Abstract
Let be a discrete group acting on a unital -algebra by -automorphisms. We characterize (in terms of the dynamics) when the inclusion has a unique conditional expectation, and when it has a unique pseudoexpectation in the sense of Pitts; we do likewise for the inclusion . As an application, we re-prove (and potentially extend) some known -simplicity results for .
Citation
Vrej Zarikian. "Unique expectations for discrete crossed products." Ann. Funct. Anal. 10 (1) 60 - 71, February 2019. https://doi.org/10.1215/20088752-2018-0008
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