We also study the approximately trivial extensions.
dc.descriptionto appear Canad J. Math
dc.identifierhttps://arxiv.org/abs/math/0401241
dc.identifierhttp://arxiv.org/abs/math/0401241
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/69897
dc.subjectOperator Algebras
dc.subject46L05; 46L35
dc.titleExtensions by simple $C^*$-algebras -- Quasidiagonal extensions
dc.typetext

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