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Seminar information archive
Seminar information archive ～12/08｜Today's seminar 12/09 | Future seminars 12/10～
2021/04/22
Tokyo-Nagoya Algebra Seminar
16:00-17:30 Online
Please see the URL below for details on the online seminar.
Julian Külshammer (Uppsala University)
Exact categories via A-infinity algebras (English)
http://www.math.nagoya-u.ac.jp/~aaron.chan/TNAseminar.html
Please see the URL below for details on the online seminar.
Julian Külshammer (Uppsala University)
Exact categories via A-infinity algebras (English)
[ Abstract ]
Many instances of extension closed subcategories appear throughout representation theory, e.g. filtered modules, Gorenstein projectives, as well as modules of finite projective dimension. In the first part of the talk, I will outline a general strategy to realise such subcategories as categories of induced modules from a subalgebra using A-infinity algebras. In the second part, I will describe how this strategy has been successfully applied for the exact category of filtered modules over a quasihereditary algebra. In particular I will present compatibility results of this approach with heredity ideals in a quasihereditary algebra from joint work with Teresa Conde.
[ Reference URL ]Many instances of extension closed subcategories appear throughout representation theory, e.g. filtered modules, Gorenstein projectives, as well as modules of finite projective dimension. In the first part of the talk, I will outline a general strategy to realise such subcategories as categories of induced modules from a subalgebra using A-infinity algebras. In the second part, I will describe how this strategy has been successfully applied for the exact category of filtered modules over a quasihereditary algebra. In particular I will present compatibility results of this approach with heredity ideals in a quasihereditary algebra from joint work with Teresa Conde.
http://www.math.nagoya-u.ac.jp/~aaron.chan/TNAseminar.html
Applied Analysis
16:30-18:00 Online
( )
Relaxation of Optimal Transport problem on finite state space via Bregman divergence (Japanese)
[ Reference URL ]
https://forms.gle/yg9XZDVdxYG6qMos8
( )
Relaxation of Optimal Transport problem on finite state space via Bregman divergence (Japanese)
[ Reference URL ]
https://forms.gle/yg9XZDVdxYG6qMos8
Information Mathematics Seminar
16:50-18:35 Online
Hiroshi Fujiwara (BroadBand Tower, Inc.)
Look back on the half life of a challenge to Digital technology and Entrepreneurship (Japanese)
https://docs.google.com/forms/d/1zdmPdHWcVgH6Sn62nVHNp0ODVBJ7fyHKJHdABtDd_Tw
Hiroshi Fujiwara (BroadBand Tower, Inc.)
Look back on the half life of a challenge to Digital technology and Entrepreneurship (Japanese)
[ Abstract ]
Recollection on the half life of a challenge to Digital technology and Entrepreneurship
[ Reference URL ]Recollection on the half life of a challenge to Digital technology and Entrepreneurship
https://docs.google.com/forms/d/1zdmPdHWcVgH6Sn62nVHNp0ODVBJ7fyHKJHdABtDd_Tw
2021/04/21
Algebraic Geometry Seminar
15:00-16:00 Room #ZOOM (Graduate School of Math. Sci. Bldg.)
Masafumi Hattori (Kyoto)
A decomposition formula for J-stability and its applications (日本語)
Masafumi Hattori (Kyoto)
A decomposition formula for J-stability and its applications (日本語)
[ Abstract ]
J-stability is an analog of K-stability and plays an important role in K-stability for general polarized varieties (not only for Kahler-Einstein metrics). Strikingly, G.Chen proved uniform J-stability and slope uniform J-stability are equivalent, analogous to Ross-Thomas slope theory and Mumford-Takemoto slope theory for vector bundles, by differential geometric arguments recently. However, this fact has not been proved in algebro-geometric way before. In this talk, I would like to explain a decomposition formula of non-Archimedean J-functional, the (n+1)-dimensional intersection number into n-dimensional intersection numbers and its applications to prove the fact for surfaces and to construct a K-stable but not uniformly K-stable lc pair. Based on arXiv:2103.04603
J-stability is an analog of K-stability and plays an important role in K-stability for general polarized varieties (not only for Kahler-Einstein metrics). Strikingly, G.Chen proved uniform J-stability and slope uniform J-stability are equivalent, analogous to Ross-Thomas slope theory and Mumford-Takemoto slope theory for vector bundles, by differential geometric arguments recently. However, this fact has not been proved in algebro-geometric way before. In this talk, I would like to explain a decomposition formula of non-Archimedean J-functional, the (n+1)-dimensional intersection number into n-dimensional intersection numbers and its applications to prove the fact for surfaces and to construct a K-stable but not uniformly K-stable lc pair. Based on arXiv:2103.04603
Seminar on Probability and Statistics
14:30-16:00 Room # (Graduate School of Math. Sci. Bldg.)
