The Noncommutative Geometry of k-graph C*-Algebras

dc.creatorPask, David
dc.creatorRennie, Adam
dc.creatorSims, Aidan
dc.date2005-12-19
dc.date2007-01-17
dc.date.accessioned2026-07-07T07:41:16Z
dc.date.available2026-07-07T07:41:16Z
dc.descriptionThis paper is comprised of two related parts. First we discuss which k-graph algebras have faithful gauge invariant traces, where the gauge action of $\T^k$ is the canonical one. We give a sufficient condition for the existence of such a trace, identify the C*-algebras of k-graphs satisfying this condition up to Morita equivalence, and compute their K-theory. For k-graphs with faithful gauge invariant trace, we construct a smooth $(k,\infty)$-summable semifinite spectral triple. We use the semifinite local index theorem to compute the pairing with K-theory. This numerical pairing can be obtained by applying the trace to a KK-pairing with values in the K-theory of the fixed point algebra of the $\T^k$ action. As with graph algebras, the index pairing is an invariant for a finer structure than the isomorphism class of the algebra.
dc.description38 pages, some pictures drawn in picTeX Some minor technical revisions. Material has been reorganised with detailed discussion of k-graphs admitting graph traces shortened and moved to an appendix. This version to appear in K-theory
dc.identifierhttps://arxiv.org/abs/math/0512438
dc.identifierhttp://arxiv.org/abs/math/0512438
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/122042
dc.subjectOperator Algebras
dc.subjectK-Theory and Homology
dc.subject46L05
dc.titleThe Noncommutative Geometry of k-graph C*-Algebras
dc.typetext

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