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Seminar information archive
Seminar information archive ～07/26｜Today's seminar 07/27 | Future seminars 07/28～
2009/02/10
GCOE Seminars
15:00-16:00 Room #270 (Graduate School of Math. Sci. Bldg.)
Piermarco Cannarsa (Univ. degli Studi Roma "Tor Vergata")
Carleman estimates for degenerate parabolic operators with application to null controllability
Piermarco Cannarsa (Univ. degli Studi Roma "Tor Vergata")
Carleman estimates for degenerate parabolic operators with application to null controllability
[ Abstract ]
From the controllability viewpoint, the behavior of uniformly parabolic equations is by now well understood. On the contrary, fewer results are known for degenerate parabolic equations, even though such a class of operators arise in many applied, as well as theoretical, problems.
A fairly complete analysis of the null controllability properties of degenerate parabolic equations in one space dimension was completed in a series of recent works by the speaker and coauthors. The aim of this talk is to review the above theory and present some recent results obtained in collaboration with P. Martinez and J.Vancostenoble for higher dimensional problems. Essential tools of such an approach are adapted Carleman estimates and Hardy type inequalities.
From the controllability viewpoint, the behavior of uniformly parabolic equations is by now well understood. On the contrary, fewer results are known for degenerate parabolic equations, even though such a class of operators arise in many applied, as well as theoretical, problems.
A fairly complete analysis of the null controllability properties of degenerate parabolic equations in one space dimension was completed in a series of recent works by the speaker and coauthors. The aim of this talk is to review the above theory and present some recent results obtained in collaboration with P. Martinez and J.Vancostenoble for higher dimensional problems. Essential tools of such an approach are adapted Carleman estimates and Hardy type inequalities.
GCOE Seminars
16:15-17:15 Room #270 (Graduate School of Math. Sci. Bldg.)
Yurii Anikonov (Sobolev Institute of Mathematics)
Constructive methods in inverse problems
Yurii Anikonov (Sobolev Institute of Mathematics)
Constructive methods in inverse problems
[ Abstract ]
New representations for solutions and coefficients of evolutionary equations are presented. On the basic of these representations theorems of solvability for inverse problems are obtained. This direction develops constructibility in the theory and applications of inverse problems to differential equations
New representations for solutions and coefficients of evolutionary equations are presented. On the basic of these representations theorems of solvability for inverse problems are obtained. This direction develops constructibility in the theory and applications of inverse problems to differential equations
2009/02/07
Monthly Seminar on Arithmetic of Automorphic Forms
13:30-16:00 Room #123 (Graduate School of Math. Sci. Bldg.)
河村隆 (成蹊大学) 13:30-14:30
次数2のモジュラー群の基本領域における行列式の最小値
早田孝博 (山形大学・工学部) 15:00-16:00
Siegel's fundamental domain of degree 2 and Groebner method
河村隆 (成蹊大学) 13:30-14:30
次数2のモジュラー群の基本領域における行列式の最小値
早田孝博 (山形大学・工学部) 15:00-16:00
Siegel's fundamental domain of degree 2 and Groebner method
2009/02/06
GCOE lecture series
15:00-16:00 Room #370 (Graduate School of Math. Sci. Bldg.)
Vladimir Romanov (Sobolev Instutite of Mathematics)
ASYMPTOTIC EXPANSIONS FOR SOME HYPERBOLIC EQUATIONS 第2講
Vladimir Romanov (Sobolev Instutite of Mathematics)
ASYMPTOTIC EXPANSIONS FOR SOME HYPERBOLIC EQUATIONS 第2講
[ Abstract ]
For a linear second-order hyperbolic equation with variable coefficients the fundamental solution for the Cauchy problem is considered. An asymptotic expansion of this solution in a neighborhood of the characteristic cone is introduced and explicit formulae for coefficients of this expansion are derived. Similar questions are discussed for the elasticity equations related to an inhomogeneous isotropic medium.
For a linear second-order hyperbolic equation with variable coefficients the fundamental solution for the Cauchy problem is considered. An asymptotic expansion of this solution in a neighborhood of the characteristic cone is introduced and explicit formulae for coefficients of this expansion are derived. Similar questions are discussed for the elasticity equations related to an inhomogeneous isotropic medium.
thesis presentations
09:45-11:00 Room #118 (Graduate School of Math. Sci. Bldg.)