Han Liang Gan (University of Waikato)
Stationary distribution approximations for two-island and seed bank models (ENGLISH)
https://docs.google.com/forms/d/e/1FAIpQLSfLezQNquom7pjodIrc1suI0o5rsWg9AHNv7cix0A7h39tx-g/viewform
Han Liang Gan (University of Waikato)
Stationary distribution approximations for two-island and seed bank models (ENGLISH)
[ Abstract ]
Asia-Pacific Seminar in Probability and Statistics (APSPS)
https://sites.google.com/view/apsps/home
Two-island Wright-Fisher models are used to model genetic frequencies and variability for subdivided populations. One of the key components of the model is the level of migration between the two
islands. We show that as the population size increases, the appropriate approximation and limit for the stationary distribution of a two-island Wright-Fisher Markov chain depends on the level of migration. In a seed bank model, individuals in one of the islands stay dormant rather than reproduce. We give analogous results for the seed bank model, compare and contrast the differences and examine the effect the seed bank has on genetic variability. Our results are derived from a new development of Stein's method for the two-island diffusion model and existing results for Stein's method for the Dirichlet distribution.
This talk is based on joint work with Adrian Röllin, Nathan Ross and Maite Wilke Berenguer.
[ Reference URL ]Asia-Pacific Seminar in Probability and Statistics (APSPS)
https://sites.google.com/view/apsps/home
Two-island Wright-Fisher models are used to model genetic frequencies and variability for subdivided populations. One of the key components of the model is the level of migration between the two
islands. We show that as the population size increases, the appropriate approximation and limit for the stationary distribution of a two-island Wright-Fisher Markov chain depends on the level of migration. In a seed bank model, individuals in one of the islands stay dormant rather than reproduce. We give analogous results for the seed bank model, compare and contrast the differences and examine the effect the seed bank has on genetic variability. Our results are derived from a new development of Stein's method for the two-island diffusion model and existing results for Stein's method for the Dirichlet distribution.
This talk is based on joint work with Adrian Röllin, Nathan Ross and Maite Wilke Berenguer.
https://docs.google.com/forms/d/e/1FAIpQLSfLezQNquom7pjodIrc1suI0o5rsWg9AHNv7cix0A7h39tx-g/viewform
Seminar on Probability and Statistics
14:30-16:00 Room # (Graduate School of Math. Sci. Bldg.)
Han Liang Gan (University of Waikato)
Stationary distribution approximations for two-island and seed bank models
https://docs.google.com/forms/d/e/1FAIpQLSfLezQNquom7pjodIrc1suI0o5rsWg9AHNv7cix0A7h39tx-g/viewform
Han Liang Gan (University of Waikato)
Stationary distribution approximations for two-island and seed bank models
[ Abstract ]
Asia-Pacific Seminar in Probability and Statistics (APSPS)
https://sites.google.com/view/apsps/home
Two-island Wright-Fisher models are used to model genetic frequencies and variability for subdivided populations. One of the key components of the model is the level of migration between the two islands. We show that as the population size increases, the appropriate approximation and limit for the stationary distribution of a two-island Wright-Fisher Markov chain depends on the level of migration. In a seed bank model, individuals in one of the islands stay dormant rather than reproduce. We give analogous results for the seed bank model, compare and contrast the differences and examine the effect the seed bank has on genetic variability. Our results are derived from a new development of Stein's method for the two-island diffusion model and existing results for
Stein's method for the Dirichlet distribution.
