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Future seminars
Seminar information archive ～04/27｜Today's seminar 04/28 | Future seminars 04/29～
2026/05/07
Applied Analysis
16:00-17:30 Room # 002 (Graduate School of Math. Sci. Bldg.)
Kenta Kumagai (the University of Tokyo)
Large-time behavior and grow-up rates of inhomogeneous semilinear heat equations, via the bifurcation structure of the stationary problem (Japanese)
Kenta Kumagai (the University of Tokyo)
Large-time behavior and grow-up rates of inhomogeneous semilinear heat equations, via the bifurcation structure of the stationary problem (Japanese)
2026/05/11
Seminar on Geometric Complex Analysis
10:30-12:00 Room #126 (Graduate School of Math. Sci. Bldg.)
Luc Pirio (CNRS)
(English)
[ Reference URL ]
https://forms.gle/8ERsVDLuKHwbVzm57
Luc Pirio (CNRS)
(English)
[ Reference URL ]
https://forms.gle/8ERsVDLuKHwbVzm57
2026/05/12
Tuesday Seminar on Topology
16:00-17:00 Online
Pre-registration required. See our seminar webpage.
Sanghoon Kwak (Seoul National University)
Mapping class group of Infinite graph: 'Big' Out(Fn) (ENGLISH)
https://park.itc.u-tokyo.ac.jp/MSF/topology/TuesdaySeminar/index_e.html
Pre-registration required. See our seminar webpage.
Sanghoon Kwak (Seoul National University)
Mapping class group of Infinite graph: 'Big' Out(Fn) (ENGLISH)
[ Abstract ]
Algom-Kfir and Bestvina introduced the mapping class groups of locally finite, infinite graphs in 2021. Since Out(Fn) can be realized as the mapping group of a finite graph, their construction may be viewed as a "big" version of Out(Fn). In this talk, we survey the algebraic and coarse geometric properties of these groups and discuss a relationship with mapping class groups of infinite-type surfaces ("big mapping class groups"). This talk is based on joint work with Ryan Dickmann, George Domat, and Hannah Hoganson, in various collaborations.
[ Reference URL ]Algom-Kfir and Bestvina introduced the mapping class groups of locally finite, infinite graphs in 2021. Since Out(Fn) can be realized as the mapping group of a finite graph, their construction may be viewed as a "big" version of Out(Fn). In this talk, we survey the algebraic and coarse geometric properties of these groups and discuss a relationship with mapping class groups of infinite-type surfaces ("big mapping class groups"). This talk is based on joint work with Ryan Dickmann, George Domat, and Hannah Hoganson, in various collaborations.
https://park.itc.u-tokyo.ac.jp/MSF/topology/TuesdaySeminar/index_e.html
Operator Algebra Seminars
16:45-18:15 Room #126 (Graduate School of Math. Sci. Bldg.)
Camila Sehnem (RIMS, Kyoto Univ.)
Injective envelopes for partial $C^*$-dynamical systems
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
Camila Sehnem (RIMS, Kyoto Univ.)
Injective envelopes for partial $C^*$-dynamical systems
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
Algebraic Geometry Seminar
13:30-15:00 Room #128 (Graduate School of Math. Sci. Bldg.)
Shuji Saito (University of Tokyo)
TBA
Shuji Saito (University of Tokyo)
TBA
[ Abstract ]
TBA
TBA
2026/05/14
Geometric Analysis Seminar
14:30-16:45 Room #117 (Graduate School of Math. Sci. Bldg.)
Jacob Bernstein (Johns Hopkins University) 14:30-15:30
Complexity of submanifolds and Colding-Minicozzi entropy (英語)
https://sites.google.com/g.ecc.u-tokyo.ac.jp/geometricanalysisseminar/
Peter Topping (University of Warwick) 15:45-16:45
TBA (英語)
https://sites.google.com/g.ecc.u-tokyo.ac.jp/geometricanalysisseminar/
Jacob Bernstein (Johns Hopkins University) 14:30-15:30
Complexity of submanifolds and Colding-Minicozzi entropy (英語)
[ Abstract ]
Colding-Minicozzi entropy is a natural quantity associated to mean curvature flow which measures complexity of submanifolds of Euclidean space. We discuss some (nearly) optimal relationships between entropy and areas of (minimal) submanifolds of the sphere.
