Text only print
Full screen print
Seminar information archive
Seminar information archive ～05/20｜Today's seminar 05/21 | Future seminars 05/22～
2010/02/17
GCOE lecture series
10:30-16:00 Room #126 (Graduate School of Math. Sci. Bldg.)
Yves Benoist (Paris Sud) 10:30-11:30
Discrete groups acting on homogeneous spaces I
Discrete groups acting on homogeneous spaces II
Yves Benoist (Paris Sud) 10:30-11:30
Discrete groups acting on homogeneous spaces I
[ Abstract ]
In this course I will focus on recent advances
on our understanding of discrete subgroups of Lie groups.
I will first survey how ideas from semisimple algebraic groups,
ergodic theory and representation theory help us to understand properties of these discrete subgroups.
I will then focus on a joint work with Jean-Francois Quint
studying the dynamics of these discrete subgroups on finite volume homogeneous spaces and proving the following result:
We fix two integral matrices A and B of size d, of determinant 1,
and such that no finite union of vector subspaces is invariant by A and B.
We fix also an irrational point on the d-dimensional torus. We will then prove that for n large the set of images of this point by the words in A and B of length at most n becomes equidistributed in the torus.
Yves Benoist (Paris Sud) 15:00-16:00In this course I will focus on recent advances
on our understanding of discrete subgroups of Lie groups.
I will first survey how ideas from semisimple algebraic groups,
ergodic theory and representation theory help us to understand properties of these discrete subgroups.
I will then focus on a joint work with Jean-Francois Quint
studying the dynamics of these discrete subgroups on finite volume homogeneous spaces and proving the following result:
We fix two integral matrices A and B of size d, of determinant 1,
and such that no finite union of vector subspaces is invariant by A and B.
We fix also an irrational point on the d-dimensional torus. We will then prove that for n large the set of images of this point by the words in A and B of length at most n becomes equidistributed in the torus.
Discrete groups acting on homogeneous spaces II
Seminar on Probability and Statistics
15:00-16:10 Room #128 (Graduate School of Math. Sci. Bldg.)
清 智也 (東京大学 情報理工学系研究科)
勾配写像で表される球面上の確率分布族
https://www.ms.u-tokyo.ac.jp/~kengok/statseminar/2009/14.html
清 智也 (東京大学 情報理工学系研究科)
勾配写像で表される球面上の確率分布族
[ Abstract ]
球面上の確率分布族は、方向統計学において重要である。本講演では、コスト凸関数 (c-凸関数)と呼ばれる関数とその勾配写像を用いて、球面上の分布族を構成する。 コスト凸関数とは、最適輸送理論の分野で導入された概念であり、ユークリッド空間 における凸関数をリーマン多様体の場合へ拡張させたものである。提案する分布族の 性質をいくつか示し、簡単な方向データの解析例を示す。
[ Reference URL ]球面上の確率分布族は、方向統計学において重要である。本講演では、コスト凸関数 (c-凸関数)と呼ばれる関数とその勾配写像を用いて、球面上の分布族を構成する。 コスト凸関数とは、最適輸送理論の分野で導入された概念であり、ユークリッド空間 における凸関数をリーマン多様体の場合へ拡張させたものである。提案する分布族の 性質をいくつか示し、簡単な方向データの解析例を示す。
https://www.ms.u-tokyo.ac.jp/~kengok/statseminar/2009/14.html
2010/02/16
Tuesday Seminar on Topology
17:30-18:30 Room #056 (Graduate School of Math. Sci. Bldg.)
Dieter Kotschick (Univ. M\"unchen)
Characteristic numbers of algebraic varieties
Dieter Kotschick (Univ. M\"unchen)
Characteristic numbers of algebraic varieties
[ Abstract ]
The Chern numbers of n-dimensional smooth projective varieties span a vector space whose dimension is the number of partitions of n. This vector space has many natural subspaces, some of which are quite small, for example the subspace spanned by Hirzebruch--Todd numbers, the subspace of topologically invariant combinations of Chern numbers, the subspace determined by the Hodge numbers, and the subspace of Chern numbers that can be bounded in terms of Betti numbers. I shall explain the relation between these subspaces, and characterize them in several ways. This leads in particular to the solution of a long-standing open problem originally formulated by Hirzebruch in the 1950s.
