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Seminar information archive
Seminar information archive ～04/18｜Today's seminar 04/19 | Future seminars 04/20～
thesis presentations
9:15-10:30 Room #128 (Graduate School of Math. Sci. Bldg.)
INOUE Daisuke (Graduate School of Mathematical Sciences University of Tokyo)
Numerical Methods for Nonlinear Partial Differential Equations Arising from Large-Scale Multi-Agent Control Problems
（大規模マルチエージェント制御問題に現れる非線形偏微分方程式の数値計算）
INOUE Daisuke (Graduate School of Mathematical Sciences University of Tokyo)
Numerical Methods for Nonlinear Partial Differential Equations Arising from Large-Scale Multi-Agent Control Problems
（大規模マルチエージェント制御問題に現れる非線形偏微分方程式の数値計算）
thesis presentations
11:00-12:15 Room #118 (Graduate School of Math. Sci. Bldg.)
SHIMADA Ryosuke (Graduate School of Mathematical Sciences University of Tokyo)
Geometric Structure of Affine Deligne-Lusztig Varieties for GLn
（GLnのアファインDeligne-Lusztig多様体の幾何構造）
SHIMADA Ryosuke (Graduate School of Mathematical Sciences University of Tokyo)
Geometric Structure of Affine Deligne-Lusztig Varieties for GLn
（GLnのアファインDeligne-Lusztig多様体の幾何構造）
thesis presentations
11:00-12:15 Room #128 (Graduate School of Math. Sci. Bldg.)
ETO Tokuhiro (Graduate School of Mathematical Sciences University of Tokyo)
Numerical Analysis for Geometric Evolution Equations
（幾何学的発展方程式に対する数値解析）
ETO Tokuhiro (Graduate School of Mathematical Sciences University of Tokyo)
Numerical Analysis for Geometric Evolution Equations
（幾何学的発展方程式に対する数値解析）
thesis presentations
13:00-14:15 Room #126 (Graduate School of Math. Sci. Bldg.)
OIKAWA Mizuki (Graduate School of Mathematical Sciences University of Tokyo)
Equivariant α-induction Frobenius algebras and related constructions of tensor categories
（同変α-誘導フロベニウス代数と関連するテンソル圏の構成）
OIKAWA Mizuki (Graduate School of Mathematical Sciences University of Tokyo)
Equivariant α-induction Frobenius algebras and related constructions of tensor categories
（同変α-誘導フロベニウス代数と関連するテンソル圏の構成）
thesis presentations
14:45-16:00 Room #118 (Graduate School of Math. Sci. Bldg.)
KOIZUMI Junnosuke (Graduate School of Mathematical Sciences University of Tokyo)
Study of motives with modulus using Q-divisors
（モジュラス付きモチーフのQ因子を用いた研究）
KOIZUMI Junnosuke (Graduate School of Mathematical Sciences University of Tokyo)
Study of motives with modulus using Q-divisors
（モジュラス付きモチーフのQ因子を用いた研究）
thesis presentations
14:45-16:00 Room #122 (Graduate School of Math. Sci. Bldg.)
MIYAZAWA Jin (Graduate School of Mathematical Sciences University of Tokyo)
Real Seiberg-Witten theory and its applications to surfaces in 4-manifolds
（実Seiberg-Witten理論とその4次元多様体に埋め込まれた曲面への応用）
MIYAZAWA Jin (Graduate School of Mathematical Sciences University of Tokyo)
Real Seiberg-Witten theory and its applications to surfaces in 4-manifolds
（実Seiberg-Witten理論とその4次元多様体に埋め込まれた曲面への応用）
thesis presentations
14:45-16:00 Room #126 (Graduate School of Math. Sci. Bldg.)
HASHIBA Yasuhito (Graduate School of Mathematical Sciences University of Tokyo)
On the structure of crossed product von Neumann algebras
（接合積von Neumann環の構造について）
HASHIBA Yasuhito (Graduate School of Mathematical Sciences University of Tokyo)
On the structure of crossed product von Neumann algebras
（接合積von Neumann環の構造について）
thesis presentations
14:45-16:00 Room #128 (Graduate School of Math. Sci. Bldg.)
YAMAGISHI Hayate ( )
Asymptotic expansion of estimators related to diffusion processes driven by fractional Brownian motion
（非整数ブラウン運動によって駆動される拡散過程に関わる推定量の漸近展開）
YAMAGISHI Hayate ( )
Asymptotic expansion of estimators related to diffusion processes driven by fractional Brownian motion
（非整数ブラウン運動によって駆動される拡散過程に関わる推定量の漸近展開）
2024/01/25
Information Mathematics Seminar
16:50-18:35 Room #056 (Graduate School of Math. Sci. Bldg.)
