本文印刷
全画面プリント
過去の記録
過去の記録 ～06/12｜本日 06/13 | 今後の予定 06/14～
代数幾何学セミナー
15:30-17:00 数理科学研究科棟(駒場) 128号室
いつもと曜日・場所が異なります
Jungkai Alfred Chen 氏 (National Taiwan University)
Three Dimensional Birational Geoemtry--updates and problems (ENGLISH)
いつもと曜日・場所が異なります
Jungkai Alfred Chen 氏 (National Taiwan University)
Three Dimensional Birational Geoemtry--updates and problems (ENGLISH)
[ 講演概要 ]
In this talk I will talk about some recent results on
biratioanl classification and biratioanl geoemtry of threefolds.
Given a threefold of general type, we improved our previous result by
showing that $Vol \\ge 1/1680$ and $|mK_X|$ is biratioanl for $m \\ge
61$.
Compare with the worst known example that $X_{46} \\subset
\\mathbb{P}(4,5,6,7,23)$, one also knows that there are only finiteley
many singularities type
for threefolds of general type with $1/1680 \\le Vol \\le 1/420$. It is
then intereting to study threefolds of general type with given basket
of singularities and with given fiber structure.
Concerning threefolds with intermediate Kodaira dimension, we
considered the effective Iitaka fibration. For this purpose, it is
interesting to study threefolds with $\\kappa=1$ with given basket of
singularities and abelian fibration.
For explicit birational geoemtry, we will show our result that each
biratioanl map in minimal model program can be factored into a
sequence of following maps (or its inverse)
1. a divisorial contraction to a point of index r with discrepancy 1/r.
2. a blowup along a smooth curve
3. a flop
In this talk I will talk about some recent results on
biratioanl classification and biratioanl geoemtry of threefolds.
Given a threefold of general type, we improved our previous result by
showing that $Vol \\ge 1/1680$ and $|mK_X|$ is biratioanl for $m \\ge
61$.
Compare with the worst known example that $X_{46} \\subset
\\mathbb{P}(4,5,6,7,23)$, one also knows that there are only finiteley
many singularities type
for threefolds of general type with $1/1680 \\le Vol \\le 1/420$. It is
then intereting to study threefolds of general type with given basket
of singularities and with given fiber structure.
Concerning threefolds with intermediate Kodaira dimension, we
considered the effective Iitaka fibration. For this purpose, it is
interesting to study threefolds with $\\kappa=1$ with given basket of
singularities and abelian fibration.
For explicit birational geoemtry, we will show our result that each
biratioanl map in minimal model program can be factored into a
sequence of following maps (or its inverse)
1. a divisorial contraction to a point of index r with discrepancy 1/r.
2. a blowup along a smooth curve
3. a flop
2013年01月11日(金)
講演会
10:00-11:00 数理科学研究科棟(駒場) 123号室
Sven Raum 氏 (KU Leuven)
A duality between easy quantum groups and reflection groups (ENGLISH)
Sven Raum 氏 (KU Leuven)
A duality between easy quantum groups and reflection groups (ENGLISH)
講演会
11:15-12:15 数理科学研究科棟(駒場) 123号室
An Speelman 氏 (KU Leuven)
Some non-uniqueness results for Cartan subalgebras in II$_1$ factors (ENGLISH)
An Speelman 氏 (KU Leuven)
Some non-uniqueness results for Cartan subalgebras in II$_1$ factors (ENGLISH)
講演会
14:00-15:00 数理科学研究科棟(駒場) 123号室
Ionut Chifan 氏 (University of Iowa)
Structural results for II$_1$ factors of negatively curved groups (ENGLISH)
Ionut Chifan 氏 (University of Iowa)
Structural results for II$_1$ factors of negatively curved groups (ENGLISH)
講演会
15:15-16:15 数理科学研究科棟(駒場) 123号室
Karen Strung 氏 (Universit\"at M\"unster)
UHF slicing and classification of nuclear $C^*$-algebras (ENGLISH)
Karen Strung 氏 (Universit\"at M\"unster)
UHF slicing and classification of nuclear $C^*$-algebras (ENGLISH)
講演会
16:30-17:30 数理科学研究科棟(駒場) 123号室
Hannes Thiel 氏 (University of Copenhagen)
The generator problem for $C^*$-algebras (ENGLISH)
Hannes Thiel 氏 (University of Copenhagen)
The generator problem for $C^*$-algebras (ENGLISH)
GCOEセミナー
10:00-11:00 数理科学研究科棟(駒場) 123号室
このセミナーはMiniworkshop on Operator Algebras Iの一環として行われます
Sven Raum 氏 (KU Leuven)
A duality between easy quantum groups and reflection groups (ENGLISH)
