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Seminar information archive
Seminar information archive ～02/15｜Today's seminar 02/16 | Future seminars 02/17～
Operator Algebra Seminars
15:15-18:00 Room #126 (Graduate School of Math. Sci. Bldg.)
澤田恒河 (東大数理) 15:15-16:15
The Pimsner-Voiculescu AF-embedding of the irrational rotation $C^*$-algebra and its subalgebra
水田有一 (東大数理) 16:30-18:00
A Note on Weak Amenability
澤田恒河 (東大数理) 15:15-16:15
The Pimsner-Voiculescu AF-embedding of the irrational rotation $C^*$-algebra and its subalgebra
水田有一 (東大数理) 16:30-18:00
A Note on Weak Amenability
Functional Analysis Seminar
14:00-17:00 Room #370 (Graduate School of Math. Sci. Bldg.)
Ivana Alexandrova (East Carolina University)
Semi-Classical Structure of the Scattering Amplitude and the Spectral Function for Schrodinger Operators
Ivana Alexandrova (East Carolina University)
Semi-Classical Structure of the Scattering Amplitude and the Spectral Function for Schrodinger Operators
2007/01/23
Tuesday Seminar on Topology
16:30-18:30 Room #056 (Graduate School of Math. Sci. Bldg.)
中田 文憲 (東京大学大学院数理科学研究科) 16:30-17:30
The twistor correspondence for self-dual Zollfrei metrics
----their singularities and reduction
On the homology group of $Out(F_n)$
中田 文憲 (東京大学大学院数理科学研究科) 16:30-17:30
The twistor correspondence for self-dual Zollfrei metrics
----their singularities and reduction
[ Abstract ]
C. LeBrun and L. J. Mason investigated a twistor-type correspondence
between indefinite conformal structures of signature (2,2) with some properties
and totally real embeddings from RP^3 to CP^3.
In this talk, two themes following LeBrun and Mason are explained.
First we consider an additional structure:
the conformal structure is equipped with a null surface foliation
which has some singularity.
We establish a global twistor correspondence for such structures,
and we show that a low dimensional correspondence
between some quotient spaces is induced from this twistor correspondence.
Next we formulate a certain singularity for the conformal structures.
We generalize the formulation of LeBrun and Mason's theorem
admitting the singularity, and we show explicit examples.
大橋 了 (東京大学大学院数理科学研究科) 17:30-18:30C. LeBrun and L. J. Mason investigated a twistor-type correspondence
between indefinite conformal structures of signature (2,2) with some properties
and totally real embeddings from RP^3 to CP^3.
In this talk, two themes following LeBrun and Mason are explained.
First we consider an additional structure:
the conformal structure is equipped with a null surface foliation
which has some singularity.
We establish a global twistor correspondence for such structures,
and we show that a low dimensional correspondence
between some quotient spaces is induced from this twistor correspondence.
Next we formulate a certain singularity for the conformal structures.
We generalize the formulation of LeBrun and Mason's theorem
admitting the singularity, and we show explicit examples.
On the homology group of $Out(F_n)$
[ Abstract ]
Suppose $F_n$ is the free group of rank $n$,
$Out(F_n) = Aut(F_n)/Inn(F_n)$ the outer automorphism group of $F_n$.
We compute $H_*(Out(F_n);\\mathbb{Q})$ for $n\\leq 6$ and conclude
that non-trivial classes in this range are generated
by Morita classes $\\mu_i \\in H_{4i}(Out(F_{2i+2});\\mathbb{Q})$.
Also we compute odd primary part of $H^*(Out(F_4);\\mathbb{Z})$.
Suppose $F_n$ is the free group of rank $n$,
$Out(F_n) = Aut(F_n)/Inn(F_n)$ the outer automorphism group of $F_n$.
We compute $H_*(Out(F_n);\\mathbb{Q})$ for $n\\leq 6$ and conclude
that non-trivial classes in this range are generated
by Morita classes $\\mu_i \\in H_{4i}(Out(F_{2i+2});\\mathbb{Q})$.
Also we compute odd primary part of $H^*(Out(F_4);\\mathbb{Z})$.
