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過去の記録 ～04/25｜本日 04/26 | 今後の予定 04/27～
2013年04月16日(火)
Lie群論・表現論セミナー
16:30-18:30 数理科学研究科棟(駒場) 126号室
Michael Pevzner 氏 (Reims University) 16:30-17:30
Non-standard models for small representations of GL(n,R) (ENGLISH)
Degenerate principal series of symplectic groups (ENGLISH)
Michael Pevzner 氏 (Reims University) 16:30-17:30
Non-standard models for small representations of GL(n,R) (ENGLISH)
[ 講演概要 ]
We shall present new models for some parabolically induced
unitary representations of the real general linear group which involve Weyl symbolic calculus and furnish very efficient tools in studying branching laws for such representations.
Pierre Clare 氏 (Penn. State University, USA) 17:30-18:30We shall present new models for some parabolically induced
unitary representations of the real general linear group which involve Weyl symbolic calculus and furnish very efficient tools in studying branching laws for such representations.
Degenerate principal series of symplectic groups (ENGLISH)
[ 講演概要 ]
We will discuss properties of representations of symplectic groups induced from maximal parabolic subgroups of Heisenberg type, including K-types formulas, expressions of intertwining operators and the study of their spectrum.
We will discuss properties of representations of symplectic groups induced from maximal parabolic subgroups of Heisenberg type, including K-types formulas, expressions of intertwining operators and the study of their spectrum.
2013年04月15日(月)
講演会
15:00-16:30 数理科学研究科棟(駒場) 126号室
Janna Lierl 氏 (University of Bonn)
Two-sided bounds for the Dirichlet heat kernel on inner uniform domains (ENGLISH)
Janna Lierl 氏 (University of Bonn)
Two-sided bounds for the Dirichlet heat kernel on inner uniform domains (ENGLISH)
[ 講演概要 ]
I will present sharp two-sided bounds for the heat kernel in domains with Dirichlet boundary conditions. The domain is assumed to satisfy an inner uniformity condition. This includes any convex domain, the complement of any convex domain in Euclidean space, and the interior of the Koch snowflake.
The heat kernel estimates hold in the abstract setting of metric measure spaces equipped with a (possibly non-symmetric) Dirichlet form. The underlying space is assumed to satisfy a Poincare inequality and volume doubling.
The results apply, for example, to the Dirichlet heat kernel associated with a divergence form operator with bounded measurable coefficients and symmetric, uniformly elliptic second order part.
This is joint work with Laurent Saloff-Coste.
I will present sharp two-sided bounds for the heat kernel in domains with Dirichlet boundary conditions. The domain is assumed to satisfy an inner uniformity condition. This includes any convex domain, the complement of any convex domain in Euclidean space, and the interior of the Koch snowflake.
The heat kernel estimates hold in the abstract setting of metric measure spaces equipped with a (possibly non-symmetric) Dirichlet form. The underlying space is assumed to satisfy a Poincare inequality and volume doubling.
The results apply, for example, to the Dirichlet heat kernel associated with a divergence form operator with bounded measurable coefficients and symmetric, uniformly elliptic second order part.
This is joint work with Laurent Saloff-Coste.
講演会
16:45-18:15 数理科学研究科棟(駒場) 126号室
Amir Dembo 氏 (Stanford University)
Persistence Probabilities (ENGLISH)
Amir Dembo 氏 (Stanford University)
Persistence Probabilities (ENGLISH)
[ 講演概要 ]
Persistence probabilities concern how likely it is that a stochastic process has a long excursion above fixed level and of what are the relevant scenarios for this behavior. Power law decay is expected in many cases of physical significance and the issue is to determine its power exponent parameter. I will survey recent progress in this direction (jointly with Jian Ding, Fuchang Gao, and Sumit Mukherjee), dealing with random algebraic polynomials of independent coefficients, iterated partial sums and other auto-regressive sequences, and with the solution to heat equation initiated by white noise.
Persistence probabilities concern how likely it is that a stochastic process has a long excursion above fixed level and of what are the relevant scenarios for this behavior. Power law decay is expected in many cases of physical significance and the issue is to determine its power exponent parameter. I will survey recent progress in this direction (jointly with Jian Ding, Fuchang Gao, and Sumit Mukherjee), dealing with random algebraic polynomials of independent coefficients, iterated partial sums and other auto-regressive sequences, and with the solution to heat equation initiated by white noise.
