74 citations · 76 across the 5 of their papers we have counts for
6 papers
On the Notion of Relative Property (T) for Inclusions of Von Neumann Algebras
Jesse Peterson, Sorin Popa
We prove that the notion of relative property (T) (or rigidity) for inclusions of finite von Neumann algebras defined in [Po1] is equivalent to a weaker property, in which no ``con…
A Unique Decomposition Result for HT Factors with Torsion Free Core
Sorin Popa
We prove that II factors have a unique (up to unitary conjugacy) cross-product type decomposition around ``core subfactors'' satisfying the property HT and a…
Perturbations of Subalgebras of Type Factors
Sorin Popa, Allan Sinclair, Roger Smith
We consider two von Neumann subalgebras $\cl B_0$ and $\cl B$ of a type factor $\cl N$. For a map on $\cl N$, we define \[\|ϕ\|_{\infty,2}=\sup\{\|ϕ(x)\|_2\colon…
On the Fundamental Group of Type II Factors
Sorin Popa
We present here a shorter version of the proof of a result from our paper ``On a class of type II factors with Betti numbers invariants'', showing that the von Neumann factor a…
On a Class of Type II Factors with Betti Numbers Invariants
Sorin Popa
We prove that a type II factor can have at most one Cartan subalgebra satisfying a combination of rigidity and compact approximation properties. We use this result to s…
Examples of subfactors with property T standard invariant
Dietmar Bisch, Sorin Popa
Let H and K be two finite groups with a properly outer action on the II_1 factor M. We prove that the group type inclusions , studied earlier by Bisch and…