2007/01/22
Seminar on Geometric Complex Analysis
10:30-12:00 Room #128 (Graduate School of Math. Sci. Bldg.)
Hanjin Lee (Seoul National University)
Omori-Yau generalized maximum principle
Hanjin Lee (Seoul National University)
Omori-Yau generalized maximum principle
2007/01/19
Lectures
10:30-12:00 Room #056 (Graduate School of Math. Sci. Bldg.)
Alex Mahalov (Arizona State University)
3D Navier-Stokes and Euler Equations with Uniformly Large Initial Vorticity: Global Regularity and Three-Dimensional Euler Dynamics
Alex Mahalov (Arizona State University)
3D Navier-Stokes and Euler Equations with Uniformly Large Initial Vorticity: Global Regularity and Three-Dimensional Euler Dynamics
2007/01/18
Lectures
13:00-14:30 Room #056 (Graduate School of Math. Sci. Bldg.)
Alex Mahalov (Arizona State University)
3D Navier-Stokes and Euler Equations with Uniformly Large Initial Vorticity: Global Regularity and Three-Dimensional Euler Dynamics
Alex Mahalov (Arizona State University)
3D Navier-Stokes and Euler Equations with Uniformly Large Initial Vorticity: Global Regularity and Three-Dimensional Euler Dynamics
[ Abstract ]
We prove existence on infinite time intervals of regular solutions to the 3D Navier-Stokes Equations for fully three-dimensional initial data characterized by uniformly large vorticity; smoothness assumptions for initial data are the same as in local existence theorems. There are no conditional assumptions on the properties of solutions at later times, nor are the global solutions close to any 2D manifold. The global existence is proven using techniques of fast singular oscillating limits, Lemmas on restricted convolutions and the Littlewood-Paley dyadic decomposition. In the second part of the talk, we analyze regularity and dynamics of the 3D Euler equations in cylindrical domains with weakly aligned large initial vorticity.
We prove existence on infinite time intervals of regular solutions to the 3D Navier-Stokes Equations for fully three-dimensional initial data characterized by uniformly large vorticity; smoothness assumptions for initial data are the same as in local existence theorems. There are no conditional assumptions on the properties of solutions at later times, nor are the global solutions close to any 2D manifold. The global existence is proven using techniques of fast singular oscillating limits, Lemmas on restricted convolutions and the Littlewood-Paley dyadic decomposition. In the second part of the talk, we analyze regularity and dynamics of the 3D Euler equations in cylindrical domains with weakly aligned large initial vorticity.
Operator Algebra Seminars
16:30-18:00 Room #126 (Graduate School of Math. Sci. Bldg.)
酒匂宏樹 (東大数理)
Twisted Bernoulli shift actions of $Z^2 \\rtimes SL(2,Z)$
酒匂宏樹 (東大数理)
Twisted Bernoulli shift actions of $Z^2 \\rtimes SL(2,Z)$
Applied Analysis
16:00-17:30 Room #056 (Graduate School of Math. Sci. Bldg.)
LIANG Xing (東京大学大学院数理科学研究科 / 日本学術振興会)
Asymptotic Speeds of Spread and Traveling Waves for Monotone Semiflows with Applications
LIANG Xing (東京大学大学院数理科学研究科 / 日本学術振興会)
Asymptotic Speeds of Spread and Traveling Waves for Monotone Semiflows with Applications
[ Abstract ]
The theory of asymptotic speeds of spread and monotone traveling waves is established for a class of monotone discrete and continuous-time semiflows and is applied to a functional differential equation with diffusion, a time-delayed lattice population model and a reaction-diffusion equation in an infinite
cylinder.
The theory of asymptotic speeds of spread and monotone traveling waves is established for a class of monotone discrete and continuous-time semiflows and is applied to a functional differential equation with diffusion, a time-delayed lattice population model and a reaction-diffusion equation in an infinite
cylinder.
2007/01/17
PDE Real Analysis Seminar
10:30-11:30 Room #056 (Graduate School of Math. Sci. Bldg.)