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
Nikolay Shcherbina 氏 (University of Wuppertal)
On defining functions for unbounded pseudoconvex domains (ENGLISH)
Nikolay Shcherbina 氏 (University of Wuppertal)
On defining functions for unbounded pseudoconvex domains (ENGLISH)
[ 講演概要 ]
We show that every strictly pseudoconvex domain $\Omega$ with smooth boundary in a complex manifold $M$ admits a global defining function, i.e. a smooth plurisubharmonic function $\varphi \colon U \to \mathbf{R}$ defined on an open neighbourhood $U \subset M$ of $\Omega$ such that $\Omega =\{ \varphi < 0 \}$, $d\varphi \not= 0$ on $b\Omega$ and $\varphi$ is strictly plurisubharmonic near $b\Omega$. We then introduce the notion of the kernel $K(\Omega)$ of an arbitrary domain $\Omega \subset M$ as the set of all points where every smooth and bounded from above plurisubharmonic function on $\Omega$ fails to be strictly plurisubharmonic. If $\Omega$ is not relatively compact in $M$, then in general $K(\Omega)$ is nonempty, even in the case when $M$ is Stein. It is shown that every strictly pseudoconvex domain $\Omega \subset M$ with smooth boundary admits a global defining function that is strictly plurisubharmonic precisely in the complement of $K(\Omega)$. We then investigate properties of the kernel. Among other results we prove 1-pseudoconcavity of the kernel, we show that in general the kernel does not possess any analytic structure, and we investigate Liouville type properties of the kernel.
We show that every strictly pseudoconvex domain $\Omega$ with smooth boundary in a complex manifold $M$ admits a global defining function, i.e. a smooth plurisubharmonic function $\varphi \colon U \to \mathbf{R}$ defined on an open neighbourhood $U \subset M$ of $\Omega$ such that $\Omega =\{ \varphi < 0 \}$, $d\varphi \not= 0$ on $b\Omega$ and $\varphi$ is strictly plurisubharmonic near $b\Omega$. We then introduce the notion of the kernel $K(\Omega)$ of an arbitrary domain $\Omega \subset M$ as the set of all points where every smooth and bounded from above plurisubharmonic function on $\Omega$ fails to be strictly plurisubharmonic. If $\Omega$ is not relatively compact in $M$, then in general $K(\Omega)$ is nonempty, even in the case when $M$ is Stein. It is shown that every strictly pseudoconvex domain $\Omega \subset M$ with smooth boundary admits a global defining function that is strictly plurisubharmonic precisely in the complement of $K(\Omega)$. We then investigate properties of the kernel. Among other results we prove 1-pseudoconcavity of the kernel, we show that in general the kernel does not possess any analytic structure, and we investigate Liouville type properties of the kernel.
2013年04月11日(木)
幾何コロキウム
10:00-11:30 数理科学研究科棟(駒場) 122号室
開始時間と開催場所などは変更されることがあるので, セミナーごとにご確認ください.
Jeff Viaclovsky 氏 (University of Wisconsin)
Critical metrics on connected sums of Einstein four-manifolds (ENGLISH)
開始時間と開催場所などは変更されることがあるので, セミナーごとにご確認ください.
Jeff Viaclovsky 氏 (University of Wisconsin)
Critical metrics on connected sums of Einstein four-manifolds (ENGLISH)
[ 講演概要 ]
I will discuss a gluing procedure designed to obtain critical metrics of quadratic Riemannian functionals on connected sums of certain Einstein four-manifolds. Start with two Einstein four-manifolds of positive scalar curvature which are "rigid". Using the Green's function for the conformal Laplacian, convert one of these into an asymptotically flat (AF) scalar-flat metric. A "naive" approximate critical metric is obtained by identifying the boundary of a large ball in the AF metric with the boundary of a small ball in the other compact Einstein metric, using cutoff functions to glue together the AF metric with a suitably scaled compact metric in order to obtain a smooth metric on the connected sum. It turns out that this naive approximate metric is too rough, and must be refined in order to compute the leading term of the Kuranishi map. The main application is an existence result using two well-known Einstein manifolds as building blocks: the Fubini-Study metric on $¥mathbb{CP}^2$ and the product metric on $S^2 ¥times S^2$. Using these factors in various gluing configurations, a zero of the Kuranishi map is then found for a specific quadratic Riemannian functional on certain connected sums. The exact functional depends on the geometry of the factors, and also on the mass of the AF metric. Using certain quotients of $S^2 ¥times S^2$ as one of the gluing factors, several non-simply connected examples are also obtained. This is joint work with Matt Gursky.
