Operator Algebra Seminars

Date, time & place Wednesday 16:30 - 18:00 122Room #122 (Graduate School of Math. Sci. Bldg.)

Seminar information archive

2010/11/30

16:30-18:00   Room #122 (Graduate School of Math. Sci. Bldg.)
Yi-Jun Yao (Fudan Univ.)
Noncommutative geometry and Rankin-Cohen brackets (ENGLISH)

2010/11/25

16:30-18:00   Room #122 (Graduate School of Math. Sci. Bldg.)
Reiji Tomatsu (Tokyo Univ. Science)
Classification of actions of Kac algebras (JAPANESE)

2010/11/18

16:30-18:00   Room #122 (Graduate School of Math. Sci. Bldg.)
Jean Roydor (Univ. Tokyo)
Perturbation of dual operator algebras and similarity (ENGLISH)

2010/11/04

16:30-18:00   Room #122 (Graduate School of Math. Sci. Bldg.)
Yoshiko Ogata (Univ.Tokyo)
Nonequilibrium Statistical Mechanics (JAPANESE)

2010/10/28

16:30-18:00   Room #122 (Graduate School of Math. Sci. Bldg.)
Makoto Yamashita (Univ. Tokyo)
Type III representations of the infinite symmetric group (ENGLISH)
[ Abstract ]
Based on earlier results about the structure of the II$_1$ representations of the infinite symmetric group, we investigate its type III representations and the related inclusion of von Neumann algebras of type III.

2010/10/21

16:30-18:00   Room #122 (Graduate School of Math. Sci. Bldg.)
Benoit Collins (Univ. Ottawa)
Free probability and entropy additivity problems for Quantum information theory (ENGLISH)

2010/10/14

16:30-18:00   Room #122 (Graduate School of Math. Sci. Bldg.)
Yasuyuki Kawahigashi (Univ. Tokyo)
Nonstandard analysis for operator algebraists (JAPANESE)

2010/07/22

16:30-18:00   Room #128 (Graduate School of Math. Sci. Bldg.)
Owen Sizemore (UCLA)
$W^*$ Rigidity for actions of wreath product groups (ENGLISH)
[ Abstract ]
The past 8 years have seen much progress in the classification of
actions of groups on measure spaces. Much of this is due to new powerful
techniques in operator algebras. We will survey some of these results
as well as the new operator algebra techniques. We will then give new
results concerning the classification of actions of wreath product groups.

2010/07/15

16:30-18:00   Room #128 (Graduate School of Math. Sci. Bldg.)
Narutaka Ozawa (Univ. Tokyo)
Type II$_1$ von Neumann representations for Hecke operators on Maass forms (after F. Radulescu) (ENGLISH)

2010/07/08

16:30-18:00   Room #122 (Graduate School of Math. Sci. Bldg.)
Dave Penneys (UC Berkeley)
Killing weeds with annular multiplicities $*10$ via quadratic tangles (ENGLISH)
[ Abstract ]
In recent work with Morrison, Peters, and Snyder, we eliminate two
families of possible principal graphs with graph norms less than 5 using
techniques derived from Jones' work on quadratic tangles.

2010/07/06

16:30-18:00   Room #118 (Graduate School of Math. Sci. Bldg.)
Robert Sims (Univ. Arizona)
On the Existence of the Dynamics for Anharmonic Quantum Oscillator Systems (ENGLISH)

2010/06/24

16:30-18:00   Room #128 (Graduate School of Math. Sci. Bldg.)
Thomas Sinclair (Vanderbilt Univ.)
Strong solidity of factors from lattices in SO(n,1) and SU(n,1) (ENGLISH)
[ Abstract ]
Generalizing techniques found in Ozawa and Popa,
On a class of II$_1$ factors with at most one Cartan subalgebra, II''
(Amer. J. Math., to appear), we show that the group factors of ICC
lattices in SO(n,1) and SU(n,1), $n\\ge2$, are strongly solid. If
time permits, we will also discuss applications to $L^2$-rigidity.