Alex Mahalov (Department of Mathematics and Statistics, Department of Mechanical and Aerospace Engineering, Program in Environmental Fluid Dynamics, Arizona State University )
Fast Singular Oscillating Limits of Hydrodynamic PDEs: application to 3D Euler, Navier-Stokes and MHD equations
http://coe.math.sci.hokudai.ac.jp/
Alex Mahalov (Department of Mathematics and Statistics, Department of Mechanical and Aerospace Engineering, Program in Environmental Fluid Dynamics, Arizona State University )
Fast Singular Oscillating Limits of Hydrodynamic PDEs: application to 3D Euler, Navier-Stokes and MHD equations
[ Abstract ]
Methods of harmonic analysis and dispersive properties are applied
to 3d hydrodynamic equations to obtain long-time and/or global existence results to the Cauchy problem for special classes of 3d initial data. Smoothness assumptions for initial data are the same as in local existence theorems. Techniques for fast singular oscillating limits are used and large and/or infinite time regularity is obtained by bootstrapping from global regularity of the limit equations.
The latter gain regularity from 3d nonlinear cancellation of oscillations.
Applications include Euler, Navier-Stokes, Boussinesq and MHD equations, in infinite, periodic and bounded cylindrical domains.
[ Reference URL ]Methods of harmonic analysis and dispersive properties are applied
to 3d hydrodynamic equations to obtain long-time and/or global existence results to the Cauchy problem for special classes of 3d initial data. Smoothness assumptions for initial data are the same as in local existence theorems. Techniques for fast singular oscillating limits are used and large and/or infinite time regularity is obtained by bootstrapping from global regularity of the limit equations.
The latter gain regularity from 3d nonlinear cancellation of oscillations.
Applications include Euler, Navier-Stokes, Boussinesq and MHD equations, in infinite, periodic and bounded cylindrical domains.
http://coe.math.sci.hokudai.ac.jp/
Lectures
15:30-17:00 Room #470 (Graduate School of Math. Sci. Bldg.)
市原直幸 氏 (大阪大学基礎工学研究科)
Hamilton-Jacobi方程式の漸近解とその周辺の話題
市原直幸 氏 (大阪大学基礎工学研究科)
Hamilton-Jacobi方程式の漸近解とその周辺の話題
Seminar on Probability and Statistics
16:20-17:30 Room #128 (Graduate School of Math. Sci. Bldg.)
玉置 健一郎 (早稲田大学)
Second order optimality for estimators in time series regression models
https://www.ms.u-tokyo.ac.jp/~kengok/statseminar/2006/17.html
玉置 健一郎 (早稲田大学)
Second order optimality for estimators in time series regression models
[ Abstract ]
We consider the second order asymptotic properties of an efficient frequency domain regression coefficient estimator $\\hat{\\beta}$ proposed by Hannan (1963). This estimator is a semiparametric estimator based on nonparametric spectral estimators. We derive the second order Edgeworth expansion of the distribution of $\\hat{\\beta}$. Then it is shown that the second order asymptotic properties are independent of the bandwidth choice for residual spectral estimator, which implies that $\\hat{\\beta}$ has the same rate of convergence as in regular parametric estimation. This is a sharp contrast with the general semiparametric estimation theory. We also examine the second order Gaussian efficiency of $\\hat{\\beta}$. Numerical studies are given to confirm the theoretical results.
[ Reference URL ]We consider the second order asymptotic properties of an efficient frequency domain regression coefficient estimator $\\hat{\\beta}$ proposed by Hannan (1963). This estimator is a semiparametric estimator based on nonparametric spectral estimators. We derive the second order Edgeworth expansion of the distribution of $\\hat{\\beta}$. Then it is shown that the second order asymptotic properties are independent of the bandwidth choice for residual spectral estimator, which implies that $\\hat{\\beta}$ has the same rate of convergence as in regular parametric estimation. This is a sharp contrast with the general semiparametric estimation theory. We also examine the second order Gaussian efficiency of $\\hat{\\beta}$. Numerical studies are given to confirm the theoretical results.
https://www.ms.u-tokyo.ac.jp/~kengok/statseminar/2006/17.html
Lectures
16:30-18:00 Room #122 (Graduate School of Math. Sci. Bldg.)
Mourad Bellassoued (Faculte des Sciences de Bizerte)
Recovering a potential in the wave equation via Dirichlet-to-Neumann map.
