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Future seminars
Seminar information archive ～06/10｜Today's seminar 06/11 | Future seminars 06/12～
2026/06/15
Tokyo Probability Seminar
16:00-17:30 Room #126 (Graduate School of Math. Sci. Bldg.)
We are having teatime from 15:15 in the common room on the second floor. Please join us.
Tomoyuki Ichiba (University of California Santa Barbara)
Feynman formula for discrete-time quantum walk and its applications
We are having teatime from 15:15 in the common room on the second floor. Please join us.
Tomoyuki Ichiba (University of California Santa Barbara)
Feynman formula for discrete-time quantum walk and its applications
[ Abstract ]
We explicitly connect (discrete-time) quantum walks on Z with a four-state Markov additive process via a Feynman-type formula. Using this representation, we derive a relation between the spectral decomposition of the Markov additive process and the limiting density of the homogeneous quantum walk. In addition, we consider a space-time rescaling of quantum walks, which leads to a system of quantum transport PDEs of Dirac type in continuous time and space with phase interaction and potential terms. Our probabilistic representation for this type of PDE offers its stochastic extension as well as an efficient Monte Carlo computational technique. This is joint work with Jean-Pierre Fouque and Ka Lok Lam.
We explicitly connect (discrete-time) quantum walks on Z with a four-state Markov additive process via a Feynman-type formula. Using this representation, we derive a relation between the spectral decomposition of the Markov additive process and the limiting density of the homogeneous quantum walk. In addition, we consider a space-time rescaling of quantum walks, which leads to a system of quantum transport PDEs of Dirac type in continuous time and space with phase interaction and potential terms. Our probabilistic representation for this type of PDE offers its stochastic extension as well as an efficient Monte Carlo computational technique. This is joint work with Jean-Pierre Fouque and Ka Lok Lam.
FJ-LMI Seminar
10:30-12:00 Room #002 (Graduate School of Math. Sci. Bldg.)
Eric Leclerc, . Fabrizio Cleri, Yuki Miura, Stephane Poulain (LIMMS & IIS of The University of Tokyo)
- Introduction to a quantum inspired model of the mitochondria dysfunction in liver disease;
- From Boltzmann to Lindblad: quantum systems out of equilibrium;
- A hybrid liver model of mechanistic ODE systems and machine learning;
- Presentation of research background in bioinformatics and genomics, and introduction to new research projects for in silico liver organ physiology modeling using AI and informatics tools. (英語)
Eric Leclerc, . Fabrizio Cleri, Yuki Miura, Stephane Poulain (LIMMS & IIS of The University of Tokyo)
- Introduction to a quantum inspired model of the mitochondria dysfunction in liver disease;
- From Boltzmann to Lindblad: quantum systems out of equilibrium;
- A hybrid liver model of mechanistic ODE systems and machine learning;
- Presentation of research background in bioinformatics and genomics, and introduction to new research projects for in silico liver organ physiology modeling using AI and informatics tools. (英語)
[ Abstract ]
These 4 short presentations will focus on possible interactions between two laboratories.
These 4 short presentations will focus on possible interactions between two laboratories.
2026/06/16
Operator Algebra Seminars
16:45-18:15 Room #126 (Graduate School of Math. Sci. Bldg.)
Hiroki Ishikura (RIMS, Kyoto Univ.)
Borel planar complexes and soficity
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
Hiroki Ishikura (RIMS, Kyoto Univ.)
Borel planar complexes and soficity
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
Tuesday Seminar on Topology
16:00-17:30 Room #hybrid/128 (Graduate School of Math. Sci. Bldg.)
Pre-registration required. See our seminar webpage.
Yuto Moriwaki (RIKEN iTHEMS)
Conformally flat factorization homology (JAPANESE)
https://park.itc.u-tokyo.ac.jp/MSF/topology/TuesdaySeminar/index_e.html
Pre-registration required. See our seminar webpage.
