Boundary actions for affine buildings and higher rank Cuntz-Krieger algebras

Guyan Robertson

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Boundary actions for affine buildings and higher rank Cuntz-Krieger algebras

Guyan Robertson

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Abstract

Let $\G$ be a group of type rotating automorphisms of an affine building $\cB$ of type $\wt A_2$. If $\G$ acts freely on the vertices of $\cB$ with finitely many orbits, and if $\Omega$ is the (maximal) boundary of $\cB$, then $C(\Om)\rtimes \G$ is a p.i.s.u.n. $C^*$-algebra. This algebra has a structure theory analogous to that of a simple Cuntz-Krieger algebra and is the motivation for a theory of higher rank Cuntz-Krieger algebras, which has been developed by T. Steger and G. Robertson. The K-theory of these algebras can be computed explicitly in the rank two case. For the rank two examples of the form $C(\Om)\rtimes \G$ which arise from boundary actions on $\wt A_2$ buildings, the two K-groups coincide.

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BibTeX RIS

Guyan Robertson. 2000-03-10. Boundary actions for affine buildings and higher rank Cuntz-Krieger algebras. https://arxiv.org/abs/math/0003061

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