I will discuss a gluing procedure designed to obtain critical metrics of quadratic Riemannian functionals on connected sums of certain Einstein four-manifolds. Start with two Einstein four-manifolds of positive scalar curvature which are "rigid". Using the Green's function for the conformal Laplacian, convert one of these into an asymptotically flat (AF) scalar-flat metric. A "naive" approximate critical metric is obtained by identifying the boundary of a large ball in the AF metric with the boundary of a small ball in the other compact Einstein metric, using cutoff functions to glue together the AF metric with a suitably scaled compact metric in order to obtain a smooth metric on the connected sum. It turns out that this naive approximate metric is too rough, and must be refined in order to compute the leading term of the Kuranishi map. The main application is an existence result using two well-known Einstein manifolds as building blocks: the Fubini-Study metric on $¥mathbb{CP}^2$ and the product metric on $S^2 ¥times S^2$. Using these factors in various gluing configurations, a zero of the Kuranishi map is then found for a specific quadratic Riemannian functional on certain connected sums. The exact functional depends on the geometry of the factors, and also on the mass of the AF metric. Using certain quotients of $S^2 ¥times S^2$ as one of the gluing factors, several non-simply connected examples are also obtained. This is joint work with Matt Gursky.
2013年04月10日(水)
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
武石拓也 氏 (東大数理)
On nuclearity of $C^*$-algebras associated with Fell bundles over \\'etale groupoids (ENGLISH)
武石拓也 氏 (東大数理)
On nuclearity of $C^*$-algebras associated with Fell bundles over \\'etale groupoids (ENGLISH)
代数学コロキウム
17:30-18:30 数理科学研究科棟(駒場) 056号室
Deepam Patel 氏 (University of Amsterdam)
Motivic structure on higher homotopy of non-nilpotent spaces (ENGLISH)
Deepam Patel 氏 (University of Amsterdam)
Motivic structure on higher homotopy of non-nilpotent spaces (ENGLISH)
[ 講演概要 ]
In his fundamental paper on the projective line minus three points, Deligne constructed certain extensions of mixed Tate motives arising from the fundamental group of the projective line minus three points. Since then, motivic structures on homotopy groups have been studied by many authors. In this talk, we will construct a motivic structure on the (nilpotent completion of) n-th homotopy group of P^{n} minus n+2 hyperplanes in general position.
(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.)
In his fundamental paper on the projective line minus three points, Deligne constructed certain extensions of mixed Tate motives arising from the fundamental group of the projective line minus three points. Since then, motivic structures on homotopy groups have been studied by many authors. In this talk, we will construct a motivic structure on the (nilpotent completion of) n-th homotopy group of P^{n} minus n+2 hyperplanes in general position.
(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04月09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
藤 博之 氏 (東京大学大学院数理科学研究科)
色付きHOMFLYホモロジーと超A-多項式 (JAPANESE)
Tea: 16:00 - 16:30 コモンルーム
藤 博之 氏 (東京大学大学院数理科学研究科)
色付きHOMFLYホモロジーと超A-多項式 (JAPANESE)
[ 講演概要 ]
本講演では,結び目に対する色付きHOMFLYホモロジーとその漸近的振る舞いに関する研究を紹介する.近年,色付きHOMFLY多項式の圏化がスペクトル系列に基づく公理系による定義と位相的弦理論に基づく物理的定義の双方が提唱され,それらの興味深い一致が様々な形で確かめられている.我々の研究では,完全対称表現に対する色付きHOMFLYホモロジーの漸近的振る舞いに関して,体積予想と類似の解析を行い,その結果,A-多項式の一般化となる“超 A-多項式”を通じて,色付きHOMFLYホモロジーのある量子構造が見出された.本講演では,こうした圏化の側面について,物理的解釈を交えながら紹介したい.尚,本講演はS. Gukov, M. Stosic, P. Sulkowski の3氏との共同研究に基づく.
