Abstract. It is shown that topological freeness of Rieffel's induced representation functor implies that any C * -algebra generated by a faithful covariant representation of a Hilbert bimodule X over a C * -algebra A is canonically isomorphic to the crossed product A ⋊ X Z. An ideal lattice description and a simplicity criterion for A ⋊ X Z are established.
IntroductionThe topological freeness is a condition expressed in terms of the dual system allowing to relate the ideal structure of the crossed product to that of the original algebra. In particular, it implies that every faithful representation of the C * -dynamical system integrates to a faithful representation of the reduced crossed product. The idea behind this notion probably goes back to works of W. Arveson in late 60's of XX century, and for the first time was explicitly formulated by D. [12, Thm. 3.7].In the present paper we prove a statement that generalizes all the aforementioned theorems in the case G = Z and which is formulated in terms of the crossed product A ⋊ X Z, introduced in [1], of a Hilbert bimodule X. Thus potentially, by passing to the core C * -algebra, see [1, Thm. 3.1], it may be applied to all the C * -algebras equipped with a semi-saturated circle action and thereby to all relative CuntzPimsner algebras [13]. As a corollary of our main result we provide an ideal lattice description (in the case the dual system is free) and a simplicity criterion for the algebras considered.Conventions. In essence we follow the notation and conventions adopted in [1]. For maps γ : A × B → C such as inner products, multiplications or representations we denote by γ(A, B) the closed linear span of the set {γ(a, b) ∈ C : a ∈ A, b ∈ B}. An ideal in a C * -algebra is a closed two-sided one, and [π] stands for the unitary equivalence class of a representation π.2010 Mathematics Subject Classification. Primary 46L08, Secondary 46L55.