[ 参考URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/mini2013-1.htm
このセミナーはMiniworkshop on Operator Algebras Iの一環として行われます
Sven Raum 氏 (KU Leuven)
A duality between easy quantum groups and reflection groups (ENGLISH)
[ 参考URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/mini2013-1.htm
GCOEセミナー
11:15-12:15 数理科学研究科棟(駒場) 123号室
このセミナーはMiniworkshop on Operator Algebras Iの一環として行われます
An Speelman 氏 (KU Leuven)
Some non-uniqueness results for Cartan subalgebras in II$_1$ factors (ENGLISH)
[ 参考URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/mini2013-1.htm
このセミナーはMiniworkshop on Operator Algebras Iの一環として行われます
An Speelman 氏 (KU Leuven)
Some non-uniqueness results for Cartan subalgebras in II$_1$ factors (ENGLISH)
[ 参考URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/mini2013-1.htm
2013年01月08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
金行壮二 氏 (上智大学(名誉教授))
On the group of holomorphic and anti-holomorphic transformations
of a compact Hermitian symmetric space and the $G$-structure (JAPANESE)
金行壮二 氏 (上智大学(名誉教授))
On the group of holomorphic and anti-holomorphic transformations
of a compact Hermitian symmetric space and the $G$-structure (JAPANESE)
[ 講演概要 ]
Let $M$ be a compact irreducible Hermitian symmetric space. We determine the full group of holomorphic and anti-holomorphic transformations of $M$. Also we characterize that full group as the automorphism group of the $G$-structure on $M$, called a generalized conformal structure.
Let $M$ be a compact irreducible Hermitian symmetric space. We determine the full group of holomorphic and anti-holomorphic transformations of $M$. Also we characterize that full group as the automorphism group of the $G$-structure on $M$, called a generalized conformal structure.
GCOEレクチャーズ
16:30-17:30 数理科学研究科棟(駒場) 118号室
Kazufumi Ito 氏 (North Carolina State Univ.)
Probing factions and Direct sampling method (ENGLISH)
Kazufumi Ito 氏 (North Carolina State Univ.)
Probing factions and Direct sampling method (ENGLISH)
[ 講演概要 ]
We develop probing functions for inverse medium problems arising in Helmholtz and conductivity and Schrodinger equations. direct sampling methods for determining inhomogeneous inclusions using a limited number of Cauchy data.
We develop probing functions for inverse medium problems arising in Helmholtz and conductivity and Schrodinger equations. direct sampling methods for determining inhomogeneous inclusions using a limited number of Cauchy data.
2013年01月07日(月)
GCOEレクチャーズ
16:30-17:30 数理科学研究科棟(駒場) 118号室
Kazufumi Ito 氏 (North Carolina State Univ.)
Traffic flow modeling and Hamilton Jacobi equation (ENGLISH)
Kazufumi Ito 氏 (North Carolina State Univ.)
Traffic flow modeling and Hamilton Jacobi equation (ENGLISH)
[ 講演概要 ]
A traffic model based on Hamilton Jacobi equations are developed. The model incorporates the sag and source conditions of traffic flows and predict and classify the traffic congestion.
A traffic model based on Hamilton Jacobi equations are developed. The model incorporates the sag and source conditions of traffic flows and predict and classify the traffic congestion.
2012年12月26日(水)
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
Henrik Densing Petersen 氏 (Univ. Copenhagen) 15:45-16:45
Trouble in paradise (ENGLISH)
Stella Anevski 氏 (Univ. Copenhagen) 17:00-18:00
Algebraic K-theory of generalized schemes (ENGLISH)
Henrik Densing Petersen 氏 (Univ. Copenhagen) 15:45-16:45
Trouble in paradise (ENGLISH)
Stella Anevski 氏 (Univ. Copenhagen) 17:00-18:00
Algebraic K-theory of generalized schemes (ENGLISH)
2012年12月21日(金)
GCOEレクチャーズ
15:00-16:00 数理科学研究科棟(駒場) 126号室
Kazufumi Ito 氏 (North Carolina State Univ.)
Evolution equation approach to Fractional Differential Equations (ENGLISH)
Kazufumi Ito 氏 (North Carolina State Univ.)
Evolution equation approach to Fractional Differential Equations (ENGLISH)
[ 講演概要 ]
A class of fractional differential equations is formulated as an evolution equation on the memory space with non-local boundary condition. Based on such a formulation the mathematical theory of evolution equations is applied to concrete examples of nonlinear fractional PDEs.