中岡 宏行 (東京大学大学院数理科学研究科)
Brauer Groups,Mackey and Tambara functors on profinite groups,and 2-dimensional homological algebra(Brauer群、プロ有限群上のMackey及び丹原関手と2次元ホモロジー代数)
中岡 宏行 (東京大学大学院数理科学研究科)
Brauer Groups,Mackey and Tambara functors on profinite groups,and 2-dimensional homological algebra(Brauer群、プロ有限群上のMackey及び丹原関手と2次元ホモロジー代数)
thesis presentations
11:00-12:15 Room #118 (Graduate School of Math. Sci. Bldg.)
廣惠 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)(GL(4,R)の退化主系列表現の一般Whittaker関数)
廣惠 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)(GL(4,R)の退化主系列表現の一般Whittaker関数)
thesis presentations
13:00-14:15 Room #118 (Graduate School of Math. Sci. Bldg.)
阿部 紀行 (東京大学大学院数理科学研究科)
On the existence of homomorphisms between principal series of complex semisimple Lie groups(複素半単純リー群の主系列表現の間の準同型の存在について)
阿部 紀行 (東京大学大学院数理科学研究科)
On the existence of homomorphisms between principal series of complex semisimple Lie groups(複素半単純リー群の主系列表現の間の準同型の存在について)
thesis presentations
11:00-12:15 Room #122 (Graduate School of Math. Sci. Bldg.)
中村 伊南沙 (東京大学大学院数理科学研究科)
Surface links which are coverings of a trivial torus knot(自明なトーラスの被覆の形をした曲面結び目の研究)
中村 伊南沙 (東京大学大学院数理科学研究科)
Surface links which are coverings of a trivial torus knot(自明なトーラスの被覆の形をした曲面結び目の研究)
thesis presentations
13:00-14:15 Room #122 (Graduate School of Math. Sci. Bldg.)
山下 温 (東京大学大学院数理科学研究科)
Compactification of the homeomorphism group of a graph(グラフの同相群のコンパクト化について)
山下 温 (東京大学大学院数理科学研究科)
Compactification of the homeomorphism group of a graph(グラフの同相群のコンパクト化について)
thesis presentations
09:45-11:00 Room #126 (Graduate School of Math. Sci. Bldg.)
乙部 達志 (東京大学大学院数理科学研究科)
Large deviations and theorems of law of large numbers' type for the processes related to the interface models(
界面モデルに関連した確率過程に対する大偏差原理と大数の法則型極限定理)
乙部 達志 (東京大学大学院数理科学研究科)
Large deviations and theorems of law of large numbers' type for the processes related to the interface models(
界面モデルに関連した確率過程に対する大偏差原理と大数の法則型極限定理)
thesis presentations
13:00-14:15 Room #126 (Graduate School of Math. Sci. Bldg.)
米田 剛 (東京大学大学院数理科学研究科)
On the Navier-Stokes equations in a rotating frame and the functional-differential equations of advanced type - a Fourier analysis approach(フーリエ解析的手法による回転場内の流体方程式と進み型関数微分方程式の考察)
米田 剛 (東京大学大学院数理科学研究科)
On the Navier-Stokes equations in a rotating frame and the functional-differential equations of advanced type - a Fourier analysis approach(フーリエ解析的手法による回転場内の流体方程式と進み型関数微分方程式の考察)
thesis presentations
11:00-12:15 Room #128 (Graduate School of Math. Sci. Bldg.)
野田 秀明 (東京大学大学院数理科学研究科)
Short time asymptotic behavior and large deviations for Brownian motion on scale irregular Sierpinski gaskets(非正規なシェルピンスキーガスケット上のブラウン運動に対する熱核の短時間漸近挙動と大偏差原理)
野田 秀明 (東京大学大学院数理科学研究科)
Short time asymptotic behavior and large deviations for Brownian motion on scale irregular Sierpinski gaskets(非正規なシェルピンスキーガスケット上のブラウン運動に対する熱核の短時間漸近挙動と大偏差原理)
thesis presentations
13:00-14:15 Room #128 (Graduate School of Math. Sci. Bldg.)
河内 一樹 (東京大学大学院数理科学研究科)
Rumor Transmission Models and Persistence Analysis(流言伝播モデルとパーシステンス解析)
河内 一樹 (東京大学大学院数理科学研究科)
Rumor Transmission Models and Persistence Analysis(流言伝播モデルとパーシステンス解析)
thesis presentations
14:15-15:30 Room #128 (Graduate School of Math. Sci. Bldg.)
