作用素環セミナー
過去の記録 ~07/02|次回の予定|今後の予定 07/03~
開催情報 | 水曜日 16:30~18:00 数理科学研究科棟(駒場) 122号室 |
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担当者 | 河東 泰之 |
セミナーURL | https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm |
過去の記録
2011年02月18日(金)
10:30-12:00 数理科学研究科棟(駒場) 122号室
Pedram Hekmati 氏 (Univ. Adelaide)
Dirac families and 1-cocycles (ENGLISH)
Pedram Hekmati 氏 (Univ. Adelaide)
Dirac families and 1-cocycles (ENGLISH)
[ 講演概要 ]
Families of Dirac type operators, transforming covariantly under the projective action of the loop group $LG$, determine a class in twisted K-theory on compact Lie groups $G$. The loop group is the gauge group of a principal $G$-bundle over the circle and an interesting problem is to try to generalise the circle to a higher dimensional compact manifold. This is far from obvious and some of the difficulties can be modelled in a slightly simpler setting, by replacing $LG$ and gauge connections by objects which have only small differentiability in the Sobolev sense. In this talk, I will provide some background to this problem and explain how 1-cocycles naturally appear in this construction.
Families of Dirac type operators, transforming covariantly under the projective action of the loop group $LG$, determine a class in twisted K-theory on compact Lie groups $G$. The loop group is the gauge group of a principal $G$-bundle over the circle and an interesting problem is to try to generalise the circle to a higher dimensional compact manifold. This is far from obvious and some of the difficulties can be modelled in a slightly simpler setting, by replacing $LG$ and gauge connections by objects which have only small differentiability in the Sobolev sense. In this talk, I will provide some background to this problem and explain how 1-cocycles naturally appear in this construction.
2011年02月10日(木)
16:30-18:00 数理科学研究科棟(駒場) 122号室
Alan Weinstein 氏 (UC Berkeley)
Symplectic and quantum categories (ENGLISH)
Alan Weinstein 氏 (UC Berkeley)
Symplectic and quantum categories (ENGLISH)
2011年01月28日(金)
14:45-16:15 数理科学研究科棟(駒場) 122号室
勝良健史 氏 (慶応大学)
Semiprojectivity of graph algebras (ENGLISH)
勝良健史 氏 (慶応大学)
Semiprojectivity of graph algebras (ENGLISH)
2011年01月27日(木)
16:30-18:00 数理科学研究科棟(駒場) 122号室
高井博司 氏 (首都大学東京)
Entire Cyclic Cohomology of Noncommutative Riemann Surfaces (JAPANESE)
高井博司 氏 (首都大学東京)
Entire Cyclic Cohomology of Noncommutative Riemann Surfaces (JAPANESE)
2011年01月20日(木)
16:30-18:00 数理科学研究科棟(駒場) 122号室
見村万佐人 氏 (東大数理)
Property (TT)/T and homomorphism rigidity into Out$(F_n)$ (JAPANESE)
見村万佐人 氏 (東大数理)
Property (TT)/T and homomorphism rigidity into Out$(F_n)$ (JAPANESE)
[ 講演概要 ]
講演者の以下のような最近の結果を紹介する:
「$G$を普遍格子SL$_m(Z[x_1,...,x_k])$ ($m$は3以上)または斜交普遍格子Sp$_{2m}(Z[x_1,...,x_k])$ ($m$は2以上)の指数有限の部分群とする ($k$は任意の自然数). このとき, $G$から曲面(コンパクトで向きづけ可能)の写像類群への; または, 有限生成自由群の(外部)自己同型群への準同型は有限の像をもつ.」
証明のキーとなるのが ``性質(TT)/T'' なる群の性質である. (Kazhdanの性質(T)をご存知の方は, それをある方向に強めたものとお考えください. ) この性質にスポットを当てて, 結果の証明のあらすじを説明する.