Mourad Bellassoued (Faculte des Sciences de Bizerte)
Recovering a potential in the wave equation via Dirichlet-to-Neumann map.
2007/01/16
Tuesday Seminar on Topology
16:30-18:30 Room #056 (Graduate School of Math. Sci. Bldg.)
笹平 裕史 (東京大学大学院数理科学研究科) 16:30-17:30
An $SO(3)$-version of $2$-torsion instanton invariants
On the non-acyclic Reidemeister torsion for knots
笹平 裕史 (東京大学大学院数理科学研究科) 16:30-17:30
An $SO(3)$-version of $2$-torsion instanton invariants
[ Abstract ]
We construct invariants for simply connected, non-spin $4$-manifolds using torsion cohomology classes of moduli spaces of ASD connections on $SO(3)$-bundles. The invariants are $SO(3)$-version of Fintushel-Stern's $2$-torsion instanton invariants. We show that this $SO(3)$-torsion invariant of $2CP^2 \\# -CP^2$ is non-trivial, while it is known that any invariants of $2CP^2 \\# - CP^2$ coming from the Seiberg-Witten theory are trivial
since $2CP^2 \\# -CP^2$ has a positive scalar curvature metric.
山口 祥司 (東京大学大学院数理科学研究科) 17:30-18:30We construct invariants for simply connected, non-spin $4$-manifolds using torsion cohomology classes of moduli spaces of ASD connections on $SO(3)$-bundles. The invariants are $SO(3)$-version of Fintushel-Stern's $2$-torsion instanton invariants. We show that this $SO(3)$-torsion invariant of $2CP^2 \\# -CP^2$ is non-trivial, while it is known that any invariants of $2CP^2 \\# - CP^2$ coming from the Seiberg-Witten theory are trivial
since $2CP^2 \\# -CP^2$ has a positive scalar curvature metric.
On the non-acyclic Reidemeister torsion for knots
[ Abstract ]
The Reidemeister torsion is an invariant of a CW-complex and a representation of its fundamental group. We consider the Reidemeister torsion for a knot exterior in a homology three sphere and a representation given by the composition of an SL(2, C)- (or SU(2)-) representation of the knot group and the adjoint action to the Lie algebra.
We will see that this invariant is expressed by the differential coefficient of the twisted Alexander invariant of the knot and investigate some properties of the invariant by using this relation.
The Reidemeister torsion is an invariant of a CW-complex and a representation of its fundamental group. We consider the Reidemeister torsion for a knot exterior in a homology three sphere and a representation given by the composition of an SL(2, C)- (or SU(2)-) representation of the knot group and the adjoint action to the Lie algebra.
We will see that this invariant is expressed by the differential coefficient of the twisted Alexander invariant of the knot and investigate some properties of the invariant by using this relation.
Lectures
16:30-18:00 Room #122 (Graduate School of Math. Sci. Bldg.)
Mourad Bellassoued (Faculte des Sciences de Bizerte)
Recovering a potential from partial Cauchy data for the Schrödinger equation.
Mourad Bellassoued (Faculte des Sciences de Bizerte)
Recovering a potential from partial Cauchy data for the Schrödinger equation.
2007/01/15
Seminar on Geometric Complex Analysis
10:30-12:00 Room #128 (Graduate School of Math. Sci. Bldg.)
竹内 潔 (筑波大学数理物質科学研究科)
Lagragian constructions for various topological invariants of algebraic varieties (東大数理、松井優氏との共同研究)
竹内 潔 (筑波大学数理物質科学研究科)
Lagragian constructions for various topological invariants of algebraic varieties (東大数理、松井優氏との共同研究)
Lectures
16:30-18:00 Room #122 (Graduate School of Math. Sci. Bldg.)
Mourad Bellassoued (Faculte des Sciences de Bizerte)
Recovering a potential from full Cauchy data for the Schrödinger equation.
Mourad Bellassoued (Faculte des Sciences de Bizerte)
Recovering a potential from full Cauchy data for the Schrödinger equation.