This talk is based on joint work with Adrian Röllin, Nathan Ross and Maite Wilke Berenguer.
[ Reference URL ]Asia-Pacific Seminar in Probability and Statistics (APSPS)
https://sites.google.com/view/apsps/home
Two-island Wright-Fisher models are used to model genetic frequencies and variability for subdivided populations. One of the key components of the model is the level of migration between the two islands. We show that as the population size increases, the appropriate approximation and limit for the stationary distribution of a two-island Wright-Fisher Markov chain depends on the level of migration. In a seed bank model, individuals in one of the islands stay dormant rather than reproduce. We give analogous results for the seed bank model, compare and contrast the differences and examine the effect the seed bank has on genetic variability. Our results are derived from a new development of Stein's method for the two-island diffusion model and existing results for
Stein's method for the Dirichlet distribution.
This talk is based on joint work with Adrian Röllin, Nathan Ross and Maite Wilke Berenguer.
https://docs.google.com/forms/d/e/1FAIpQLSfLezQNquom7pjodIrc1suI0o5rsWg9AHNv7cix0A7h39tx-g/viewform
2021/04/20
Tuesday Seminar on Topology
17:00-18:00 Online
Pre-registration required. See our seminar webpage.
Ken’ichi Ohshika (Gakushuin University)
Realisation of measured laminations on boundaries of convex cores (JAPANESE)
https://u-tokyo-ac-jp.zoom.us/meeting/register/tJUpcOCppzwpGd3r_XqdszQ1XN6FvXpNURbj
Pre-registration required. See our seminar webpage.
Ken’ichi Ohshika (Gakushuin University)
Realisation of measured laminations on boundaries of convex cores (JAPANESE)
[ Abstract ]
I shall present a generalisation of the theorem by Bonahon-Otal concerning realisation of measured laminations as bending laminations of geometrically finite groups, to general Kleinian surface groups which might be geometrically infinite. Our proof is based on analysis of geometric limits, and is independent of the technique of hyperbolic cone-manifolds employed by Bonahon-Otal. This is joint work with Shinpei Baba (Osaka Univ.).
[ Reference URL ]I shall present a generalisation of the theorem by Bonahon-Otal concerning realisation of measured laminations as bending laminations of geometrically finite groups, to general Kleinian surface groups which might be geometrically infinite. Our proof is based on analysis of geometric limits, and is independent of the technique of hyperbolic cone-manifolds employed by Bonahon-Otal. This is joint work with Shinpei Baba (Osaka Univ.).
https://u-tokyo-ac-jp.zoom.us/meeting/register/tJUpcOCppzwpGd3r_XqdszQ1XN6FvXpNURbj
Operator Algebra Seminars
16:45-18:15 Online
Yusuke Isono (RIMS, Kyoto Univ.)
Boundary and rigidity of nonsingular Bernoulli actions
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
Yusuke Isono (RIMS, Kyoto Univ.)
