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過去の記録
過去の記録 ～04/26｜本日 04/27 | 今後の予定 04/28～
GCOEセミナー
16:00-17:00 数理科学研究科棟(駒場) 370号室
Victor Isakov 氏 (The Wichita State University)
Increasing stability of the continuation for the Helmholtz type equations (ENGLISH)
Victor Isakov 氏 (The Wichita State University)
Increasing stability of the continuation for the Helmholtz type equations (ENGLISH)
[ 講演概要 ]
We derive conditional stability estimates for the Helmholtz type equations which are becoming of Lipschitz type for large frequencies/wave numbers. Proofs use splitting solutions into low and high frequencies parts where we use energy (in particular) Carleman estimates. We discuss numerical confirmation and open problems.
We derive conditional stability estimates for the Helmholtz type equations which are becoming of Lipschitz type for large frequencies/wave numbers. Proofs use splitting solutions into low and high frequencies parts where we use energy (in particular) Carleman estimates. We discuss numerical confirmation and open problems.
GCOEセミナー
17:00-18:00 数理科学研究科棟(駒場) 370号室
Jin Cheng 氏 (Fudan University)
A numerical method for solving the inverse heat conduction problem without initial value (ENGLISH)
Jin Cheng 氏 (Fudan University)
A numerical method for solving the inverse heat conduction problem without initial value (ENGLISH)
[ 講演概要 ]
In this talk, we will present some results for the inverse heat conduction problem for the heat equation of determining a boundary value at in an unreachable part of the boundary. The main difficulty for this problem is that the initial value is unknown by the practical reason. A new method is prposed to solve this problem and the nuemrical tests show the effective of this method. Some theoretic analysis will be presented. This is a joint work with J Nakagawa, YB Wang, M Yamamoto.
In this talk, we will present some results for the inverse heat conduction problem for the heat equation of determining a boundary value at in an unreachable part of the boundary. The main difficulty for this problem is that the initial value is unknown by the practical reason. A new method is prposed to solve this problem and the nuemrical tests show the effective of this method. Some theoretic analysis will be presented. This is a joint work with J Nakagawa, YB Wang, M Yamamoto.
代数学コロキウム
16:40-17:40 数理科学研究科棟(駒場) 056号室
Stephen Lichtenbaum 氏 (Brown University)
Special values of zeta-functions of schemes (ENGLISH)
Stephen Lichtenbaum 氏 (Brown University)
Special values of zeta-functions of schemes (ENGLISH)
[ 講演概要 ]
We will give conjectured formulas giving the behavior of the
seta-function of regular schemes projective and flat over Spec Z at
non-positive integers in terms of Weil-etale cohomology. We will also
explain the conjectured relationship of Weil-etale cohomology to etale
cohomology, which makes it possible to express these formulas also in terms
of etale cohomology.
We will give conjectured formulas giving the behavior of the
seta-function of regular schemes projective and flat over Spec Z at
non-positive integers in terms of Weil-etale cohomology. We will also
explain the conjectured relationship of Weil-etale cohomology to etale
cohomology, which makes it possible to express these formulas also in terms
of etale cohomology.
2014年01月14日(火)
FMSPレクチャーズ
14:50-16:20 数理科学研究科棟(駒場) 056号室
Rinat Kashaev 氏 (University of Geneva)
Lectures on quantum Teichmüller theory III (ENGLISH)
http://fmsp.ms.u-tokyo.ac.jp/FMSPLectures_Kashaev.pdf
Rinat Kashaev 氏 (University of Geneva)
Lectures on quantum Teichmüller theory III (ENGLISH)
[ 講演概要 ]
Quantum Teichmüller theory leads to a family of unitary infinite dimensional projective representations of the mapping class groups of punctured surfaces. One of the recent applications of this theory is the construction of state integral three-manifold invariants related with hyperbolic geometry.
In these lectures it is planned to address the following subjects:
1) Penner’s coordinates in the decorated Teichmüller space.