Yasunari Suzuki (NTT)
Design and control of fault-tolerant quantum computer (Japanese)
Yasunari Suzuki (NTT)
Design and control of fault-tolerant quantum computer (Japanese)
[ Abstract ]
To demonstrate quantum computational advantage, we need quantum error-correction technology to reduce effective error rates to a small value. In this talk, we explain methods to fault-tolerantly control encoded logical information and methods to translate practical algorithms to basic operations.
To demonstrate quantum computational advantage, we need quantum error-correction technology to reduce effective error rates to a small value. In this talk, we explain methods to fault-tolerantly control encoded logical information and methods to translate practical algorithms to basic operations.
thesis presentations
9:15-10:30 Room #122 (Graduate School of Math. Sci. Bldg.)
TAKANO Akihiro (Graduate School of Mathematical Sciences University of Tokyo)
Studies on knot theory using braid groups and Thompson’s group
（組み紐群とトンプソン群を用いた結び目理論の研究）
TAKANO Akihiro (Graduate School of Mathematical Sciences University of Tokyo)
Studies on knot theory using braid groups and Thompson’s group
（組み紐群とトンプソン群を用いた結び目理論の研究）
thesis presentations
9:15-10:30 Room #128 (Graduate School of Math. Sci. Bldg.)
HIGASHI Kohei (Graduate School of Mathematical Sciences University of Tokyo)
Fuzzy cellular automaton and systems with singular integrals and their applications
（ファジーセルオートマトンおよび特異積分をもつシステムの数理とその応用）
HIGASHI Kohei (Graduate School of Mathematical Sciences University of Tokyo)
Fuzzy cellular automaton and systems with singular integrals and their applications
（ファジーセルオートマトンおよび特異積分をもつシステムの数理とその応用）
thesis presentations
11:00-12:15 Room #118 (Graduate School of Math. Sci. Bldg.)
Li Kimihiko (Graduate School of Mathematical Sciences University of Tokyo)
q-de Rham complexes of higher level
（高レベルq-ド・ラーム複体）
Li Kimihiko (Graduate School of Mathematical Sciences University of Tokyo)
q-de Rham complexes of higher level
（高レベルq-ド・ラーム複体）
thesis presentations
11:00-12:15 Room #122 (Graduate School of Math. Sci. Bldg.)
Wang Gefei (Graduate School of Mathematical Sciences University of Tokyo)
On the Rational Cohomology of Spin Hyperelliptic Mapping Class Groups
（スピン超楕円的写像類群の有理コホモロジーについて）
Wang Gefei (Graduate School of Mathematical Sciences University of Tokyo)
On the Rational Cohomology of Spin Hyperelliptic Mapping Class Groups
（スピン超楕円的写像類群の有理コホモロジーについて）
thesis presentations
11:00-12:15 Room #126 (Graduate School of Math. Sci. Bldg.)
WATANABE Yuta (Graduate School of Mathematical Sciences University of Tokyo)
Bogomolov-Sommese vanishing with multiplier ideals and studies on positivity of singular Hermitian metrics on holomorphic vector bundles
（乗数イデアル層を含むBogomolov-Sommese 消滅定理と正則ベクトル束の特異エルミート計量に関する正値性の研究）
WATANABE Yuta (Graduate School of Mathematical Sciences University of Tokyo)
Bogomolov-Sommese vanishing with multiplier ideals and studies on positivity of singular Hermitian metrics on holomorphic vector bundles
（乗数イデアル層を含むBogomolov-Sommese 消滅定理と正則ベクトル束の特異エルミート計量に関する正値性の研究）
thesis presentations
11:00-12:15 Room #128 (Graduate School of Math. Sci. Bldg.)
OHASHI Haruka (Graduate School of Mathematical Sciences University of Tokyo)
Construction of non-integrable three-state Markov processes with solvable steady states
（可解な定常分布をもつ非可積分3状態マルコフ過程の構成）
OHASHI Haruka (Graduate School of Mathematical Sciences University of Tokyo)
Construction of non-integrable three-state Markov processes with solvable steady states
（可解な定常分布をもつ非可積分3状態マルコフ過程の構成）
thesis presentations
13:00-14:15 Room #122 (Graduate School of Math. Sci. Bldg.)