Boundary and rigidity of nonsingular Bernoulli actions
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
2021/04/19
Seminar on Geometric Complex Analysis
10:30-12:00 Online
Shouhei Ma (Tokyo Institute of Technology)
カスプと有理同値 (Japanese)
https://u-tokyo-ac-jp.zoom.us/meeting/register/tJ0vcu2rrDIqG9Rv5AT0Mpi37urIkJ1IRldB
Shouhei Ma (Tokyo Institute of Technology)
カスプと有理同値 (Japanese)
[ Abstract ]
標題の「カスプ」とはいわゆるモジュラー多様体の（ベイリー・ボレル）コンパクト化の境界成分のことである。
1970年代にマニンとドリンフェルトは合同モジュラー曲線の２つのカスプの差がピカール群において有限位数であることを発見した。
代数サイクルの観点からこの現象の高次元版をいくつか古典的な系列のモジュラー多様体の（ベイリー・ボレル、トロイダル）コンパクト化に対して調べたので、それについて報告する。
[ Reference URL ]標題の「カスプ」とはいわゆるモジュラー多様体の（ベイリー・ボレル）コンパクト化の境界成分のことである。
1970年代にマニンとドリンフェルトは合同モジュラー曲線の２つのカスプの差がピカール群において有限位数であることを発見した。
代数サイクルの観点からこの現象の高次元版をいくつか古典的な系列のモジュラー多様体の（ベイリー・ボレル、トロイダル）コンパクト化に対して調べたので、それについて報告する。
https://u-tokyo-ac-jp.zoom.us/meeting/register/tJ0vcu2rrDIqG9Rv5AT0Mpi37urIkJ1IRldB
2021/04/15
Applied Analysis
2021/04/14
Algebraic Geometry Seminar
15:00-16:00 Room #Zoom (Graduate School of Math. Sci. Bldg.)
Kenta Sato (Kyushu)
Arithmetic deformation of F-singularities (日本語)
Kenta Sato (Kyushu)
Arithmetic deformation of F-singularities (日本語)
[ Abstract ]
None
None
2021/04/13
Tuesday Seminar on Topology
17:00-18:00 Online
Pre-registration required. See our seminar webpage.
Tetsuya Ito (Kyoto University)
Quantitative Birman-Menasco theorem and applications to crossing number (JAPANESE)
https://u-tokyo-ac-jp.zoom.us/meeting/register/tJUpcOCppzwpGd3r_XqdszQ1XN6FvXpNURbj
Pre-registration required. See our seminar webpage.
Tetsuya Ito (Kyoto University)
Quantitative Birman-Menasco theorem and applications to crossing number (JAPANESE)
[ Abstract ]
Birman-Menasco proved that there are finitely many knots having a given genus and braid index. We give a quantitative version of Birman-Menasco finiteness theorem; an estimate of the crossing number of knots in terms of genus and braid index. As applications, we give various supporting evidences of various conjectural properties of the crossing number of knots.
[ Reference URL ]Birman-Menasco proved that there are finitely many knots having a given genus and braid index. We give a quantitative version of Birman-Menasco finiteness theorem; an estimate of the crossing number of knots in terms of genus and braid index. As applications, we give various supporting evidences of various conjectural properties of the crossing number of knots.
https://u-tokyo-ac-jp.zoom.us/meeting/register/tJUpcOCppzwpGd3r_XqdszQ1XN6FvXpNURbj
Operator Algebra Seminars
16:45-18:15 Online
Yasuhito Hashiba (Univ. Tokyo)
On central sequence algebras of tracial von Neumann algebras
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
Yasuhito Hashiba (Univ. Tokyo)
On central sequence algebras of tracial von Neumann algebras
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
2021/04/08
Tokyo-Nagoya Algebra Seminar
16:00-17:30 Online
Please see the URL below for details on the online seminar.
Kevin Coulembier (Univeristy of Sydney)
Abelian envelopes of monoidal categories (English)
http://www.math.nagoya-u.ac.jp/~aaron.chan/TNAseminar.html
Please see the URL below for details on the online seminar.
Kevin Coulembier (Univeristy of Sydney)
Abelian envelopes of monoidal categories (English)
[ Abstract ]
For the purposes of this talk, a ‘tensor category’ is an abelian rigid monoidal category, linear over some field. I will try to argue that there are good reasons (inspired by classification attempts of tensor categories, by motives, by Frobenius twists on tensor categories and by the idea of universal tensor categories), to try to associate tensor categories to non-abelian rigid monoidal categories. Then I will comment on some of the recent progress made on such constructions (in work of Benson, Comes, Entova, Etingof, Heidersdof, Hinich, Ostrik, Serganova and myself).
