過去の記録

2012年02月01日(水)

PDE実解析研究会

10:30-11:30   数理科学研究科棟(駒場) 056号室

Chun Liu 氏 (University of Tokyo / Penn State University)
Energetic variational approach: generalized diffusion, stochastic differential equations and optimal transport (ENGLISH)
[ 講演概要 ]
In the talk, I will explore the general framework of energetic variational approaches, which are the direct consequences of classical isothermal thermodynamics, and their particular applications in generalized diffusion problems. In particular, we reveal the roles of different stochastic integrations (Ito's form, Stratonovich's form and other possible forms) and the Wasserstein metric and the procedure of optimal transport in the context of general framework of theories of linear responses.

2012年01月31日(火)

解析学火曜セミナー

16:30-18:00   数理科学研究科棟(駒場) 128号室
Michel Chipot 氏 (University of Zurich)
Obstacle problems in unbounded domains (ENGLISH)
[ 講演概要 ]
We will present a formulation of obstacle problems in unbounded
domains when the energy method does not work, i.e. whenthe force does not belong to H^{-1}.

2012年01月30日(月)

代数幾何学セミナー

15:30-17:00   数理科学研究科棟(駒場) 122号室

On varieties of globally F-regular type (JAPANESE)
[ 講演概要 ]
I will talk about recent topics on varieties of globally F-regular type.

複素解析幾何セミナー

10:30-12:00   数理科学研究科棟(駒場) 128号室
Damian Brotbek 氏 (University of Tokyo)
Differential equations as embedding obstructions and vanishing theorems (ENGLISH)
[ 講演概要 ]
Given a smooth projective variety $X$ it is natural to wonder what is the smallest integer $N$ such that one can embed $X$ into $\mathbf{P}^N$. In this talk I will first recall what can be said for any smooth projective variety, then I will explain how the existence of some particular differential equations on $X$ yields obstructions to the existence of some projective embeddings.

2012年01月27日(金)

談話会・数理科学講演会

16:30-17:30   数理科学研究科棟(駒場) 123号室

お茶&Coffee&お菓子: 16:00～16:30 (コモンルーム)。

[ 講演概要 ]

2012年01月26日(木)

作用素環セミナー

16:30-18:00   数理科学研究科棟(駒場) 117号室
Catherine Oikonomides 氏 (東大数理)
The transverse fundamental class of linear foliations
on torus bundles over the circle (ENGLISH)

2012年01月24日(火)

数値解析セミナー

16:30-18:00   数理科学研究科棟(駒場) 002号室

http://www.ms.u-tokyo.ac.jp/gcoe/index.html

フェーズフィールドモデルによるき裂進展シミュレーションとその応用について (JAPANESE)
[ 講演概要 ]

[ 講演参考URL ]
http://www.infsup.jp/utnas/

2012年01月23日(月)

代数幾何学セミナー

15:30-17:00   数理科学研究科棟(駒場) 122号室

Sigularities and Kodaira dimension of the moduli of stable sheaves on Enriques surfaces (JAPANESE)
[ 講演概要 ]
We shall estimate singularities of moduli of stable sheaves on Enriques/hyper-elliptic surfaces via the Kuranishi theory, consider when its singularities are canonical, and calculate its Kodaira dimension.

複素解析幾何セミナー

10:30-12:00   数理科学研究科棟(駒場) 128号室

Twistor correspondence for R-invariant indefinite self-dual metric on R^4 (JAPANESE)

GCOEレクチャーズ

13:30-15:00   数理科学研究科棟(駒場) 122号室

Mihai Paun 氏 (Institut Élie Cartan and KIAS)
TBA(中止になりました) (ENGLISH)

2012年01月20日(金)

Kavli IPMU Komaba Seminar

14:45-16:15   数理科学研究科棟(駒場) 056号室
Albrecht Klemm 氏 (The University of Bonn)
Refined holomorphic anomaly equations (ENGLISH)
[ 講演概要 ]
We propose a derivation of refined holomophic
anomaly equation from the word-sheet point of
view and discuss the interpretation of the
refined BPS invariants for local Calabi-Yau
spaces.

2012年01月19日(木)

応用解析セミナー

16:00-17:30   数理科学研究科棟(駒場) 128号室
Philippe G. LeFloch 氏 (Univ. Paris 6 / CNRS)
Undercompressible shocks and moving phase boundaries
(ENGLISH)
[ 講演概要 ]
I will present a study of traveling wave solutions to third-order, diffusive-dispersive equations, which arise in the modeling of complex fluid flows and represent regularization-sensitive wave patterns, especially undercompressive shock waves and moving phase boundaries. The qualitative properties of these (possibly oscillatory) traveling waves are well-understood in terms of the so-called kinetic relation, and this has led to a new theory of (nonclassical) solutions to nonlinear hyperbolic systems. Relevant papers are available at the link: www.philippelefloch.org.