A class of fractional differential equations is formulated as an evolution equation on the memory space with non-local boundary condition. Based on such a formulation the mathematical theory of evolution equations is applied to concrete examples of nonlinear fractional PDEs.
2012年12月19日(水)
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
Mihaita Berbec 氏 (KU Leuven) 15:45-16:45
$W^*$-superrigidity for left-right wreath products (ENGLISH)
Zhuang Niu 氏 (Univ. Wyoming) 17:00-18:00
A classification of approximate subhomogeneous $C^*$-algebras (ENGLISH)
Mihaita Berbec 氏 (KU Leuven) 15:45-16:45
$W^*$-superrigidity for left-right wreath products (ENGLISH)
Zhuang Niu 氏 (Univ. Wyoming) 17:00-18:00
A classification of approximate subhomogeneous $C^*$-algebras (ENGLISH)
幾何コロキウム
10:30-12:00 数理科学研究科棟(駒場) 128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.
藤原 耕二 氏 (京都大学)
ベイユ・ピーターソン空間上のファンク距離 (JAPANESE)
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.
藤原 耕二 氏 (京都大学)
ベイユ・ピーターソン空間上のファンク距離 (JAPANESE)
[ 講演概要 ]
タイヒミュラー空間上のベイユ・ピーターソン距離に関するファンク関数について論じる。ファンク関数は、写像類群で不変な非対称距離になる。元々は、ユークリッド空間の凸領域に対してファンクが定義した概念で、その対称化はヒルベルト距離である。
タイヒミュラー空間上のベイユ・ピーターソン距離に関するファンク関数について論じる。ファンク関数は、写像類群で不変な非対称距離になる。元々は、ユークリッド空間の凸領域に対してファンクが定義した概念で、その対称化はヒルベルト距離である。
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
中村 健太郎 氏 (北海道大学)
A generalization of Kato's local epsilon conjecture for
(φ, Γ)-modules over the Robba ring (JAPANESE)
中村 健太郎 氏 (北海道大学)
A generalization of Kato's local epsilon conjecture for
(φ, Γ)-modules over the Robba ring (JAPANESE)
[ 講演概要 ]
In his preprint “Lectures on the approach to Iwasawa theory of Hasse-Weil L-functions via B_dR, Part II ", Kazuya Kato proposed a conjecture called local epsilon conjecture. This conjecture predicts that the determinant of the Galois cohomology of a family of p-adic Galois representations has a canonical base whose specializations at de Rham points can be characterized by using Bloch-Kato exponential, L-factors and Deligne-Langlands epsilon constants of the associated Weil-Deligne representations.
In my talk, I generalize his conjecture for families of (φ, Γ)-modules over the Robba ring, and prove a part of this conjecture in the trianguline case. The two key ingredients are the recent result of Kedlaya-Pottharst-Xiao on the finiteness of cohomologies of (φ, Γ)-modules and my result on Bloch-Kato exponential map for (φ, Γ)-modules.
In his preprint “Lectures on the approach to Iwasawa theory of Hasse-Weil L-functions via B_dR, Part II ", Kazuya Kato proposed a conjecture called local epsilon conjecture. This conjecture predicts that the determinant of the Galois cohomology of a family of p-adic Galois representations has a canonical base whose specializations at de Rham points can be characterized by using Bloch-Kato exponential, L-factors and Deligne-Langlands epsilon constants of the associated Weil-Deligne representations.
In my talk, I generalize his conjecture for families of (φ, Γ)-modules over the Robba ring, and prove a part of this conjecture in the trianguline case. The two key ingredients are the recent result of Kedlaya-Pottharst-Xiao on the finiteness of cohomologies of (φ, Γ)-modules and my result on Bloch-Kato exponential map for (φ, Γ)-modules.
