Text only print
Full screen print
Seminar information archive
Seminar information archive ～09/18｜Today's seminar 09/19 | Future seminars 09/20～
Operator Algebra Seminars
16:45-18:15 Online
Yoshimichi Ueda (Nagoya Univ.)
On Arveson's boundary theorem (English)
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
Yoshimichi Ueda (Nagoya Univ.)
On Arveson's boundary theorem (English)
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
2020/06/17
Number Theory Seminar
17:30-18:30 Online
Christophe Breuil (CNRS, Université Paris-Sud)
On modular representations of GL_2(L) for unramified L (ENGLISH)
https://www.ms.u-tokyo.ac.jp/~t-saito/todai_IHES.html
Christophe Breuil (CNRS, Université Paris-Sud)
On modular representations of GL_2(L) for unramified L (ENGLISH)
[ Abstract ]
Let p be a prime number and L a finite unramified extension of Q_p. We give a survey of past and new results on smooth admissible representations of GL_2(L) that appear in mod p cohomology. This is joint work with Florian Herzig, Yongquan Hu, Stefano Morra and Benjamin Schraen.
[ Reference URL ]Let p be a prime number and L a finite unramified extension of Q_p. We give a survey of past and new results on smooth admissible representations of GL_2(L) that appear in mod p cohomology. This is joint work with Florian Herzig, Yongquan Hu, Stefano Morra and Benjamin Schraen.
https://www.ms.u-tokyo.ac.jp/~t-saito/todai_IHES.html
2020/06/11
Operator Algebra Seminars
16:45-18:15 Online
Makoto Yamashita (Univ. Oslo)
Homology and K-theory of torsion free ample groupoids and Smale spaces (English)
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
Makoto Yamashita (Univ. Oslo)
Homology and K-theory of torsion free ample groupoids and Smale spaces (English)
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
Information Mathematics Seminar
16:50-18:35 Online
Hiroshi Fujiwara (BroadBand Tower, Inc.)
Big picture of the modern AI and Machine learning in the basics (Japanese)
[学外用] https://docs.google.com/forms/d/1d1RWvV8j1TzXg8eF93zMZeIzJeIvdq9zY8htO8w2St0/ [学内用] https://bit.ly/2zCBj8x (g.ecc.u-tokyo.ac.jpアカウントでアクセスできます)
Hiroshi Fujiwara (BroadBand Tower, Inc.)
Big picture of the modern AI and Machine learning in the basics (Japanese)
[ Abstract ]
Explanation of the modern AI and Machine learning
[ Reference URL ]Explanation of the modern AI and Machine learning
[学外用] https://docs.google.com/forms/d/1d1RWvV8j1TzXg8eF93zMZeIzJeIvdq9zY8htO8w2St0/ [学内用] https://bit.ly/2zCBj8x (g.ecc.u-tokyo.ac.jpアカウントでアクセスできます)
2020/06/08
Seminar on Geometric Complex Analysis
10:30-12:00 Online
HASHIMOTO Yoshinori (Tokyo Institute of Technology)
Applications of the Quot-scheme limit to variational aspects of the Hermitian-Einstein metric
https://forms.gle/vSFPoVR6ugrkTGhX7
HASHIMOTO Yoshinori (Tokyo Institute of Technology)
Applications of the Quot-scheme limit to variational aspects of the Hermitian-Einstein metric
[ Abstract ]
The Kobayashi-Hitchin correspondence, proved by Donaldson and Uhlenbeck-Yau by using the nonlinear PDE theory, states that the existence of Hermitian-Einstein metrics on a holomorphic vector bundle is equivalent to an algebro-geometric stability condition. We present some results that exhibit an explicit link between differential and algebraic geometry in the above correspondence, from a variational point of view. The key to such results is an object called the Quot-scheme limit of Fubini-Study metrics, which is used to evaluate certain algebraic 1-parameter subgroups of Hermitian metrics by using the theory of Quot-schemes in algebraic geometry. This method also works for the proof of the correspondence between the balanced metrics and the Gieseker stability, as originally proved by X.W. Wang. Joint work with Julien Keller.