[ Reference URL ]Colding-Minicozzi entropy is a natural quantity associated to mean curvature flow which measures complexity of submanifolds of Euclidean space. We discuss some (nearly) optimal relationships between entropy and areas of (minimal) submanifolds of the sphere.
https://sites.google.com/g.ecc.u-tokyo.ac.jp/geometricanalysisseminar/
Peter Topping (University of Warwick) 15:45-16:45
TBA (英語)
[ Abstract ]
TBA
[ Reference URL ]TBA
https://sites.google.com/g.ecc.u-tokyo.ac.jp/geometricanalysisseminar/
2026/05/19
Operator Algebra Seminars
16:45-18:15 Room #126 (Graduate School of Math. Sci. Bldg.)
Hiroro Kamikawa (Kyoto Univ.)
TBA
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
Hiroro Kamikawa (Kyoto Univ.)
TBA
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
PDE Real Analysis Seminar
10:30-11:30 Room #128 (Graduate School of Math. Sci. Bldg.)
Nao Hamamuki (Faculty of Science, Hokkaido University)
Gagliardo-Nirenberg型不等式を、遠方で減衰する対数凹関数に対して導きます。証明では、関数から定まるエントロピーに対する上下からの評価が鍵となります。上からの評価には対数型ソボレフの不等式、下からの評価には関数の対数凹性を利用します。また、得られたGagliardo-Nirenberg型不等式における定数の精度についても議論します。さらに、完全非線形楕円型固有値問題の解に適用して、固有値に対する下からの評価を導きます。本講演の内容は、藤田安啓氏、五十嵐蓮氏との共同研究に基づきます。 (日本語)
Nao Hamamuki (Faculty of Science, Hokkaido University)
Gagliardo-Nirenberg型不等式を、遠方で減衰する対数凹関数に対して導きます。証明では、関数から定まるエントロピーに対する上下からの評価が鍵となります。上からの評価には対数型ソボレフの不等式、下からの評価には関数の対数凹性を利用します。また、得られたGagliardo-Nirenberg型不等式における定数の精度についても議論します。さらに、完全非線形楕円型固有値問題の解に適用して、固有値に対する下からの評価を導きます。本講演の内容は、藤田安啓氏、五十嵐蓮氏との共同研究に基づきます。 (日本語)
[ Abstract ]
Gagliardo-Nirenberg型不等式を、遠方で減衰する対数凹関数に対して導きます。証明では、関数から定まるエントロピーに対する上下からの評価が鍵となります。上からの評価には対数型ソボレフの不等式、下からの評価には関数の対数凹性を利用します。また、得られたGagliardo-Nirenberg型不等式における定数の精度についても議論します。さらに、完全非線形楕円型固有値問題の解に適用して、固有値に対する下からの評価を導きます。本講演の内容は、藤田安啓氏、五十嵐蓮氏との共同研究に基づきます。
Gagliardo-Nirenberg型不等式を、遠方で減衰する対数凹関数に対して導きます。証明では、関数から定まるエントロピーに対する上下からの評価が鍵となります。上からの評価には対数型ソボレフの不等式、下からの評価には関数の対数凹性を利用します。また、得られたGagliardo-Nirenberg型不等式における定数の精度についても議論します。さらに、完全非線形楕円型固有値問題の解に適用して、固有値に対する下からの評価を導きます。本講演の内容は、藤田安啓氏、五十嵐蓮氏との共同研究に基づきます。
2026/05/22
Algebraic Geometry Seminar
13:15-14:45 Room #117 (Graduate School of Math. Sci. Bldg.)
Justin Sawon (University of North Carolina Chapel Hill)
Classification results for Lagrangian fibrations
Justin Sawon (University of North Carolina Chapel Hill)
Classification results for Lagrangian fibrations
[ Abstract ]
A Lagrangian fibration on a holomorphic symplectic manifold or variety is one whose general fibre is an abelian variety that is Lagrangian with respect to the symplectic form. Examples were constructed by Beauville/Mukai whose fibres are Jacobians of curves, and by Markushevich-Tikhomirov, Arbarella-Sacca-Ferretti, Matteini, S-Shen, and Brakkee-Camere-Grossi-Pertusi-Sacca-Viktorova whose fibres are Prym varieties of curves with involutions. In all of these examples the family of curves is a linear system on a K3 surface, suggesting the question: is this always the case? Markushevich answered this affirmatively in the genus two case: if the relative compactified Jacobian of a family of genus two curves is a Lagrangian fibration then the curves all lie on a K3 surface, and the Lagrangian fibration is a Beauville-Mukai system. In this talk I will describe our generalization of this result to higher genus, and also to relative Prym varieties of genus three covers with involutions (joint work with Xuqiang Qin).