講演者の以下のような最近の結果を紹介する:
「$G$を普遍格子SL$_m(Z[x_1,...,x_k])$ ($m$は3以上)または斜交普遍格子Sp$_{2m}(Z[x_1,...,x_k])$ ($m$は2以上)の指数有限の部分群とする ($k$は任意の自然数). このとき, $G$から曲面(コンパクトで向きづけ可能)の写像類群への; または, 有限生成自由群の(外部)自己同型群への準同型は有限の像をもつ.」
証明のキーとなるのが ``性質(TT)/T'' なる群の性質である. (Kazhdanの性質(T)をご存知の方は, それをある方向に強めたものとお考えください. ) この性質にスポットを当てて, 結果の証明のあらすじを説明する.
2011年01月18日(火)
16:30-18:00 数理科学研究科棟(駒場) 118号室
Claude-Alain Pillet 氏 (Univ. de Toulon et du Var)
Scattering induced current in a tight binding band (ENGLISH)
Claude-Alain Pillet 氏 (Univ. de Toulon et du Var)
Scattering induced current in a tight binding band (ENGLISH)
2011年01月13日(木)
16:30-18:00 数理科学研究科棟(駒場) 122号室
Robert Coquereaux 氏 (CNRS/CPT)
Global dimensions for fusion categories of type $(G,k)$ (ENGLISH)
Robert Coquereaux 氏 (CNRS/CPT)
Global dimensions for fusion categories of type $(G,k)$ (ENGLISH)
2011年01月11日(火)
16:30-18:00 数理科学研究科棟(駒場) 122号室
Raphael Ponge 氏 (Univ. Tokyo)
Noncommutative geometry and diffeomorphism-invariant geometries (ENGLISH)
Raphael Ponge 氏 (Univ. Tokyo)
Noncommutative geometry and diffeomorphism-invariant geometries (ENGLISH)
2010年12月16日(木)
16:30-18:00 数理科学研究科棟(駒場) 122号室
Marco Merkli 氏 (Memorial Univ. Newfoundland)
Evolution of Quantum Dynamical Systems (ENGLISH)
Marco Merkli 氏 (Memorial Univ. Newfoundland)
Evolution of Quantum Dynamical Systems (ENGLISH)
2010年12月16日(木)
15:15-16:15 数理科学研究科棟(駒場) 122号室
Nicolas Monod 氏 (EPFL)
Fixed point theorems and derivations (ENGLISH)
Nicolas Monod 氏 (EPFL)
Fixed point theorems and derivations (ENGLISH)
2010年12月09日(木)
16:30-18:00 数理科学研究科棟(駒場) 122号室
Ryszard Nest 氏 (Univ. Copenhagen)
Spectral flow associated to KMS states with periodic KMS group action (ENGLISH)
Ryszard Nest 氏 (Univ. Copenhagen)
Spectral flow associated to KMS states with periodic KMS group action (ENGLISH)
2010年11月30日(火)
16:30-18:00 数理科学研究科棟(駒場) 122号室
Yi-Jun Yao 氏 (Fudan Univ.)
Noncommutative geometry and Rankin-Cohen brackets (ENGLISH)
Yi-Jun Yao 氏 (Fudan Univ.)
Noncommutative geometry and Rankin-Cohen brackets (ENGLISH)
2010年11月25日(木)
16:30-18:00 数理科学研究科棟(駒場) 122号室
戸松玲治 氏 (東京理科大)
Kac 環の作用の分類 (JAPANESE)
戸松玲治 氏 (東京理科大)
Kac 環の作用の分類 (JAPANESE)
2010年11月18日(木)
16:30-18:00 数理科学研究科棟(駒場) 122号室
Jean Roydor 氏 (Univ. Tokyo)
Perturbation of dual operator algebras and similarity (ENGLISH)
Jean Roydor 氏 (Univ. Tokyo)
Perturbation of dual operator algebras and similarity (ENGLISH)
2010年11月04日(木)
16:30-18:00 数理科学研究科棟(駒場) 122号室
緒方芳子 氏 (東大数理)
Nonequilibrium Statistical Mechanics (JAPANESE)
緒方芳子 氏 (東大数理)
Nonequilibrium Statistical Mechanics (JAPANESE)
2010年10月28日(木)
16:30-18:00 数理科学研究科棟(駒場) 122号室
山下真 氏 (東大数理)
Type III representations of the infinite symmetric group (ENGLISH)
山下真 氏 (東大数理)
Type III representations of the infinite symmetric group (ENGLISH)
[ 講演概要 ]
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.