本講演では,結び目に対する色付きHOMFLYホモロジーとその漸近的振る舞いに関する研究を紹介する.近年,色付きHOMFLY多項式の圏化がスペクトル系列に基づく公理系による定義と位相的弦理論に基づく物理的定義の双方が提唱され,それらの興味深い一致が様々な形で確かめられている.我々の研究では,完全対称表現に対する色付きHOMFLYホモロジーの漸近的振る舞いに関して,体積予想と類似の解析を行い,その結果,A-多項式の一般化となる“超 A-多項式”を通じて,色付きHOMFLYホモロジーのある量子構造が見出された.本講演では,こうした圏化の側面について,物理的解釈を交えながら紹介したい.尚,本講演はS. Gukov, M. Stosic, P. Sulkowski の3氏との共同研究に基づく.
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
笹木集夢 氏 (東海大学)
A characterization of non-tube type Hermitian symmetric spaces by visible actions
(JAPANESE)
笹木集夢 氏 (東海大学)
A characterization of non-tube type Hermitian symmetric spaces by visible actions
(JAPANESE)
[ 講演概要 ]
We consider a non-symmetric complex Stein manifold D
which is realized as a line bundle over the complexification of a non-compact irreducible Hermitian symmetric space G/K.
In this talk, we will explain that the compact group action on D is strongly visible in the sense of Toshiyuki Kobayashi if and only if G/K is of non-tube type.
In particular, we focus on our construction of slice which meets every orbit in D from the viewpoint of group theory, namely,
we find an A-part of a generalized Cartan decomposition for homogeneous space D.
We note that our choice of A-part is an abelian.
We consider a non-symmetric complex Stein manifold D
which is realized as a line bundle over the complexification of a non-compact irreducible Hermitian symmetric space G/K.
In this talk, we will explain that the compact group action on D is strongly visible in the sense of Toshiyuki Kobayashi if and only if G/K is of non-tube type.
In particular, we focus on our construction of slice which meets every orbit in D from the viewpoint of group theory, namely,
we find an A-part of a generalized Cartan decomposition for homogeneous space D.
We note that our choice of A-part is an abelian.
2013年04月08日(月)
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
二木 昭人 氏 (東大数理)
ケーラー・アインシュタイン計量と K 安定性 (JAPANESE)
二木 昭人 氏 (東大数理)
ケーラー・アインシュタイン計量と K 安定性 (JAPANESE)
[ 講演概要 ]
ケーラー・アインシュタイン計量の存在と K 安定性の同値性に関する Chen-Donaldson-Sun, Tian の証明の概略を解説する.
ケーラー・アインシュタイン計量の存在と K 安定性の同値性に関する Chen-Donaldson-Sun, Tian の証明の概略を解説する.
2013年04月02日(火)
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
大島芳樹 氏 (Kavli IPMU, the University of Tokyo)
Zuckerman導来関手加群の離散的分岐則 (JAPANESE)
大島芳樹 氏 (Kavli IPMU, the University of Tokyo)
Zuckerman導来関手加群の離散的分岐則 (JAPANESE)
[ 講演概要 ]
We consider the restriction of Zuckerman's derived functor modules with respect to symmetric pairs of real reductive groups. When they are discretely decomposable, explicit formulas for the branching laws are obtained by using a realization as D-module on the flag variety and the generalized BGG resolution. In this talk we would like to illustrate how to derive the formulas with a few examples.
We consider the restriction of Zuckerman's derived functor modules with respect to symmetric pairs of real reductive groups. When they are discretely decomposable, explicit formulas for the branching laws are obtained by using a realization as D-module on the flag variety and the generalized BGG resolution. In this talk we would like to illustrate how to derive the formulas with a few examples.
2013年03月30日(土)
東京無限可積分系セミナー
13:30-15:30 数理科学研究科棟(駒場) 002号室
Simon Wood 氏 (Kavli IPMU)
On the extended algebra of type sl_2 at positive rational level (ENGLISH)
Simon Wood 氏 (Kavli IPMU)
On the extended algebra of type sl_2 at positive rational level (ENGLISH)
[ 講演概要 ]
I will be presenting my recent work with Akihiro Tsuchiya
(arXiv:1302.6435).