Yuto Moriwaki (RIKEN iTHEMS)
Conformally flat factorization homology (JAPANESE)
[ Abstract ]
This talk presents conformally flat factorization homology, introduced as a conformal Riemannian analogue of Lurie's factorization homology. Ordinary factorization homology takes a d-disk algebra as input and produces invariants of d-dimensional manifolds that are independent of the choice of metric. In contrast, conformally flat factorization homology takes as input a conformally flat d-disk algebra, which is an algebra over the operad formed by conformal open embeddings of disks, and constructs, via its left Kan extension, metric-dependent invariants of conformally flat Riemannian manifolds.
This theory provides a framework connecting representations of local conformal transformations with Riemannian geometric invariants, and describes the local structure of d-dimensional conformal field theory. The talk will also discuss concrete examples constructed using Bergman spaces and Grunsky operators in dimension two, and using unitary representations of SO+(d,1) in dimensions three and higher.
This talk is based on arXiv:2602.08729 and arXiv:2603.06491.
[ Reference URL ]This talk presents conformally flat factorization homology, introduced as a conformal Riemannian analogue of Lurie's factorization homology. Ordinary factorization homology takes a d-disk algebra as input and produces invariants of d-dimensional manifolds that are independent of the choice of metric. In contrast, conformally flat factorization homology takes as input a conformally flat d-disk algebra, which is an algebra over the operad formed by conformal open embeddings of disks, and constructs, via its left Kan extension, metric-dependent invariants of conformally flat Riemannian manifolds.
This theory provides a framework connecting representations of local conformal transformations with Riemannian geometric invariants, and describes the local structure of d-dimensional conformal field theory. The talk will also discuss concrete examples constructed using Bergman spaces and Grunsky operators in dimension two, and using unitary representations of SO+(d,1) in dimensions three and higher.
This talk is based on arXiv:2602.08729 and arXiv:2603.06491.
https://park.itc.u-tokyo.ac.jp/MSF/topology/TuesdaySeminar/index_e.html
2026/06/22
Seminar on Geometric Complex Analysis
10:30-12:00 Room #126 (Graduate School of Math. Sci. Bldg.)
Online only. No in-person attendance.
Naoto Yotsutani (Shizuoka Univ./IMAG, Univ. Montpellier)
Secondary polytopes of spherical varieties (Japanese)
https://forms.gle/8ERsVDLuKHwbVzm57
Online only. No in-person attendance.
Naoto Yotsutani (Shizuoka Univ./IMAG, Univ. Montpellier)
Secondary polytopes of spherical varieties (Japanese)
[ Abstract ]
This talk is based on ongoing joint work with Thibaut Delcroix and King Leung Lee. Our main objective is to investigate the Chow stability of spherical varieties.
A celebrated theorem of Gelfand, Kapranov, Sturmfels, and Zelevinsky (1992) states that the Chow polytopes of projective toric varieties coincide with their secondary polytopes. In the spherical setting, one can construct an analogous polytope, which may be viewed as a natural generalization of the secondary polytope of a toric variety. In this talk, I will explain the construction of this polytope and its relation to Chow stability. Particular emphasis will be placed on how the classical GKZ argument in the toric setting can be adapted to the broader context of spherical varieties.
[ Reference URL ]This talk is based on ongoing joint work with Thibaut Delcroix and King Leung Lee. Our main objective is to investigate the Chow stability of spherical varieties.
A celebrated theorem of Gelfand, Kapranov, Sturmfels, and Zelevinsky (1992) states that the Chow polytopes of projective toric varieties coincide with their secondary polytopes. In the spherical setting, one can construct an analogous polytope, which may be viewed as a natural generalization of the secondary polytope of a toric variety. In this talk, I will explain the construction of this polytope and its relation to Chow stability. Particular emphasis will be placed on how the classical GKZ argument in the toric setting can be adapted to the broader context of spherical varieties.
https://forms.gle/8ERsVDLuKHwbVzm57
Tokyo Probability Seminar
16:00-17:30 Room #126 (Graduate School of Math. Sci. Bldg.)
We are having teatime from 15:15 in the common room on the second floor. Please join us.