[ Reference URL ]The Kobayashi-Hitchin correspondence, proved by Donaldson and Uhlenbeck-Yau by using the nonlinear PDE theory, states that the existence of Hermitian-Einstein metrics on a holomorphic vector bundle is equivalent to an algebro-geometric stability condition. We present some results that exhibit an explicit link between differential and algebraic geometry in the above correspondence, from a variational point of view. The key to such results is an object called the Quot-scheme limit of Fubini-Study metrics, which is used to evaluate certain algebraic 1-parameter subgroups of Hermitian metrics by using the theory of Quot-schemes in algebraic geometry. This method also works for the proof of the correspondence between the balanced metrics and the Gieseker stability, as originally proved by X.W. Wang. Joint work with Julien Keller.
https://forms.gle/vSFPoVR6ugrkTGhX7
2020/06/05
Colloquium
15:30-16:30 Online
Please register at the link below to attend this online colloquium
Kohei Iwaki (Graduate School of Mathematical Sciences, University of Tokyo)
Exact WKB analysis and related topics
https://zoom.us/webinar/register/WN_ezXY3HjIQcCK2G9V-2CYrw
Please register at the link below to attend this online colloquium
Kohei Iwaki (Graduate School of Mathematical Sciences, University of Tokyo)
Exact WKB analysis and related topics
[ Abstract ]
Exact WKB analysis, developed by Voros et.al., is an effective method for global study of (singularly perturbed) ordinary differential equations defined on a complex domain. After recalling several fundamental facts on exact WKB analysis, I'll talk about relationships to other research topics, such as cluster algebras, topological recursion, integrable systems of Painlevé type, etc.
[ Reference URL ]Exact WKB analysis, developed by Voros et.al., is an effective method for global study of (singularly perturbed) ordinary differential equations defined on a complex domain. After recalling several fundamental facts on exact WKB analysis, I'll talk about relationships to other research topics, such as cluster algebras, topological recursion, integrable systems of Painlevé type, etc.
https://zoom.us/webinar/register/WN_ezXY3HjIQcCK2G9V-2CYrw
2020/06/04
Operator Algebra Seminars
16:45-18:15 Online
Yuhei Suzuki (Hokkaido Univ.)
Equivariant $O_2$-absorption theorem for exact groups
Yuhei Suzuki (Hokkaido Univ.)
Equivariant $O_2$-absorption theorem for exact groups
Information Mathematics Seminar
16:50-18:35 Online
Hiroshi Fujiwara (BroadBand Tower, Inc.)
Telework society and importance of the cyber security to increase
Hiroshi Fujiwara (BroadBand Tower, Inc.)
Telework society and importance of the cyber security to increase
[ Abstract ]
Explanation on telework society and importance of the cyber security
Explanation on telework society and importance of the cyber security
2020/05/28
Operator Algebra Seminars
16:45-18:15 Online
Yosuke Kubota (Shinshu Univ.)
Index theorem of lattice Wilson-Dirac operators and almost-commuting matrices (English)
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
Yosuke Kubota (Shinshu Univ.)
Index theorem of lattice Wilson-Dirac operators and almost-commuting matrices (English)
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
2020/05/27
Number Theory Seminar
17:30-18:30 Online
Kenichi Bannai (Keio University/RIKEN)
Shintani generating class and the p-adic polylogarithm for totally real fields (ENGLISH)
https://www.ms.u-tokyo.ac.jp/~t-saito/todai_IHES.html
Kenichi Bannai (Keio University/RIKEN)
Shintani generating class and the p-adic polylogarithm for totally real fields (ENGLISH)
[ Abstract ]
In this talk, we will give a new interpretation of Shintani's work concerning the generating function of nonpositive values of Hecke $L$-functions for totally real fields. In particular, we will construct a canonical class, which we call the Shintani generating class, in the cohomology of a certain quotient stack of an infinite direct sum of algebraic tori associated with a fixed totally real field. Using our observation that cohomology classes, not functions, play an important role in the higher dimensional case, we proceed to newly define the p-adic polylogarithm function in this case, and investigate its relation to the special value of p-adic Hecke $L$-functions. Some observations concerning the quotient stack will also be discussed. This is a joint work with Kei Hagihara, Kazuki Yamada, and Shuji Yamamoto.
