Homotopy of product systems and K-theory of Cuntz-Nica-Pimsner algebras

Abstract

We introduce the notion of a homotopy of product systems, and show that the Cuntz-Nica-Pimsner algebras of homotopic product systems over N^k have isomorphic K-theory. As an application, we give a new proof that the K-theory of a 2-graph C*-algebra is independent of the factorisation rules, and we further show that the K-theory of any twisted k-graph C*-algebra is independent of the twisting 2-cocycle. We also explore applications to K-theory for the C*-algebras of single-vertex k-graphs, reducing the question of whether the $K$-theory is independent of the factorisation rules to a question about path-connectedness of the space of solutions to an equation of Yang-Baxter type.

25 pages. This version matched published version in Indiana U. Math. J. Corrects an equation on page 9 that cut off mid line

References in corpus (5)

• Simplicity of C*-algebras associated to higher-rank graphs
• C*-algebras associated to product systems of Hilbert bimodules
• Gauge-invariant ideals in the C*-algebras of finitely aligned higher-rank graphs
• On the K-theory of twisted higher-rank-graph C*-algebras
• Graded C*-algebras, graded K-theory, and twisted P-graph C*-algebras

Cited by in corpus (1)

• Remarks On the K-theory of C*-Algebras of Products of Odometers