2) Ratio coordinates.
3) Quantization.
4) The length spectrum of simple closed curves.
[ 参考URL ]Quantum Teichmüller theory leads to a family of unitary infinite dimensional projective representations of the mapping class groups of punctured surfaces. One of the recent applications of this theory is the construction of state integral three-manifold invariants related with hyperbolic geometry.
In these lectures it is planned to address the following subjects:
1) Penner’s coordinates in the decorated Teichmüller space.
2) Ratio coordinates.
3) Quantization.
4) The length spectrum of simple closed curves.
http://fmsp.ms.u-tokyo.ac.jp/FMSPLectures_Kashaev.pdf
トポロジー火曜セミナー
17:00-18:00 数理科学研究科棟(駒場) 056号室
Tea: 16:30 - 17:00 コモンルーム
Rinat Kashaev 氏 (University of Geneva)
State-integral partition functions on shaped triangulations (ENGLISH)
Tea: 16:30 - 17:00 コモンルーム
Rinat Kashaev 氏 (University of Geneva)
State-integral partition functions on shaped triangulations (ENGLISH)
[ 講演概要 ]
Quantum Teichm\\"uller theory can be promoted to a
generalized TQFT within the combinatorial framework of shaped
triangulations with the tetrahedral weight functions given in
terms of the Weil-Gelfand-Zak transformation of Faddeev.FN"s
quantum dilogarithm. By using simple examples, I will
illustrate the connection of this theory with the hyperbolic
geometry in three dimensions.
Quantum Teichm\\"uller theory can be promoted to a
generalized TQFT within the combinatorial framework of shaped
triangulations with the tetrahedral weight functions given in
terms of the Weil-Gelfand-Zak transformation of Faddeev.FN"s
quantum dilogarithm. By using simple examples, I will
illustrate the connection of this theory with the hyperbolic
geometry in three dimensions.
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
伊藤 健一 氏 (筑波大)
Threshold properties for one-dimensional discrete Schr\\"odinger operators (JAPANESE)
伊藤 健一 氏 (筑波大)
Threshold properties for one-dimensional discrete Schr\\"odinger operators (JAPANESE)
[ 講演概要 ]
We study the relation between the generalized eigenspace and the asymptotic expansion of the resolvent around the threshold $0$ for the one-dimensional discrete Schr\\"odinger operator on $\\mathbb Z$. We decompose the generalized eigenspace into the subspaces corresponding to the eigenstates and the resonance states only by their asymptotics at infinity, and classify the coefficient operators of the singlar part of resolvent expansion completely in terms of these eigenspaces. Here the generalized eigenspace we consider is largest possible. For an explicit computation of the resolvent expansion we apply the expansion scheme of Jensen-Nenciu (2001). This talk is based on the recent joint work with Arne Jensen (Aalborg University).
We study the relation between the generalized eigenspace and the asymptotic expansion of the resolvent around the threshold $0$ for the one-dimensional discrete Schr\\"odinger operator on $\\mathbb Z$. We decompose the generalized eigenspace into the subspaces corresponding to the eigenstates and the resonance states only by their asymptotics at infinity, and classify the coefficient operators of the singlar part of resolvent expansion completely in terms of these eigenspaces. Here the generalized eigenspace we consider is largest possible. For an explicit computation of the resolvent expansion we apply the expansion scheme of Jensen-Nenciu (2001). This talk is based on the recent joint work with Arne Jensen (Aalborg University).