I will explain how to construct a certain VOA called the "extended
algebra of type sl_2 at positive rational level"
as a subVOA of a lattice VOA, by means of screening operators. I will
then show that this VOA carries a kind of exterior sl_2 action and then
show how one can compute the structure Zhu's algebra and the Poisson
algebra as well as classify all simple modules by using the screening
operators and the sl_2 action. Important concepts such as screening
operators or Zhu's algebra and the Poisson algebra of a VOA will be
reviewed in the talk.
I will be presenting my recent work with Akihiro Tsuchiya
(arXiv:1302.6435).
I will explain how to construct a certain VOA called the "extended
algebra of type sl_2 at positive rational level"
as a subVOA of a lattice VOA, by means of screening operators. I will
then show that this VOA carries a kind of exterior sl_2 action and then
show how one can compute the structure Zhu's algebra and the Poisson
algebra as well as classify all simple modules by using the screening
operators and the sl_2 action. Important concepts such as screening
operators or Zhu's algebra and the Poisson algebra of a VOA will be
reviewed in the talk.
2013年03月19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) 002号室
Tea: 16:00 - 16:30 コモンルーム
川室 圭子 氏 (University of Iowa)
Open book foliation and application to contact topology (ENGLISH)
Tea: 16:00 - 16:30 コモンルーム
川室 圭子 氏 (University of Iowa)
Open book foliation and application to contact topology (ENGLISH)
[ 講演概要 ]
Open book foliation is a generalization of Birman and Menasco's braid foliation. Any 3-manifold admits open book decompositions. Open book foliation is a singular foliation on an embedded surface, and is define by the intersection of a surface and the pages of the open book decomposition. By Giroux's identification of open books and contact structures one can use open book foliation method to study contact structures. In this talk I define the open book foliation and show some applications to contact topology. This is joint work with Tetsuya Ito (University of British Columbia).
Open book foliation is a generalization of Birman and Menasco's braid foliation. Any 3-manifold admits open book decompositions. Open book foliation is a singular foliation on an embedded surface, and is define by the intersection of a surface and the pages of the open book decomposition. By Giroux's identification of open books and contact structures one can use open book foliation method to study contact structures. In this talk I define the open book foliation and show some applications to contact topology. This is joint work with Tetsuya Ito (University of British Columbia).
2013年03月18日(月)
作用素環セミナー
16:00-17:30 数理科学研究科棟(駒場) 118号室
安藤浩志 氏 (IHES)
Ultraproducts of von Neumann algebras (JAPANESE)
安藤浩志 氏 (IHES)
Ultraproducts of von Neumann algebras (JAPANESE)
談話会・数理科学講演会
15:00-17:30 数理科学研究科棟(駒場) 050号室
旧記録は、上記セミナーURLにあります。
お茶&Coffee&お菓子: 16:00～16:30 (大講義室ロビー)。
野口潤次郎 氏 (東京大学大学院数理科学研究科) 15:00-16:00
値分布と多変数関数論 (JAPANESE)
微分方程式をめぐって (JAPANESE)
旧記録は、上記セミナーURLにあります。
お茶&Coffee&お菓子: 16:00～16:30 (大講義室ロビー)。
野口潤次郎 氏 (東京大学大学院数理科学研究科) 15:00-16:00
