Strong Singularity of Singular Masas in II_1 Factors

dc.creatorSinclair, Allan
dc.creatorSmith, Roger
dc.creatorWhite, Stuart
dc.creatorWiggins, Alan
dc.date2006-01-24
dc.date.accessioned2026-07-07T09:57:43Z
dc.date.available2026-07-07T09:57:43Z
dc.descriptionA singular masa $A$ in a $\rm{II}_{1}$ factor $N$ is defined by the property that any unitary $w\in N$ for which $A=wAw^*$ must lie in $A$. A strongly singular masa $A$ is one that satisfies the inequality $$\| E_A- E_{wAw^*}\|_{\infty,2}\geq\|w- E_A(w)\|_2$$ for all unitaries $w\in N$, where $E_A$ is the conditional expectation of $N$ onto $A$, and $\|\cdot\|_{\infty,2}$ is defined for bounded maps $ϕ:N\to N$ by $\sup\{\|ϕ(x)\|_2:x\in N, \|x\|\leq 1\}$. Strong singularity easily implies singularity, and the main result of this paper shows the reverse implication.
dc.description10 pages
dc.identifierhttps://arxiv.org/abs/math/0601594
dc.identifierhttp://arxiv.org/abs/math/0601594
dc.identifierIllinois J. Math. 51 (4) 2007, 1077-1084
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/167449
dc.subjectOperator Algebras
dc.subject46L10
dc.titleStrong Singularity of Singular Masas in II_1 Factors
dc.typetext

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