Lie群論・表現論セミナー
16:30-18:00 数理科学研究科棟(駒場) 126号室
森真樹 氏 (東京大学大学院数理科学研究科)
セルラー代数の手法によるHecke-Cliffordスーパー代数の単純加群の分類
(JAPANESE)
森真樹 氏 (東京大学大学院数理科学研究科)
セルラー代数の手法によるHecke-Cliffordスーパー代数の単純加群の分類
(JAPANESE)
[ 講演概要 ]
Hecke--Cliffordスーパー代数はA型岩堀--Hecke代数のスーパー版である。
その単純加群の分類は、Brundan, Kleshchevと土岡により
アフィンLie代数の圏論化の手法を用いて行われた。しかしこの構成は
とても抽象的であり実際に単純加群の構造を詳しく調べるのは難しい。
そこで本講演では、より具体的な単純加群の構成方法を紹介する。
これはGrahamとLehrerによるセルラー代数の理論を拡張した手法である。
ここではSpecht加群のスーパー類似にCliffordスーパー代数が
右から作用することが鍵となる。森田コンテクストと呼ばれる
道具を用いることで、このCliffordスーパー代数の単純加群から
Hecke--Cliffordスーパー代数の単純加群を作ることができる。
Hecke--Cliffordスーパー代数はA型岩堀--Hecke代数のスーパー版である。
その単純加群の分類は、Brundan, Kleshchevと土岡により
アフィンLie代数の圏論化の手法を用いて行われた。しかしこの構成は
とても抽象的であり実際に単純加群の構造を詳しく調べるのは難しい。
そこで本講演では、より具体的な単純加群の構成方法を紹介する。
これはGrahamとLehrerによるセルラー代数の理論を拡張した手法である。
ここではSpecht加群のスーパー類似にCliffordスーパー代数が
右から作用することが鍵となる。森田コンテクストと呼ばれる
道具を用いることで、このCliffordスーパー代数の単純加群から
Hecke--Cliffordスーパー代数の単純加群を作ることができる。
GCOEセミナー
15:00-16:00 数理科学研究科棟(駒場) 118号室
Oleg Emanouilov 氏 (Colorado State University)
Calderon problem for Maxwell's equations in cylindrical domain (ENGLISH)
Oleg Emanouilov 氏 (Colorado State University)
Calderon problem for Maxwell's equations in cylindrical domain (ENGLISH)
[ 講演概要 ]
We prove some uniqueness results in determination of the conductivity, the permeability and the permittivity of Maxwell's equations from partial Dirichlet-to-Neumann map.
We prove some uniqueness results in determination of the conductivity, the permeability and the permittivity of Maxwell's equations from partial Dirichlet-to-Neumann map.
2014年01月11日(土)
保型形式の整数論月例セミナー
14:00-16:00 数理科学研究科棟(駒場) 123号室
Dihua Jiang 氏 (School of Mathematics, University of Minnesota) 14:00-14:45
A product of tensor product L-functions of quasi-split classical groups of Hermitian type. (jointly with Lei Zhang) (ENGLISH)
Dihua Jiang 氏 (School of Mathematics, University of Minnesota) 15:00-15:45
A product of tensor product L-functions of quasi-split classical groups of Hermitian type, Part II. (jointly with Lei Zhang) (ENGLISH)
Dihua Jiang 氏 (School of Mathematics, University of Minnesota) 14:00-14:45
A product of tensor product L-functions of quasi-split classical groups of Hermitian type. (jointly with Lei Zhang) (ENGLISH)
Dihua Jiang 氏 (School of Mathematics, University of Minnesota) 15:00-15:45
A product of tensor product L-functions of quasi-split classical groups of Hermitian type, Part II. (jointly with Lei Zhang) (ENGLISH)
2014年01月10日(金)
FMSPレクチャーズ
14:50-16:20 数理科学研究科棟(駒場) 056号室
Rinat Kashaev 氏 (University of Geneva)
Lectures on quantum Teichmüller theory II (ENGLISH)
http://fmsp.ms.u-tokyo.ac.jp/FMSPLectures_Kashaev.pdf
Rinat Kashaev 氏 (University of Geneva)
Lectures on quantum Teichmüller theory II (ENGLISH)
[ 講演概要 ]
Quantum Teichmüller theory leads to a family of unitary infinite dimensional projective representations of the mapping class groups of punctured surfaces. One of the recent applications of this theory is the construction of state integral three-manifold invariants related with hyperbolic geometry.