[ Reference URL ]For the purposes of this talk, a ‘tensor category’ is an abelian rigid monoidal category, linear over some field. I will try to argue that there are good reasons (inspired by classification attempts of tensor categories, by motives, by Frobenius twists on tensor categories and by the idea of universal tensor categories), to try to associate tensor categories to non-abelian rigid monoidal categories. Then I will comment on some of the recent progress made on such constructions (in work of Benson, Comes, Entova, Etingof, Heidersdof, Hinich, Ostrik, Serganova and myself).
http://www.math.nagoya-u.ac.jp/~aaron.chan/TNAseminar.html
2021/04/06
Operator Algebra Seminars
16:45-18:15 Online
Frederic Latremoliere (Univ. Denver)
Finite Dimensional Approximations of Spectral Triples on Quantum tori (English)
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
Frederic Latremoliere (Univ. Denver)
Finite Dimensional Approximations of Spectral Triples on Quantum tori (English)
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
2021/03/29
Seminar on Probability and Statistics
14:00-15:10 Online
Register at least 3 days before at the reference URL. The URL for participation sent before the seminar.
Masaaki Imaizumi (University of Tokyo)
On Gaussian Approximation for M-Estimator (JAPANESE)
https://docs.google.com/forms/d/e/1FAIpQLSfjQhmmZjWUllB6pQeEMGDRcLCe_0JPgVbEA05rHtcDYAZzqg/viewform
Register at least 3 days before at the reference URL. The URL for participation sent before the seminar.
Masaaki Imaizumi (University of Tokyo)
On Gaussian Approximation for M-Estimator (JAPANESE)
[ Abstract ]
This study develops a non-asymptotic Gaussian approximation theory for distributions of M-estimators, which are defined as maximizers of empirical criterion functions. In existing mathematical statistics literature, numerous studies have focused on approximating the distributions of the M-estimators for statistical inference. In contrast to the existing approaches, which mainly focus on limiting behaviors, this study employs a non-asymptotic approach, establishes abstract Gaussian approximation results for maximizers of empirical criteria, and proposes a Gaussian multiplier bootstrap approximation method. Our developments can be considered as extensions of the seminal works on the approximation theory for distributions of suprema of empirical processes toward their maximizers. Through this work, we shed new lights on the statistical theory of M-estimators. Our theory covers not only regular estimators, such as the least absolute deviations, but also some non-regular cases where it is difficult to derive or to approximate numerically the limiting distributions such as non-Donsker classes and cube root estimators.
[ Reference URL ]This study develops a non-asymptotic Gaussian approximation theory for distributions of M-estimators, which are defined as maximizers of empirical criterion functions. In existing mathematical statistics literature, numerous studies have focused on approximating the distributions of the M-estimators for statistical inference. In contrast to the existing approaches, which mainly focus on limiting behaviors, this study employs a non-asymptotic approach, establishes abstract Gaussian approximation results for maximizers of empirical criteria, and proposes a Gaussian multiplier bootstrap approximation method. Our developments can be considered as extensions of the seminal works on the approximation theory for distributions of suprema of empirical processes toward their maximizers. Through this work, we shed new lights on the statistical theory of M-estimators. Our theory covers not only regular estimators, such as the least absolute deviations, but also some non-regular cases where it is difficult to derive or to approximate numerically the limiting distributions such as non-Donsker classes and cube root estimators.
https://docs.google.com/forms/d/e/1FAIpQLSfjQhmmZjWUllB6pQeEMGDRcLCe_0JPgVbEA05rHtcDYAZzqg/viewform
2021/03/24
Seminar on Probability and Statistics
14:30-16:00 Online
Register at least 3 days before at the reference URL. The URL for participation sent before the seminar.
Rachel Fewster (University of Auckland)
Stochastic modelling in ecology: why is it interesting? (ENGLISH)
https://docs.google.com/forms/d/e/1FAIpQLSf05P9fCZ5Wkasc7clW1XBpkeONPSjPKuCkNYb3oIqnOAu5Mg/viewform
Register at least 3 days before at the reference URL. The URL for participation sent before the seminar.
