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Seminar information archive
Seminar information archive ～05/09｜Today's seminar 05/10 | Future seminars 05/11～
2006/05/22
Seminar on Geometric Complex Analysis
10:30-12:00 Room #128 (Graduate School of Math. Sci. Bldg.)
Marco Brunella (Bourgogne)
Uniformisation of Holomorphic Foliations by Curves I (Part II on May 29)
Marco Brunella (Bourgogne)
Uniformisation of Holomorphic Foliations by Curves I (Part II on May 29)
[ Abstract ]
In the first lecture, we give a definition of "leaf" for a singular holomorphic one-dimensional foliation on a projective manifold. The definition is such that the leaves of a foliation glue together in a nice way, giving a "covering tube" which is a sort of semi-global flow box. This is, in some sense, the topological part of the theory. In the second lecture, we prove some convexity property of this covering tube. As a corollary we obtain that, when there are hyperbolic leaves, the leafwise Poincare' metric has some remarkable positivity property. In the third lecture, we study foliations all of whose leaves are parabolic. Using a suitable extension theorem for certain meromorphic maps, we show how to generalise the above positivity property to this degenerate class of foliations.
In the first lecture, we give a definition of "leaf" for a singular holomorphic one-dimensional foliation on a projective manifold. The definition is such that the leaves of a foliation glue together in a nice way, giving a "covering tube" which is a sort of semi-global flow box. This is, in some sense, the topological part of the theory. In the second lecture, we prove some convexity property of this covering tube. As a corollary we obtain that, when there are hyperbolic leaves, the leafwise Poincare' metric has some remarkable positivity property. In the third lecture, we study foliations all of whose leaves are parabolic. Using a suitable extension theorem for certain meromorphic maps, we show how to generalise the above positivity property to this degenerate class of foliations.
Seminar on Geometric Complex Analysis
15:00-16:30 Room #470 (Graduate School of Math. Sci. Bldg.)
Nessim Sibony (Paris Sud)
Laminations with Singularities by Riemann Surfaces II
Nessim Sibony (Paris Sud)
Laminations with Singularities by Riemann Surfaces II
2006/05/20
Monthly Seminar on Arithmetic of Automorphic Forms
13:30-15:45 Room #123 (Graduate School of Math. Sci. Bldg.)
水野 義紀 (慶應大学COE研究員) 13:30-14:30
The Koecher-Maass series for real analytic Siegel-Eisenstein series
Standard L-functions for generic cusp forms on GSp(2)
水野 義紀 (慶應大学COE研究員) 13:30-14:30
The Koecher-Maass series for real analytic Siegel-Eisenstein series
[ Abstract ]
非正則のジーゲル保型形式に対して、そのKoecher-Maass級数を定義し、その解析接続・関数等式を得ることは、正則のときMaassが発展させた方法でうまくいくかどうかはわかっていないと思われます。一変数半整数の実解析的Eisenstein級数のRankin-Selberg convolutionの解析接続、関数等式を示し、伊吹山・桂田の明示公式を用いた実解析的Siegel-Eisenstein級数のKoecher-Maass級数への応用(解析接続、関数等式)を述べます。
石井 卓 (東京大学大学院数理科学研究科) 14:45-15:45非正則のジーゲル保型形式に対して、そのKoecher-Maass級数を定義し、その解析接続・関数等式を得ることは、正則のときMaassが発展させた方法でうまくいくかどうかはわかっていないと思われます。一変数半整数の実解析的Eisenstein級数のRankin-Selberg convolutionの解析接続、関数等式を示し、伊吹山・桂田の明示公式を用いた実解析的Siegel-Eisenstein級数のKoecher-Maass級数への応用(解析接続、関数等式)を述べます。
Standard L-functions for generic cusp forms on GSp(2)
[ Abstract ]
Whittaker模型を持つようなGSp(2)の尖点保型表現に付随するスタンダードL関数(5次のオイラー積)を、Ginzburg-Rallis-Soudry ('97)やBump-Friedberg-Ginzburg ('99)によって与えれたゼータ積分を通じて解析接続する方法について、これまでに得られた結果を紹介する。
Whittaker模型を持つようなGSp(2)の尖点保型表現に付随するスタンダードL関数(5次のオイラー積)を、Ginzburg-Rallis-Soudry ('97)やBump-Friedberg-Ginzburg ('99)によって与えれたゼータ積分を通じて解析接続する方法について、これまでに得られた結果を紹介する。
2006/05/18
Applied Analysis
16:00-17:30 Room #056 (Graduate School of Math. Sci. Bldg.)