PEREZ VALDES VICTOR (Graduate School of Mathematical Sciences University of Tokyo)
Construction and classification of matrix-valued differential symmetry breaking operators from S3 to S2
（3次元球面から2次元球面への対称性破れの行列値微分作用素の構成と分類について）
PEREZ VALDES VICTOR (Graduate School of Mathematical Sciences University of Tokyo)
Construction and classification of matrix-valued differential symmetry breaking operators from S3 to S2
（3次元球面から2次元球面への対称性破れの行列値微分作用素の構成と分類について）
thesis presentations
13:00-14:15 Room #126 (Graduate School of Math. Sci. Bldg.)
UEDA Kento (Graduate School of Mathematical Sciences University of Tokyo)
Error Distribution for One-Dimensional Stochastic Differential Equation Driven By Fractional Brownian motion
（非整数ブラウン運動で駆動される1次元確率微分方程式の誤差分布）
UEDA Kento (Graduate School of Mathematical Sciences University of Tokyo)
Error Distribution for One-Dimensional Stochastic Differential Equation Driven By Fractional Brownian motion
（非整数ブラウン運動で駆動される1次元確率微分方程式の誤差分布）
thesis presentations
14:45-16:00 Room #128 (Graduate School of Math. Sci. Bldg.)
HU XIN (Graduate School of Mathematical Sciences University of Tokyo)
On the hydrodynamic limit of the Boltzmann equation and its numerical computation
（ボルツマン方程式の流体力学極限とその数値計算について）
HU XIN (Graduate School of Mathematical Sciences University of Tokyo)
On the hydrodynamic limit of the Boltzmann equation and its numerical computation
（ボルツマン方程式の流体力学極限とその数値計算について）
2024/01/24
Classical Analysis
10:30-12:00 Room #122 (Graduate School of Math. Sci. Bldg.)
Gergő Nemes (Tokyo Metropolitan University)
On the Borel summability of formal solutions of certain higher-order linear ordinary differential equations (English)
Gergő Nemes (Tokyo Metropolitan University)
On the Borel summability of formal solutions of certain higher-order linear ordinary differential equations (English)
[ Abstract ]
We will consider a class of $n$th-order linear ordinary differential equations with a large parameter $u$. Analytic solutions of these equations can be described by (divergent) formal series in
descending powers of $u$. We shall demonstrate that, given mild conditions on the potential functions of the equation, the formal solutions are Borel summable with respect to the parameter $u$ in large, unbounded domains of the independent variable. We will establish that the formal series expansions serve as asymptotic expansions, uniform with respect to the independent variable, for the Borel re-summed exact solutions. Additionally, the exact solutions can be expressed using factorial series in the parameter, and these expansions converge in half-planes, uniformly with respect to the independent variable. To illustrate our theory, we apply it to an $n$th-order Airy-type equation.
Related preprint: https://arxiv.org/abs/2312.14449
We will consider a class of $n$th-order linear ordinary differential equations with a large parameter $u$. Analytic solutions of these equations can be described by (divergent) formal series in
descending powers of $u$. We shall demonstrate that, given mild conditions on the potential functions of the equation, the formal solutions are Borel summable with respect to the parameter $u$ in large, unbounded domains of the independent variable. We will establish that the formal series expansions serve as asymptotic expansions, uniform with respect to the independent variable, for the Borel re-summed exact solutions. Additionally, the exact solutions can be expressed using factorial series in the parameter, and these expansions converge in half-planes, uniformly with respect to the independent variable. To illustrate our theory, we apply it to an $n$th-order Airy-type equation.
Related preprint: https://arxiv.org/abs/2312.14449
Number Theory Seminar
17:00-18:00 Room #056 (Graduate School of Math. Sci. Bldg.)
Yong Suk Moon (BIMSA)
Purity for p-adic Galois representations (English)
Yong Suk Moon (BIMSA)
Purity for p-adic Galois representations (English)
[ Abstract ]
Given a smooth p-adic formal scheme, Tsuji proved a purity result for crystalline local systems on its generic fiber. In this talk, we will discuss a generalization for log-crystalline local systems on the generic fiber of a semistable p-adic formal scheme. This is based on a joint work with Du, Liu, and Shimizu.
Given a smooth p-adic formal scheme, Tsuji proved a purity result for crystalline local systems on its generic fiber. In this talk, we will discuss a generalization for log-crystalline local systems on the generic fiber of a semistable p-adic formal scheme. This is based on a joint work with Du, Liu, and Shimizu.
2024/01/23
Tuesday Seminar on Topology
17:00-18:00 Room #ハイブリッド開催/056 (Graduate School of Math. Sci. Bldg.)