Rachel Fewster (University of Auckland)
Stochastic modelling in ecology: why is it interesting? (ENGLISH)
[ Abstract ]
Asia-Pacific Seminar in Probability and Statistics https://sites.google.com/view/apsps/home
The ecological sciences offer rich pickings for stochastic modellers. There is currently an abundance of new technologies for monitoring wildlife and biodiversity, for which no practicable data-analysis methods exist. Often, modelling approaches that are motivated by a specific problem with relatively narrow focus can turn out to have surprisingly broad application elsewhere. As the generality of the problem structure becomes clear, this can also motivate new statistical theory.
I will describe some ecological modelling scenarios that have led to interesting developments from methodological and theoretical perspectives. As time allows, these will include: saddlepoint approximations for dealing with data corrupted by non-invertible linear transformations; information theory for assuring that it is a good idea to unite data from multiple sources; and methods for dealing with so-called 'enigmatic' data from remote sensors, involving a blend of ideas from point processes, queuing theory, and trigonometry. All scenarios will be generously illustrated with pictures of charismatic wildlife.
This talk covers joint work with numerous collaborators, especially Joey Wei Zhang, Mark Bravington, Peter Jupp, Jesse Goodman, Martin Hazelton, Godrick Oketch, Ben Stevenson, David Borchers, Paul van Dam-Bates, and Stephen Marsland.
[ Reference URL ]Asia-Pacific Seminar in Probability and Statistics https://sites.google.com/view/apsps/home
The ecological sciences offer rich pickings for stochastic modellers. There is currently an abundance of new technologies for monitoring wildlife and biodiversity, for which no practicable data-analysis methods exist. Often, modelling approaches that are motivated by a specific problem with relatively narrow focus can turn out to have surprisingly broad application elsewhere. As the generality of the problem structure becomes clear, this can also motivate new statistical theory.
I will describe some ecological modelling scenarios that have led to interesting developments from methodological and theoretical perspectives. As time allows, these will include: saddlepoint approximations for dealing with data corrupted by non-invertible linear transformations; information theory for assuring that it is a good idea to unite data from multiple sources; and methods for dealing with so-called 'enigmatic' data from remote sensors, involving a blend of ideas from point processes, queuing theory, and trigonometry. All scenarios will be generously illustrated with pictures of charismatic wildlife.
This talk covers joint work with numerous collaborators, especially Joey Wei Zhang, Mark Bravington, Peter Jupp, Jesse Goodman, Martin Hazelton, Godrick Oketch, Ben Stevenson, David Borchers, Paul van Dam-Bates, and Stephen Marsland.
https://docs.google.com/forms/d/e/1FAIpQLSf05P9fCZ5Wkasc7clW1XBpkeONPSjPKuCkNYb3oIqnOAu5Mg/viewform
2021/03/19
Colloquium
15:00-17:30 Online
Yoshikazu Giga (University of Tokyo) 15:00-16:00
Effects of viscosity and diffusion described by differential equations (JAPANESE)
Toshitake Kohno (Meiji University/University of Tokyo) 16:30-17:30
Monodromy representations in higher categories and iterated integrals (JAPANESE)
Yoshikazu Giga (University of Tokyo) 15:00-16:00
Effects of viscosity and diffusion described by differential equations (JAPANESE)
Toshitake Kohno (Meiji University/University of Tokyo) 16:30-17:30
Monodromy representations in higher categories and iterated integrals (JAPANESE)
Lectures
18:00-19:00 Online
Day 3 of a series of three lectures (3/17,18,19)
Matthew Morrow (CNRS, IMJ-PRG)
Progress in syntomic cohomology (ENGLISH)
https://www.ms.u-tokyo.ac.jp/~shiho/spparis/index.html
Day 3 of a series of three lectures (3/17,18,19)
Matthew Morrow (CNRS, IMJ-PRG)
Progress in syntomic cohomology (ENGLISH)
[ Abstract ]
The talks will present a survey of the (quasi)syntomic cohomology theory introduced by Bhatt, Scholze, and the speaker; this provides a variant of the syntomic cohomology of Fontaine, Kato, and Messing which has the advantage of being defined in a greater degree of generality and working well with torsion coefficients even for small primes. Although it underlies in principle a general theory of p-adic étale motivic cohomology, the talks will probably focus more on arithmetic aspects such as applications in p-adic Hodge theory. Based on various projects joint with Antieau, Bhatt, Clausen, Kelly, Lüders, Mathew, Nikolaus, and Scholze.