値分布と多変数関数論 (JAPANESE)
[ 講演概要 ]
解析関数を調べる研究が、特別な解析関数を個々に調べることから解析性を持つ関数を一般に調べる理論に独立した転機をなしたのは「ピカールの定理」であると言われている。自然に解析関数論は、一変数から多変数を扱うようになる。そして多変数関数論は岡潔により基礎が完成された。最も本質的な性質は「連接性」であることが岡により見抜かれ「岡の3連接定理」が証明された。その後の進展・整理は素早く、1950年代には「岡-カルタン理論」として確立された。
一方、ピカールの定理はネヴァンリンナにより定量的な値分布論へと発展した。高次元値分布を展開しようとすると多変数関数論の基礎が必要になってくる。その基礎的な部分はW. Stollがやった。私が研究に参加し始めたのは1972年頃で、GriffithsーKingのActa論文や小林双曲的多様体の理論が広まり始めた時期であった。その頃に考え始めた問題がどのように進展し、解決したもの、未解決問題、出てきた問題について考えてみたい。
大島 利雄 氏 (東京大学大学院数理科学研究科) 16:30-17:30解析関数を調べる研究が、特別な解析関数を個々に調べることから解析性を持つ関数を一般に調べる理論に独立した転機をなしたのは「ピカールの定理」であると言われている。自然に解析関数論は、一変数から多変数を扱うようになる。そして多変数関数論は岡潔により基礎が完成された。最も本質的な性質は「連接性」であることが岡により見抜かれ「岡の3連接定理」が証明された。その後の進展・整理は素早く、1950年代には「岡-カルタン理論」として確立された。
一方、ピカールの定理はネヴァンリンナにより定量的な値分布論へと発展した。高次元値分布を展開しようとすると多変数関数論の基礎が必要になってくる。その基礎的な部分はW. Stollがやった。私が研究に参加し始めたのは1972年頃で、GriffithsーKingのActa論文や小林双曲的多様体の理論が広まり始めた時期であった。その頃に考え始めた問題がどのように進展し、解決したもの、未解決問題、出てきた問題について考えてみたい。
微分方程式をめぐって (JAPANESE)
[ 講演概要 ]
講演者が50年あまりにわたって関わってきた微分方程式と,それをめぐる話題を振り返ってみる.最初は定数係数の常微分方程式から偏微分方程式で,Fourier解析や多変数関数論が関わる.次に超局所解析と接触幾何の問題,また等質空間と結びついて,境界値問題,コンパクト化,表現論,積分幾何や量子化,特殊関数などへと関連が拡がった.最近は,代数的線型常微分方程式の研究を進めている.最もホットな話題はそれの古典極限の代数曲線,特に種数による分類とシンプレクティック空間における特異点解消などとの関連である.
講演者が50年あまりにわたって関わってきた微分方程式と,それをめぐる話題を振り返ってみる.最初は定数係数の常微分方程式から偏微分方程式で,Fourier解析や多変数関数論が関わる.次に超局所解析と接触幾何の問題,また等質空間と結びついて,境界値問題,コンパクト化,表現論,積分幾何や量子化,特殊関数などへと関連が拡がった.最近は,代数的線型常微分方程式の研究を進めている.最もホットな話題はそれの古典極限の代数曲線,特に種数による分類とシンプレクティック空間における特異点解消などとの関連である.
2013年03月15日(金)
作用素環セミナー
15:45-18:00 数理科学研究科棟(駒場) 118号室
Lucio Cirio 氏 (Univ. M\"unster) 15:45-16:45
Infinitesimal 2-Yang-Baxter operators from a categorification
of the Knizhnik-Zamolodchikov connection (ENGLISH)
Sutanu Roy 氏 (Univ. G\"ottingen) 17:00-18:00
Twisted tensor product of $C^*$-algebras (ENGLISH)
Lucio Cirio 氏 (Univ. M\"unster) 15:45-16:45
Infinitesimal 2-Yang-Baxter operators from a categorification
of the Knizhnik-Zamolodchikov connection (ENGLISH)
Sutanu Roy 氏 (Univ. G\"ottingen) 17:00-18:00
Twisted tensor product of $C^*$-algebras (ENGLISH)
数値解析セミナー
10:00-12:15 数理科学研究科棟(駒場) 056号室
本セミナーは、グローバルCOE事業「数学新展開の研究教育拠点」(東京大学)の援助を受け、GCOEセミナーして行われています。
https://www.ms.u-tokyo.ac.jp/gcoe/index.html
Irene Vignon-Clementel 氏 (INRIA Paris Rocquencourt )
Complex flow at the boundaries of branched models: numerical aspects (ENGLISH)
[ 参考URL ]
http://www.infsup.jp/utnas/
本セミナーは、グローバルCOE事業「数学新展開の研究教育拠点」(東京大学)の援助を受け、GCOEセミナーして行われています。
https://www.ms.u-tokyo.ac.jp/gcoe/index.html
Irene Vignon-Clementel 氏 (INRIA Paris Rocquencourt )
Complex flow at the boundaries of branched models: numerical aspects (ENGLISH)
[ 参考URL ]
http://www.infsup.jp/utnas/
作用素環セミナー
14:30-15:30 数理科学研究科棟(駒場) 118号室
Stefano Rossi 氏 (Univ. Roma II)
The connected component of a compact quantum group (ENGLISH)
Stefano Rossi 氏 (Univ. Roma II)
The connected component of a compact quantum group (ENGLISH)
作用素環セミナー
13:15-14:15 数理科学研究科棟(駒場) 118号室
Jean Roydor 氏 (Univ. Bordeaux)
Two Amir-Cambern type theorems for $C^*$-algebras (ENGLISH)
Jean Roydor 氏 (Univ. Bordeaux)
Two Amir-Cambern type theorems for $C^*$-algebras (ENGLISH)
PDE実解析研究会
10:30-11:30 数理科学研究科棟(駒場) 128号室
北海道大学のHPには、第1回(2004年9月29日)～第38回(2008年10月15日)までの情報が掲載されております。