Pre-registration required. See our seminar webpage.
Gefei Wang (The University of Tokyo)
On the rational cohomology of spin hyperelliptic mapping class groups (JAPANESE)
https://park.itc.u-tokyo.ac.jp/MSF/topology/TuesdaySeminar/index_e.html
Pre-registration required. See our seminar webpage.
Gefei Wang (The University of Tokyo)
On the rational cohomology of spin hyperelliptic mapping class groups (JAPANESE)
[ Abstract ]
Let $G$ be the subgroup $S_{n−q} \times S_q$ of the $n$-th symmetric group $S_n$ for $n-q \ge q$. In this talk, we study the $G$-invariant part of the rational cohomology group of the pure braid group $P_n$. The invariant part $H^*(P_n)^G$ includes the rational cohomology of a spin hyperelliptic mapping class group of genus $g$ as a subalgebra when $n=2g+2$. Based on the study of Lehrer-Solomon, we prove that they are independent of n and q in degree $* \le q-1$. We also give a formula to calculate the dimension of $H^* (P_n)^G$ and calculate it in all degree for $q \le 3$.
[ Reference URL ]Let $G$ be the subgroup $S_{n−q} \times S_q$ of the $n$-th symmetric group $S_n$ for $n-q \ge q$. In this talk, we study the $G$-invariant part of the rational cohomology group of the pure braid group $P_n$. The invariant part $H^*(P_n)^G$ includes the rational cohomology of a spin hyperelliptic mapping class group of genus $g$ as a subalgebra when $n=2g+2$. Based on the study of Lehrer-Solomon, we prove that they are independent of n and q in degree $* \le q-1$. We also give a formula to calculate the dimension of $H^* (P_n)^G$ and calculate it in all degree for $q \le 3$.
https://park.itc.u-tokyo.ac.jp/MSF/topology/TuesdaySeminar/index_e.html
FJ-LMI Seminar
13:30-14:40 Room #118 (Graduate School of Math. Sci. Bldg.)
Antoine DIEZ (京都大学, Kyoto University, ASHBi)
Particle systems with geometrical constraints and applications (英語)
https://fj-lmi.cnrs.fr/seminars/
Antoine DIEZ (京都大学, Kyoto University, ASHBi)
Particle systems with geometrical constraints and applications (英語)
[ Abstract ]
Since the pioneering work of Boltzmann, statistical physics has moti-vated the mathematical study or large systems of interacting particles, especially at the interface between stochastic analysis and PDE. More recently, there has been a surge of interest to consider applications to life sciences, where particles can be seen as convenient modeling entities to represent e.g. cell aggregates, bacterial swarms or animal societies. An important question in this context is the link between the microscopic agent-based description and the macroscopic continuum PDE description. Unlike physical systems which generally obey conservation laws, biological systems are rather subjects to constraints which are more geometrical in nature: volume constraints, shape or internal structure for instance. This poses a number of challenges on the modeling, analytical and numerical aspects. In this talk, I will first review earlier works on the study of particle systems with geometrical constraints. Then I will introduce a new framework, based on optimal transport theory, to model particles with arbitrary shapes and deformability properties. I will discuss potential applications in biology and compare this novel approach to other more classical methods.
[ Reference URL ]Since the pioneering work of Boltzmann, statistical physics has moti-vated the mathematical study or large systems of interacting particles, especially at the interface between stochastic analysis and PDE. More recently, there has been a surge of interest to consider applications to life sciences, where particles can be seen as convenient modeling entities to represent e.g. cell aggregates, bacterial swarms or animal societies. An important question in this context is the link between the microscopic agent-based description and the macroscopic continuum PDE description. Unlike physical systems which generally obey conservation laws, biological systems are rather subjects to constraints which are more geometrical in nature: volume constraints, shape or internal structure for instance. This poses a number of challenges on the modeling, analytical and numerical aspects. In this talk, I will first review earlier works on the study of particle systems with geometrical constraints. Then I will introduce a new framework, based on optimal transport theory, to model particles with arbitrary shapes and deformability properties. I will discuss potential applications in biology and compare this novel approach to other more classical methods.
https://fj-lmi.cnrs.fr/seminars/
2024/01/19
Colloquium
15:30-16:30 Room #大講義室(auditorium) (Graduate School of Math. Sci. Bldg.)
If you do not belong to Graduate School of Mathematical Sciences, the University of Tokyo, please apply from the form at [Reference URL].