[ Abstract ]
In this lectures we survey recent progress on the problem of determining a potential by measuring the Dirichlet to Neumann map
for the associated Schr\\"odinger equation or wave equation. We make emphasis on the new results obtained with M.Yamamoto which is concerned with the case that the measurements are made on a strict
subset of the boundary for the wave equation.
In this lectures we survey recent progress on the problem of determining a potential by measuring the Dirichlet to Neumann map
for the associated Schr\\"odinger equation or wave equation. We make emphasis on the new results obtained with M.Yamamoto which is concerned with the case that the measurements are made on a strict
subset of the boundary for the wave equation.
Lectures
16:00-17:30 Room #056 (Graduate School of Math. Sci. Bldg.)
Antonio DeSimone (SISSA (International School for Advanced Studies))
Analysis of physical systems involving multiple spatial scales: some case studies
Antonio DeSimone (SISSA (International School for Advanced Studies))
Analysis of physical systems involving multiple spatial scales: some case studies
[ Abstract ]
Variational methods have recently proved to be a powerful tool in deriving macroscopic models for phenomena whose physics is decided at the sub-miccron scale.
We will use two case studies to illustrate this point, namely, that of liquid crystal elastomers and that of superhydrophobic surfaces.
Liquid crystal elastomers are solids which combine the optical properties of liquid crystals with the mechanical properties of rubbery solids. They display phase transformations, material instabilities, and microstructures in a way simalr to shape-memory alloys.
The richness of the underlying material symmetries makes the mathematical analysis of this system particularly rewarding. Recent progress, ranging from analytical relaxation results to numerical simulations of the macroscopic mechanical response will be reviewed.
Variational methods have recently proved to be a powerful tool in deriving macroscopic models for phenomena whose physics is decided at the sub-miccron scale.
We will use two case studies to illustrate this point, namely, that of liquid crystal elastomers and that of superhydrophobic surfaces.
Liquid crystal elastomers are solids which combine the optical properties of liquid crystals with the mechanical properties of rubbery solids. They display phase transformations, material instabilities, and microstructures in a way simalr to shape-memory alloys.
The richness of the underlying material symmetries makes the mathematical analysis of this system particularly rewarding. Recent progress, ranging from analytical relaxation results to numerical simulations of the macroscopic mechanical response will be reviewed.
