Seminar information archive

Seminar information archive ~05/28Today's seminar 05/29 | Future seminars 05/30~

2009/06/08

Seminar on Geometric Complex Analysis

10:30-12:00   Room #126 (Graduate School of Math. Sci. Bldg.)
大沢健夫 (名古屋大学)
正因子の正値性について

Kavli IPMU Komaba Seminar

17:00-18:30   Room #002 (Graduate School of Math. Sci. Bldg.)
Kiyonori Gomi (Kyoto University)
Multiplication in differential cohomology and cohomology operation
[ Abstract ]
The notion of differential cohomology refines generalized
cohomology theory so as to incorporate information of differential
forms. The differential version of the ordinary cohomology has been
known as the Cheeger-Simons cohomology or the smooth Deligne
cohomology, while the general case was introduced by Hopkins and
Singer around 2002.

The theme of my talk is the cohomology operation induced from the
squaring map in the differential ordinary cohomology and the
differential K-cohomology: I will relate these operations to the
Steenrod operation and the Adams operation. I will also explain the
roles that the squaring maps play in 5-dimensional Chern-Simons theory
for pairs of B-fields and Hamiltonian quantization of generalized
abelian gauge fields.

2009/06/04

Operator Algebra Seminars

16:30-18:00   Room #056 (Graduate School of Math. Sci. Bldg.)
中神祥臣 (日本女子大)
Determinant for rectangular martices

2009/06/03

Seminar on Mathematics for various disciplines

10:30-11:30   Room #056 (Graduate School of Math. Sci. Bldg.)
須藤孝一 (大阪大学)
Evolution of microstructures on crystal surfaces by surface diffusion
[ Abstract ]
We have studied the shape evolution of microstructures fabricated on silicon surfaces by surface diffusion during annealing. Various interesting phenomena, such as corner rounding, facet growth, and void formation, have been experimentally observed. We discuss these observations both from macroscopic and mesoscopic viewpoints. The evolution of macroscopic surface profiles is discussed using evolution equations based on the continuum surface picture. We analyze the mesoscopic scale aspects of the shape evolution using a step-flow model.

Seminar on Probability and Statistics

15:00-16:10   Room #128 (Graduate School of Math. Sci. Bldg.)
山田 亮 (東京大学医科学研究所 ヒトゲノム解析センター ゲノム機能解析分野)
遺伝的多様性を捉える
[ Abstract ]
遺伝統計学は、遺伝子の多様性と生物個体の特徴(形質)の多様性との間の関係を検出するための方法を提供する学問分野である。
遺伝情報はDNAの塩基配列にその多くが刻まれているが、昨今、このDNA配列に関する実験技法が急速に発展し、同一種内のDNA配列が、非常に多様かつ不均一な集団を構成していることが明らかになってきた。
DNA配列多様性と形質多様性との関係を検出するにあたり、このDNA配列集団の多様性と不均一性は、遺伝因子間の非独立性として、関係検出過程に大きな影響を与えることから、DNA配列集団の多様性の把握そのものが、遺伝統計学の課題となっている。
ヒトDNA配列は4種類の塩基が長さ30億であるため、『生命体として成立しうる』という制約の下、非常に多様な配列を取り得る。このDNA配列が取り得る範囲をDNA配列の空間とみなしたとき、DNA配列集団の多様性は、その空間におけるDNA配列集団の分布状態となる。
本セミナーでは、DNA配列集団の分布状態を捉える方法について検討する。
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~kengok/statseminar/2009/04.html

Number Theory Seminar

16:30-18:30   Room #056 (Graduate School of Math. Sci. Bldg.)
Bruno Kahn (Paris第7大学)
Motives and adjoints

2009/06/02

Tuesday Seminar on Topology

16:30-18:00   Room #056 (Graduate School of Math. Sci. Bldg.)
Alexander Voronov (University of Minnesota)
Graph homology: Koszul duality = Verdier duality
[ Abstract ]
Graph cohomology appears in computation of the cohomology of the moduli space of Riemann surfaces and the outer automorphism group of a free group. In the former case, it is graph cohomology of the commutative and Lie types, in the latter it is ribbon graph cohomology, that is to say, graph cohomology of the associative type. The presence of these three basic types of algebraic structures hints at a relation between Koszul duality for operads and Poincare-Lefschetz duality for manifolds. I will show how the more general Verdier duality for certain sheaves on the moduli spaces of graphs associated to Koszul operads corresponds to Koszul duality of operads. This is a joint work with Andrey Lazarev.