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年10月21日(木)
16:30-18:00 数理科学研究科棟(駒場) 122号室
Benoit Collins 氏 (Univ. Ottawa)
Free probability and entropy additivity problems for Quantum information theory (ENGLISH)
Benoit Collins 氏 (Univ. Ottawa)
Free probability and entropy additivity problems for Quantum information theory (ENGLISH)
2010年10月14日(木)
16:30-18:00 数理科学研究科棟(駒場) 122号室
河東泰之 氏 (東大数理)
Nonstandard analysis for operator algebraists (JAPANESE)
河東泰之 氏 (東大数理)
Nonstandard analysis for operator algebraists (JAPANESE)
2010年07月22日(木)
16:30-18:00 数理科学研究科棟(駒場) 128号室
Owen Sizemore 氏 (UCLA)
$W^*$ Rigidity for actions of wreath product groups (ENGLISH)
Owen Sizemore 氏 (UCLA)
$W^*$ Rigidity for actions of wreath product groups (ENGLISH)
[ 講演概要 ]
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.
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年07月15日(木)
16:30-18:00 数理科学研究科棟(駒場) 128号室
小沢登高 氏 (東大数理)
Type II$_1$ von Neumann representations for Hecke operators on Maass forms (after F. Radulescu) (ENGLISH)
小沢登高 氏 (東大数理)
Type II$_1$ von Neumann representations for Hecke operators on Maass forms (after F. Radulescu) (ENGLISH)
2010年07月08日(木)
16:30-18:00 数理科学研究科棟(駒場) 122号室
Dave Penneys 氏 (UC Berkeley)
Killing weeds with annular multiplicities $*10$ via quadratic tangles (ENGLISH)
Dave Penneys 氏 (UC Berkeley)
Killing weeds with annular multiplicities $*10$ via quadratic tangles (ENGLISH)
[ 講演概要 ]
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年07月06日(火)
16:30-18:00 数理科学研究科棟(駒場) 118号室
Robert Sims 氏 (Univ. Arizona)
On the Existence of the Dynamics for Anharmonic Quantum Oscillator Systems (ENGLISH)
Robert Sims 氏 (Univ. Arizona)
On the Existence of the Dynamics for Anharmonic Quantum Oscillator Systems (ENGLISH)
2010年06月24日(木)
16:30-18:00 数理科学研究科棟(駒場) 128号室
Thomas Sinclair 氏 (Vanderbilt Univ.)
Strong solidity of factors from lattices in SO(n,1) and SU(n,1) (ENGLISH)
Thomas Sinclair 氏 (Vanderbilt Univ.)
Strong solidity of factors from lattices in SO(n,1) and SU(n,1) (ENGLISH)
[ 講演概要 ]
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年06月17日(木)
16:30-18:00 数理科学研究科棟(駒場) 128号室
Feng Xu 氏 (UC Riverside)
On a relative version of Wall's conjecture (ENGLISH)
Feng Xu 氏 (UC Riverside)
On a relative version of Wall's conjecture (ENGLISH)
2010年06月10日(木)
16:30-18:00 数理科学研究科棟(駒場) 128号室
Mikael Pichot 氏 (IPMU)
Random groups and nonarchimedean lattices (JAPANESE)
Mikael Pichot 氏 (IPMU)
Random groups and nonarchimedean lattices (JAPANESE)