In these lectures it is planned to address the following subjects:
1) Penner’s coordinates in the decorated Teichmüller space.
2) Ratio coordinates.
3) Quantization.
4) The length spectrum of simple closed curves.
[ 参考URL ]Quantum Teichmüller theory leads to a family of unitary infinite dimensional projective representations of the mapping class groups of punctured surfaces. One of the recent applications of this theory is the construction of state integral three-manifold invariants related with hyperbolic geometry.
In these lectures it is planned to address the following subjects:
1) Penner’s coordinates in the decorated Teichmüller space.
2) Ratio coordinates.
3) Quantization.
4) The length spectrum of simple closed curves.
http://fmsp.ms.u-tokyo.ac.jp/FMSPLectures_Kashaev.pdf
2014年01月09日(木)
FMSPレクチャーズ
14:50-16:20 数理科学研究科棟(駒場) 056号室
Rinat Kashaev 氏 (University of Geneva)
Lectures on quantum Teichmüller theory I (ENGLISH)
http://fmsp.ms.u-tokyo.ac.jp/FMSPLectures_Kashaev.pdf
Rinat Kashaev 氏 (University of Geneva)
Lectures on quantum Teichmüller theory I (ENGLISH)
[ 講演概要 ]
Quantum Teichmüller theory leads to a family of unitary infinite dimensional projective representations of the mapping class groups of punctured surfaces. One of the recent applications of this theory is the construction of state integral three-manifold invariants related with hyperbolic geometry.
In these lectures it is planned to address the following subjects:
1) Penner’s coordinates in the decorated Teichmüller space.
2) Ratio coordinates.
3) Quantization.
4) The length spectrum of simple closed curves.
[ 参考URL ]Quantum Teichmüller theory leads to a family of unitary infinite dimensional projective representations of the mapping class groups of punctured surfaces. One of the recent applications of this theory is the construction of state integral three-manifold invariants related with hyperbolic geometry.
In these lectures it is planned to address the following subjects:
1) Penner’s coordinates in the decorated Teichmüller space.
2) Ratio coordinates.
3) Quantization.
4) The length spectrum of simple closed curves.
http://fmsp.ms.u-tokyo.ac.jp/FMSPLectures_Kashaev.pdf
2014年01月08日(水)
作用素環セミナー
16:30-18:00 数理科学研究科棟(駒場) 122号室
渕野昌 氏 (神戸大)
Dow's metrization theorem and beyond (JAPANESE)
渕野昌 氏 (神戸大)
Dow's metrization theorem and beyond (JAPANESE)
代数学コロキウム
16:40-17:40 数理科学研究科棟(駒場) 056号室
吉川祥 氏 (東京大学数理科学研究科)
楕円曲線の判別式の巾根と等分点 (JAPANESE)
吉川祥 氏 (東京大学数理科学研究科)
楕円曲線の判別式の巾根と等分点 (JAPANESE)
[ 講演概要 ]
We give an explicit and intrinsic description of (the torsor defined by the 12th roots of) the discriminant of an elliptic curve using the group of its 12-torsion points and the Weil pairing. As an application, we extend a result of Coates (which deals with the characteristic 0 case) to the case where the characteristic of the base field is not 2 or 3. This is a joint work with Kohei Fukuda.
We give an explicit and intrinsic description of (the torsor defined by the 12th roots of) the discriminant of an elliptic curve using the group of its 12-torsion points and the Weil pairing. As an application, we extend a result of Coates (which deals with the characteristic 0 case) to the case where the characteristic of the base field is not 2 or 3. This is a joint work with Kohei Fukuda.
