Asymptotic unitary equivalence in C*-algebras
H Lin, Z Niu�- Russian Journal of Mathematical Physics, 2015 - Springer
H Lin, Z Niu
Russian Journal of Mathematical Physics, 2015•SpringerAbstract Let C= C (X) be the unital C*-algebra of all continuous functions on a finite CW
complex X and let A be a unital simple C*-algebra with tracial rank at most one. We show
that two unital monomorphisms φ, ψ: C→ A are asymptotically unitarily equivalent, ie, there
exists a continuous path of unitaries {ut: t∈[0, 1)}⊂ A such that lim t→ 1 u* t φ (f) ut= ψ (f) for
all f∈ C (X) if and only if [φ]=[ψ] in KK (C, A), τ◦ φ= τ◦ ψ for all τ∈ T (A), and φ†= ψ†, where T
(A) is the simplex of tracial states of A and φ†, ψ†: U∞(C)/DU∞(C)→ U∞(A)/DU∞(A) are�…
complex X and let A be a unital simple C*-algebra with tracial rank at most one. We show
that two unital monomorphisms φ, ψ: C→ A are asymptotically unitarily equivalent, ie, there
exists a continuous path of unitaries {ut: t∈[0, 1)}⊂ A such that lim t→ 1 u* t φ (f) ut= ψ (f) for
all f∈ C (X) if and only if [φ]=[ψ] in KK (C, A), τ◦ φ= τ◦ ψ for all τ∈ T (A), and φ†= ψ†, where T
(A) is the simplex of tracial states of A and φ†, ψ†: U∞(C)/DU∞(C)→ U∞(A)/DU∞(A) are�…
Abstract
Let C = C(X) be the unital C*-algebra of all continuous functions on a finite CW complex X and let A be a unital simple C*-algebra with tracial rank at most one. We show that two unital monomorphisms φ,ψ: C → A are asymptotically unitarily equivalent, i.e., there exists a continuous path of unitaries {u t : t ∈ [0, 1)} ⊂ A such that lim t→1 u* t φ(f)u t = ψ(f) for all f ∈ C(X) if and only if [φ] = [ψ] in KK(C,A), τ ◦φ = τ ◦ψ for all τ ∈ T(A), and φ † = ψ †, where T(A) is the simplex of tracial states of A and φ †, ψ †: U ∞(C)/DU ∞(C) → U ∞(A)/DU ∞(A) are the induced homomorphisms and where U ∞(A) = ∪ k=1 ∞ U(M k (A)) and U ∞(C) = ∪ k=1 ∞ U(M k (C)) are usual infinite unitary groups, respectively, and DU ∞(A) and DU ∞(C) are the commutator subgroups of U ∞(A) and U ∞(C), respectively. We actually prove a more general result for the case in which C is any general unital AH-algebra.
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