Caterina Zeppieri 氏 (Universität Münster)
Geometric rigidity for incompatible fields and an application to strain-gradient plasticity (ENGLISH)
北海道大学のHPには、第1回(2004年9月29日)～第38回(2008年10月15日)までの情報が掲載されております。
Caterina Zeppieri 氏 (Universität Münster)
Geometric rigidity for incompatible fields and an application to strain-gradient plasticity (ENGLISH)
[ 講演概要 ]
Motivated by the study of nonlinear plane elasticity in presence of edge dislocations, in this talk we show that in dimension two the Friesecke, James, and Müller Rigidity Estimate holds true also for matrix-fields with nonzero curl, modulo an error depending on the total mass of the curl.
The above generalised rigidity is then used to derive a strain-gradient model for plasticity from semi-discrete nonlinear dislocation energies by Gamma-convergence.
The above results are obtained in collaboration with S. Müller (University of Bonn, Germany) and L. Scardia (University of Glasgow, UK).
Motivated by the study of nonlinear plane elasticity in presence of edge dislocations, in this talk we show that in dimension two the Friesecke, James, and Müller Rigidity Estimate holds true also for matrix-fields with nonzero curl, modulo an error depending on the total mass of the curl.
The above generalised rigidity is then used to derive a strain-gradient model for plasticity from semi-discrete nonlinear dislocation energies by Gamma-convergence.
The above results are obtained in collaboration with S. Müller (University of Bonn, Germany) and L. Scardia (University of Glasgow, UK).
2013年03月11日(月)
作用素環セミナー
09:45-12:00 数理科学研究科棟(駒場) 123号室
Tristan Bice 氏 (York Univ.) 09:45-10:45
Traces and Ultrapowers (ENGLISH)
David Penneys 氏 (Univ. Toronto) 11:00-12:00
Constructing subfactors with jellyfish (ENGLISH)
Tristan Bice 氏 (York Univ.) 09:45-10:45
Traces and Ultrapowers (ENGLISH)
David Penneys 氏 (Univ. Toronto) 11:00-12:00
Constructing subfactors with jellyfish (ENGLISH)
作用素環セミナー
13:30-18:15 数理科学研究科棟(駒場) 123号室
Danny Hey 氏 (Univ. Toronto) 13:30-14:30
Classification and the Toms-Winter Conjecture (ENGLISH)
Stephen Curran 氏 (UCLA) 14:45-15:45
Free probability and planar algebras (ENGLISH)
Rasmus Bentmann 氏 (Univ. Copenhagen) 16:00-17:00
Kirchberg $X$-algebras with real rank zero and intermediate cancellation (ENGLISH)
Luis Santiago-Moreno 氏 (Univ. Oregon) 17:15-18:15
Classifying $C^*$-algebras up to W-stability (ENGLISH)
Danny Hey 氏 (Univ. Toronto) 13:30-14:30
Classification and the Toms-Winter Conjecture (ENGLISH)
Stephen Curran 氏 (UCLA) 14:45-15:45
Free probability and planar algebras (ENGLISH)
Rasmus Bentmann 氏 (Univ. Copenhagen) 16:00-17:00
Kirchberg $X$-algebras with real rank zero and intermediate cancellation (ENGLISH)
Luis Santiago-Moreno 氏 (Univ. Oregon) 17:15-18:15
Classifying $C^*$-algebras up to W-stability (ENGLISH)
GCOEセミナー
14:45-15:45 数理科学研究科棟(駒場) 123号室
このセミナーはMiniworkshop on Operator Algebras IVの一環として行われます
Stephen Curran 氏 (UCLA)
Free probability and planar algebras (ENGLISH)
[ 参考URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/mini2013-4.htm
このセミナーはMiniworkshop on Operator Algebras IVの一環として行われます
Stephen Curran 氏 (UCLA)
Free probability and planar algebras (ENGLISH)