2010/06/17

16:30-18:00   Room #128 (Graduate School of Math. Sci. Bldg.)
Feng Xu (UC Riverside)
On a relative version of Wall's conjecture (ENGLISH)

2010/06/10

16:30-18:00   Room #128 (Graduate School of Math. Sci. Bldg.)
Mikael Pichot (IPMU)
Random groups and nonarchimedean lattices (JAPANESE)

2010/06/03

16:30-18:00   Room #122 (Graduate School of Math. Sci. Bldg.)
Makoto Yamashita (Univ. Tokyo)
Fixed Points in the Stone-Cech boundary of Groups (ENGLISH)
[ Abstract ]
We discuss the class of discrete groups which admit fixed points under the adjoint action on the Stone-Cech boundary. Such groups have vanishing $L^2$-Betti numbers, and nonamenable ones fail to have property (AO).

2010/05/27

16:30-18:00   Room #128 (Graduate School of Math. Sci. Bldg.)
Catherine Oikonomides (Univ. Tokyo)
The C*-algebra of codimension one foliations which are almost without holonomy (ENGLISH)

2010/05/06

16:30-18:00   Room #128 (Graduate School of Math. Sci. Bldg.)
Makoto Yamashita (Univ. Tokyo)
Connes-Landi Deformation of Spectral Triples (ENGLISH)
[ Abstract ]
We describe a way to deform spectral triples with a 2-torus action and a real deformation parameter, motivated by deformation of manifolds after Connes-Landi. Such deformations are shown to have naturally isomorphic K-theoretic invariants independent of the deformation parameter.

2010/04/22

16:30-18:00   Room #128 (Graduate School of Math. Sci. Bldg.)
Nigel Higson (Pennsylvania State Univ.)
The Baum-Connes Conjecture and Group Representations (ENGLISH)
[ Abstract ]
The Baum-Connes conjecture asserts a sort of duality between the reduced unitary dual of a group and (a variant of) the classifying space of the group. The conjectured duality occurs at the level of K-theory. For example, for free abelian groups it amounts to a K-theoretic form of Fourier-Mukai duality. The conjecture has well-known applications in topology and geometry, but it also resonates in various ways with Lie groups and representation theory. I'll try to indicate how this comes about, and then focus on a fairly new aspect of the relationship that develops some early ideas of Mackey.

2010/02/18

16:30-18:00   Room #128 (Graduate School of Math. Sci. Bldg.)
Roberto Longo (University of Rome, Tor Vergata)
Von Neumann Algebras and Boundary Quantum Field Theory

2010/01/21

16:30-18:00   Room #128 (Graduate School of Math. Sci. Bldg.)

On Subfactors Arising from Asymptotic Representations of Symmetric Groups

2010/01/19

16:30-18:00   Room #126 (Graduate School of Math. Sci. Bldg.)

Entire Cyclic Cohomology of Noncommutative Spheres

2010/01/14

16:30-18:00   Room #128 (Graduate School of Math. Sci. Bldg.)
Marius Junge (Univ. Illinois, Urbana-Champaign)
Applications of operator algebras in Quantum information theory

2010/01/07

16:30-18:00   Room #128 (Graduate School of Math. Sci. Bldg.)
Luc Rey-Bellet (Univ. Massachusetts)
Large deviations, Billiards, and Non-equilibrium Statistical Mechanics

2009/12/22

14:40-18:00   Room #128 (Graduate School of Math. Sci. Bldg.)

Symmetric representations of the group of diffeomorphisms of $\\mathbb R$
David Kerr (Texas A&M Univ.) 16:30-18:00
Topological entropy for actions of sofic groups

2009/12/17

16:30-18:00   Room #128 (Graduate School of Math. Sci. Bldg.)

Almost commuting unitaries and ${\\mathbb{Z}}^2$-action