A Lagrangian fibration on a holomorphic symplectic manifold or variety is one whose general fibre is an abelian variety that is Lagrangian with respect to the symplectic form. Examples were constructed by Beauville/Mukai whose fibres are Jacobians of curves, and by Markushevich-Tikhomirov, Arbarella-Sacca-Ferretti, Matteini, S-Shen, and Brakkee-Camere-Grossi-Pertusi-Sacca-Viktorova whose fibres are Prym varieties of curves with involutions. In all of these examples the family of curves is a linear system on a K3 surface, suggesting the question: is this always the case? Markushevich answered this affirmatively in the genus two case: if the relative compactified Jacobian of a family of genus two curves is a Lagrangian fibration then the curves all lie on a K3 surface, and the Lagrangian fibration is a Beauville-Mukai system. In this talk I will describe our generalization of this result to higher genus, and also to relative Prym varieties of genus three covers with involutions (joint work with Xuqiang Qin).
Colloquium
15:30-16:30 Room #NISSAY Lecture Hall (Graduate School of Math. Sci. Bldg.)
Evgeny Shinder (University of Sheffield / University of Tokyo)
Gromov's cancellation question in birational algebraic geometry
Evgeny Shinder (University of Sheffield / University of Tokyo)
Gromov's cancellation question in birational algebraic geometry
[ Abstract ]
Gromov's 1999 cancellation question is: given two open embeddings of a variety U into a variety X, do they always have isomorphic closed complements? In my joint work with Hsueh-Yung Lin we reformulate this question in terms of the structure of the Grothendieck ring of varieties and answer it in various situations. The answer will be positive or negative depending on the dimension of varieties and the ground field. Finally, I will present an application to the structure of the Cremona group of birational self-maps of the projective space.
Gromov's 1999 cancellation question is: given two open embeddings of a variety U into a variety X, do they always have isomorphic closed complements? In my joint work with Hsueh-Yung Lin we reformulate this question in terms of the structure of the Grothendieck ring of varieties and answer it in various situations. The answer will be positive or negative depending on the dimension of varieties and the ground field. Finally, I will present an application to the structure of the Cremona group of birational self-maps of the projective space.
2026/05/25
Seminar on Geometric Complex Analysis
10:30-12:00 Room #126 (Graduate School of Math. Sci. Bldg.)
Misa Ohashi (Nagoya Institute of Technology)
(Japanese)
[ Reference URL ]
https://forms.gle/8ERsVDLuKHwbVzm57
Misa Ohashi (Nagoya Institute of Technology)
(Japanese)
[ Reference URL ]
https://forms.gle/8ERsVDLuKHwbVzm57
2026/05/26
Operator Algebra Seminars
16:45-18:15 Room #126 (Graduate School of Math. Sci. Bldg.)
Takumi Nishihara (RIMS, Kyoto Univ.)
Compact group actions and $G$-kernels on von Neumann algebras
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar-e.htm
Takumi Nishihara (RIMS, Kyoto Univ.)
Compact group actions and $G$-kernels on von Neumann algebras
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar-e.htm
Numerical Analysis Seminar
16:30-18:00 Room #002 (Graduate School of Math. Sci. Bldg.)
Qin Sheng (Baylor University)
Advances in Splitting: Intercardinal Approaches to Nonlinear Hideo Kawarada Equations
(English)
https://sites.google.com/g.ecc.u-tokyo.ac.jp/utnas-bulletin-board/
Qin Sheng (Baylor University)
Advances in Splitting: Intercardinal Approaches to Nonlinear Hideo Kawarada Equations
(English)
[ Abstract ]
This presentation addresses two main issues. First, we shall discuss recent advancements in both exponential and non-exponential splitting methods, with particular emphasis on their stability, accuracy and global error estimates. Second, we shall introduce a new splitting configuration for solving nonlinear Hideo Kawarada equations with mixed derivative terms. This approach leads to intercardinal splitting finite-difference schemes that provide efficient and accurate numerical approximations of the underlying solutions.
We shall further demonstrate that the resulting implicit methods are numerically stable, convergent, and efficient, while preserving key physical properties such as the positivity and monotonicity. The dynamic orders of accuracy of the proposed algorithms will be illustrated using generalized Milne devices. Simulation examples of the solution procedure will be presented and investigated, and several open problems will also be outlined.