GCOEセミナー
15:45-16:45 数理科学研究科棟(駒場) 118号室
Mihaita Berbec 氏 (KU Leuven)
$W^*$-superrigidity for left-right wreath products (ENGLISH)
Mihaita Berbec 氏 (KU Leuven)
$W^*$-superrigidity for left-right wreath products (ENGLISH)
2012年12月18日(火)
FMSPレクチャーズ
10:30-11:30 数理科学研究科棟(駒場) 056号室
Jie Jiang 氏 (Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences)
On convergence to equilibrium with applications of Lojasiewicz-Simon
inequality (II) (ENGLISH)
Jie Jiang 氏 (Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences)
On convergence to equilibrium with applications of Lojasiewicz-Simon
inequality (II) (ENGLISH)
2012年12月17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
生駒 英晃 氏 (京都大学)
算術多様体上のノルムの小さい基底の存在について
(JAPANESE)
生駒 英晃 氏 (京都大学)
算術多様体上のノルムの小さい基底の存在について
(JAPANESE)
[ 講演概要 ]
I would like to talk about some recent work of mine on the asymptotic behavior of the successive minima associated to a graded arithmetic linear series. A complete arithmetic linear series belonging to a hermitian line bundle on an arithmetic variety is defined as the Z-module of the global sections endowed with the supremum-norm, and the successive minima are invariants that measure the size of the sections with small norms.
If time permits, I would like to also explain some close relationship between the results and the general equi-distribution theory of rational points on an arithmetic variety.
I would like to talk about some recent work of mine on the asymptotic behavior of the successive minima associated to a graded arithmetic linear series. A complete arithmetic linear series belonging to a hermitian line bundle on an arithmetic variety is defined as the Z-module of the global sections endowed with the supremum-norm, and the successive minima are invariants that measure the size of the sections with small norms.
If time permits, I would like to also explain some close relationship between the results and the general equi-distribution theory of rational points on an arithmetic variety.
2012年12月15日(土)
東京無限可積分系セミナー
13:30-15:00 数理科学研究科棟(駒場) 117号室
Vincent Pasquier 氏 (CEA, Saclay, France)
current and integrability (ENGLISH)
Vincent Pasquier 氏 (CEA, Saclay, France)
current and integrability (ENGLISH)
[ 講演概要 ]
I will describe some problems related to currents in XXZ chains:
Drude conductivity, Linbladt equation, tasep, matrix ansatz,
in particular the relation of permanent currents with integrability.
If time permits I will also discuss a nonrelated subject:
deformation of fusion rules in minimal models and Macdonald polynomials.
I will describe some problems related to currents in XXZ chains:
Drude conductivity, Linbladt equation, tasep, matrix ansatz,
in particular the relation of permanent currents with integrability.
If time permits I will also discuss a nonrelated subject:
deformation of fusion rules in minimal models and Macdonald polynomials.
2012年12月13日(木)
代数幾何学セミナー
10:40-12:10 数理科学研究科棟(駒場) 118号室
いつもと曜日・時間・場所が異なります
Jean-Paul Brasselet 氏 (CNRS (Luminy))
The asymptotic variety of polynomial maps (ENGLISH)
いつもと曜日・時間・場所が異なります
Jean-Paul Brasselet 氏 (CNRS (Luminy))
The asymptotic variety of polynomial maps (ENGLISH)
[ 講演概要 ]
The asymptotic variety, or set of non-properness has been intensively studied by Zbigniew Jelonek. In a recent paper, Anna and Guillaume Valette associate to a polynomial map $F: {\\mathbb C}^n \\to {\\mathbb C}^n$ a singular variety $N_F$ and relate properness property of $F$ to the vanishing of some intersection homology groups of $N_F$. I will explain how stratifications of the asymptotic variety of $F$ play an important role in the story and how recently, one of my students, Nguyen Thi Bich Thuy, found a nice way to exhibit such a suitable stratification.
The asymptotic variety, or set of non-properness has been intensively studied by Zbigniew Jelonek. In a recent paper, Anna and Guillaume Valette associate to a polynomial map $F: {\\mathbb C}^n \\to {\\mathbb C}^n$ a singular variety $N_F$ and relate properness property of $F$ to the vanishing of some intersection homology groups of $N_F$. I will explain how stratifications of the asymptotic variety of $F$ play an important role in the story and how recently, one of my students, Nguyen Thi Bich Thuy, found a nice way to exhibit such a suitable stratification.
2012年12月12日(水)
代数学コロキウム
18:00-19:00 数理科学研究科棟(駒場) 002号室
François Charles 氏 (CNRS & Université de Rennes 1)
The Tate conjecture for K3 surfaces and holomorphic symplectic varieties over finite fields (ENGLISH)
François Charles 氏 (CNRS & Université de Rennes 1)
The Tate conjecture for K3 surfaces and holomorphic symplectic varieties over finite fields (ENGLISH)
[ 講演概要 ]
We prove the Tate conjecture for divisors on reductions of holomorphic symplectic varieties over finite fields -- with some restrictions on the characteristic of the base field. We will be concerned mostly with the supersingular case. As a special case, we prove the Tate conjecture, also known as Artin's conjecture in our case, for K3 surfaces over finite fields of characteristic at least 5 and for codimension 2 cycles on cubic fourfolds.