2013年12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) 118号室
増本周平 氏 (東大数理)
Countable Chain Condition for $C^*$-algebras (ENGLISH)
増本周平 氏 (東大数理)
Countable Chain Condition for $C^*$-algebras (ENGLISH)
2013年12月25日(水)
GCOEセミナー
16:00-17:00 数理科学研究科棟(駒場) 270号室
Kazufumi Ito 氏 (North Carolina State University)
Nonsmooth Nonconvex Optimization Problems (ENGLISH)
Kazufumi Ito 氏 (North Carolina State University)
Nonsmooth Nonconvex Optimization Problems (ENGLISH)
[ 講演概要 ]
A general class of nonsmooth nonconvex optimization problems is discussed. A general existence theory of solutions, the Lagrange multiplier theory and sensitivity analysis of the optimal value function are developed. Concrete examples are presented to demonstrate the applicability of our approach.
A general class of nonsmooth nonconvex optimization problems is discussed. A general existence theory of solutions, the Lagrange multiplier theory and sensitivity analysis of the optimal value function are developed. Concrete examples are presented to demonstrate the applicability of our approach.
2013年12月24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
Tirasan Khandhawit 氏 (Kavli IPMU)
Stable homotopy type for monopole Floer homology (ENGLISH)
Tea: 16:00 - 16:30 コモンルーム
Tirasan Khandhawit 氏 (Kavli IPMU)
Stable homotopy type for monopole Floer homology (ENGLISH)
[ 講演概要 ]
In this talk, I will try to give an overview of the
construction of stable homotopy type for monopole Floer homology. The
construction associates a stable homotopy object to 3-manifolds, which
will recover the Floer groups by appropriate homology theory. The main
ingredients are finite dimensional approximation technique and Conley
index theory. In addition, I will demonstrate construction for certain
3-manifolds such as the 3-torus.
In this talk, I will try to give an overview of the
construction of stable homotopy type for monopole Floer homology. The
construction associates a stable homotopy object to 3-manifolds, which
will recover the Floer groups by appropriate homology theory. The main
ingredients are finite dimensional approximation technique and Conley
index theory. In addition, I will demonstrate construction for certain
3-manifolds such as the 3-torus.
2013年12月20日(金)
GCOEセミナー
15:00-16:00 数理科学研究科棟(駒場) 118号室
Mourad Bellassoued 氏 (Bizerte University)
Determination of the magnetic field in an anisotropic Schrodinger equation (ENGLISH)
Mourad Bellassoued 氏 (Bizerte University)
Determination of the magnetic field in an anisotropic Schrodinger equation (ENGLISH)
[ 講演概要 ]
This talk is devoted to the study of the following inverse boundary value problem: given a Riemannian manifold with boundary, determine the magnetic potential in a dynamical Schroedinger equation in a magnetic field from the observations made at the boundary.
This talk is devoted to the study of the following inverse boundary value problem: given a Riemannian manifold with boundary, determine the magnetic potential in a dynamical Schroedinger equation in a magnetic field from the observations made at the boundary.
2013年12月19日(木)
講演会
17:00-18:00 数理科学研究科棟(駒場) 270号室
Guanghui Hu 氏 (WIAS, Germany)
Inverse elastic wave scattering from rigid diffraction gratings (ENGLISH)
Guanghui Hu 氏 (WIAS, Germany)
Inverse elastic wave scattering from rigid diffraction gratings (ENGLISH)
[ 講演概要 ]
In recent years, Schwarz reflection principles have been used to prove uniqueness in inverse scattering by bounded obstacles and unbounded periodic structures of polygonal or polyhedral type with only one or several incident plane waves.
Such a principle for the Navier equation is established by far only underthe third or fourth kind boundary conditions, and still remains unknown in the more practical case of the Dirichlet boundary condition.
In this talk we will discuss the uniqueness in inverse elastic scattering from rigid diffraction gratings of polygonal type, where the total displacement vanishes on the scattering surface. Mathematically, this can be modeled by the Dirichlet boundary value problem for the Navier equation in periodic structures. We prove that such diffraction gratings can be uniquely
determined from the near-field data corresponding to a finite number of incident elastic plane waves.
This is a joint work with J. Elschner and M. Yamamoto.