川上 拓志 (東京大学大学院数理科学研究科)
Generalized Okubo systems and the middle convolution(一般大久保型方程式とミドルコンボルーション)
川上 拓志 (東京大学大学院数理科学研究科)
Generalized Okubo systems and the middle convolution(一般大久保型方程式とミドルコンボルーション)
GCOE Seminars
16:15-17:00 Room #370 (Graduate School of Math. Sci. Bldg.)
G. Yuan (Northeast Normal Univ.)
Inverse problems and observability inequalities for plate equations and Schrodinger equations.
G. Yuan (Northeast Normal Univ.)
Inverse problems and observability inequalities for plate equations and Schrodinger equations.
[ Abstract ]
In this talk, we will present some results on inverse problems and observability inequalities for some plate and Schrodinger equaions by using several kinds of Carleman estimates.
In this talk, we will present some results on inverse problems and observability inequalities for some plate and Schrodinger equaions by using several kinds of Carleman estimates.
2009/02/05
Lectures
17:00-18:30 Room #117 (Graduate School of Math. Sci. Bldg.)
Freddy DELBAEN (チューリッヒ工科大学名誉教授)
Introduction to Coherent Risk Measure
Freddy DELBAEN (チューリッヒ工科大学名誉教授)
Introduction to Coherent Risk Measure
Applied Analysis
16:00-17:30 Room #002 (Graduate School of Math. Sci. Bldg.)
Jin CHENG (程 晋) (復旦大学)
Heat transfer in composite materials with Stenfen-Boltzmann conditions and related inverse problems
Jin CHENG (程 晋) (復旦大学)
Heat transfer in composite materials with Stenfen-Boltzmann conditions and related inverse problems
[ Abstract ]
In this talk, we will present our recent results on the mathematical model of the heat transfer in the composite materials. The related inverse problems are discussed. The numerical results show our methods are effective.
In this talk, we will present our recent results on the mathematical model of the heat transfer in the composite materials. The related inverse problems are discussed. The numerical results show our methods are effective.
thesis presentations
15:45-17:00 Room #118 (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)(SU(2,2)の主系列の(g,K)-加群構造と関連するWHITTAKER関数)
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)(SU(2,2)の主系列の(g,K)-加群構造と関連するWHITTAKER関数)
thesis presentations
11:00-12:15 Room #126 (Graduate School of Math. Sci. Bldg.)
関 行宏 (東京大学大学院数理科学研究科)
On behavior of solutions near singularities for nonlinear diffusion equations(非線形拡散方程式の特異点近くでの解の挙動)
関 行宏 (東京大学大学院数理科学研究科)
On behavior of solutions near singularities for nonlinear diffusion equations(非線形拡散方程式の特異点近くでの解の挙動)
thesis presentations
13:00-14:15 Room #126 (Graduate School of Math. Sci. Bldg.)
山﨑 智裕 (東京大学大学院数理科学研究科)
Inverse Problems Related with Non-symmetric Operators and Inverse Problem for One-dimensional Fractional Partial Differential Equation(非対称作用素に関する逆問題と1次元非整数階偏微分方程式に関する逆問題)
山﨑 智裕 (東京大学大学院数理科学研究科)
Inverse Problems Related with Non-symmetric Operators and Inverse Problem for One-dimensional Fractional Partial Differential Equation(非対称作用素に関する逆問題と1次元非整数階偏微分方程式に関する逆問題)
thesis presentations
14:15-15:30 Room #126 (Graduate School of Math. Sci. Bldg.)
坂本 健一 (東京大学大学院数理科学研究科)
Inverse Source Problems for diffusion Equations and Fractional Diffusion Equations(拡散方程式及び非整数階拡散方程式に対するソース項決定逆問題)
坂本 健一 (東京大学大学院数理科学研究科)
Inverse Source Problems for diffusion Equations and Fractional Diffusion Equations(拡散方程式及び非整数階拡散方程式に対するソース項決定逆問題)
thesis presentations
13:00-14:15 Room #128 (Graduate School of Math. Sci. Bldg.)
劉 雪峰 (東京大学大学院数理科学研究科)
Analysis of error constants for linear conforming and nonconforming finite elements(適合および非適合1次有限要素の誤差定数の解析)
劉 雪峰 (東京大学大学院数理科学研究科)
Analysis of error constants for linear conforming and nonconforming finite elements(適合および非適合1次有限要素の誤差定数の解析)
2009/02/04
Seminar on Probability and Statistics
15:00-16:10 Room #128 (Graduate School of Math. Sci. Bldg.)