The Chern numbers of n-dimensional smooth projective varieties span a vector space whose dimension is the number of partitions of n. This vector space has many natural subspaces, some of which are quite small, for example the subspace spanned by Hirzebruch--Todd numbers, the subspace of topologically invariant combinations of Chern numbers, the subspace determined by the Hodge numbers, and the subspace of Chern numbers that can be bounded in terms of Betti numbers. I shall explain the relation between these subspaces, and characterize them in several ways. This leads in particular to the solution of a long-standing open problem originally formulated by Hirzebruch in the 1950s.
2010/02/05
thesis presentations
09:45-11:00 Room #118 (Graduate School of Math. Sci. Bldg.)
Takahiro Tsushima (University of Tokyo)
Elementary computation of ramified components of Jacobi sum Hecke characters (JAPANESE)
Takahiro Tsushima (University of Tokyo)
Elementary computation of ramified components of Jacobi sum Hecke characters (JAPANESE)
thesis presentations
11:00-12:15 Room #118 (Graduate School of Math. Sci. Bldg.)
Tomoyuki Abe (University of Tokyo)
Comparison between Swan conductors and characteristic cycles (JAPANESE)
Tomoyuki Abe (University of Tokyo)
Comparison between Swan conductors and characteristic cycles (JAPANESE)
thesis presentations
13:00-14:15 Room #118 (Graduate School of Math. Sci. Bldg.)
宮﨑 直 (東京大学大学院数理科学研究科)
The structures of generalized principal series representations of SL(3,R) and related Whittaker functions (SL(3,R)の一般主系列表現の構造と関連するWhittaker関数)
宮﨑 直 (東京大学大学院数理科学研究科)
The structures of generalized principal series representations of SL(3,R) and related Whittaker functions (SL(3,R)の一般主系列表現の構造と関連するWhittaker関数)
thesis presentations
14:15-15:30 Room #118 (Graduate School of Math. Sci. Bldg.)
長谷川 泰子 (東京大学大学院数理科学研究科)
PRINCIPAL SERIES AND GENERALIZED PRINCIPAL SERIES WHITTAKER FUNCTIONS WITH PERIPHERAL K-TYPES ON THE REAL SYMPLECTIC GROUP OF RANK 2 (実二次シンプレクティック群上の主系列表現及び一般主系列表現の周辺的K-TYPEを持つWHITTAKER 関数)
長谷川 泰子 (東京大学大学院数理科学研究科)
PRINCIPAL SERIES AND GENERALIZED PRINCIPAL SERIES WHITTAKER FUNCTIONS WITH PERIPHERAL K-TYPES ON THE REAL SYMPLECTIC GROUP OF RANK 2 (実二次シンプレクティック群上の主系列表現及び一般主系列表現の周辺的K-TYPEを持つWHITTAKER 関数)
thesis presentations
09:45-11:00 Room #122 (Graduate School of Math. Sci. Bldg.)
二木 昌宏 (東京大学大学院数理科学研究科)
On the generalized suspension theorem for directed Fukaya categories (有向深谷圏の懸垂定理の一般化について)
二木 昌宏 (東京大学大学院数理科学研究科)
On the generalized suspension theorem for directed Fukaya categories (有向深谷圏の懸垂定理の一般化について)
thesis presentations
11:00-12:15 Room #122 (Graduate School of Math. Sci. Bldg.)
松尾 信一郎 (東京大学大学院数理科学研究科)
On the Runge theorem for instantons (インスタントンに対するRungeの近似定理について)
松尾 信一郎 (東京大学大学院数理科学研究科)
On the Runge theorem for instantons (インスタントンに対するRungeの近似定理について)
thesis presentations
11:00-12:15 Room #126 (Graduate School of Math. Sci. Bldg.)
西岡 斉治 (東京大学大学院数理科学研究科)
Solvability and irreducibility of difference equations (差分方程式の可解性と既約性)
西岡 斉治 (東京大学大学院数理科学研究科)
Solvability and irreducibility of difference equations (差分方程式の可解性と既約性)
thesis presentations
13:00-14:15 Room #126 (Graduate School of Math. Sci. Bldg.)
水田 有一 (東京大学大学院数理科学研究科)
Weak Amenability for a Group Acting on a Finite Dimensional CAT(0) Cube Complex (有限次元CAT(0)方体複体に作用する群の弱従順性)
水田 有一 (東京大学大学院数理科学研究科)
Weak Amenability for a Group Acting on a Finite Dimensional CAT(0) Cube Complex (有限次元CAT(0)方体複体に作用する群の弱従順性)
thesis presentations
14:15-15:30 Room #126 (Graduate School of Math. Sci. Bldg.)