Manasa Nagatsu (Kyoto University)
Large $N$ expansion for smooth multi-trace spectral statistics of
classical matrix ensembles, central limit theorems and matrix integrals.
We are having teatime from 15:15 in the common room on the second floor. Please join us.
Manasa Nagatsu (Kyoto University)
Large $N$ expansion for smooth multi-trace spectral statistics of
classical matrix ensembles, central limit theorems and matrix integrals.
[ Abstract ]
We consider expectations of the form $E [tr h_1(X_1^N)... tr h_r(X_r^N)]$,
where $X_i^N$ are self-adjoint polynomials in various independent
classical random matrices and $h_i$ are smooth test function and obtain a
large $N$ expansion of these quantities, building on the framework of
polynomial approximation and Bernstein-type inequalities recently
developed by Chen, Garza-Vargas, Tropp, and van Handel.
As applications of the above, we prove the higher-order asymptotic
vanishing of cumulants for smooth linear statistics, establish a Central
Limit Theorem, and demonstrate the existence of formal asymptotic
expansions for the free energy and observables of matrix integrals with
smooth potentials.
In addition to presenting these results, we will briefly review the role
of linear statistics in random matrix theory and discuss the motivation
behind the large $N$ expansion framework introduced in the context of
strong convergence.
This talk is based on joint work with Benoit Collins.
We consider expectations of the form $E [tr h_1(X_1^N)... tr h_r(X_r^N)]$,
where $X_i^N$ are self-adjoint polynomials in various independent
classical random matrices and $h_i$ are smooth test function and obtain a
large $N$ expansion of these quantities, building on the framework of
polynomial approximation and Bernstein-type inequalities recently
developed by Chen, Garza-Vargas, Tropp, and van Handel.
As applications of the above, we prove the higher-order asymptotic
vanishing of cumulants for smooth linear statistics, establish a Central
Limit Theorem, and demonstrate the existence of formal asymptotic
expansions for the free energy and observables of matrix integrals with
smooth potentials.
In addition to presenting these results, we will briefly review the role
of linear statistics in random matrix theory and discuss the motivation
behind the large $N$ expansion framework introduced in the context of
strong convergence.
This talk is based on joint work with Benoit Collins.
2026/06/23
Operator Algebra Seminars
16:45-18:15 Room #126 (Graduate School of Math. Sci. Bldg.)
Ravi Mistry (the University of Tokyo)
Knots, Invariants, QFT, and Beyond
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
Ravi Mistry (the University of Tokyo)
Knots, Invariants, QFT, and Beyond
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
Tuesday Seminar on Topology
16:00-17:30 Room #hybrid/056 (Graduate School of Math. Sci. Bldg.)
Pre-registration required. See our seminar webpage.
Andrei Pajitnov (Université de Nantes)
Morse-Novikov theory for links (ENGLISH)
https://park.itc.u-tokyo.ac.jp/MSF/topology/TuesdaySeminar/index_e.html
Pre-registration required. See our seminar webpage.
Andrei Pajitnov (Université de Nantes)
Morse-Novikov theory for links (ENGLISH)
[ Abstract ]
Let M be a compact manifold with a non-empty boundary N, and x an element of the first cohomology group of M. We assume that the restriction of x to N can be represented by a fibration over a circle. The Morse-Novikov number MN(M,x) is the minimal possible number of critical points of a Morse map f of M to a circle, such that [f]=x, and the restriction of f to N is a fibration over the circle. In this talk we present our results about the Morse-Novikov numbers for the exteriors of links in 3-sphere. This is joint work with L. Chen and H. Endo.
[ Reference URL ]Let M be a compact manifold with a non-empty boundary N, and x an element of the first cohomology group of M. We assume that the restriction of x to N can be represented by a fibration over a circle. The Morse-Novikov number MN(M,x) is the minimal possible number of critical points of a Morse map f of M to a circle, such that [f]=x, and the restriction of f to N is a fibration over the circle. In this talk we present our results about the Morse-Novikov numbers for the exteriors of links in 3-sphere. This is joint work with L. Chen and H. Endo.
https://park.itc.u-tokyo.ac.jp/MSF/topology/TuesdaySeminar/index_e.html
2026/06/25
Applied Analysis
16:00-17:30 Room # 002 (Graduate School of Math. Sci. Bldg.)
