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Operator Algebra Seminars
Seminar information archive ～09/18｜Next seminar｜Future seminars 09/19～
| Date, time & place | Wednesday 16:30 - 18:00 122Room #122 (Graduate School of Math. Sci. Bldg.) |
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Seminar information archive
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)
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.
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)
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)
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.
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)
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)
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)
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).
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)
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)
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.
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)
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.
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
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.)
山下真 (東大数理)
On Subfactors Arising from Asymptotic Representations of Symmetric Groups
山下真 (東大数理)
On Subfactors Arising from Asymptotic Representations of Symmetric Groups
2010/01/19
16:30-18:00 Room #126 (Graduate School of Math. Sci. Bldg.)
高井博司 (首都大学東京)
Entire Cyclic Cohomology of Noncommutative Spheres
高井博司 (首都大学東京)
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
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
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.)
谷本溶 (Univ. Roma ``Tor Vergata'') 14:40-16:10
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
谷本溶 (Univ. Roma ``Tor Vergata'') 14:40-16:10
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.)
佐藤康彦 (北海道大理)
Almost commuting unitaries and ${\\mathbb{Z}}^2$-action
佐藤康彦 (北海道大理)
Almost commuting unitaries and ${\\mathbb{Z}}^2$-action
2009/12/10
16:30-18:00 Room #128 (Graduate School of Math. Sci. Bldg.)
張欽 (東大数理)
Symmetric norms and spaces of operators modelled on a semifinite von Neumann algebra
張欽 (東大数理)
Symmetric norms and spaces of operators modelled on a semifinite von Neumann algebra
2009/12/03
16:30-18:00 Room #128 (Graduate School of Math. Sci. Bldg.)
見村万佐人 (東大数理)
Vanishing of quasi-homomorphisms and the stable commutator
lengths on special linear groups over euclidean rings
見村万佐人 (東大数理)
Vanishing of quasi-homomorphisms and the stable commutator
lengths on special linear groups over euclidean rings
2009/11/12
16:30-18:00 Room #128 (Graduate School of Math. Sci. Bldg.)
酒匂宏樹 (東大数理)
Recent results for amalgamated free products of type II$_1$ factors
酒匂宏樹 (東大数理)
Recent results for amalgamated free products of type II$_1$ factors
2009/10/29
16:30-18:00 Room #128 (Graduate School of Math. Sci. Bldg.)
Robert Coquereaux (CNRS/CPT, Marseille)
Fusion graphs for Lie groups at level k and quantum symmetries
Robert Coquereaux (CNRS/CPT, Marseille)
Fusion graphs for Lie groups at level k and quantum symmetries
2009/10/22
16:30-18:00 Room #128 (Graduate School of Math. Sci. Bldg.)
Adam Skalski (Lancaster University)
On some questions related to Voiculescu's noncommutative topological entropy
Adam Skalski (Lancaster University)
On some questions related to Voiculescu's noncommutative topological entropy
2009/09/07
17:00-18:30 Room #056 (Graduate School of Math. Sci. Bldg.)
Marek Bozejko (University of Wroclaw)
Generalized Gaussian field, theta function of Jacobi and functor of second quantization
Marek Bozejko (University of Wroclaw)
Generalized Gaussian field, theta function of Jacobi and functor of second quantization
2009/07/23
16:30-18:00 Room #056 (Graduate School of Math. Sci. Bldg.)
Catherine Oikonomides (慶応大理工)
Cyclic cohomology and the Novikov conjecture
Catherine Oikonomides (慶応大理工)
Cyclic cohomology and the Novikov conjecture
2009/07/16
16:30-18:00 Room #056 (Graduate School of Math. Sci. Bldg.)
Ingo Runkel (King's College London)
Algebraic structures in conformal field theory
Ingo Runkel (King's College London)
Algebraic structures in conformal field theory
[ Abstract ]
It turned out to be fruitful to isolate questions in CFT which can be formulated in a purely categorical fashion. The way left and right moving degrees of freedom can be combined to a consistent theory is an example of this, the relevant structure being a commutative symmetric Frobenius algebra. This is true independently of whether CFT is formulated via sewing of surfaces or nets of operator algebras. Another example is modular invariance, which has a surprising alternative formulation as a certain maximality condition.
It turned out to be fruitful to isolate questions in CFT which can be formulated in a purely categorical fashion. The way left and right moving degrees of freedom can be combined to a consistent theory is an example of this, the relevant structure being a commutative symmetric Frobenius algebra. This is true independently of whether CFT is formulated via sewing of surfaces or nets of operator algebras. Another example is modular invariance, which has a surprising alternative formulation as a certain maximality condition.
2009/07/09
16:30-18:00 Room #056 (Graduate School of Math. Sci. Bldg.)
Mikael Pichot (東大数物連携宇宙研究機構)
Examples of groups of intermediate rank
Mikael Pichot (東大数物連携宇宙研究機構)
Examples of groups of intermediate rank