In recent years, Schwarz reflection principles have been used to prove uniqueness in inverse scattering by bounded obstacles and unbounded periodic structures of polygonal or polyhedral type with only one or several incident plane waves.
Such a principle for the Navier equation is established by far only underthe third or fourth kind boundary conditions, and still remains unknown in the more practical case of the Dirichlet boundary condition.
In this talk we will discuss the uniqueness in inverse elastic scattering from rigid diffraction gratings of polygonal type, where the total displacement vanishes on the scattering surface. Mathematically, this can be modeled by the Dirichlet boundary value problem for the Navier equation in periodic structures. We prove that such diffraction gratings can be uniquely
determined from the near-field data corresponding to a finite number of incident elastic plane waves.
This is a joint work with J. Elschner and M. Yamamoto.
FMSPレクチャーズ
17:00-18:00 数理科学研究科棟(駒場) 270号室
Guanghui Hu 氏 (WIAS, Germany)
Inverse elastic wave scattering from rigid diffraction gratings (ENGLISH)
http://fmsp.ms.u-tokyo.ac.jp/FMSPLectures_Hu.pdf
Guanghui Hu 氏 (WIAS, Germany)
Inverse elastic wave scattering from rigid diffraction gratings (ENGLISH)
[ 講演概要 ]
In recent years, Schwarz reflection principles have been used to prove uniqueness in inverse scattering by bounded obstacles and unbounded periodic structures of polygonal or polyhedral type with only one or several incident plane waves.
Such a principle for the Navier equation is established by far only underthe third or fourth kind boundary conditions, and still remains unknown in the more practical case of the Dirichlet boundary condition.
In this talk we will discuss the uniqueness in inverse elastic scattering from rigid diffraction gratings of polygonal type, where the total displacement vanishes on the scattering surface. Mathematically, this can be modeled by the Dirichlet boundary value problem for the Navier equation in periodic structures. We prove that such diffraction gratings can be uniquely
determined from the near-field data corresponding to a finite number of incident elastic plane waves.
This is a joint work with J. Elschner and M. Yamamoto.
[ 参考URL ]In recent years, Schwarz reflection principles have been used to prove uniqueness in inverse scattering by bounded obstacles and unbounded periodic structures of polygonal or polyhedral type with only one or several incident plane waves.
Such a principle for the Navier equation is established by far only underthe third or fourth kind boundary conditions, and still remains unknown in the more practical case of the Dirichlet boundary condition.
In this talk we will discuss the uniqueness in inverse elastic scattering from rigid diffraction gratings of polygonal type, where the total displacement vanishes on the scattering surface. Mathematically, this can be modeled by the Dirichlet boundary value problem for the Navier equation in periodic structures. We prove that such diffraction gratings can be uniquely
determined from the near-field data corresponding to a finite number of incident elastic plane waves.
This is a joint work with J. Elschner and M. Yamamoto.
http://fmsp.ms.u-tokyo.ac.jp/FMSPLectures_Hu.pdf
2013年12月18日(水)
代数学コロキウム
18:00-19:00 数理科学研究科棟(駒場) 117号室
いつもと場所が異なりますのでご注意ください
加藤和也 氏 (シカゴ大学)
Heights of motives (ENGLISH)
いつもと場所が異なりますのでご注意ください
加藤和也 氏 (シカゴ大学)
Heights of motives (ENGLISH)
[ 講演概要 ]
The height of a rational number a/b (a, b integers which are coprime) is defined as max(|a|, |b|). A rational number with small (resp. big) height is a simple (resp. complicated) number. Though the notion height is so naive, height has played fundamental roles in number theory. There are important variants of this notion. In 1983, when Faltings proved Mordell conjecture, Faltings first proved Tate conjecture for abelian variaties by defining heights of abelian varieties, and then he deduced Mordell conjecture from the latter conjecture. I explain that his height of an abelian variety is generalized to the height of a motive. This generalization of height is related to open problems in number theory. If we can prove finiteness of the number of motives of bounded heights, we can prove important conjectures in number theory such as general Tate conjecture and Mordell-Weil type conjectures in many cases.