石井 仁司 (早稲田大学 教育学部 理学科 数学専修)
Asymptotic behavior for large-time of solutions of Hamilton-Jacobi equations in n space
石井 仁司 (早稲田大学 教育学部 理学科 数学専修)
Asymptotic behavior for large-time of solutions of Hamilton-Jacobi equations in n space
2006/05/17
Seminar on Probability and Statistics
16:20-17:30 Room #128 (Graduate School of Math. Sci. Bldg.)
Arnak DALALYAN (Universite Paris 6, France)
Second-order efficiency in the semiparametric problem of estimating the shift of a signal
Arnak DALALYAN (Universite Paris 6, France)
Second-order efficiency in the semiparametric problem of estimating the shift of a signal
2006/05/16
Tuesday Seminar on Topology
17:00-18:30 Room #056 (Graduate School of Math. Sci. Bldg.)
Laurentiu Maxim (University of Illinois at Chicago)
Fundamental groups of complements to complex hypersurfaces
Laurentiu Maxim (University of Illinois at Chicago)
Fundamental groups of complements to complex hypersurfaces
[ Abstract ]
I will survey various Alexander-type invariants of hypersurface complements, with an emphasis on obstructions on the type of groups that can arise as fundamental groups of complements to affine hypersurfaces.
I will survey various Alexander-type invariants of hypersurface complements, with an emphasis on obstructions on the type of groups that can arise as fundamental groups of complements to affine hypersurfaces.
Lie Groups and Representation Theory
16:30-18:00 Room #126 (Graduate School of Math. Sci. Bldg.)
大島 利雄 (東京大学大学院数理科学研究科)
確定特異点型の可換な微分作用素系について
大島 利雄 (東京大学大学院数理科学研究科)
確定特異点型の可換な微分作用素系について
[ Abstract ]
実簡約Lie群やその対称空間をコンパクト多様体に実現すると,不変微分作用素系はその境界に沿って確定特異点を持つ可換微分作用素系となる.
可換微分作用素系がただ一つの作用素から特徴づけられることを基に,境界の近傍で多価解析的な同時固有関数の一般的構成を考察し,表現論,特にWhittaker模型などへの応用を論じる(Harish-Chandra同型やGoodman-Wallach作用素の微分方程式論の立場からの解釈などを含む).
実簡約Lie群やその対称空間をコンパクト多様体に実現すると,不変微分作用素系はその境界に沿って確定特異点を持つ可換微分作用素系となる.
可換微分作用素系がただ一つの作用素から特徴づけられることを基に,境界の近傍で多価解析的な同時固有関数の一般的構成を考察し,表現論,特にWhittaker模型などへの応用を論じる(Harish-Chandra同型やGoodman-Wallach作用素の微分方程式論の立場からの解釈などを含む).
2006/05/15
Seminar on Geometric Complex Analysis
10:30-12:00 Room #128 (Graduate School of Math. Sci. Bldg.)
Nessim Sibony (Paris Sud)
Laminations with Singularities by Riemann Surfaces I (Part II on May 22)
Nessim Sibony (Paris Sud)
Laminations with Singularities by Riemann Surfaces I (Part II on May 22)
[ Abstract ]
The basic example of a lamination, possibly with singularites, by Riemann surfaces, is the closure of a leaf of a holomorphic foliation in the complex projective plane.There are also many examples arising from the theory of iteration of a holomorphic map. The goal is to introduce tools in order to understand the globalproperties of leaves of a holomorphic lamination, mostly in compact Kaehler manifolds. We will develop the following topics.