(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.)
We prove the Tate conjecture for divisors on reductions of holomorphic symplectic varieties over finite fields -- with some restrictions on the characteristic of the base field. We will be concerned mostly with the supersingular case. As a special case, we prove the Tate conjecture, also known as Artin's conjecture in our case, for K3 surfaces over finite fields of characteristic at least 5 and for codimension 2 cycles on cubic fourfolds.
(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.)
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
N. Christopher Phillips 氏 (Univ. Oregon)
Large subalgebras of crossed product $C^*$-algebras (ENGLISH)
N. Christopher Phillips 氏 (Univ. Oregon)
Large subalgebras of crossed product $C^*$-algebras (ENGLISH)
FMSPレクチャーズ
16:30-18:00 数理科学研究科棟(駒場) 118号室
N. Christopher Phillips 氏 (Univ. Oregon)
Large subalgebras of crossed product C*-algebras (ENGLISH)
N. Christopher Phillips 氏 (Univ. Oregon)
Large subalgebras of crossed product C*-algebras (ENGLISH)
[ 講演概要 ]
This is work in progress; not everything has been checked.
We define a "large subalgebra" and a "centrally large subalgebra" of a C*-algebra. The motivating example is what we now call the "orbit breaking subalgebra" of the crossed product by a minimal homeomorphism h of a compact metric space X. Let v be the standard unitary in the crossed product C* (Z, X, h). For a closed subset Y of X, we form the subalgebra of C* (Z, X, h) generated by C (X) and all elements f v for f in C (X) such that f vanishes on Y. When each orbit meets Y at most once, this subalgebra is centrally large in the crossed product. Crossed products by smooth free minimal actions of Zd also contain centrally large subalgebras which are simple direct limits, with no dimension growth, of recursive subhomogeneous algebras.
If B is a large subalgebra of A, then the Cuntz semigroups of A and B are the almost the same: if one deletes the classes of nonzero projections, then the inclusion is a bijection on what is left. Also (joint work with Dawn Archey), if B is a centrally large subalgebra of A, and B has stable rank one, then so does A. Moreover, if B is a centrally large subalgebra of A, if B is Z-stable, and if A is nuclear, then A is Z-stable.
This is work in progress; not everything has been checked.
We define a "large subalgebra" and a "centrally large subalgebra" of a C*-algebra. The motivating example is what we now call the "orbit breaking subalgebra" of the crossed product by a minimal homeomorphism h of a compact metric space X. Let v be the standard unitary in the crossed product C* (Z, X, h). For a closed subset Y of X, we form the subalgebra of C* (Z, X, h) generated by C (X) and all elements f v for f in C (X) such that f vanishes on Y. When each orbit meets Y at most once, this subalgebra is centrally large in the crossed product. Crossed products by smooth free minimal actions of Zd also contain centrally large subalgebras which are simple direct limits, with no dimension growth, of recursive subhomogeneous algebras.
If B is a large subalgebra of A, then the Cuntz semigroups of A and B are the almost the same: if one deletes the classes of nonzero projections, then the inclusion is a bijection on what is left. Also (joint work with Dawn Archey), if B is a centrally large subalgebra of A, and B has stable rank one, then so does A. Moreover, if B is a centrally large subalgebra of A, if B is Z-stable, and if A is nuclear, then A is Z-stable.
2012年12月11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
Ismar Volic 氏 (Wellesley College)
Homotopy-theoretic methods in the study of spaces of knots and links (ENGLISH)
Tea: 16:00 - 16:30 コモンルーム
Ismar Volic 氏 (Wellesley College)
Homotopy-theoretic methods in the study of spaces of knots and links (ENGLISH)
[ 講演概要 ]
I will survey the ways in which some homotopy-theoretic
methods, manifold calculus of functors main among them, have in recent
years been used for extracting information about the topology of
spaces of knots and links. Cosimplicial spaces and operads will also
be featured. I will end with some recent results about spaces of
homotopy string links and in particular about how one can use functor
calculus in combination with configuration space integrals to extract
information about Milnor invariants.
I will survey the ways in which some homotopy-theoretic
methods, manifold calculus of functors main among them, have in recent
years been used for extracting information about the topology of
spaces of knots and links. Cosimplicial spaces and operads will also
be featured. I will end with some recent results about spaces of
homotopy string links and in particular about how one can use functor
calculus in combination with configuration space integrals to extract
information about Milnor invariants.
< 前へ 123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196 次へ >