2007/01/12
Colloquium
16:30-17:30 Room #123 (Graduate School of Math. Sci. Bldg.)
鳥海光弘 (東京大学・大学院新領域創成科学研究科)
地球変動にまつわるおかしな現象、2題
1、プレート境界で砂と泥に起こる雪だるま現象
2、プレート境界地震は確率共鳴か
鳥海光弘 (東京大学・大学院新領域創成科学研究科)
地球変動にまつわるおかしな現象、2題
1、プレート境界で砂と泥に起こる雪だるま現象
2、プレート境界地震は確率共鳴か
[ Abstract ]
地球科学における興味ある現象2題‐巨大固液混合体はどのように振舞うか。
最近の固体地球科学の大きな関心はプレート境界付近における固体・流体混合物質の挙動と境界型地震破壊やすべり運動、火山活動などとの関係である。プレート境界は地球上でもっとも活動的な部分であり、地球表層部分と地球内部とのエネルギー交換や物質交換が最も多く行われる部分でもある。とくに日本海溝や伊豆マリアナ海溝、南海トラフ、琉球海溝などの沈み込み境界部付近の地震波探査、電磁気探査、ボーリング掘削、などの研究がんたくさんの新しい事実を描き出している。
今回興味ある話として紹介するのは、プレート沈み込み境界では、海溝底で堆積した砂泥層が海洋プレートに乗ってプレート境界に引きずり込まれ、排水する過程で砂と泥に分離し、巨大な砂の塊が泥の層の中に分散する現象である。この現象の数理は砂が水を保持して流動化する過程と、プレート境界に持ち込まれた含水地質体が長期にわたりせん断変形を受ける過程で、砂の部分が次第に雪だるま状に衝突・合体する過程で示され、歪により巨大化する砂の塊は数キロに達することもありえる。こうして出来るプレート境界の構造は、大きさ分布がべき的になる砂の塊が境界に沿って拡がった泥の層内にクラスター上に分布するパターンを形成するだう。こうした構造形成はプレート境界部の力学特性を決めているだろう。
第2の話題はプレート境界における破壊の確率共鳴というテーマである、最近の研究ではプレート境界において発生する中小規模の地震はrepeating earthquakesまたはsimilar earthquakesとも呼ばれ、同一場所で繰り返しおこるせん断クラックである。そのサイズは0.01‐1km程度である。一方、巨大地震はこれに比べて大きく100kmx10km以上の破壊面をもつ。しかしこの巨大さにもかかわらず、やはり同一箇所が繰り返し破壊し、これをアスペリティと呼んでいる。一方、こうしたアスペリティの周囲は非アスペリティとよばれ、ゆっくりと滑っていて、流体を保持した岩石が分布し、低密度となっている。問題は大小の規模の破壊がどのような関係にあるのかという古典的なテーマである。プレート境界面上のいろいろな大きさのアスペリティが互いに重ならないであり続けているのか、もしくは互いに重なっているのかは重大である。観測的には巨大地震の破壊面は他の小さい破壊面と重なっている。つまり、境界面では、中小の多数のアスペリティが確率的に活動していて、巨大破壊の時にはそれらのアスペリティが一斉に動き出すということであろう。今回の話題提供ではこうした現象を確率共鳴として考えてみよう。
地球科学における興味ある現象2題‐巨大固液混合体はどのように振舞うか。
最近の固体地球科学の大きな関心はプレート境界付近における固体・流体混合物質の挙動と境界型地震破壊やすべり運動、火山活動などとの関係である。プレート境界は地球上でもっとも活動的な部分であり、地球表層部分と地球内部とのエネルギー交換や物質交換が最も多く行われる部分でもある。とくに日本海溝や伊豆マリアナ海溝、南海トラフ、琉球海溝などの沈み込み境界部付近の地震波探査、電磁気探査、ボーリング掘削、などの研究がんたくさんの新しい事実を描き出している。
今回興味ある話として紹介するのは、プレート沈み込み境界では、海溝底で堆積した砂泥層が海洋プレートに乗ってプレート境界に引きずり込まれ、排水する過程で砂と泥に分離し、巨大な砂の塊が泥の層の中に分散する現象である。この現象の数理は砂が水を保持して流動化する過程と、プレート境界に持ち込まれた含水地質体が長期にわたりせん断変形を受ける過程で、砂の部分が次第に雪だるま状に衝突・合体する過程で示され、歪により巨大化する砂の塊は数キロに達することもありえる。こうして出来るプレート境界の構造は、大きさ分布がべき的になる砂の塊が境界に沿って拡がった泥の層内にクラスター上に分布するパターンを形成するだう。こうした構造形成はプレート境界部の力学特性を決めているだろう。
第2の話題はプレート境界における破壊の確率共鳴というテーマである、最近の研究ではプレート境界において発生する中小規模の地震はrepeating earthquakesまたはsimilar earthquakesとも呼ばれ、同一場所で繰り返しおこるせん断クラックである。そのサイズは0.01‐1km程度である。一方、巨大地震はこれに比べて大きく100kmx10km以上の破壊面をもつ。しかしこの巨大さにもかかわらず、やはり同一箇所が繰り返し破壊し、これをアスペリティと呼んでいる。一方、こうしたアスペリティの周囲は非アスペリティとよばれ、ゆっくりと滑っていて、流体を保持した岩石が分布し、低密度となっている。問題は大小の規模の破壊がどのような関係にあるのかという古典的なテーマである。プレート境界面上のいろいろな大きさのアスペリティが互いに重ならないであり続けているのか、もしくは互いに重なっているのかは重大である。観測的には巨大地震の破壊面は他の小さい破壊面と重なっている。つまり、境界面では、中小の多数のアスペリティが確率的に活動していて、巨大破壊の時にはそれらのアスペリティが一斉に動き出すということであろう。今回の話題提供ではこうした現象を確率共鳴として考えてみよう。
2007/01/11
Lectures
16:00-17:30 Room #123 (Graduate School of Math. Sci. Bldg.)
Oleg Yu. Emanouilov (Colorado State University)
Some Problems of Global Controllability of Burgers Equation and Navier-Stokes system.
