Semi-regular masas of transfinite length

dc.creatorWhite, Stuart
dc.creatorWiggins, Alan
dc.date2006-11-20
dc.date.accessioned2026-07-07T08:37:50Z
dc.date.available2026-07-07T08:37:50Z
dc.descriptionIn 1965 Tauer produced a countably infinite family of semi-regular masas in the hyperfinite $\mathrm{II}_1$ factor, no pair of which are conjugate by an automorphism. This was achieved by iterating the process of passing to the algebra generated by the normalisers and, for each $n\in\mathbb N$, finding masas for which this procedure terminates at the $n$-th stage. Such masas are said to have length $n$. In this paper we consider a transfinite version of this idea, giving rise to a notion of ordinal valued length. We show that all countable ordinals arise as lengths of semi-regular masas in the hyperfinite $\mathrm{II}_1$ factor. Furthermore, building on work of Jones and Popa, we obtain all possible combinations of regular inclusions of irreducible subfactors in the normalising tower.
dc.description14 pages
dc.identifierhttps://arxiv.org/abs/math/0611615
dc.identifierhttp://arxiv.org/abs/math/0611615
dc.identifierInternat. J. Math. Vol. 18, No. 9 (2007) 995--1007
dc.identifierdoi:10.1142/S0129167X07004424
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/140542
dc.subjectOperator Algebras
dc.subject46L10
dc.titleSemi-regular masas of transfinite length
dc.typetext

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