English

Cancellation and stable rank for direct limits of recursive subhomogeneous algebras

Operator Algebras 2007-05-23 v1

Abstract

We prove the following results for a unital simple direct limit AA of recursive subhomogeneous algebras with no dimension growth: (1) A has stable rank 1. (2) The projections in M(A)M_{\infty} (A) satisfy cancellation: if eqfqe \oplus q \sim f \oplus q, then efe \sim f. (3) AA satisfies Blackadar's Second Fundamental Comparability Question: if p,qM(A)p, q \in M_{\infty} (A) are projections such that τ(p)<τ(q)\tau (p) < \tau (q) for all normalized traces τ\tau on AA, then pp is equivalent to a subprojection of qq. (4) K0(A)K_0 (A) is unperforated for the strict order: if ηK0(A)\eta \in K_0 (A) and there is n>0n > 0 such that nη>0n \eta > 0, then η>0\eta > 0. The last three of these results hold under certain weaker dimension growth conditions and without assuming simplicity. We use these results to obtain previously unknown information on the ordered K-theory of the crossed product C(Z,X,h)C^* (Z, X, h) obtained from a minimal homeomorphism of an infinite finite dimensional compact metric space XX. Specifically, K0(C(Z,X,h))K_0 (C^* (Z, X, h)) is unperforated for the strict order, and satisfies the following K-theoretic version of Blackadar's Second Fundamental Comparability Question: if ηK0(A)\eta \in K_0 (A) satisfies τ(\et)>0\tau_* (\et) > 0 for all normalized traces τ\tau on AA, then there is a projection pM(A)p \in M_{\infty} (A) such that η=[p]\eta = [p].

Keywords

Cite

@article{arxiv.math/0101157,
  title  = {Cancellation and stable rank for direct limits of recursive subhomogeneous algebras},
  author = {N. Christopher Phillips},
  journal= {arXiv preprint arXiv:math/0101157},
  year   = {2007}
}

Comments

27 pages, AMSLaTeX