酒匂 宏樹 (東京大学大学院数理科学研究科)
Stone-Čech boundaries of discrete groups and measure equivalence theory (離散群のストーン-チェック境界と測度同値理論)
酒匂 宏樹 (東京大学大学院数理科学研究科)
Stone-Čech boundaries of discrete groups and measure equivalence theory (離散群のストーン-チェック境界と測度同値理論)
thesis presentations
09:45-11:00 Room #128 (Graduate School of Math. Sci. Bldg.)
西山 了允 (東京大学大学院数理科学研究科)
CONSTRUCTION OF ISOTROPIC CELLULAR AUTOMATON AND ITS APPLICATION (等方セル・オートマトンの構成とその応用)
西山 了允 (東京大学大学院数理科学研究科)
CONSTRUCTION OF ISOTROPIC CELLULAR AUTOMATON AND ITS APPLICATION (等方セル・オートマトンの構成とその応用)
2010/02/04
thesis presentations
09:45-11:00 Room #122 (Graduate School of Math. Sci. Bldg.)
久野 雄介 (東京大学大学院数理科学研究科)
The Meyer functions for projective varieties and their applications to local signatures for fibered 4-manifolds (射影多様体に対するMeyer函数と,その局所符号数への応用)
久野 雄介 (東京大学大学院数理科学研究科)
The Meyer functions for projective varieties and their applications to local signatures for fibered 4-manifolds (射影多様体に対するMeyer函数と,その局所符号数への応用)
thesis presentations
11:00-12:15 Room #122 (Graduate School of Math. Sci. Bldg.)
服部 広大 (東京大学大学院数理科学研究科)
On hyperkähler manifolds of type A∞ (A∞型超ケーラー多様体について)
服部 広大 (東京大学大学院数理科学研究科)
On hyperkähler manifolds of type A∞ (A∞型超ケーラー多様体について)
thesis presentations
13:00-14:15 Room #122 (Graduate School of Math. Sci. Bldg.)
篠原 克寿 (東京大学大学院数理科学研究科)
On the index problem for C1-generic wild homoclinic classes (C1通有的に野性的なホモクリニック類の指数問題について)
篠原 克寿 (東京大学大学院数理科学研究科)
On the index problem for C1-generic wild homoclinic classes (C1通有的に野性的なホモクリニック類の指数問題について)
thesis presentations
14:15-15:30 Room #122 (Graduate School of Math. Sci. Bldg.)
佐藤 正寿 (東京大学大学院数理科学研究科)
The abelianization of the level d mapping class group (レベルd写像類群のアーベル化)
佐藤 正寿 (東京大学大学院数理科学研究科)
The abelianization of the level d mapping class group (レベルd写像類群のアーベル化)
thesis presentations
14:15-15:30 Room #126 (Graduate School of Math. Sci. Bldg.)
毛 仕寛 (東京大学大学院数理科学研究科)
Singularities for Solutions to Schrödinger Equations (シュレーディンガー方程式の解の特異性)
毛 仕寛 (東京大学大学院数理科学研究科)
Singularities for Solutions to Schrödinger Equations (シュレーディンガー方程式の解の特異性)
thesis presentations
15:45-17:00 Room #126 (Graduate School of Math. Sci. Bldg.)
Si, Duc Quang (東京大学大学院数理科学研究科)
Nevanlinna theory for holomorphic mappings and related problems (正則写像のネヴァンリンナ理論と関連する問題)
Si, Duc Quang (東京大学大学院数理科学研究科)
Nevanlinna theory for holomorphic mappings and related problems (正則写像のネヴァンリンナ理論と関連する問題)
thesis presentations
11:00-12:15 Room #128 (Graduate School of Math. Sci. Bldg.)
高岡 洋介 (東京大学大学院数理科学研究科)
On existence of models for the logical system MPCL (単相格論理系におけるモデルの存在について)
高岡 洋介 (東京大学大学院数理科学研究科)
On existence of models for the logical system MPCL (単相格論理系におけるモデルの存在について)
thesis presentations
13:00-14:15 Room #128 (Graduate School of Math. Sci. Bldg.)