三浦 良造 (一橋大学国際企業戦略研究科)
Non-Parametric Statistics for a partial sums of iid observations: New Trials
https://www.ms.u-tokyo.ac.jp/~kengok/statseminar/2008/13.html
三浦 良造 (一橋大学国際企業戦略研究科)
Non-Parametric Statistics for a partial sums of iid observations: New Trials
[ Abstract ]
I would lke to review Alpha- quantiles and Ranks with "Empirical Distributions" defined on partial sums of iid. observations discussed in the time continuous version (Brownian Motion).. Then revisiting the formulation of classical estimand and estimators for iid observations , described for example in Fillipova's paper, I would lik,e to discuss on what we could do for our partial sums of iid observations in orde to define our non-parametric estimators and estimands. I will be talking only on the ideas, but mathematical proofs will not be provided.
[ Reference URL ]I would lke to review Alpha- quantiles and Ranks with "Empirical Distributions" defined on partial sums of iid. observations discussed in the time continuous version (Brownian Motion).. Then revisiting the formulation of classical estimand and estimators for iid observations , described for example in Fillipova's paper, I would lik,e to discuss on what we could do for our partial sums of iid observations in orde to define our non-parametric estimators and estimands. I will be talking only on the ideas, but mathematical proofs will not be provided.
https://www.ms.u-tokyo.ac.jp/~kengok/statseminar/2008/13.html
Seminar on Probability and Statistics
16:20-17:30 Room #128 (Graduate School of Math. Sci. Bldg.)
深澤 正彰 (大阪大学 金融・保険教育研究センター)
Black-Scholes 周りの摂動展開について(前半)/ 確率積分の離散化誤差について(後半)
https://www.ms.u-tokyo.ac.jp/~kengok/statseminar/2008/14.html
深澤 正彰 (大阪大学 金融・保険教育研究センター)
Black-Scholes 周りの摂動展開について(前半)/ 確率積分の離散化誤差について(後半)
[ Abstract ]
(前半)確率ボラティリティモデルに対して知られている, Black-Scholes モデル周りでの各種摂動展開が統一的にマルチンゲール展開の理論によって 厳密に正当化かつ一般化されることを示す. またとくに拡散過程モデルに 対しては再生法を用いてより精密な結果を与える.
(後半)確率積分の近似として, 増大停止時刻列による区間分割 Riemann 和 をとったとき, その近似誤差の漸近分布を与える. ファイナンスへの応用とし てデルタヘッジエラーを解析し, 取引費用を考慮した上で漸近的に平均2乗誤 差を最小化する戦略を定義する.
[ Reference URL ](前半)確率ボラティリティモデルに対して知られている, Black-Scholes モデル周りでの各種摂動展開が統一的にマルチンゲール展開の理論によって 厳密に正当化かつ一般化されることを示す. またとくに拡散過程モデルに 対しては再生法を用いてより精密な結果を与える.
(後半)確率積分の近似として, 増大停止時刻列による区間分割 Riemann 和 をとったとき, その近似誤差の漸近分布を与える. ファイナンスへの応用とし てデルタヘッジエラーを解析し, 取引費用を考慮した上で漸近的に平均2乗誤 差を最小化する戦略を定義する.
https://www.ms.u-tokyo.ac.jp/~kengok/statseminar/2008/14.html
Lectures
16:00-17:30 Room #002 (Graduate School of Math. Sci. Bldg.)
Bendong LOU (婁 本東) (同済大学)
Traveling waves of a curvature flow in almost periodic media
Bendong LOU (婁 本東) (同済大学)
Traveling waves of a curvature flow in almost periodic media
[ Abstract ]
In a plane media with almost periodic vertical striations, we study a curvature flow and construct two kinds of traveling waves, one having a straight line like profile and the other having a V shaped profile. For each of the first kind of traveling waves, its profile is the graph of a function whose derivative is almost periodic. For each of the second kind of traveling waves, its profile is like a pulsating cone, with tails asymptotically approach the first kind of traveling waves.
Also we consider a homogenization problem and provide an explicit formula for the homogenized traveling speed.
This is joint work with Xinfu Chen.
In a plane media with almost periodic vertical striations, we study a curvature flow and construct two kinds of traveling waves, one having a straight line like profile and the other having a V shaped profile. For each of the first kind of traveling waves, its profile is the graph of a function whose derivative is almost periodic. For each of the second kind of traveling waves, its profile is like a pulsating cone, with tails asymptotically approach the first kind of traveling waves.
Also we consider a homogenization problem and provide an explicit formula for the homogenized traveling speed.
This is joint work with Xinfu Chen.
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