Tuesday Seminar of Analysis

16:30-18:00   Room #128 (Graduate School of Math. Sci. Bldg.)
神本 晋吾 (東京大数理)
無限階擬微分作用素の形式核関数について

2009/05/28

Operator Algebra Seminars

16:30-18:00   Room #056 (Graduate School of Math. Sci. Bldg.)
佐藤康彦 (北大理)
The Rohlin property for automorphisms of the Jiang-Su algebra

2009/05/27

Number Theory Seminar

16:30-17:30   Room #056 (Graduate School of Math. Sci. Bldg.)
Gombodorj Bayarmagnai (東京大学大学院数理科学研究科)
The (g,K)-module structure of principal series and related Whittaker functions of SU(2,2)

2009/05/26

Tuesday Seminar of Analysis

16:30-18:00   Room #128 (Graduate School of Math. Sci. Bldg.)
Myriam Ounaies (Strasbourg大学数学科)
Intrepolation problems in H¥"ormander algebras
[ Abstract ]
We call Hörmander algebras the spaces $A_p(\\mathbb C)$ of entire functions $f$ such that, for all $z$ in $\\mathbb C$, \\[|f(z)|\\le Ae^{Bp(z)},\\] where $A$ and $B$ are some positive constants (depending on $f$) and $p$ is a subharmonic weight. We consider the following interpolation problem : Given a discrete sequence $\\{a_j\\}$ of complex numbers and a sequence of complex values $\\{b_j\\}$, under what conditions does there exist a function $f\\in A_p(\\mathbb C)$ such that $f(a_j)=b_j$ for all $j$ ? In other words, what is the trace of $A_p(\\mathbb C)$ on $\\{a_j\\}$ ?
We say that $\\{a_j\\}$ is an interpolating sequence if the trace is defined by the space of all $\\{b_j\\}$ satisfying $|b_j|\\le A'e^{B'p(a_j)}$, for some constants $A',B'>0$.
We use Hörmander's $L^2$-estimates for the $\\bar\\partial$-equation to describe the trace when the weight $p$ is radial and doubling and to characterize the interpolating sequences for more general weights.

Tuesday Seminar on Topology

16:30-18:00   Room #056 (Graduate School of Math. Sci. Bldg.)
境 圭一 (東京大学大学院数理科学研究科)
Configuration space integrals and the cohomology of the space of long embeddings

[ Abstract ]
It is known that some non-trivial cohomology classes, such as finite type invariants for (long) 1-knots (Bott-Taubes, Kohno, ...) and invariants for codimension two, odd dimensional long embeddings (Bott, Cattaneo-Rossi, Watanabe) are given as configuration space integrals associated with trivalent graphs.
In this talk, I will describe more cohomology classes by means of configuration space integral, in particular those arising from non-trivalent graphs and a new formulation of the Haefliger invariant for long 3-embeddings in 6-space, in relation to Budney's little balls operad action and Roseman-Takase's deform-spinning.
This is in part a joint work with Tadayuki Watanabe.