岩尾 慎介 (東京大学大学院数理科学研究科)
Exact Solutions of Ultradiscrete Integrable Systems (超離散可積分系の厳密解)
岩尾 慎介 (東京大学大学院数理科学研究科)
Exact Solutions of Ultradiscrete Integrable Systems (超離散可積分系の厳密解)
thesis presentations
14:15-15:30 Room #128 (Graduate School of Math. Sci. Bldg.)
中田 庸一 (東京大学大学院数理科学研究科)
Vertex operators and background solutions for ultradiscrete soliton equations (超離散ソリトン方程式における頂点作用素と背景解)
中田 庸一 (東京大学大学院数理科学研究科)
Vertex operators and background solutions for ultradiscrete soliton equations (超離散ソリトン方程式における頂点作用素と背景解)
2010/02/02
Lie Groups and Representation Theory
16:30-18:00 Room #056 (Graduate School of Math. Sci. Bldg.)
Fanny Kassel (Orsay)
Deformation of compact quotients of homogeneous spaces
Fanny Kassel (Orsay)
Deformation of compact quotients of homogeneous spaces
[ Abstract ]
Let G/H be a reductive homogeneous space. In all known examples, if
G/H admits compact Clifford-Klein forms, then it admits "standard"
ones, by uniform lattices of some reductive subgroup L of G acting
properly on G/H. In order to obtain more generic Clifford-Klein forms,
we prove that for L of real rank 1, if one slightly deforms in G a
uniform lattice of L, then its action on G/H remains properly
discontinuous. As an application, we obtain compact quotients of SO(2,2n)/U(1,n) by Zariski-dense discrete subgroups of SO(2,2n) acting properly discontinuously.
Let G/H be a reductive homogeneous space. In all known examples, if
G/H admits compact Clifford-Klein forms, then it admits "standard"
ones, by uniform lattices of some reductive subgroup L of G acting
properly on G/H. In order to obtain more generic Clifford-Klein forms,
we prove that for L of real rank 1, if one slightly deforms in G a
uniform lattice of L, then its action on G/H remains properly
discontinuous. As an application, we obtain compact quotients of SO(2,2n)/U(1,n) by Zariski-dense discrete subgroups of SO(2,2n) acting properly discontinuously.
Tuesday Seminar on Topology
16:30-18:00 Room #056 (Graduate School of Math. Sci. Bldg.)
Fanny Kassel (Univ. Paris-Sud, Orsay)
Deformation of compact quotients of homogeneous spaces
Fanny Kassel (Univ. Paris-Sud, Orsay)
Deformation of compact quotients of homogeneous spaces
[ Abstract ]
Let G/H be a reductive homogeneous space. In all known examples, if
G/H admits compact Clifford-Klein forms, then it admits "standard"
ones, by uniform lattices of some reductive subgroup L of G acting
properly on G/H. In order to obtain more generic Clifford-Klein forms,
we prove that for L of real rank 1, if one slightly deforms in G a
uniform lattice of L, then its action on G/H remains properly
discontinuous. As an application, we obtain compact quotients of
SO(2,2n)/U(1,n) by Zariski-dense discrete subgroups of SO(2,2n) acting
properly discontinuously.
https://www.ms.u-tokyo.ac.jp/~toshi/seminar/ut-seminar2010.html#20100202kassel
Let G/H be a reductive homogeneous space. In all known examples, if
G/H admits compact Clifford-Klein forms, then it admits "standard"
ones, by uniform lattices of some reductive subgroup L of G acting
properly on G/H. In order to obtain more generic Clifford-Klein forms,
we prove that for L of real rank 1, if one slightly deforms in G a
uniform lattice of L, then its action on G/H remains properly
discontinuous. As an application, we obtain compact quotients of
SO(2,2n)/U(1,n) by Zariski-dense discrete subgroups of SO(2,2n) acting
properly discontinuously.
https://www.ms.u-tokyo.ac.jp/~toshi/seminar/ut-seminar2010.html#20100202kassel
2010/02/01
Seminar on Geometric Complex Analysis
10:30-12:00 Room #128 (Graduate School of Math. Sci. Bldg.)
大沢健夫 (名古屋大学多元数理科学研究科)
Connectedness of Levi nonflat pseudoconvex hypersurfaces in Kaehler manifolds
大沢健夫 (名古屋大学多元数理科学研究科)
Connectedness of Levi nonflat pseudoconvex hypersurfaces in Kaehler manifolds
< Previous 123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195 Next >