Kenji Fukaya (Simons Center for Geometry and Physics)
Lagrangian correspondence and Floer theory (JAPANESE)
https://forms.gle/7T6ewXWtrVEKM9dY7
If you do not belong to Graduate School of Mathematical Sciences, the University of Tokyo, please apply from the form at [Reference URL].
Kenji Fukaya (Simons Center for Geometry and Physics)
Lagrangian correspondence and Floer theory (JAPANESE)
[ Abstract ]
It was proposed by Weinstein that the morphism of the `category’ of symplectic manifold should be a Lagrangian correspondence (a Lagrangian submanifold of the direct product).
Gromov-Witten invariant is not functorial for this functor.
However Lagrangian Floer theory is functorial.
I will explain present status of the study of this functoriality and a few of its applications.
[ Reference URL ]It was proposed by Weinstein that the morphism of the `category’ of symplectic manifold should be a Lagrangian correspondence (a Lagrangian submanifold of the direct product).
Gromov-Witten invariant is not functorial for this functor.
However Lagrangian Floer theory is functorial.
I will explain present status of the study of this functoriality and a few of its applications.
https://forms.gle/7T6ewXWtrVEKM9dY7
2024/01/16
Operator Algebra Seminars
16:45-18:15 Room #128 (Graduate School of Math. Sci. Bldg.)
Miho Mukohara (Univ. Tokyo)
Inclusions of simple C$^*$-algebras arising from isometrically shift absorbing actions
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
Miho Mukohara (Univ. Tokyo)
Inclusions of simple C$^*$-algebras arising from isometrically shift absorbing actions
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
Tuesday Seminar on Topology
17:00-18:00 Room #ハイブリッド開催/056 (Graduate School of Math. Sci. Bldg.)
Pre-registration required. See our seminar webpage.
Jin Miyazawa (The University of Tokyo)
A gauge theoretic invariant of embedded surfaces in 4-manifolds and exotic P2-knots (JAPANESE)
https://park.itc.u-tokyo.ac.jp/MSF/topology/TuesdaySeminar/index_e.html
Pre-registration required. See our seminar webpage.
Jin Miyazawa (The University of Tokyo)
A gauge theoretic invariant of embedded surfaces in 4-manifolds and exotic P2-knots (JAPANESE)
[ Abstract ]
When two embeddings of surfaces on a 4-dimensional manifold are given, if they are topologically isotopic but not smoothly isotopic, we call them a pair of exotic surfaces. While there is a great deal of study of exotic surfaces in 4-manifolds, studies of closed exotic surfaces in S4 are limited. In particular, the existence of orientable exotic surfaces in S4 remains unknown to date. There are some examples of non-orientable exotic surfaces in S4, including the initial example given by Finashin-Kreck-Viro in 1988, but all such cases have genus greater than or equal to 5. The difficulty in detecting exotic surfaces in S4 is to prove that two embeddings of surfaces are not smoothly isotopic. All examples of exotic non-orientable surfaces in S4 have been detected by proving the 4-manifolds obtained by the double branched covers are exotic. If we attempt to apply this technique to low-genus non-orientable surfaces in S4, we have to discover exotic small 4-manifolds, which is known to be difficult. In this seminar, we construct an invariant for embedded surfaces in 4-manifolds using Real Seiberg-Witten theory. As an application, we give an infinite family of exotic embeddings into S4 for the real projective plane.
[ Reference URL ]When two embeddings of surfaces on a 4-dimensional manifold are given, if they are topologically isotopic but not smoothly isotopic, we call them a pair of exotic surfaces. While there is a great deal of study of exotic surfaces in 4-manifolds, studies of closed exotic surfaces in S4 are limited. In particular, the existence of orientable exotic surfaces in S4 remains unknown to date. There are some examples of non-orientable exotic surfaces in S4, including the initial example given by Finashin-Kreck-Viro in 1988, but all such cases have genus greater than or equal to 5. The difficulty in detecting exotic surfaces in S4 is to prove that two embeddings of surfaces are not smoothly isotopic. All examples of exotic non-orientable surfaces in S4 have been detected by proving the 4-manifolds obtained by the double branched covers are exotic. If we attempt to apply this technique to low-genus non-orientable surfaces in S4, we have to discover exotic small 4-manifolds, which is known to be difficult. In this seminar, we construct an invariant for embedded surfaces in 4-manifolds using Real Seiberg-Witten theory. As an application, we give an infinite family of exotic embeddings into S4 for the real projective plane.
https://park.itc.u-tokyo.ac.jp/MSF/topology/TuesdaySeminar/index_e.html
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