(本講演は「東京北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, Morningside Center of MathematicsとIHESの双方向同時中継で行います.)
The height of a rational number a/b (a, b integers which are coprime) is defined as max(|a|, |b|). A rational number with small (resp. big) height is a simple (resp. complicated) number. Though the notion height is so naive, height has played fundamental roles in number theory. There are important variants of this notion. In 1983, when Faltings proved Mordell conjecture, Faltings first proved Tate conjecture for abelian variaties by defining heights of abelian varieties, and then he deduced Mordell conjecture from the latter conjecture. I explain that his height of an abelian variety is generalized to the height of a motive. This generalization of height is related to open problems in number theory. If we can prove finiteness of the number of motives of bounded heights, we can prove important conjectures in number theory such as general Tate conjecture and Mordell-Weil type conjectures in many cases.
(本講演は「東京北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, Morningside Center of MathematicsとIHESの双方向同時中継で行います.)
2013年12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
中村 伊南沙 氏 (東京大学大学院数理科学研究科)
Satellites of an oriented surface link and their local moves (JAPANESE)
Tea: 16:00 - 16:30 コモンルーム
中村 伊南沙 氏 (東京大学大学院数理科学研究科)
Satellites of an oriented surface link and their local moves (JAPANESE)
[ 講演概要 ]
For an oriented surface link $F$ in $\\mathbb{R}^4$,
we consider a satellite construction of a surface link, called a
2-dimensional braid over $F$, which is in the form of a covering over
$F$. We introduce the notion of an $m$-chart on a surface diagram
$p(F)\\subset \\mathbb{R}^3$ of $F$, which is a finite graph on $p(F)$
satisfying certain conditions and is an extended notion of an
$m$-chart on a 2-disk presenting a surface braid.
A 2-dimensional braid over $F$ is presented by an $m$-chart on $p(F)$.
It is known that two surface links are equivalent if and only if their
surface diagrams are related by a finite sequence of ambient isotopies
of $\\mathbb{R}^3$ and local moves called Roseman moves.
We show that Roseman moves for surface diagrams with $m$-charts can be
well-defined. Further, we give some applications.
For an oriented surface link $F$ in $\\mathbb{R}^4$,
we consider a satellite construction of a surface link, called a
2-dimensional braid over $F$, which is in the form of a covering over
$F$. We introduce the notion of an $m$-chart on a surface diagram
$p(F)\\subset \\mathbb{R}^3$ of $F$, which is a finite graph on $p(F)$
satisfying certain conditions and is an extended notion of an
$m$-chart on a 2-disk presenting a surface braid.
A 2-dimensional braid over $F$ is presented by an $m$-chart on $p(F)$.
It is known that two surface links are equivalent if and only if their
surface diagrams are related by a finite sequence of ambient isotopies
of $\\mathbb{R}^3$ and local moves called Roseman moves.
We show that Roseman moves for surface diagrams with $m$-charts can be
well-defined. Further, we give some applications.
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
Fabricio Macia 氏 (Universidad Politécnica de Madrid)
Dispersion and observability for completely integrable Schrödinger flows (ENGLISH)
Fabricio Macia 氏 (Universidad Politécnica de Madrid)
Dispersion and observability for completely integrable Schrödinger flows (ENGLISH)
[ 講演概要 ]
I will present some results on weak dispersion and unique continuation (observability) for linear Schrödinger
equations that are obtained as the quantization of a completely integrable Hamiltonian system.
The model case corresponds to the linear Schrödinger equation (with a potential) on the flat torus.
Our results are obtained through a detailed analysis of semiclassical measures corresponding to
sequences of solutions, which is performed using a two-microlocal approach.
This is a joint work with Nalini Anantharaman and Clotilde Fermanian-Kammerer.
