Seminar information archive

Seminar information archive ~06/15Today's seminar 06/16 | Future seminars 06/17~

thesis presentations

11:00-12:15   Online
INATSUGU Haruhiko (Graduate School of Mathematical Sciences University of Tokyo)
Statistical Inference for Stochastic Differential Equations with Jumps:Global Filtering Approach
(ジャンプを含む確率微分方程式に対する統計推測:
大域的フィルターによる方法)
[ Reference URL ]
https://forms.gle/bdsntP4pZ4TMaehF9

thesis presentations

9:15-10:30   Online
SUZUKI Masamitsu (Graduate School of Mathematical Sciences University of Tokyo)
Local in time solvability for reaction-diffusion systems with rapidly growing nonlinear terms
(速く増大する非線形項を持つ連立反応拡散方程式の時間局所可解性)
[ Reference URL ]
https://forms.gle/bdsntP4pZ4TMaehF9

thesis presentations

11:00-12:15   Online
NAKANISHI Toru (Graduate School of Mathematical Sciences University of Tokyo)
Finite element analysis for radially symmetric solutions of nonlinear heat equations
(非線形熱方程式の球対称解に対する有限要素解析)
[ Reference URL ]
https://forms.gle/bdsntP4pZ4TMaehF9

thesis presentations

11:00-12:15   Online
TAKEUCHI Daichi (Graduate School of Mathematical Sciences University of Tokyo)
On the epsilon factors of ℓ-adic sheaves on varieties
(多様体上のℓ進層のイプシロン因子について)
[ Reference URL ]
https://forms.gle/bdsntP4pZ4TMaehF9

2021/01/25

Seminar on Geometric Complex Analysis

10:30-12:00   Online
Young-Jun Choi (Pusan National University)
Existence of a complete holomorphic vector field via the Kähler-Einstein metric
[ Abstract ]
A fundamental problem in Several Complex Variables is to classify bounded pseudoconvex domains in the complex Euclidean space with a noncompact automorphism group, especially with a compact quotient. In the results of Wong-Rosay and Frankel, they make use of the "Scaling method'' for obtaining an 1-parameter family of automorphisms, which generates a holomorphic vector field.
In this talk, we discuss the existence of a nowhere vanishing complete holomorphic vector filed on a strongly pseudoconvex manifold admtting a negatively curved Kähler-Einstein metric and discrete sequence of automorphisms by introducing the scaling method on potentials of the Kähler-Einstein metric.
[ Reference URL ]
https://zoom.us/meeting/register/tJ0vcu2rrDIqG9Rv5AT0Mpi37urIkJ1IRldB

2021/01/22

Colloquium

15:30-16:30   Online
Please register at the link below to attend this online colloquium
Hiraku Nakajima (Kavli IPMU)
Convolution algebras and a new proof of Kazhdan-Lusztig formula (JAPANESE)
[ Reference URL ]
https://forms.gle/AAVzoCGPyLmzDJHf7

2021/01/21

Information Mathematics Seminar

16:50-18:35   Online
Yasunari Suzuki (NTT)
Topological quantum error-correcting codes and fault-tolerant quantum computing (Japanese)
[ Abstract ]
Explanation on topological quantum error-correcting codes and fault-tolerant quantum computing
[ Reference URL ]
https://docs.google.com/forms/d/1yIKNrwSLsdYt_rivZI8JxhIu3kWtJua5hG8nV5FYbCk/

Tokyo-Nagoya Algebra Seminar

17:00-18:30   Online
Please see the URL below for details on the online seminar.
Hideya Watanabe (Kyoto University)
Based modules over the i-quantum group of type AI (Japanese)
[ Abstract ]
In recent years, i-quantum groups are intensively studied because of their importance in various branches of mathematics and physics. Although i-quantum groups are thought of as generalizations of Drinfeld-Jimbo quantum groups, their representation theory is much more difficult than that of quantum groups. In this talk, I will focus on the i-quantum group of type AI. It is a non-standard quantization of the special orthogonal Lie algebra so_n. I will report my recent research on based modules, which are modules equipped with distinguished bases, called the i-canonical bases. The first main result is a new combinatorial formula describing the branching rule from sl_n to so_n. The second one is the irreducibility of cell modules associated with the i-canonical bases.
[ Reference URL ]
http://www.math.nagoya-u.ac.jp/~aaron.chan/TNAseminar.html

Operator Algebra Seminars

16:45-18:15   Online
Kan Kitamura (Univ. Tokyo)
On induction along a homomorphism of compact quantum groups
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm

2021/01/20

Number Theory Seminar

17:00-18:00   Online
Yuta Saito (University of Tokyo)
Overconvergent Lubin-Tate $(\varphi, \Gamma)$-modules for different uniformizers (Japanese)
[ Abstract ]
$(\varphi, \Gamma)$-modules are used for investigating p-adic Galois representations, which has an important role in constructing the p-adic local Langlands correspondence for GL_2(Q_p). When we try to construct the p-adic local correspondence for GL_2(F) for a general local field F, we want more useful and more suitable $(\varphi, \Gamma)$-modules. Lubin-Tate $(\varphi, \Gamma)$-modules are the candidates for such $(\varphi, \Gamma)$-modules. Lubin-Tate extensions are used for defining Lubin-Tate $(\varphi, \Gamma)$-modules. However, these extensions depend on the choice of uniformizers and the behavior of Lubin-Tate $(\varphi, \Gamma)$-modules for different uniformizers has not been discussed so much. We focus on overconvergency and discuss the coincidence for 2-dimensional triangulable $(\varphi, \Gamma)$-modules for different uniformizers.

2021/01/18

Seminar on Geometric Complex Analysis

10:30-12:00   Online
HAMANO Sachiko (Osaka City University)
The hydrodynamic period matrices and closings of an open Riemann surface of finite genus
[ Abstract ]
A closing of an open Riemann srface $R$ of finite genus is a shorter name of a closed Riemann surface of the same genus into which $R$ can be embedded by a homology type preserving conformal mapping. We observe the Riemann period matrices of all closings of $R$ in the Siegel upper half space. It is known that every hydrodynamic differential on $R$ yields a closing of $R$ called a hydrodynamic closing. (A hydrodynamic differential is a holomorphic which describes a steady flow on $R$ of an ideal fluid.) We study the period matices induced by hydrodynamic closings of $R$. This is a joint work with Masakazu Shiba.
[ Reference URL ]
https://zoom.us/meeting/register/tJ0vcu2rrDIqG9Rv5AT0Mpi37urIkJ1IRldB

2021/01/14

Information Mathematics Seminar

16:50-18:35   Online
Yasunari Suzuki (NTT)
Introduction to quantum computation and quantum error-correcting codes (Japanese)
[ Abstract ]
Introduction to quantum computation and quantum error-correcting codes
[ Reference URL ]
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.
Ryo Ohkawa (Kobe University)
$(-2)$ blow-up formula (Japanese)
[ Reference URL ]
http://www.math.nagoya-u.ac.jp/~aaron.chan/TNAseminar.html

Operator Algebra Seminars

16:45-18:15   Online
Masato Mimura (Tohoku Univ.)
The Green-Tao theorem for number fields
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm

Mathematical Biology Seminar

15:00-16:00   Room # (Graduate School of Math. Sci. Bldg.)
Yusuke Asai (National Center for Global Health and Medicine)
Estimation of the evacuation effect from Wuhan, China, during COVID-19 outbreak

2021/01/13

Discrete mathematical modelling seminar

17:00-18:00   Online
This seminar will be held using Zoom. If you wish to participate, please contact R. Willox by email.
Akihito Yoneyama (Institute of Physics, Graduate School of Arts and Sciences, the University of Tokyo)
Tetrahedron and 3D reflection equation from PBW bases of the nilpotent subalgebra of quantum superalgebras (in Japanese)
[ Abstract ]
We study transition matrices of PBW bases of the nilpotent subalgebra of quantum superalgebras associated with all possible Dynkin diagrams of type A and B in the case of rank 2 and 3, and examine relationships with three-dimensional (3D) integrability. We obtain new solutions to the Zamolodchikov tetrahedron equation via type A and the 3D reflection equation via type B, where the latter equation was proposed by Isaev and Kulish as a 3D analog of the reflection equation of Cherednik. As a by-product of our approach, the Bazhanov-Sergeev solution to the Zamolodchikov tetrahedron equation is characterized as the transition matrix for a particular case of type A, which clarifies an algebraic origin of it. Our work is inspired by the recent developments connecting transition matrices for quantum non-super algebras with intertwiners of irreducible representations of quantum coordinate rings. We also discuss the crystal limit of transition matrices, which gives a super analog of transition maps of Lusztig's parametrizations of the canonical basis.

https://arxiv.org/abs/2012.13385

Seminar on Probability and Statistics

14:30-15:30   Room #Zoom (Graduate School of Math. Sci. Bldg.)
Pierre Lafaye de Micheaux (UNSW)
Depth of Curve Data and Applications (ENGLISH)
[ Abstract ]
[ Reference URL ]
https://sites.google.com/view/apsps/previous-speakers

2021/01/12

Numerical Analysis Seminar

16:30-18:00   Online
Takaharu Yaguchi (Kobe University)
DGNet: Deep Energy-Based Modeling of Discrete-Time Physics and Related Topics (Japanese)
[ Reference URL ]
https://forms.gle/DpuhGupZ7NYbot5d7

Tuesday Seminar on Topology

17:00-18:00   Online
Pre-registration required. See our seminar webpage.
Mitsuaki Kimura (The University of Tokyo)
Bounded cohomology of volume-preserving diffeomorphism groups (JAPANESE)
[ Abstract ]
Let M be a complete Riemannian manifold of finite volume. Brandenbursky and Marcinkowski proved that the third bounded cohomology of the volume-preserving diffeomorphism group of M is infinite dimensional when the fundamental group of M is "complicated enough". For example, if M is two-dimensional, the above condition is satisfied if the Euler characteristic is negative. Recently, we have extended this result in the following two directions.