2012年01月18日(水)

GCOEレクチャーズ

15:30-17:00   数理科学研究科棟(駒場) 122号室

Mihai Paun 氏 (Institut Élie Cartan and KIAS)
TBA(中止になりました) (ENGLISH)

2012年01月17日(火)

トポロジー火曜セミナー

16:30-18:00   数理科学研究科棟(駒場) 056号室
Tea: 16:00 - 16:30 コモンルーム

On the Johnson cokernels of the mapping class group of a surface (joint work with Naoya Enomoto) (JAPANESE)
[ 講演概要 ]
In general, the Johnson homomorphisms of the mapping class group of a surface are used to investigate graded quotients of the Johnson filtration of the mapping class group. These graded quotients are considered as a sequence of approximations of the Torelli group. Now, there is a broad range of remarkable results for the Johnson homomorphisms.
In this talk, we concentrate our focus on the cokernels of the Johnson homomorphisms of the mapping class group. By a work of Shigeyuki Morita and Hiroaki Nakamura, it is known that an Sp-irreducible module [k] appears in the cokernel of the k-th Johnson homomorphism with multiplicity one if k=2m+1 for any positive integer m. In general, however, to determine Sp-structure of the cokernel is quite a difficult preblem.
Our goal is to show that we have detected new irreducible components in the cokernels. More precisely, we will show that there appears an Sp-irreducible module [1^k] in the cokernel of the k-th Johnson homomorphism with multiplicity one if k=4m+1 for any positive integer m.

数値解析セミナー

17:00-18:00   数理科学研究科棟(駒場) 123号室

http://www.ms.u-tokyo.ac.jp/gcoe/index.html

ある面積保存スキームを用いた移動境界を持つ流れ問題の数値計算 (JAPANESE)
[ 講演概要 ]

[ 講演参考URL ]
http://www.infsup.jp/utnas/

2012年01月16日(月)

代数幾何学セミナー

15:30-17:00   数理科学研究科棟(駒場) 122号室

Mihai Paun 氏 (Institut Élie Cartan and KIAS)
TBA(中止になりました) (JAPANESE)

複素解析幾何セミナー

10:30-12:00   数理科学研究科棟(駒場) 128号室

A ramification theorem for the ratio of canonical forms of flat surfaces in hyperbolic 3-space (JAPANESE)
[ 講演概要 ]
We provide an effective ramification theorem for the ratio of canonical forms of weakly complete flat fronts in the hyperbolic 3-space. As an application, we give a simple proof of the classification of complete nonsingular flat surfaces in the hyperbolic 3-space.

作用素環セミナー

16:30-18:00   数理科学研究科棟(駒場) 117号室

Is an irng singly generated as an ideal? (JAPANESE)

GCOEレクチャーズ

15:30-17:00   数理科学研究科棟(駒場) 122号室

Mihai Paun 氏 (Institut Élie Cartan and KIAS)
TBA(中止になりました) (ENGLISH)

2012年01月12日(木)

代数学コロキウム

18:15-19:15   数理科学研究科棟(駒場) 056号室
Toby Gee 氏 (Imperial College London)
New perspectives on the Breuil-Mézard conjecture (joint with M. Emerton)
(ENGLISH)
[ 講演概要 ]
I will discuss joint work with Matthew Emerton on geometric approaches to the Breuil-Mézard conjecture, generalising a geometric approach of Breuil and Mézard. I will discuss a proof of the geometric version of the original conjecture, as well as work in progress on a geometric version of the conjecture which does not make use of a fixed residual representation.

(本講演は「東京パリ数論幾何セミナー」として、インターネットによる東大数理とIHESとの双方向同時中継で行います。)

2012年01月06日(金)

作用素環セミナー

16:30-18:00   数理科学研究科棟(駒場) 118号室

Diagrammatical methods in theory of subfactors (ENGLISH)

2012年01月05日(木)

作用素環セミナー

16:30-18:00   数理科学研究科棟(駒場) 117号室

Classification and amenability in theory of von Neumann algebras (ENGLISH)

2011年12月27日(火)

作用素環セミナー

14:30-18:00   数理科学研究科棟(駒場) 117号室

Deformation of algebras associated to group cocycles (JAPANESE)

Construction of wedge-local nets through
Longo-Witten endomorphisms (JAPANESE)

GCOEセミナー

13:30-14:30   数理科学研究科棟(駒場) 370号室
Yichao Zhu 氏 (University of Oxford)
The Modelling of Dislocations in the Early Stage of the Metal Fatigue (ENGLISH)
[ 講演概要 ]
Understanding fatigue of metal under cyclic loads is crucial for some fields in mechanical engineering, such as the design of wheels of high speed trains and the aeroplane engine. Experimentally it has been found that this type of
fatigue is closely related to a ladder shape pattern of dislocations known as a persistent slip band (PSB) at a microscopic level. In this talk, a quantitative description for the formation of PSBs is proposed from two angles: 1. the motion of a single dislocation analysed by using asymptotic expansions and numerical simulations; 2. the collective behaviour of a large number of dislocations analysed by using a method of multiple scales.

GCOEセミナー

14:30-15:30   数理科学研究科棟(駒場) 370号室
Manabu Machida 氏 (University of Michigan)
Wave Transport in Random Media and Inverse Problems (ENGLISH)
[ 講演概要 ]
Wave transport in random media is described by the radiative transport equation, which is a linear Boltzmann equation. Such transport phenomena are characterized by two optical parameters in the equation: the absorption and scattering coefficients. In this talk, inverse problems of determining optical parameters will be considered and the Lipschitz stability will be proved using a Carleman estimate. One application of this inverse problem is optical tomography, which detects tumors in a human body using (unlike X-ray CT scan) near-infrared light. I will also present tomographic images of lemon and lotus root slices which are obtained by numerically solving the radiative transport equation with the method of rotated reference frames.