[ 参考URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/mini2013-4.htm
2013年03月08日(金)
FMSPレクチャーズ
10:30-12:00 数理科学研究科棟(駒場) 056号室
Benjamin Burton 氏 (The University of Queensland, Australia)
Knots, algorithms and linear programming: the quest to solve unknot recognition in polynomial time (ENGLISH)
Benjamin Burton 氏 (The University of Queensland, Australia)
Knots, algorithms and linear programming: the quest to solve unknot recognition in polynomial time (ENGLISH)
[ 講演概要 ]
In this talk we explore new approaches to the old and difficult computational problem of unknot recognition. Although the best known algorithms for this problem run in exponential time, there is increasing evidence that a polynomial time solution might be possible. We outline several promising approaches, in which computational geometry, linear programming and greedy algorithms all play starring roles. We finish with a new algorithm that combines techniques from topology and combinatorial optimisation, which is the first to exhibit "real world" polynomial time behaviour: although it is still exponential time in theory, exhaustive experimentation shows that this algorithm can solve unknot recognition for "practical" inputs by running just a linear number of linear programs.
This is joint work with Melih Ozlen.
In this talk we explore new approaches to the old and difficult computational problem of unknot recognition. Although the best known algorithms for this problem run in exponential time, there is increasing evidence that a polynomial time solution might be possible. We outline several promising approaches, in which computational geometry, linear programming and greedy algorithms all play starring roles. We finish with a new algorithm that combines techniques from topology and combinatorial optimisation, which is the first to exhibit "real world" polynomial time behaviour: although it is still exponential time in theory, exhaustive experimentation shows that this algorithm can solve unknot recognition for "practical" inputs by running just a linear number of linear programs.
This is joint work with Melih Ozlen.
2013年03月07日(木)
統計数学セミナー
14:50-16:00 数理科学研究科棟(駒場) 006号室
参加をご希望される方は鎌谷 (阪大基礎工); kamatani at sigmath.es.osaka-u.ac.jpまでご連絡ください.
前園 宣彦 氏 (九州大学)
符号検定の連続化と有意確率の近似について (JAPANESE)
http://www.sigmath.es.osaka-u.ac.jp/~kamatani/statseminar/2012/16.html
参加をご希望される方は鎌谷 (阪大基礎工); kamatani at sigmath.es.osaka-u.ac.jpまでご連絡ください.
前園 宣彦 氏 (九州大学)
符号検定の連続化と有意確率の近似について (JAPANESE)
[ 講演概要 ]
本講演では符号検定の連続化とその分布の近似を議論する.カーネル型分布関数の推 定量を利用して検定統計量を構成し,そのPitmanの漸近相対効率は符号検定と同じで あることを示す.また新しい検定統計量はdistribution-freeではないが,漸近分布 は母集団分布に依存しないことを議論し,近似分布の改良であるエッジワース展開を 求める.カーネルの取り方により,エッジワース展開が分布に依存しないように構成 することが可能であることも示す.本研究は九州大学大学院数理学府・魯夢欣さんと の共同研究である.
[ 参考URL ]本講演では符号検定の連続化とその分布の近似を議論する.カーネル型分布関数の推 定量を利用して検定統計量を構成し,そのPitmanの漸近相対効率は符号検定と同じで あることを示す.また新しい検定統計量はdistribution-freeではないが,漸近分布 は母集団分布に依存しないことを議論し,近似分布の改良であるエッジワース展開を 求める.カーネルの取り方により,エッジワース展開が分布に依存しないように構成 することが可能であることも示す.本研究は九州大学大学院数理学府・魯夢欣さんと の共同研究である.
http://www.sigmath.es.osaka-u.ac.jp/~kamatani/statseminar/2012/16.html
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