-Poincare metric on a hyperbolic lamination.
-Positive cycles and positive harmonic currents directed by a lamination.
-Ahlfors construction of positive harmonic currents.
-Cohomological and geometrical intersection of positive harmonic currents.
The basic example of a lamination, possibly with singularites, by Riemann surfaces, is the closure of a leaf of a holomorphic foliation in the complex projective plane.There are also many examples arising from the theory of iteration of a holomorphic map. The goal is to introduce tools in order to understand the globalproperties of leaves of a holomorphic lamination, mostly in compact Kaehler manifolds. We will develop the following topics.
-Poincare metric on a hyperbolic lamination.
-Positive cycles and positive harmonic currents directed by a lamination.
-Ahlfors construction of positive harmonic currents.
-Cohomological and geometrical intersection of positive harmonic currents.
2006/05/12
Colloquium
16:30-17:30 Room #123 (Graduate School of Math. Sci. Bldg.)
浜窪 隆雄 氏, 油谷 浩幸 (東京大学先端科学技術センター)
ポストゲノム時代のシステム生物学の問題について
浜窪 隆雄 氏, 油谷 浩幸 (東京大学先端科学技術センター)
ポストゲノム時代のシステム生物学の問題について
[ Abstract ]
ヒトゲノム30億塩基対のシークエンスは解読されましたが、その遺伝暗号の意味がわかっている部分はほんの数パーセントにすぎません。DNAチップや質量分析機の発達とコンピューターの進歩により、細胞や組織で読まれている遺伝子の量や生ずるタンパク質の種類を網羅的に解析する手段ができています。これらのトランスクリプトーム解析やプロテオーム解析により多数の遺伝子あるいはタンパク質の挙動を調べることが可能になってくると、生命現象の基礎となっている調節メカニズムが単一分子の相互作用だけで説明できないのではないかと思われてきました。多数分子の挙動とそれらの相互作用をどのように解析することができるかということが、生命現象を分子から生体システムとして理解するために必要なのではないかと感じています。これまで、我々の解析で得られているデータをお示しし、現在の生命科学が直面しつつある問題点を説明できればと思います。
ヒトゲノム30億塩基対のシークエンスは解読されましたが、その遺伝暗号の意味がわかっている部分はほんの数パーセントにすぎません。DNAチップや質量分析機の発達とコンピューターの進歩により、細胞や組織で読まれている遺伝子の量や生ずるタンパク質の種類を網羅的に解析する手段ができています。これらのトランスクリプトーム解析やプロテオーム解析により多数の遺伝子あるいはタンパク質の挙動を調べることが可能になってくると、生命現象の基礎となっている調節メカニズムが単一分子の相互作用だけで説明できないのではないかと思われてきました。多数分子の挙動とそれらの相互作用をどのように解析することができるかということが、生命現象を分子から生体システムとして理解するために必要なのではないかと感じています。これまで、我々の解析で得られているデータをお示しし、現在の生命科学が直面しつつある問題点を説明できればと思います。
2006/05/10
Seminar on Probability and Statistics
16:20-17:30 Room #128 (Graduate School of Math. Sci. Bldg.)
Arnak DALALYAN (Universite Paris 6, France)
Asymptotic statistical equivalence for diffusion processes II
https://www.ms.u-tokyo.ac.jp/~kengok/statseminar/2006/01.html
Arnak DALALYAN (Universite Paris 6, France)
Asymptotic statistical equivalence for diffusion processes II
[ Abstract ]
We consider the experiment of a continuously observed scalar diffusion process with unknown drift function. In the stationary case, we prove that this experment is locally asymptotically equivalent to a simple Gaussian white noise experiment. We also derive the rate of convergence of the Le Cam's distance and describe the Markov kernel attaining this rate of convergence. These results are obtained in collaboration with Markus Reiss.