Oleg Yu. Emanouilov (Colorado State University)
Some Problems of Global Controllability of Burgers Equation and Navier-Stokes system.
2007/01/10
Lectures
16:00-17:30 Room #118 (Graduate School of Math. Sci. Bldg.)
Oleg Yu. Emanouilov (Colorado State University)
Some Problems of Global Controllability of Burgers Equation and Navier-Stokes system.
Oleg Yu. Emanouilov (Colorado State University)
Some Problems of Global Controllability of Burgers Equation and Navier-Stokes system.
2007/01/09
Lectures
16:00-17:30 Room #118 (Graduate School of Math. Sci. Bldg.)
Oleg Yu. Emanouilov (Colorado State University)
Some Problems of Global Controllability of Burgers Equation and Navier-Stokes system.
Oleg Yu. Emanouilov (Colorado State University)
Some Problems of Global Controllability of Burgers Equation and Navier-Stokes system.
[ Abstract ]
We show that 1-D Burgers equation is globally uncontrollable with control acting at two endpoints. Then we establish the global controllability of the 2-D Burgers equation. Finally we show that for 2-D Navier-Stokes system the problem of global exact controllability is solvable for the dense set of the initial data with a control acting on part of the boundary.
We show that 1-D Burgers equation is globally uncontrollable with control acting at two endpoints. Then we establish the global controllability of the 2-D Burgers equation. Finally we show that for 2-D Navier-Stokes system the problem of global exact controllability is solvable for the dense set of the initial data with a control acting on part of the boundary.
2006/12/28
Operator Algebra Seminars
16:30-18:00 Room #126 (Graduate School of Math. Sci. Bldg.)
Roberto Longo (University of Rome)
Operator Algebras and Conformal Field Theory II
Roberto Longo (University of Rome)
Operator Algebras and Conformal Field Theory II
2006/12/25
Monthly Seminar on Arithmetic of Automorphic Forms
13:30-16:00 Room #123 (Graduate School of Math. Sci. Bldg.)
研究集会の情報 (なし)
なし
研究集会の情報 (なし)
なし
[ Abstract ]
秋から、少しお休みしていますので、替わりにまとめて集会をします。
12月25日午後から27日午後3時くらいまでです。詳細はURL:
https://www.ms.u-tokyo.ac.jp/activity/meeting061225.htm
をご覧下さい。織田孝幸
秋から、少しお休みしていますので、替わりにまとめて集会をします。
12月25日午後から27日午後3時くらいまでです。詳細はURL:
https://www.ms.u-tokyo.ac.jp/activity/meeting061225.htm
をご覧下さい。織田孝幸
2006/12/21
Seminar for Mathematical Past of Asia
17:00-18:30 Room #123 (Graduate School of Math. Sci. Bldg.)
楠葉隆徳 (大阪経済大学人間科学部)
インド数学における証明
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~kawazumi/asia.html
楠葉隆徳 (大阪経済大学人間科学部)
インド数学における証明
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~kawazumi/asia.html
Applied Analysis
16:00-17:30 Room #056 (Graduate School of Math. Sci. Bldg.)
Susan Friedlander (University of Illinois-Chicago)
An Inviscid Dyadic Model For Turbulence
Susan Friedlander (University of Illinois-Chicago)
An Inviscid Dyadic Model For Turbulence
[ Abstract ]
We discuss properties of a GOY type model for the inviscid fluid equations. We prove that the forced system has a unique equilibrium which a an exponential global attractor. Every solution blows up in H^5/6 in finite time . After this time, all solutions stay in H^s, s<5/6, and "turbulent" dissipation occurs. Onsager's conjecture is confirmed for the model system.
This is joint work with Alexey Cheskidov and Natasa Pavlovic.
We discuss properties of a GOY type model for the inviscid fluid equations. We prove that the forced system has a unique equilibrium which a an exponential global attractor. Every solution blows up in H^5/6 in finite time . After this time, all solutions stay in H^s, s<5/6, and "turbulent" dissipation occurs. Onsager's conjecture is confirmed for the model system.
This is joint work with Alexey Cheskidov and Natasa Pavlovic.
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