Xiao Dongyuan (Tohoku University)
Complete classification of traveling wave solutions to monotone dynamical systems (Japanese)
Xiao Dongyuan (Tohoku University)
Complete classification of traveling wave solutions to monotone dynamical systems (Japanese)
[ Abstract ]
To study the propagation phenomena of solutions to the reaction-diffusion equation the asymptotic behavior of traveling wave solutions plays a crucial role. When the nonlinear reaction term satisfies the monostable condition, it is known that there exists a minimal traveling wave speed, and that traveling wave solutions exist for any speed c larger than or equal to the minimal speed. It has been shown, through simple phase plane analysis, that these traveling waves can be classified into three cases based on their decay rates.
It Is expected that a similar classification should hold for more general order-preserving systems, such as nonlocal diffusion equations, Lotka–Volterra systems, and reaction–diffusion equations with time delay. However, a complete classification remains unavailable because direct phase plane analysis is no longer applicable in these settings. In this talk, I will introduce a method based on comparison argument and sliding method to classify traveling waves. This research is based on joint work with Maolin Zhou (Nankai University) and Chang-hong Wu (National Yang Ming Chiao Tung University).
To study the propagation phenomena of solutions to the reaction-diffusion equation the asymptotic behavior of traveling wave solutions plays a crucial role. When the nonlinear reaction term satisfies the monostable condition, it is known that there exists a minimal traveling wave speed, and that traveling wave solutions exist for any speed c larger than or equal to the minimal speed. It has been shown, through simple phase plane analysis, that these traveling waves can be classified into three cases based on their decay rates.
It Is expected that a similar classification should hold for more general order-preserving systems, such as nonlocal diffusion equations, Lotka–Volterra systems, and reaction–diffusion equations with time delay. However, a complete classification remains unavailable because direct phase plane analysis is no longer applicable in these settings. In this talk, I will introduce a method based on comparison argument and sliding method to classify traveling waves. This research is based on joint work with Maolin Zhou (Nankai University) and Chang-hong Wu (National Yang Ming Chiao Tung University).
2026/06/26
Colloquium
15:30-16:30 Room #NISSAY Lecture Hall (Graduate School of Math. Sci. Bldg.)
Bez Neal (Graduate School of Mathematical Sciences, The University of Tokyo)
The Kakeya conjecture and the Brascamp-Lieb inequality (日本語)
Bez Neal (Graduate School of Mathematical Sciences, The University of Tokyo)
The Kakeya conjecture and the Brascamp-Lieb inequality (日本語)
[ Abstract ]
Despite being ostensibly a problem in geometric measure theory,
the Kakeya conjecture has huge significance in modern Fourier analysis.
After discussing this connection,
I will explain the relevance of the Brascamp-Lieb inequality in this context
and introduce some recent progress in the theory of this inequality.
Despite being ostensibly a problem in geometric measure theory,
the Kakeya conjecture has huge significance in modern Fourier analysis.
After discussing this connection,
I will explain the relevance of the Brascamp-Lieb inequality in this context
and introduce some recent progress in the theory of this inequality.
Geometric Analysis Seminar
13:30-14;30 Room #002 (Graduate School of Math. Sci. Bldg.)
Federica Dragoni (Cardiff University)
Convexity: from the Euclidean space to Riemannian and sub-Riemannian manifolds (英語)
https://sites.google.com/g.ecc.u-tokyo.ac.jp/geometricanalysisseminar/
Federica Dragoni (Cardiff University)
Convexity: from the Euclidean space to Riemannian and sub-Riemannian manifolds (英語)
[ Abstract ]
In this talk I will give an overview on different notions of convexity introduced in the last decades to generalise the standard (Euclidean) convexity to different geometries such as Riemannian manifolds, Carnot groups and the geometry of vector fields. Later I will show some more recent developments and how this new geometrical approach can connect most of the previous notions.