(1) When M is two-dimensional and the Euler characteristic is greater than or equal to zero.
(2) When the volume of M is infinite.

In this talk, we will mainly discuss (1). The key idea is to use the fundamental group of the configuration space of M (i.e., the braid group), rather than the fundamental group of M. If time permits, we will also explain (2). For this extension, we introduce the notion of "norm controlled cohomology".
[ Reference URL ]
https://park.itc.u-tokyo.ac.jp/MSF/topology/TuesdaySeminar/index_e.html

2021/01/07

Operator Algebra Seminars

16:45-18:15   Online
Colin McSwiggen (Univ. Tokyo)
An extremely close look at the arithmetic-geometric inequality (English)
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm

Information Mathematics Seminar

16:50-18:35   Online
Hiroshi Fujiwara (BroadBand Tower, Inc.)
The cyber attack to the Ministry of Defense-affiliated company and zero trust of Amazon/Google (Japanese)
[ Abstract ]
Explanation on the cyber attack to the Ministry of Defense-affiliated company and zero trust of Amazon/Google
[ Reference URL ]
https://forms.gle/Uhy8uBujZatjNMsGA

2020/12/24

Information Mathematics Seminar

14:55-16:40   Online
Katsuyuki Takashiam (Mitsubishi Electric Co.) 14:55-16:40
Mathematics and cryptographic applications of isogeny graphs (Japanese)
[ Abstract ]
We explain mathematics and cryptographic applications of isogeny graphs.
[ Reference URL ]
https://docs.google.com/forms/d/1yIKNrwSLsdYt_rivZI8JxhIu3kWtJua5hG8nV5FYbCk/
Hiroshi Fujiwara (株式会社ブロードバンドタワー) 16:50-18:35
Internet Business Appearance/The basics of GPU/2Iinput Quantum Gates (Japanese)
[ Abstract ]
Explabnation on the internet business appearance, the basics of GPU and 2Iinput Quantum Gates
[ Reference URL ]
https://forms.gle/Uhy8uBujZatjNMsGA

2020/12/21

Seminar on Geometric Complex Analysis

10:30-12:00   Online
Martin Sera (KUAS)
On a mixed Monge-Ampère operator for quasiplurisubharmonic functions
[ Abstract ]
This reports on a joint work with R. Lärkäng and E. Wulcan. We consider mixed Monge-Ampère products of quasiplurisubharmonic functions with analytic singularities (introduced in a previous work with H. Raufi additionally). These products have the advantage that they preserve mass (a property which is missing for non-pluripolar products).
The main result of the work presented here is that such Monge-Ampère products can be regularized as explicit one parameter limits of mixed Monge-Ampère products of smooth functions, generalizing a result of Andersson-Błocki-Wulcan. We will explain how the theory of residue currents, going back to Coleff-Herrera, Passare and others, plays an important role in the proof.
As a consequence, we get an approximation of Chern and Segre currents of certain singular hermitian metrics on vector bundles by smooth forms in the corresponding Chern and Segre classes.
[ Reference URL ]
https://zoom.us/meeting/register/tJ0vcu2rrDIqG9Rv5AT0Mpi37urIkJ1IRldB

2020/12/18

Colloquium

15:30-16:30   Online
Please register at the link below to attend this online colloquium
Toshiyasu Arai (University of Tokyo)
On Hilbert's proof theory (JAPANESE)
[ Reference URL ]
https://forms.gle/Nmi1KieFDjhchdU69

2020/12/17

Tokyo-Nagoya Algebra Seminar

16:00-17:30   Online
Please see the URL below for details on the online seminar.
Xiao-Wu Chen (University of Science and Technology of China)
The finite EI categories of Cartan type (English)
[ Abstract ]
We will recall the notion of a finite free EI category introduced by Li. To each Cartan triple, we associate a finite free EI category, called the finite EI category of Cartan type. The corresponding category algebra is isomorphic to the 1-Gorenstein algebra, introduced by Geiss-Leclerc-Schroer, that is associated to possibly another Cartan triple. The construction of the second Cartan triple is related to the well-known unfolding of valued graphs. We will apply the obtained algebra isomorphism to re-interpret some tau-locally free modules as induced modules over a certain skew group algebra. This project is joint with Ren Wang.
[ Reference URL ]
http://www.math.nagoya-u.ac.jp/~aaron.chan/TNAseminar.html

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