[ Reference URL ]We consider the experiment of a continuously observed scalar diffusion process with unknown drift function. In the stationary case, we prove that this experment is locally asymptotically equivalent to a simple Gaussian white noise experiment. We also derive the rate of convergence of the Le Cam's distance and describe the Markov kernel attaining this rate of convergence. These results are obtained in collaboration with Markus Reiss.
https://www.ms.u-tokyo.ac.jp/~kengok/statseminar/2006/01.html
2006/05/08
Seminar on Geometric Complex Analysis
10:30-12:00 Room #128 (Graduate School of Math. Sci. Bldg.)
大沢 健夫 (名古屋大学)
Real-analytic Levi-flats in complex tori
大沢 健夫 (名古屋大学)
Real-analytic Levi-flats in complex tori
2006/04/27
Applied Analysis
16:00-17:30 Room #056 (Graduate School of Math. Sci. Bldg.)
西原 健二 (早稲田大学・政治経済学術院)
消散型波動方程式のコーシー問題の解の挙動
西原 健二 (早稲田大学・政治経済学術院)
消散型波動方程式のコーシー問題の解の挙動
Seminar for Mathematical Past of Asia
17:00-18:30 Room #152 (Graduate School of Math. Sci. Bldg.)
川原 秀城 (東京大学大学院人文社会系研究科、東アジア思想文化、(兼)韓国朝鮮言語思想)
九数略──17・18世紀の朝鮮数学
川原 秀城 (東京大学大学院人文社会系研究科、東アジア思想文化、(兼)韓国朝鮮言語思想)
九数略──17・18世紀の朝鮮数学
[ Abstract ]
『九数略』は,当時の代表的な政治家兼経学者、崔錫鼎(1645- 1715)が著した数学書。内容自体は伝統の実用算術のレベルを超えていないけれども、形而上学的な易学思想をもって、朝鮮の計算術と実用数学の構造を理論的に位置づけている。また数学の基本的構造自体に西洋の3数法の深い影響があることも、この数学書の特徴の1つである。
今回は特に『九数略』の思想史的な意味に注目してその内容を紹介したい。
『九数略』は,当時の代表的な政治家兼経学者、崔錫鼎(1645- 1715)が著した数学書。内容自体は伝統の実用算術のレベルを超えていないけれども、形而上学的な易学思想をもって、朝鮮の計算術と実用数学の構造を理論的に位置づけている。また数学の基本的構造自体に西洋の3数法の深い影響があることも、この数学書の特徴の1つである。
今回は特に『九数略』の思想史的な意味に注目してその内容を紹介したい。
2006/04/26
Number Theory Seminar
16:30-17:30 Room #117 (Graduate School of Math. Sci. Bldg.)
伴 克馬 (東京大学大学院数理科学研究科)
Differential Operators of Rankin-Cohen-Ibukiyama Type for Automorphic Forms of Several Variables
伴 克馬 (東京大学大学院数理科学研究科)
Differential Operators of Rankin-Cohen-Ibukiyama Type for Automorphic Forms of Several Variables
Seminar on Probability and Statistics
16:20-17:30 Room #128 (Graduate School of Math. Sci. Bldg.)
Arnak DALALYAN (Universite Paris 6, France)
Asymptotic statistical equivalence for diffusion processes I (JAPANESE)
Arnak DALALYAN (Universite Paris 6, France)
Asymptotic statistical equivalence for diffusion processes I (JAPANESE)
[ Abstract ]
This is the first talk of a series of three talks devoted to the asymptotic statistical equivalence for diffusion processes. We will introduce the notion of Le Cam's distance between statistical experiments and will present its properties with some easy examples. Then we will show that the experiment of a discretely observed diffusion process with unknown drift is asymptoically equivalent to the experiment of continuously observed diffusion process provided that the step of discretisation is small enough (this result is due to Milstein and Nussbaum).