[ Reference URL ]In this talk I will give an overview on different notions of convexity introduced in the last decades to generalise the standard (Euclidean) convexity to different geometries such as Riemannian manifolds, Carnot groups and the geometry of vector fields. Later I will show some more recent developments and how this new geometrical approach can connect most of the previous notions.
https://sites.google.com/g.ecc.u-tokyo.ac.jp/geometricanalysisseminar/
Seminar on Probability and Statistics
13:30-14:30 Room #122 (Graduate School of Math. Sci. Bldg.)
Prof. Hsin-Hsiung 'Bill’ Huang (School of Data, Mathematical, and Statistical Sciences, University of Central Florida)
Scalable Bayesian Conformal Inference for High-Dimensional Spatiotemporal Zero-Inflated Count Data (English)
https://u-tokyo-ac-jp.zoom.us/meeting/register/UmviZSskR766wD4QoUvP2g
Prof. Hsin-Hsiung 'Bill’ Huang (School of Data, Mathematical, and Statistical Sciences, University of Central Florida)
Scalable Bayesian Conformal Inference for High-Dimensional Spatiotemporal Zero-Inflated Count Data (English)
[ Abstract ]
I will present a Bayesian framework for spatiotemporal count data with excess zeros, overdispersion, and ultrahigh-dimensional covariates. The model combines zero-inflated negative binomial regression, TPBN shrinkage priors for sparse fixed effects, graph-Laplacian or SPDE-type spatial random effects, smooth global time effects, and unit-specific Ornstein--Uhlenbeck SDE random effects. Pólya--Gamma augmentation yields a conditionally Gaussian structure, supporting both blocked Gibbs sampling and scalable structured variational inference. I will also discuss split conformal calibration for discrete predictive sets and an auxiliary LAQ/QMLE perspective for the OU component. Simulation studies and a measles surveillance analysis illustrate calibrated prediction and recovery of latent spatiotemporal structure.
[ Reference URL ]I will present a Bayesian framework for spatiotemporal count data with excess zeros, overdispersion, and ultrahigh-dimensional covariates. The model combines zero-inflated negative binomial regression, TPBN shrinkage priors for sparse fixed effects, graph-Laplacian or SPDE-type spatial random effects, smooth global time effects, and unit-specific Ornstein--Uhlenbeck SDE random effects. Pólya--Gamma augmentation yields a conditionally Gaussian structure, supporting both blocked Gibbs sampling and scalable structured variational inference. I will also discuss split conformal calibration for discrete predictive sets and an auxiliary LAQ/QMLE perspective for the OU component. Simulation studies and a measles surveillance analysis illustrate calibrated prediction and recovery of latent spatiotemporal structure.
https://u-tokyo-ac-jp.zoom.us/meeting/register/UmviZSskR766wD4QoUvP2g
2026/06/29
Seminar on Geometric Complex Analysis
10:30-12:00 Room #126 (Graduate School of Math. Sci. Bldg.)
Chin-Yu Hsiao (National Taiwan Univ.)
TBA (English)
[ Reference URL ]
https://forms.gle/8ERsVDLuKHwbVzm57
Chin-Yu Hsiao (National Taiwan Univ.)
TBA (English)
[ Reference URL ]
https://forms.gle/8ERsVDLuKHwbVzm57
2026/07/01
Number Theory Seminar
17:00-18:00 Room #117 (Graduate School of Math. Sci. Bldg.)
ISHIKURA Rintaro (University of Tokyo)
On boundedness of the number of cuspidal automorphic representations of Mp(4) ordinary at p
ISHIKURA Rintaro (University of Tokyo)
On boundedness of the number of cuspidal automorphic representations of Mp(4) ordinary at p
[ Abstract ]
We study p-ordinary cuspidal automorphic representations of the metaplectic group Mp(4) with holomorphic discrete series at infinity, whose A-parameters are tempered. Using two Iwahori-level Hecke operators, we define an ordinary projector and investigate the conditions to be ordinary at p. Fixing the level K, we prove a bound (depending only on K) for the number of genuine cuspidal automorphic representations of Mp(4) ordinary at p and containing nonzero K-fixed vectors, as the holomorphic weight varies.