[ Reference URL ]In this talk, we will give a new interpretation of Shintani's work concerning the generating function of nonpositive values of Hecke $L$-functions for totally real fields. In particular, we will construct a canonical class, which we call the Shintani generating class, in the cohomology of a certain quotient stack of an infinite direct sum of algebraic tori associated with a fixed totally real field. Using our observation that cohomology classes, not functions, play an important role in the higher dimensional case, we proceed to newly define the p-adic polylogarithm function in this case, and investigate its relation to the special value of p-adic Hecke $L$-functions. Some observations concerning the quotient stack will also be discussed. This is a joint work with Kei Hagihara, Kazuki Yamada, and Shuji Yamamoto.
https://www.ms.u-tokyo.ac.jp/~t-saito/todai_IHES.html
2020/05/25
Seminar on Geometric Complex Analysis
10:30-12:00 Online
MARUGAME Taiji (Riken AIP - Osaka University)
Characteristic forms of Cheng-Yau metric and CR invariants
[ Reference URL ]
https://forms.gle/vSFPoVR6ugrkTGhX7
MARUGAME Taiji (Riken AIP - Osaka University)
Characteristic forms of Cheng-Yau metric and CR invariants
[ Reference URL ]
https://forms.gle/vSFPoVR6ugrkTGhX7
2020/05/21
Information Mathematics Seminar
16:50-18:35 Online
Hiroshi Fujiwara (BroadBand Tower, Inc.)
From the birth of the computer to further speedup of the calculation speed
(Japanese)
https://docs.google.com/forms/d/1d1RWvV8j1TzXg8eF93zMZeIzJeIvdq9zY8htO8w2St0/
Hiroshi Fujiwara (BroadBand Tower, Inc.)
From the birth of the computer to further speedup of the calculation speed
(Japanese)
[ Abstract ]
Explanation of the birth of computer and the further speedup of calculation speed
[ Reference URL ]Explanation of the birth of computer and the further speedup of calculation speed
https://docs.google.com/forms/d/1d1RWvV8j1TzXg8eF93zMZeIzJeIvdq9zY8htO8w2St0/
Operator Algebra Seminars
16:45-18:15 Online
Takuya Takeishi (Kyoto Institute of Technology)
Partition functions as $C^*$-dynamical invariants and actions of congruence monoids (English)
Takuya Takeishi (Kyoto Institute of Technology)
Partition functions as $C^*$-dynamical invariants and actions of congruence monoids (English)
2020/05/18
Seminar on Geometric Complex Analysis
10:30-12:00 Online
KASUYA Hisashi (Osaka University)
Higgs bundles and flat connections over compact Sasakian manifolds
https://forms.gle/vSFPoVR6ugrkTGhX7
KASUYA Hisashi (Osaka University)
Higgs bundles and flat connections over compact Sasakian manifolds
[ Abstract ]
It is known that on a compact Kähler manifold, there is a correspondence between semisimple flat vector bundles and polystable higgs bundles with vanishing Chern classes via harmonic metrics (Simpson-Corlette). The purpose of this talk is to give the Sasakian (odd dimensional analogue of Kähler geometry) version of this correspondence. We prove that on a compact Sasakian manifold, there is an correspondence between semisimple flat vector bundles and the polystable basic Higgs bundles with vanishing basic Chern classes. (Joint work with Indranil Biswas, arXiv:1905.06178)
[ Reference URL ]It is known that on a compact Kähler manifold, there is a correspondence between semisimple flat vector bundles and polystable higgs bundles with vanishing Chern classes via harmonic metrics (Simpson-Corlette). The purpose of this talk is to give the Sasakian (odd dimensional analogue of Kähler geometry) version of this correspondence. We prove that on a compact Sasakian manifold, there is an correspondence between semisimple flat vector bundles and the polystable basic Higgs bundles with vanishing basic Chern classes. (Joint work with Indranil Biswas, arXiv:1905.06178)
https://forms.gle/vSFPoVR6ugrkTGhX7
2020/05/14
Operator Algebra Seminars
16:45-18:15 Online
Yusuke Isono (RIMS, Kyoto Univ.)
Connes' bicentralizer problem for q-deformed Araki-Woods algebras (English)
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
Yusuke Isono (RIMS, Kyoto Univ.)
Connes' bicentralizer problem for q-deformed Araki-Woods algebras (English)
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
Information Mathematics Seminar
16:50-18:35 Online
Hiroshi Fujiwara (BroadBand Tower, Inc.)
The past, the present, the future of the AI that a practical use stage began (Japanese)
Hiroshi Fujiwara (BroadBand Tower, Inc.)