This is the first talk of a series of three talks devoted to the asymptotic statistical equivalence for diffusion processes. We will introduce the notion of Le Cam's distance between statistical experiments and will present its properties with some easy examples. Then we will show that the experiment of a discretely observed diffusion process with unknown drift is asymptoically equivalent to the experiment of continuously observed diffusion process provided that the step of discretisation is small enough (this result is due to Milstein and Nussbaum).
2006/04/25
Tuesday Seminar on Topology
16:30-18:00 Room #056 (Graduate School of Math. Sci. Bldg.)
合田 洋 (東京農工大学)
Counting closed orbits and flow lines via Heegaard splittings
合田 洋 (東京農工大学)
Counting closed orbits and flow lines via Heegaard splittings
[ Abstract ]
Let K be a fibred knot in the 3-sphere. It is known that the Alexander polynomial of K is essentially equal to a Lefschetz zeta function obtained from the monodromy map of the fibre structure. In this talk, we discuss the non-fibred knot case. We introduce "monodromy matrix" by making use of Heegaard splitting for sutured manifolds of a knot K, and then observe a method of counting closed orbits and flow lines, which gives the Alexander polynomial of K. This observation is based on works of Donaldson and Mark. (joint work with Hiroshi Matsuda and Andrei Pajitnov)
Let K be a fibred knot in the 3-sphere. It is known that the Alexander polynomial of K is essentially equal to a Lefschetz zeta function obtained from the monodromy map of the fibre structure. In this talk, we discuss the non-fibred knot case. We introduce "monodromy matrix" by making use of Heegaard splitting for sutured manifolds of a knot K, and then observe a method of counting closed orbits and flow lines, which gives the Alexander polynomial of K. This observation is based on works of Donaldson and Mark. (joint work with Hiroshi Matsuda and Andrei Pajitnov)
Tuesday Seminar of Algebraic Analysis
16:30-18:00 Room #052 (Graduate School of Math. Sci. Bldg.)
松井 優 (東大数理)
構成可能関数のRadon変換の像の特徴付けと射影双対性への応用について
[ Reference URL ]
http://agusta.ms.u-tokyo.ac.jp/seminarphotos/Matsui2006/matsui2006_1.html
松井 優 (東大数理)
構成可能関数のRadon変換の像の特徴付けと射影双対性への応用について
[ Reference URL ]
http://agusta.ms.u-tokyo.ac.jp/seminarphotos/Matsui2006/matsui2006_1.html
2006/04/24
Seminar on Geometric Complex Analysis
10:30-12:00 Room #128 (Graduate School of Math. Sci. Bldg.)
Jonas Wiklund (名古屋大学, JSPS fellow)
Monge-Ampére mass at the boundary on some domains with corner
Jonas Wiklund (名古屋大学, JSPS fellow)
Monge-Ampére mass at the boundary on some domains with corner
[ Abstract ]
The Monge-Ampére operator is a highly non-linear operator that assigns a positive measure to every plurisubharmonic function and the null-measure to every maximal plurisubharmonic measure, whenever it is well defined. We discuss the sweeping out of this measure to the boundary for functions that essentially vanish on the boundary, and show two examples that this boundary measure vanish outside the distinguished boundary. Namely for analytic polyhedrons and for the cross product of two hyperconvex domains. Some related open problems are also mentioned.
The Monge-Ampére operator is a highly non-linear operator that assigns a positive measure to every plurisubharmonic function and the null-measure to every maximal plurisubharmonic measure, whenever it is well defined. We discuss the sweeping out of this measure to the boundary for functions that essentially vanish on the boundary, and show two examples that this boundary measure vanish outside the distinguished boundary. Namely for analytic polyhedrons and for the cross product of two hyperconvex domains. Some related open problems are also mentioned.
2006/04/21
Colloquium
16:30-17:30 Room #123 (Graduate School of Math. Sci. Bldg.)
