English

Lifting KK-elements, asymptotical unitary equivalence and classification of simple C*-algebras

Operator Algebras 2008-03-10 v3 K-Theory and Homology

Abstract

Let AA and CC be two unital simple C*-algebas with tracial rank zero. Suppose that CC is amenable and satisfies the Universal Coefficient Theorem. Denote by KKe(C,A)++{{KK}}_e(C,A)^{++} the set of those κ\kappa for which κ(K0(C)+{0})K0(A)+{0}\kappa(K_0(C)_+\setminus\{0\})\subset K_0(A)_+\setminus\{0\} and κ([1C])=[1A]\kappa([1_C])=[1_A]. Suppose that κKKe(C,A)++.\kappa\in {KK}_e(C,A)^{++}. We show that there is a unital monomorphism ϕ:CA\phi: C\to A such that [ϕ]=κ.[\phi]=\kappa. Suppose that CC is a unital AH-algebra and λ:T(A)Tf(C)\lambda: \mathrm{T}(A)\to \mathrm{T}_{\mathtt{f}}(C) is a continuous affine map for which τ(κ([p]))=λ(τ)(p)\tau(\kappa([p]))=\lambda(\tau)(p) for all projections pp in all matrix algebras of CC and any τT(A),\tau\in \mathrm{T}(A), where T(A)\mathrm{T}(A) is the simplex of tracial states of AA and Tf(C)\mathrm{T}_{\mathtt{f}}(C) is the convex set of faithful tracial states of C.C. We prove that there is a unital monomorphism ϕ:CA\phi: C\to A such that ϕ\phi induces both κ\kappa and λ.\lambda. Suppose that h:CAh: C\to A is a unital monomorphism and γHom(\Kone(C),\aff(A)).\gamma \in \mathrm{Hom}(\Kone(C), \aff(A)). We show that there exists a unital monomorphism ϕ:CA\phi: C\to A such that [ϕ]=[h][\phi]=[h] in KK(C,A),{KK}(C,A), τϕ=τh\tau\circ \phi=\tau\circ h for all tracial states τ\tau and the associated rotation map can be given by γ.\gamma. Applications to classification of simple C*-algebras are also given.

Keywords

Cite

@article{arxiv.0802.1484,
  title  = {Lifting KK-elements, asymptotical unitary equivalence and classification of simple C*-algebras},
  author = {Huaxin Lin and Zhuang Niu},
  journal= {arXiv preprint arXiv:0802.1484},
  year   = {2008}
}

Comments

The new version made a correction and removed a number of typos