[ Reference URL ]This presentation addresses two main issues. First, we shall discuss recent advancements in both exponential and non-exponential splitting methods, with particular emphasis on their stability, accuracy and global error estimates. Second, we shall introduce a new splitting configuration for solving nonlinear Hideo Kawarada equations with mixed derivative terms. This approach leads to intercardinal splitting finite-difference schemes that provide efficient and accurate numerical approximations of the underlying solutions.
We shall further demonstrate that the resulting implicit methods are numerically stable, convergent, and efficient, while preserving key physical properties such as the positivity and monotonicity. The dynamic orders of accuracy of the proposed algorithms will be illustrated using generalized Milne devices. Simulation examples of the solution procedure will be presented and investigated, and several open problems will also be outlined.
https://sites.google.com/g.ecc.u-tokyo.ac.jp/utnas-bulletin-board/
2026/06/01
Seminar on Geometric Complex Analysis
10:30-12:00 Room #126 (Graduate School of Math. Sci. Bldg.)
Yohei Komori (Waseda Univ.)
(Japanese)
[ Reference URL ]
https://forms.gle/8ERsVDLuKHwbVzm57
Yohei Komori (Waseda Univ.)
(Japanese)
[ Reference URL ]
https://forms.gle/8ERsVDLuKHwbVzm57
2026/06/02
Operator Algebra Seminars
16:45-18:15 Room #126 (Graduate School of Math. Sci. Bldg.)
Yusuke Nishinaka (Osaka Metropolitan Univ.)
Costello-Gwilliam factorization algebras and vertex algebras
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
Yusuke Nishinaka (Osaka Metropolitan Univ.)
Costello-Gwilliam factorization algebras and vertex algebras
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
2026/06/04
Applied Analysis
16:00-17:30 Room # 002 (Graduate School of Math. Sci. Bldg.)
Shobu Shiraki (University of Zagreb)
Beckner's sharp inequalities revisited on binary cubes (Japanese)
Shobu Shiraki (University of Zagreb)
Beckner's sharp inequalities revisited on binary cubes (Japanese)
[ Abstract ]
The Hausdorff–Young inequality and Young’s convolution inequality are fundamental tools in harmonic analysis. The landmark paper “Inequalities in Fourier Analysis” by William Beckner (Ann. of Math., 1975) established the exact values of the sharp constants appearing in these inequalities. Recently, these inequalities have received renewed attention in the setting of binary cubes, driven by applications in additive combinatorics through works by Kane–Tao, de Dios Pont–Greenfeld–Ivanisvili–Madrid, and others. In this discrete setting, the sharp constant is known to be 1 and is no longer the central issue. Instead, the focus shifts to the range of exponents for which the Hausdorff–Young inequality and Young’s convolution inequality hold — a range that is enlarged compared to the classical case. In this talk, we aim to fully characterize this range. This is joint work with Tonći Crmarić (University of Split) and Vjekoslav Kovač (University of Zagreb).
The Hausdorff–Young inequality and Young’s convolution inequality are fundamental tools in harmonic analysis. The landmark paper “Inequalities in Fourier Analysis” by William Beckner (Ann. of Math., 1975) established the exact values of the sharp constants appearing in these inequalities. Recently, these inequalities have received renewed attention in the setting of binary cubes, driven by applications in additive combinatorics through works by Kane–Tao, de Dios Pont–Greenfeld–Ivanisvili–Madrid, and others. In this discrete setting, the sharp constant is known to be 1 and is no longer the central issue. Instead, the focus shifts to the range of exponents for which the Hausdorff–Young inequality and Young’s convolution inequality hold — a range that is enlarged compared to the classical case. In this talk, we aim to fully characterize this range. This is joint work with Tonći Crmarić (University of Split) and Vjekoslav Kovač (University of Zagreb).
2026/06/05
Algebraic Geometry Seminar
13:15-14:45 Room #117 (Graduate School of Math. Sci. Bldg.)
Young-Hoon Kiem (Korea Institute for Advanced Study)
TBA
Young-Hoon Kiem (Korea Institute for Advanced Study)
TBA
[ Abstract ]
TBA
TBA
2026/06/09
Operator Algebra Seminars
16:45-18:15 Room #126 (Graduate School of Math. Sci. Bldg.)
Taisuke Hoshino (Univ. Tokyo)
Rigidity for graph-wreath product II$_1$ factors
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
Taisuke Hoshino (Univ. Tokyo)
Rigidity for graph-wreath product II$_1$ factors
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
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
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