Dmitri Orlov (Steklov Institute)
Homological mirror symmetry
Dmitri Orlov (Steklov Institute)
Homological mirror symmetry
[ Abstract ]
Homological mirror symmetry is a relation between algebraic and symplectic sides of a geometric object. Original mirror symmetry came from physics, but homological mirror symmetry conjecture formulated by M.Kontsevich for Calabi-Yau varieties is an attempt to give a mathematical explanation of this phenomenon. We will try to describe main principles of homological mirror symmetry and the extension to a non-Calabi-Yau case.
Homological mirror symmetry is a relation between algebraic and symplectic sides of a geometric object. Original mirror symmetry came from physics, but homological mirror symmetry conjecture formulated by M.Kontsevich for Calabi-Yau varieties is an attempt to give a mathematical explanation of this phenomenon. We will try to describe main principles of homological mirror symmetry and the extension to a non-Calabi-Yau case.
2006/04/20
Applied Mathematics
16:00-18:15 Room #123 (Graduate School of Math. Sci. Bldg.)
杉原 厚吉 (東京大学大学院情報理工学系研究科) 16:00-17:00
立体イリュージョンの世界
色彩と明暗が生む錯視
杉原 厚吉 (東京大学大学院情報理工学系研究科) 16:00-17:00
立体イリュージョンの世界
[ Abstract ]
人は写真や絵の中に3次元的な奥行きを感じ取ることができるが,実は,同一の投影図をもつ立体は無限に多く存在する.人間の立体知覚にかかわるイリュージョンをコンピュータビジョンの立場から数理的に眺めてみると,さまざまな面白い発見が得られる.たとえば,だまし絵の中だけに存在して,実際にはありえないと思われている立体が作れたりもする.
新井 仁之 (東京大学大学院数理科学研究科) 17:15-18:15人は写真や絵の中に3次元的な奥行きを感じ取ることができるが,実は,同一の投影図をもつ立体は無限に多く存在する.人間の立体知覚にかかわるイリュージョンをコンピュータビジョンの立場から数理的に眺めてみると,さまざまな面白い発見が得られる.たとえば,だまし絵の中だけに存在して,実際にはありえないと思われている立体が作れたりもする.
色彩と明暗が生む錯視
[ Abstract ]
錯視は視覚における錯覚である.しかし,じつは錯視は視覚がどのように情報処理を行っているかを知るための重要な鍵の一つである.本講演ではウェーブレットという数学的道具を用いて,視覚情報処理の非線形数理モデルを作り,色や明暗に関するさまざまな錯視発生のメカニズムに迫りたい.
錯視は視覚における錯覚である.しかし,じつは錯視は視覚がどのように情報処理を行っているかを知るための重要な鍵の一つである.本講演ではウェーブレットという数学的道具を用いて,視覚情報処理の非線形数理モデルを作り,色や明暗に関するさまざまな錯視発生のメカニズムに迫りたい.
Operator Algebra Seminars
16:30-18:00 Room #052 (Graduate School of Math. Sci. Bldg.)
戸松 玲治 (東大数理・COE)
Compact Kac 環の極小作用の分類 I
戸松 玲治 (東大数理・COE)
Compact Kac 環の極小作用の分類 I
2006/04/19
Number Theory Seminar
16:30-17:30 Room #117 (Graduate School of Math. Sci. Bldg.)
谷口 隆 (東京大学大学院数理科学研究科)
Distributions of discriminants of cubic algebras
谷口 隆 (東京大学大学院数理科学研究科)
Distributions of discriminants of cubic algebras
Seminar on Mathematics for various disciplines
10:30-11:30 Room #056 (Graduate School of Math. Sci. Bldg.)