I will present some results on weak dispersion and unique continuation (observability) for linear Schrödinger
equations that are obtained as the quantization of a completely integrable Hamiltonian system.
The model case corresponds to the linear Schrödinger equation (with a potential) on the flat torus.
Our results are obtained through a detailed analysis of semiclassical measures corresponding to
sequences of solutions, which is performed using a two-microlocal approach.
This is a joint work with Nalini Anantharaman and Clotilde Fermanian-Kammerer.
Lie群論・表現論セミナー
16:30-17:30 数理科学研究科棟(駒場) 126号室
貝塚公一 氏 (筑波大学大学院 数理物質科学研究科)
非コンパクト型対称空間におけるポアソン変換の$L^{2}$-値域の特徴
付け (JAPANESE)
貝塚公一 氏 (筑波大学大学院 数理物質科学研究科)
非コンパクト型対称空間におけるポアソン変換の$L^{2}$-値域の特徴
付け (JAPANESE)
[ 講演概要 ]
Characterizations of the joint eigenspaces of invariant
differential operators in terms of the Poisson transform have been one of the central problems in harmonic analysis on symmetric spaces.
From the point of view of spectral theory, Strichartz (J. Funct.
Anal.(1989)) formulated a conjecture concerning a certain image
characterization of the Poisson transform of the $L^{2}$-space on the boundary on symmetric spaces of noncompact type. In this talk, we employ techniques in scattering theory to present a positive answer to the Strichartz conjecture.
Characterizations of the joint eigenspaces of invariant
differential operators in terms of the Poisson transform have been one of the central problems in harmonic analysis on symmetric spaces.
From the point of view of spectral theory, Strichartz (J. Funct.
Anal.(1989)) formulated a conjecture concerning a certain image
characterization of the Poisson transform of the $L^{2}$-space on the boundary on symmetric spaces of noncompact type. In this talk, we employ techniques in scattering theory to present a positive answer to the Strichartz conjecture.
2013年12月16日(月)
FMSPレクチャーズ
15:30-16:30 数理科学研究科棟(駒場) 056号室
Jon Nimmo 氏 (Univ. of Glasgow)
The discrete Schrodinger equation for compact support potentials (ENGLISH)
http://fmsp.ms.u-tokyo.ac.jp/FMSPLectures_%20NIMMO.pdf
Jon Nimmo 氏 (Univ. of Glasgow)
The discrete Schrodinger equation for compact support potentials (ENGLISH)
[ 講演概要 ]
We consider the exact form of the Jost solutions of the discrete Schrodinger equation for arbitrary potentials with compact support. Remarkably, these solutions may be written in terms of certain explicitly defined polynomials in the non-trivial values of the potential. These polynomials also arise in the work of Yamada (2000) in connection with a birational representation of the symmetric group.
Applications of this approach to the udKdV are also discussed.
[ 参考URL ]We consider the exact form of the Jost solutions of the discrete Schrodinger equation for arbitrary potentials with compact support. Remarkably, these solutions may be written in terms of certain explicitly defined polynomials in the non-trivial values of the potential. These polynomials also arise in the work of Yamada (2000) in connection with a birational representation of the symmetric group.
Applications of this approach to the udKdV are also discussed.
http://fmsp.ms.u-tokyo.ac.jp/FMSPLectures_%20NIMMO.pdf
複素解析幾何セミナー
10:30-12:00 数理科学研究科棟(駒場) 126号室
千葉 優作 氏 (東京工業大学)
Shilov boundaries of the pluricomplex Green function's level sets (JAPANESE)
千葉 優作 氏 (東京工業大学)
Shilov boundaries of the pluricomplex Green function's level sets (JAPANESE)
[ 講演概要 ]
In this talk, we study a relation between the Shilov boundaries of the pluricomplex Green function's level sets and supports of Monge-Ampére type currents.
In this talk, we study a relation between the Shilov boundaries of the pluricomplex Green function's level sets and supports of Monge-Ampére type currents.
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