[ Reference URL ]The talks will present a survey of the (quasi)syntomic cohomology theory introduced by Bhatt, Scholze, and the speaker; this provides a variant of the syntomic cohomology of Fontaine, Kato, and Messing which has the advantage of being defined in a greater degree of generality and working well with torsion coefficients even for small primes. Although it underlies in principle a general theory of p-adic étale motivic cohomology, the talks will probably focus more on arithmetic aspects such as applications in p-adic Hodge theory. Based on various projects joint with Antieau, Bhatt, Clausen, Kelly, Lüders, Mathew, Nikolaus, and Scholze.
https://www.ms.u-tokyo.ac.jp/~shiho/spparis/index.html
2021/03/18
Lectures
17:30-18:30 Online
Day 2 of a series of three lectures (3/17,18,19)
Matthew Morrow (CNRS, IMJ-PRG)
Progress in syntomic cohomology (ENGLISH)
https://www.ms.u-tokyo.ac.jp/~shiho/spparis/index.html
Day 2 of a series of three lectures (3/17,18,19)
Matthew Morrow (CNRS, IMJ-PRG)
Progress in syntomic cohomology (ENGLISH)
[ Abstract ]
The talks will present a survey of the (quasi)syntomic cohomology theory introduced by Bhatt, Scholze, and the speaker; this provides a variant of the syntomic cohomology of Fontaine, Kato, and Messing which has the advantage of being defined in a greater degree of generality and working well with torsion coefficients even for small primes. Although it underlies in principle a general theory of p-adic étale motivic cohomology, the talks will probably focus more on arithmetic aspects such as applications in p-adic Hodge theory. Based on various projects joint with Antieau, Bhatt, Clausen, Kelly, Lüders, Mathew, Nikolaus, and Scholze.
[ Reference URL ]The talks will present a survey of the (quasi)syntomic cohomology theory introduced by Bhatt, Scholze, and the speaker; this provides a variant of the syntomic cohomology of Fontaine, Kato, and Messing which has the advantage of being defined in a greater degree of generality and working well with torsion coefficients even for small primes. Although it underlies in principle a general theory of p-adic étale motivic cohomology, the talks will probably focus more on arithmetic aspects such as applications in p-adic Hodge theory. Based on various projects joint with Antieau, Bhatt, Clausen, Kelly, Lüders, Mathew, Nikolaus, and Scholze.
https://www.ms.u-tokyo.ac.jp/~shiho/spparis/index.html
2021/03/17
Lectures
17:30-18:30 Online
Day 1 of a series of three lectures (3/17,18,19)
Matthew Morrow (CNRS, IMJ-PRG)
Progress in syntomic cohomology (ENGLISH)
https://www.ms.u-tokyo.ac.jp/~shiho/spparis/index.html
Day 1 of a series of three lectures (3/17,18,19)
Matthew Morrow (CNRS, IMJ-PRG)
Progress in syntomic cohomology (ENGLISH)
[ Abstract ]
The talks will present a survey of the (quasi)syntomic cohomology theory introduced by Bhatt, Scholze, and the speaker; this provides a variant of the syntomic cohomology of Fontaine, Kato, and Messing which has the advantage of being defined in a greater degree of generality and working well with torsion coefficients even for small primes. Although it underlies in principle a general theory of p-adic étale motivic cohomology, the talks will probably focus more on arithmetic aspects such as applications in p-adic Hodge theory. Based on various projects joint with Antieau, Bhatt, Clausen, Kelly, Lüders, Mathew, Nikolaus, and Scholze.