横山 悦郎 (学習院大学)
Oscillatory growth of a crystal controlled by interface kinetics and transport process
http://coe.math.sci.hokudai.ac.jp/sympo/various/005.html
横山 悦郎 (学習院大学)
Oscillatory growth of a crystal controlled by interface kinetics and transport process
[ Abstract ]
Periodic texture in a crystal -such as growth banding and growth striations- are believed to be caused by oscillatory growth. The origin of oscillatory growth falls into two categories, i.e., external and internal. Since the growth rate of a crystal depends strongly on the growth conditions, periodic changes of external conditions, such as temperature, concentration, convection etc., are common reasons for explaining oscillatory growth. On the other hand, it is thought that oscillatory growth can also have an internal cause, but there is no clear understanding. In this talk we propose the hypothesis of a hysteresis behaviour of growth rate to explain the formation of periodic structures of a growing crystal without a change of external conditions. Recently, evidence for our hypothesis is observed not only in the growth of a crystal but also in the motion of steps on the surface of crystals. Possibly such self-oscillatory growth can be controlled in experiments in near future.
[ Reference URL ]Periodic texture in a crystal -such as growth banding and growth striations- are believed to be caused by oscillatory growth. The origin of oscillatory growth falls into two categories, i.e., external and internal. Since the growth rate of a crystal depends strongly on the growth conditions, periodic changes of external conditions, such as temperature, concentration, convection etc., are common reasons for explaining oscillatory growth. On the other hand, it is thought that oscillatory growth can also have an internal cause, but there is no clear understanding. In this talk we propose the hypothesis of a hysteresis behaviour of growth rate to explain the formation of periodic structures of a growing crystal without a change of external conditions. Recently, evidence for our hypothesis is observed not only in the growth of a crystal but also in the motion of steps on the surface of crystals. Possibly such self-oscillatory growth can be controlled in experiments in near future.
http://coe.math.sci.hokudai.ac.jp/sympo/various/005.html
2006/04/18
Tuesday Seminar on Topology
16:30-18:00 Room #056 (Graduate School of Math. Sci. Bldg.)
Vladimir Turaev (Univ. Louis Pasteur Strasbourg)
Topology of words
Vladimir Turaev (Univ. Louis Pasteur Strasbourg)
Topology of words
[ Abstract ]
There is a parallel between words, defined as finite sequences of letters, and curves on surfaces. This allows to treat words as geometric objects and to analyze them using techniques from low-dimensional topology. I will discuss basic ideas in this direction and the resulting topological invariants of words.
There is a parallel between words, defined as finite sequences of letters, and curves on surfaces. This allows to treat words as geometric objects and to analyze them using techniques from low-dimensional topology. I will discuss basic ideas in this direction and the resulting topological invariants of words.
Lie Groups and Representation Theory
16:30-18:00 Room #126 (Graduate School of Math. Sci. Bldg.)
伴 克馬 (東京大学大学院数理科学研究科)
Rankin-Cohen-伊吹山型の微分作用素について
伴 克馬 (東京大学大学院数理科学研究科)
Rankin-Cohen-伊吹山型の微分作用素について
[ Abstract ]
正則保型形式の正則微分は一般に保型形式ではなくなるが、それらを組み合わせることで新たな正則保型形式を与えることもできる。
楕円モジュラー形式に対するRankin-Cohen微分作用素はその最も簡単な例である。伊吹山はSiegelモジュラー形式に対するこのようなタイプの微分作用素がどのような形をしているかについて、一般的な記述を与えた。
今回のセミナーでは、伊吹山による結果を表現論的な命題として捉え直し、その命題が自然にSU(p,q)やO*(2p)上の正則保型形式にも拡張されることを説明する。
正則保型形式の正則微分は一般に保型形式ではなくなるが、それらを組み合わせることで新たな正則保型形式を与えることもできる。
楕円モジュラー形式に対するRankin-Cohen微分作用素はその最も簡単な例である。伊吹山はSiegelモジュラー形式に対するこのようなタイプの微分作用素がどのような形をしているかについて、一般的な記述を与えた。
今回のセミナーでは、伊吹山による結果を表現論的な命題として捉え直し、その命題が自然にSU(p,q)やO*(2p)上の正則保型形式にも拡張されることを説明する。
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