Factors from trees

Ramagge, Jacqui; Robertson, Guyan

doi:10.1090/S0002-9939-97-03818-5

Factors from trees
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by Jacqui Ramagge and Guyan Robertson PDF

Proc. Amer. Math. Soc. 125 (1997), 2051-2055 Request permission

Abstract:

We construct factors of type $\mathrm {III}_{1/n}$ for $n\in \mathbb {N}$, $n\geq 2$, from group actions on homogeneous trees and their boundaries. Our result is a discrete analogue of a result of R.J Spatzier, where the hyperfinite factor of type $\mathrm {III}_1$ is constructed from a group action on the boundary of the universal cover of a manifold.

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