[ Reference URL ]The talks will present a survey of the (quasi)syntomic cohomology theory introduced by Bhatt, Scholze, and the speaker; this provides a variant of the syntomic cohomology of Fontaine, Kato, and Messing which has the advantage of being defined in a greater degree of generality and working well with torsion coefficients even for small primes. Although it underlies in principle a general theory of p-adic étale motivic cohomology, the talks will probably focus more on arithmetic aspects such as applications in p-adic Hodge theory. Based on various projects joint with Antieau, Bhatt, Clausen, Kelly, Lüders, Mathew, Nikolaus, and Scholze.
https://www.ms.u-tokyo.ac.jp/~shiho/spparis/index.html
2021/03/11
Information Mathematics Seminar
16:50-18:35 Online
Akiyoshi Sannai (RIKEN)
Deep learning with symmetry (Japanese)
https://docs.google.com/forms/d/1yIKNrwSLsdYt_rivZI8JxhIu3kWtJua5hG8nV5FYbCk/
Akiyoshi Sannai (RIKEN)
Deep learning with symmetry (Japanese)
[ Abstract ]
Explanation on deep learning with symmetry
[ Reference URL ]Explanation on deep learning with symmetry
https://docs.google.com/forms/d/1yIKNrwSLsdYt_rivZI8JxhIu3kWtJua5hG8nV5FYbCk/
Tokyo-Nagoya Algebra Seminar
16:00-17:30 Online
Please see the URL below for details on the online seminar.
Akihito Wachi (Hokkaido University of Education)
相対不変式で生成されるゴレンスタイン環のレフシェッツ性 (Japanese)
[ Reference URL ]
http://www.math.nagoya-u.ac.jp/~aaron.chan/TNAseminar.html
Please see the URL below for details on the online seminar.
Akihito Wachi (Hokkaido University of Education)
相対不変式で生成されるゴレンスタイン環のレフシェッツ性 (Japanese)
[ Reference URL ]
http://www.math.nagoya-u.ac.jp/~aaron.chan/TNAseminar.html
2021/03/10
Number Theory Seminar
17:00-18:00 Online
Katsuyuki Bando (University of Tokyo)
Geometric Satake equivalence in mixed characteristic and Springer correspondence (Japanese)
Katsuyuki Bando (University of Tokyo)
Geometric Satake equivalence in mixed characteristic and Springer correspondence (Japanese)
[ Abstract ]
The geometric Satake correspondence is an equivalence between the category of equivariant perverse sheaves on the affine Grassmannian and the category of representations of the Langlands dual group. It is known that there is a mixed characteristic version of the geometric Satake correspondence. The Springer correspondence is a correspondence between the category of equivariant perverse sheaves on the nilpotent cone and the category of representation of the Weyl group. In this talk, we will explain some relation between these two correspondences, including the mixed characteristic case.
The geometric Satake correspondence is an equivalence between the category of equivariant perverse sheaves on the affine Grassmannian and the category of representations of the Langlands dual group. It is known that there is a mixed characteristic version of the geometric Satake correspondence. The Springer correspondence is a correspondence between the category of equivariant perverse sheaves on the nilpotent cone and the category of representation of the Weyl group. In this talk, we will explain some relation between these two correspondences, including the mixed characteristic case.
2021/02/24
Tokyo-Nagoya Algebra Seminar
16:00-17:30 Online
Please see the URL below for details on the online seminar.
Shunya Saito (Nagoya University)
周期三角圏上の傾理論 (Japanese)
[ Reference URL ]
http://www.math.nagoya-u.ac.jp/~aaron.chan/TNAseminar.html
Please see the URL below for details on the online seminar.
Shunya Saito (Nagoya University)
周期三角圏上の傾理論 (Japanese)
[ Reference URL ]
http://www.math.nagoya-u.ac.jp/~aaron.chan/TNAseminar.html
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