2009/05/25

Seminar on Geometric Complex Analysis

10:30-12:00   Room #126 (Graduate School of Math. Sci. Bldg.)
塚本真輝 (京都大学)
Brody曲線の空間の幾何と平均次元

2009/05/22

Colloquium

16:30-17:30   Room #002 (Graduate School of Math. Sci. Bldg.)
緒方芳子 (東京大学大学院数理科学研究科)
量子スピン系における大偏差原理について
[ Abstract ]
量子スピン系における大偏差原理の研究について紹介する。特に、Gibbs State, Finitely Correlated State と呼ばれる状態についてお話しする。一次元量子スピン系の大偏差原理、Gibbs State の大偏差原理のレート関数の特徴づけ、さらに統計力学における分布の同値性の問題との関連について述べる。

Algebraic Geometry Seminar

15:00-16:30   Room #128 (Graduate School of Math. Sci. Bldg.)
Prof. Steven Zucker (Johns Hopkins University)
The RBS compactification: a real stratified space in
algebraic geometry

2009/05/20

PDE Real Analysis Seminar

10:30-11:30   Room #056 (Graduate School of Math. Sci. Bldg.)
前川泰則 (神戸大学)
Stability of the Burgers vortex
[ Abstract ]
The Burgers vortex is an exact vortex solution to the three dimensional stationary Navier-Stokes equations for viscous incompressible fluids in the presence of an axisymmetric background straining flow. In this talk we discuss the stability of the Burgers vortex with respect to two or three dimensional perturbation flows.

Mathematical Finance

17:30-19:00   Room #122 (Graduate School of Math. Sci. Bldg.)
鍛冶 俊輔 (大阪大)
Financial inverse problem and reconstruction of infinitely divisible distributions with Gaussian component (小谷真一氏(関西学院大)との共同研究)

Number Theory Seminar

16:30-17:30   Room #056 (Graduate School of Math. Sci. Bldg.)
廣江 一希 (東京大学大学院数理科学研究科)
Generalized Whittaker functions for degenerate principal series of GL(4,R)

2009/05/19

Tuesday Seminar on Topology

16:30-18:00   Room #056 (Graduate School of Math. Sci. Bldg.)
Mark Hamilton (東京大学大学院数理科学研究科, JSPS)
Geometric quantization of integrable systems
[ Abstract ]
The theory of geometric quantization is one way of producing a "quantum system" from a "classical system," and has been studied a great deal over the past several decades. It also has surprising ties to representation theory. However, despite this, there still does not exist a satisfactory theory of quantization for systems with singularities.

Geometric quantization requires the choice of a polarization; when using a real polarization to quantize a regular enough manifold, a result of Sniatycki says that the quantization can be found by counting certain objects, called Bohr-Sommerfeld fibres. However, there are many types of systems to which this result does not apply. One such type is the class of completely integrable systems, which are examples coming from mechanics that have many nice properties, but which are nontheless too singular for Sniatycki's theorem to apply.

In this talk we will explore one approach to the quantization of integrable systems, and show a Sniatycki-type relationship to Bohr-Sommerfeld fibres. However, some surprising features appear, including infinite-dimensional contributions and strong dependence on the polarization.

This is joint work with Eva Miranda.

2009/05/18

Seminar on Geometric Complex Analysis

10:30-12:00   Room #126 (Graduate School of Math. Sci. Bldg.)
本多宣博 (東京工業大学)
Conformal symmetries of self-dual hyperbolic monopole metrics (joint work with Jeff Viaclovsky)

2009/05/16

Monthly Seminar on Arithmetic of Automorphic Forms

13:30-16:00   Room #123 (Graduate School of Math. Sci. Bldg.)
水野 義紀 (徳島大学工学部) 13:30-14:30
3次元上半空間のスペクトル理論とエルミート保型形式
[ Abstract ]
3次元上半空間のスペクトル理論のエルミート保型形式への応用につい
て述べます。内容はジーゲル保型形式に対して2次元上半空間のスペクトル理論を応用す
るという今井氏による発見、及びその実際的応用のエルミート版への類似です。具体的に
は小嶋氏により発見されたエルミート版斉藤・黒川リフトに逆定理による解析的証明を与
えること、レベル付エルミート・アイゼンシュタイン級数のフーリエ係数の決定、それを
用いたp進エルミート・アイゼンシュタイン級数のエルミート・アイゼンシュタイン級数
による記述、についてです。これらにおいて必要となる「3次元上半空間のマース形式の
特殊値のある平均が、2次元上半空間のマース形式のフーリエ係数になる」というカトッ
ク・サルナック型の結果についても述べます。(p進エルミート・アイゼンシュタイン級
数については菊田俊之氏との共同研究、その他はRoland Matthes氏との共同研究です。)
宮崎 直 (東京大学数理科学研究科) 15:00-16:00
The Eisenstein series for $GL(3,Z)$ induced from cusp forms
[ Abstract ]
GL(3,Z)$に関するEisenstein級数のFourier-Whittaker展開は,
指標から誘導された場合については,Bump氏とFriedberg氏によって
明示的な表示が与えられている.ここでは,それらの類似として,
尖点形式から誘導された場合について,Fourier-Whittaker展開の
明示的な表示を与える.

