過去の記録

過去の記録 ~07/24本日 07/25 | 今後の予定 07/26~

数理人口学・数理生物学セミナー

14:00-16:00   数理科学研究科棟(駒場) 152号室
中田氏の講演と連続しておこなわれます。
中岡慎治 氏 (理化学研究所)
世代拡大モデルを用いた短期細胞増殖過程の定式化 (JAPANESE)
[ 講演概要 ]
CFSE と呼ばれる蛍光色素で標識した細胞が分裂時に蛍光強度が半減する性質を
利用することで、分裂回数毎にラベルした細胞増殖の定量的な計測が可能とな
る。抗原 刺激を与えたナイーブ T 細胞の増殖過程を CSFE 標識して経時的に蛍
光強度を計測した実験データを元に、T 細胞の短期間の増殖過程を定量的に記述
する数理モデルがこれまでにいくつか提案されてきた。ここでは、数学的な部分
に焦点を当てた研究について紹介する。 本研究では、既存の定量的数理モデル
のいくつかが、数理人口学で発展してきたパリティ拡大モデルをベースに構築し
た世代拡大モデル (generation progression model) の特別な場合に帰着できる
ことを示す。世代拡大モデルは分裂回数をステージとした再生方程式系によって
記述されるが、細胞分裂の発生確率と生存確率の時間 分布に関する仮定を変え
ることで、既存モデルを複数導出できる。加えて、基本再生産数と同様の解釈が
可能な世代拡大比が自然に導出される。世 代拡大比を計算することで、たとえ
ば一細胞レベルで細胞分裂と細胞死を経時的に計測した実験データから分裂毎の
平均的な増殖比率を計算できる ようになる。本研究でご紹介する方法論は、短
期間における細胞増殖のダイナミクスを定量的に追跡するための数理手法である
が、最後に計測可能 な量から計測が難しい幹細胞の自己複製や細胞死の起こる
率を推定するための枠組みへどう発展させていくかに関して、今後の展望を述べ
たい。

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)
[ 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

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)

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)

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)

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)

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)

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

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

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)
[ 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.

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)
[ 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.

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)
[ 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.

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)

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)
[ 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.

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)

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)
[ 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。

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)
[ 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.

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)

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)

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)
[ 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.

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)
[ 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.

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)
[ 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.

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)
[ 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.)

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)

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)
[ 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.

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