We study p-ordinary cuspidal automorphic representations of the metaplectic group Mp(4) with holomorphic discrete series at infinity, whose A-parameters are tempered. Using two Iwahori-level Hecke operators, we define an ordinary projector and investigate the conditions to be ordinary at p. Fixing the level K, we prove a bound (depending only on K) for the number of genuine cuspidal automorphic representations of Mp(4) ordinary at p and containing nonzero K-fixed vectors, as the holomorphic weight varies.
2026/07/06
Seminar on Geometric Complex Analysis
10:30-12:00 Room #126 (Graduate School of Math. Sci. Bldg.)
Xiaojun Wu (Tsukuba Univ.)
TBA (English)
[ Reference URL ]
https://forms.gle/8ERsVDLuKHwbVzm57
Xiaojun Wu (Tsukuba Univ.)
TBA (English)
[ Reference URL ]
https://forms.gle/8ERsVDLuKHwbVzm57
2026/07/07
Operator Algebra Seminars
16:45-18:15 Room #126 (Graduate School of Math. Sci. Bldg.)
Nanami Hashimoto (Keio University)
Equivalence of categories of KK-theory or E-theory for $C^*$-algebras over topological spaces by reflection functors
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
Nanami Hashimoto (Keio University)
Equivalence of categories of KK-theory or E-theory for $C^*$-algebras over topological spaces by reflection functors
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
2026/07/13
Seminar on Geometric Complex Analysis
10:30-12:00 Room #126 (Graduate School of Math. Sci. Bldg.)
Shuho Kanda (The Univ. of Tokyo)
TBA (Japanese)
[ Reference URL ]
https://forms.gle/8ERsVDLuKHwbVzm57
Shuho Kanda (The Univ. of Tokyo)
TBA (Japanese)
[ Reference URL ]
https://forms.gle/8ERsVDLuKHwbVzm57
2026/07/14
Operator Algebra Seminars
16:45-18:15 Room #126 (Graduate School of Math. Sci. Bldg.)
Hiroshi Ando (Chiba University)
TBA
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
Hiroshi Ando (Chiba University)
TBA
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
2026/07/17
Colloquium
15:30-16:30 Room #NISSAY Lecture Hall (Graduate School of Math. Sci. Bldg.)
Hiroki Matui (Graduate School of Mathematical Sciences, The University of Tokyo)
Topological Full Groups and C*-Algebras Arising from Dynamical Systems (日本語)
Hiroki Matui (Graduate School of Mathematical Sciences, The University of Tokyo)
Topological Full Groups and C*-Algebras Arising from Dynamical Systems (日本語)
[ Abstract ]
From a minimal dynamical system on a Cantor set, one can construct a countably infinite group called the topological full group. This group has the remarkable property that its commutator subgroup is simple, and various dynamical systems thus give rise to infinite groups with interesting properties. Taking as a main example the Stein groups introduced by Stein in 1992, I will survey and discuss some recent developments in this area. Time permitting, I will also touch on connections with C*-algebras constructed from dynamical systems and their K-groups, as well as with the homology groups of the dynamical systems themselves.
From a minimal dynamical system on a Cantor set, one can construct a countably infinite group called the topological full group. This group has the remarkable property that its commutator subgroup is simple, and various dynamical systems thus give rise to infinite groups with interesting properties. Taking as a main example the Stein groups introduced by Stein in 1992, I will survey and discuss some recent developments in this area. Time permitting, I will also touch on connections with C*-algebras constructed from dynamical systems and their K-groups, as well as with the homology groups of the dynamical systems themselves.
2026/07/21
Operator Algebra Seminars
16:45-18:15 Room #126 (Graduate School of Math. Sci. Bldg.)
Yusuke Isono (RIMS, Kyoto Univ.)
Introduction to Tomita--Takesaki theory
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
Yusuke Isono (RIMS, Kyoto Univ.)
Introduction to Tomita--Takesaki theory
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
