Informal von Neumann Algebras Seminar
Fall 2009

• Date: 8/31/09
  • Jesse Peterson, Vanderbilt University
  • Title: U_fin-cocycle superrigidity (after Popa) I

• Date: 9/7/09
  • Jesse Peterson, Vanderbilt University
  • Title: U_fin-cocycle superrigidity (after Popa) II

• Date: 9/14/09
  • Jesse Peterson, Vanderbilt University
  • Title: U_fin-cocycle superrigidity (after Popa) III

• Date: 9/21/09
  • Thomas Sinclair, Vanderbilt University
  • Title: An inner amenable group whose von Neumann algebra does not have property Gamma (after Vaes)
  • Abstract: Property Gamma was invented by Murray and von Neumann in order to establish the existence non-isomorphic II_1 factors. Effros later described a property of groups, inner amenability, which he showed is implied by the group von Neumann algebra possessing property Gamma. Effros conjectured that the converse was true.
    In this talk I will describe the recent construction by Stefaan Vaes of an inner amenable group whose group von Neumann algebra does not have property Gamma, settling Effros's conjecture in the negative.

• Date: 9/28/09
  • Ionut Chifan, Vanderbilt University
  • Title: W*-superrigidity (after Popa, Vaes) I

• Date: 10/5/09
  • No Seminar.

• Date: 10/12/09
  • Ionut Chifan, Vanderbilt University
  • Title: W*-superrigidity (after Popa, Vaes) II

• Date: 10/19/09
  • Cornel Pasnicu, University of Puerto Rico
  • Title: Continuous fields of Kirchberg C*-algebras
  • Abstract: In this talk we willl study the separable C*-algebras associated to continuous fields over locally compact metrizable zero-dimensional spaces whose fibers are Kirchberg C*algebras satisfying the UCT. We will show that these algebras are inductive limits of finite direct sums of Kirchberg algebras and they are classified up to isomorphism by topological invariants. This is a joint work with Marius Dadarlat, published in the J. Funct. Anal. (2005).

• Date: 10/26/09
  • Ionut Chifan, Vanderbilt University
  • Title: W*-superrigidity (after Popa, Vaes) III

• Date: 11/2/09
  • Ionut Chifan, Vanderbilt University
  • Title: W*-superrigidity (after Popa, Vaes) IV

• Date: 11/9/09
  • No Seminar. Special Session on Operator Algebras, AMS Sectional Meeting, at UC Riverside.

• Date: 11/16/09
  • Richard Burstein, Vanderbilt University
  • Title: Central sequences and s-McDuff factors, I
  • Abstract: I will discuss a recent paper of Popa, in which he constructs examples of subfactors with trivial chi invariant which are not s-McDuff. My first talk will deal primarily with the technical machinery needed to describe these examples, namely ultrafilters and central sequences.

• Date: 11/23/09
  • No Meeting, Thanksgiving Break.

• Date: 11/30/09
  • Richard Burstein, Vanderbilt University
  • Title: Central sequences and s-McDuff factors, II

• Date: 12/7/09
  • Richard Burstein, Vanderbilt University
  • Title: Central sequences and s-McDuff factors, III

• End of Fall Semester.