2009/05/14

Applied Analysis

16:00-17:30   Room #002 (Graduate School of Math. Sci. Bldg.)
東海林 まゆみ (日本女子大学・理学部・数物科学科)
Particle trajectories around a running cylinder in Brinkman's porous-media flow
[ Abstract ]
Motion of fluid particles provides us with interesting problems of dynamical
systems. We consider here the movement of particles around a running cylinder.
Classically J. C. Maxwell (1870) considered the problem in irrotational flow of
inviscid fluid. He showed that the complete solution is given by the elliptic
functions and the trajectory forms one of the elastica curves. C. Darwin ('53)
considered a similar problem for a moving sphere. In this case, the solution
cannot be written in terms of elliptic functions but can be expressed by a
simple definite integral.
We consider a similar problem in Brinkman's porous-media flow which is proposed
by Brinkman ('49). Our numerical examinations reveals some new interesting
features of the particle trajectories which are not observed in the case of
irrotational flow. We will report them.

Operator Algebra Seminars

16:30-18:00   Room #056 (Graduate School of Math. Sci. Bldg.)
Raphael Ponge (東大数理)
Noncommutative geometry and lower dimensional volumes in Riemannian and CR geometry

Mathematical Biology Seminar

16:00-17:30   Room #123 (Graduate School of Math. Sci. Bldg.)
岩見真吾 (静岡大学創造科学技術大学院)
AIDSワクチン開発への理論的介入-SHIV感染実験と数理モデル-
[ Abstract ]
慢性感染症であるという特性を有するHIV感染症の拡大を阻止するためには、予防・治療AIDSワクチンの開発が不可欠である。しかし、1998年にヒトでは初めての国際的な臨床試験が始まったバックスジェン社のAIDSワクチンは、2003年に失敗だと発表された。また、2004年メルク社の最も有望だったワクチン候補も大規模な臨床試験にまで進んだが、効果がないどころか悪影響がある可能性が判明し、2007年に打ち切られた。HIV単離からすでに25年たった今でも、まだ効果的なワクチンは開発されていない。このように、HIVに対して従来のワクチン製造法では有効なワクチンを作れなかったとなれば、何かこれまでとは違う革新的な治療戦略が必要である。そこで、本研究では、HIVとその体内での振る舞いに関する基本的な疑問と取り組み、HIVを無力化する新しい方法を見つけ出すこと目指す。まず身体に備わった免疫応答が通常どのように機能するのかを知るために、HIVとよく似たSHIVの感染実験と数理モデルを用いて、SHIVの性状、病原性、免疫反応性を明らかにする。今回のセミナーでは、培養細胞での実験データから推定可能であるウイルスの増殖率と感染力によって特徴づけられるSHIVの病原性評価理論を紹介する。

2009/05/13

Number Theory Seminar

16:30-18:45   Room #056 (Graduate School of Math. Sci. Bldg.)
大久保 俊 (東京大学大学院数理科学研究科) 16:30-17:30
剰余体が非完全な場合のB_dR^+のGalois理論
斎藤 秀司 (東京大学大学院数理科学研究科) 17:45-18:45
A counterexample of Bloch-Kato conjecture over a local field and infinite torsion in algebraic cycles of codimension two

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