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Orbit equivalence and von Neumann algebras for piecewise linear unimodal maps. (English) Zbl 1131.37007

Summary: We study the orbit equivalence \(R_{f_\alpha}\) of a family of dynamical systems \((I,f_\alpha)\) arising from the tent maps \(f_\alpha\) where \(\alpha\in ]1,2]\). We prove that the associated von Neumann algebra \(L\infty(I)\rtimes R_{f_\alpha}\) is a type III factor whenever \(\alpha\in ]\sqrt 2,2]\) and the orbit of the critical point is periodic.

MSC:

37A20 Algebraic ergodic theory, cocycles, orbit equivalence, ergodic equivalence relations
37B10 Symbolic dynamics
37E05 Dynamical systems involving maps of the interval
46L35 Classifications of \(C^*\)-algebras