The past, the present, the future of the AI that a practical use stage began (Japanese)
[ Abstract ]
The explanation on the past, the present, the future of the AI that a practical use stage began
The explanation on the past, the present, the future of the AI that a practical use stage began
2020/05/13
Number Theory Seminar
17:30-18:30 Online
Yifeng Liu (Yale University)
On the Beilinson-Bloch-Kato conjecture for Rankin-Selberg motives (ENGLISH)
https://www.ms.u-tokyo.ac.jp/~t-saito/todai_IHES.html
Yifeng Liu (Yale University)
On the Beilinson-Bloch-Kato conjecture for Rankin-Selberg motives (ENGLISH)
[ Abstract ]
In this talk, we will explain the final outcome on the Beilinson-Bloch-Kato conjecture for motives coming from certain automorphic representations of GL(n) x GL(n+1), of our recent project with Yichao Tian, Liang Xiao, Wei Zhang, and Xinwen Zhu. In particular, we show that the nonvanishing of the central L-value of the motive implies the vanishing of the corresponding Bloch-Kato Selmer group. We will also explain the main ideas and ingredients of the proof.
[ Reference URL ]In this talk, we will explain the final outcome on the Beilinson-Bloch-Kato conjecture for motives coming from certain automorphic representations of GL(n) x GL(n+1), of our recent project with Yichao Tian, Liang Xiao, Wei Zhang, and Xinwen Zhu. In particular, we show that the nonvanishing of the central L-value of the motive implies the vanishing of the corresponding Bloch-Kato Selmer group. We will also explain the main ideas and ingredients of the proof.
https://www.ms.u-tokyo.ac.jp/~t-saito/todai_IHES.html
2020/05/07
Information Mathematics Seminar
16:50-18:35 Room #Zoom（詳細は講演概要に記載） (Graduate School of Math. Sci. Bldg.)
Hiroshi Fujiwara (BroadBand Tower, Inc.)
"Who are we? Where have we come from? Where are we?
Where will we go? What is the role of the mathematical science?"
～To establish of the new academic system by the basic theory regression
type approach and the social problem solving type approach～
(Japanese)
Hiroshi Fujiwara (BroadBand Tower, Inc.)
"Who are we? Where have we come from? Where are we?
Where will we go? What is the role of the mathematical science?"
～To establish of the new academic system by the basic theory regression
type approach and the social problem solving type approach～
(Japanese)
Operator Algebra Seminars
16:45-18:15 Online
Mayuko Yamashita (RIMS, Kyoto Univ.)
A new construction of deformation quantization for Lagrangian fiber bundles (English)
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
Mayuko Yamashita (RIMS, Kyoto Univ.)
A new construction of deformation quantization for Lagrangian fiber bundles (English)
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
2020/05/01
Seminar on Probability and Statistics
17:00-18:10 Room #φ (Graduate School of Math. Sci. Bldg.)
Xiao Fang (Chinese University of Hong Kong)
High order distributional approximations by Stein's method (ENGLISH)
https://docs.google.com/forms/d/e/1FAIpQLSeSVwYsjhyQQXzjt3ZpvRh9ZEO5qZXxxLxYDYOu301Mc89RCA/viewform
Xiao Fang (Chinese University of Hong Kong)
High order distributional approximations by Stein's method (ENGLISH)
[ Abstract ]
Stein's method is a powerful tool to proving distributional approximations with error bounds. In this talk, we present two recent developments of Stein's method for high order approximations. (1) Together with Li Luo and Qi-Man Shao, we consider skewness correction in normal approximation. We prove a refined Cram¥'er-type moderate deviation result for a class of statistics possessing a local structure. We discuss applications to k-runs, U-statistics and subgraph counts. (2) Together with Anton Braverman and Jim Dai, we derive and justify new diffusion approximations with state-dependent diffusion coefficients for stationary distributions of Markov chains. We discuss applications to the Erlang-C system, a hospital inpatient flow model and the auto-regressive model.
