C*-algebras over topological spaces: filtrated K-theory

Ralf Meyer, Ryszard Nest

25 Citations (Scopus)

Abstract

We define the filtrated K-theory of a C*-algebra over a finite topological space X and explain how to construct a spectral sequence that computes the bivariant Kasparov theory over X in terms of filtrated K-theory. For finite spaces with a totally ordered lattice of open subsets, this spectral sequence becomes an exact sequence as in the Universal Coefficient Theorem, with the same consequences for classification. We also exhibit an example where filtrated K-theory is not yet a complete invariant. We describe two C*-algebras over a space X with four points that have isomorphic filtrated K-theory without being KK(X)-equivalent. For this space X, we enrich filtrated K-theory by another K-theory functor to a complete invariant up to KK(X)-equivalence that satisfies a Universal Coefficient Theorem.
Original languageEnglish
JournalCanadian Journal of Mathematics - Journal Canadien de Mathématiques
Volume64
Issue number2
Pages (from-to)368-408
ISSN0008-414X
DOIs
Publication statusPublished - Apr 2012

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