[ Reference URL ]Stein's method is a powerful tool to proving distributional approximations with error bounds. In this talk, we present two recent developments of Stein's method for high order approximations. (1) Together with Li Luo and Qi-Man Shao, we consider skewness correction in normal approximation. We prove a refined Cram¥'er-type moderate deviation result for a class of statistics possessing a local structure. We discuss applications to k-runs, U-statistics and subgraph counts. (2) Together with Anton Braverman and Jim Dai, we derive and justify new diffusion approximations with state-dependent diffusion coefficients for stationary distributions of Markov chains. We discuss applications to the Erlang-C system, a hospital inpatient flow model and the auto-regressive model.
https://docs.google.com/forms/d/e/1FAIpQLSeSVwYsjhyQQXzjt3ZpvRh9ZEO5qZXxxLxYDYOu301Mc89RCA/viewform
2020/04/30
Operator Algebra Seminars
16:45-18:15 Online
Felix Parraud (ENS Lyon)
Interpolation between random matrices and their free limit with the help of free stochastic processes (English)
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
Felix Parraud (ENS Lyon)
Interpolation between random matrices and their free limit with the help of free stochastic processes (English)
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
2020/04/23
Operator Algebra Seminars
16:45-18:15 Online
Michiya Mori (Univ. Tokyo)
Lattice isomorphisms between projection lattices of von Neumann algebras
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
Michiya Mori (Univ. Tokyo)
Lattice isomorphisms between projection lattices of von Neumann algebras
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
2020/04/22
Number Theory Seminar
17:30-18:30 Online
Arthur-César Le Bras (CNRS & Université Paris 13)
Prismatic Dieudonné theory (ENGLISH)
Arthur-César Le Bras (CNRS & Université Paris 13)
Prismatic Dieudonné theory (ENGLISH)
[ Abstract ]
I would like to explain a classification result for p-divisible groups, which unifies many of the existing results in the literature. The main tool is the theory of prisms and prismatic cohomology recently developed by Bhatt and Scholze. This is joint work with Johannes Anschütz.
I would like to explain a classification result for p-divisible groups, which unifies many of the existing results in the literature. The main tool is the theory of prisms and prismatic cohomology recently developed by Bhatt and Scholze. This is joint work with Johannes Anschütz.
2020/04/16
Seminar on Probability and Statistics
17:00-18:10 Room #φ (Graduate School of Math. Sci. Bldg.)
Masatoshi Goda (University of Tokyo)
Hawkes process and Edgeworth expansion with application to Maximum Likelihood Estimator (JAPANESE)
https://docs.google.com/forms/d/18MDagC71CtB7SJmW2s0tPIBW9YDUNWH5XH1uby2W6Xc/edit
Masatoshi Goda (University of Tokyo)
Hawkes process and Edgeworth expansion with application to Maximum Likelihood Estimator (JAPANESE)
[ Abstract ]
The Hawkes process is a point process with a self-exciting property. It has been used to model earthquakes, social media events, infections, etc. and is getting a lot of attention. However, as a real problem, there are often situations where we can not obtain data with sufficient observation time. In such cases, it is not appropriate to approximate the error distribution of an estimator by the normal distribution. We established the Edgeworth expansion for a functional of a geometric mixing process, and applied this scheme to a functional of the Hawkes process with an exponential kernel. Furthermore, we gave a more appropriate asymptotic distribution for the error of the Maximum Likelihood Estimator of the Hawks process, i.e. a higher-order asymptotic distribution than the normal distribution. Here, in addition to the details of these statements, we also present the simulation results.
[ Reference URL ]The Hawkes process is a point process with a self-exciting property. It has been used to model earthquakes, social media events, infections, etc. and is getting a lot of attention. However, as a real problem, there are often situations where we can not obtain data with sufficient observation time. In such cases, it is not appropriate to approximate the error distribution of an estimator by the normal distribution. We established the Edgeworth expansion for a functional of a geometric mixing process, and applied this scheme to a functional of the Hawkes process with an exponential kernel. Furthermore, we gave a more appropriate asymptotic distribution for the error of the Maximum Likelihood Estimator of the Hawks process, i.e. a higher-order asymptotic distribution than the normal distribution. Here, in addition to the details of these statements, we also present the simulation results.
https://docs.google.com/forms/d/18MDagC71CtB7SJmW2s0tPIBW9YDUNWH5XH1uby2W6Xc/edit
Operator Algebra Seminars
16:45-18:15 Online
Cyril Houdayer (Univ. Paris-Sud)
Structure theorem for unitary representations of irreducible lattices in product groups
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
Cyril Houdayer (Univ. Paris-Sud)
Structure theorem for unitary representations of irreducible lattices in product groups
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
< Previous 123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189 Next >
