過去の記録 ~02/20本日 02/21 | 今後の予定 02/22~



16:30-18:00   数理科学研究科棟(駒場) 118号室
嶌田洸一 氏 (Univ. Tokyo)
Rohlin Flows on Amalgamated Free Product Factors (ENGLISH)


16:40-17:40   数理科学研究科棟(駒場) 056号室
宮崎弘安 氏 (東京大学数理科学研究科)
Special values of zeta functions of singular varieties over finite fields via higher chow groups (JAPANESE)



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
早野 健太 氏 (大阪大学)
Vanishing cycles and homotopies of wrinkled fibrations (JAPANESE)
[ 講演概要 ]
Wrinkled fibrations on closed 4-manifolds are stable
maps to closed surfaces with only indefinite singularities. Such
fibrations and variants of them have been studied for the past few years
to obtain new descriptions of 4-manifolds using mapping class groups.
Vanishing cycles of wrinkled fibrations play a key role in these studies.
In this talk, we will explain how homotopies of wrinkled fibrtions affect
their vanishing cycles. Part of the results in this talk is a joint work
with Stefan Behrens (Max Planck Institute for Mathematics).


16:30-18:00   数理科学研究科棟(駒場) 118号室
5/10(金) 5/14(火) 5/21(火) 5/24(金)の4回連続講演です。部屋と時間は毎回同じです

Laurent Lafforgue 氏 (IHES)
Kernels of Langlands' automorphic transfer and non-linear Poisson formulas (ENGLISH)



10:30-12:00   数理科学研究科棟(駒場) 126号室
奥山 裕介 氏 (京都工芸繊維大学)
Geometry and analysis of isolated essential singularities and their applications (JAPANESE)
[ 講演概要 ]
We establish a rescaling principle for isolated essential singularities of holomorphic curves and quasiregular mappings, and gives several applications of it in the theory of value distribution and dynamics. This is a joint work with Pekka Pankka.



13:30-16:00   数理科学研究科棟(駒場) 123号室
石井 卓 氏 (成蹊大学) 13:30-14:30
Symplectic-orthogonal theta lifts and explicit formulas for archimedean Whittaker functions (JAPANESE)
市川 尚志 氏 (佐賀大学理工学部) 15:00-16:00
Mumford形式の無限積表示とSelbergゼータ値への応用 (JAPANESE)
[ 講演概要 ]


10:30-12:00   数理科学研究科棟(駒場) 117号室
Anatol Kirillov 氏 (RIMS Kyoto Univ.)
Saga of Dunkl elements (ENGLISH)
[ 講演概要 ]
The Dunkl operators has been introduced by C. Dunkl in the middle of
80's of the last century as a powerful mean in the study of orthogonal
polynomials related with finite Coxeter groups. Later it was discovered
a deep connection of the the Dunkl operators with the theory of
Integrable systems and Invariant Theory.
In my talk I introduce and study a certain class of nonhomogeneous
quadratic algebras together with the distinguish set of mutually
commuting elements inside of each, the so-called universal Dunkl elements.
The main problem I would like to discuss is : What is the algebra
generated by universal Dunkl elements in a different representations of
the quadratic algebra introduced ?
I'm planning to present partial answers on that problem related with
classical and quantum Schubert and Grothendieck Calculi as well as the
theory of elliptic series.
Also some interesting algebraic properties of the quadratic algebra(s)
in question will be described.



16:30-18:00   数理科学研究科棟(駒場) 118号室
5/10(金) 5/14(火) 5/21(火) 5/24(金)の4回連続講演です。

Laurent Lafforgue 氏 (IHES)
Kernels of Langlands' automorphic transfer and non-linear Poisson formulas (ENGLISH)



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.
木田 良才 氏 (京都大学)
融合積とその覆いの剛性 (JAPANESE)
[ 講演概要 ]
可算離散群 L に対し, 第二可算公理を満たす局所コンパクト位相群で L と同型な格子部分群を含むようなものを L の覆いと呼ぶ. 一般に, 与えられた L に対し L の覆い全てを記述することは極めて難しい. この問題は, 確率測度空間への群作用に対する軌道同型の問題と密接に関連し, モストウ型の剛性とも関連する. 講演では, この問題を解決するための基本的なアイデアを紹介し, この問題が解決されるような群の例を挙げたい. そのような例としては, 曲面の写像類群やある種の融合積がある. 後者の群について解決への道筋を説明したい.



16:30-18:00   数理科学研究科棟(駒場) 118号室
Paul Muhly 氏 (University of Iowa)
Boundaries for Tensor Algebras (ENGLISH)



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
伊藤 哲也 氏 (京都大学数理解析研究所)
Homological intersection in braid group representation and dual
Garside structure (JAPANESE)
[ 講演概要 ]
One method to construct linear representations of braid groups is to use
an action of braid groups on certain homology of local system coefficient.
Many famous representations, such as Burau or Lawrence-Krammer-Bigelow
representations are constructed in such a way. We show that homological
intersections on such homology groups are closely related to the dual
Garside structure, a remarkable combinatorial structure of braid, and
prove that some representations detects the length of braids in a
surprisingly simple way.
This work is partially joint with Bert Wiest (Univ. Rennes1).


16:30-18:00   数理科学研究科棟(駒場) 123号室
土屋卓也 氏 (愛媛大学大学院理工学研究科)
有限要素解析の諸問題について (JAPANESE)
[ 講演概要 ]
1968年のZlamalの論文以来、有限要素法の数学的基礎理論は急速に発展し、40年後の今日では、少なくとも基礎的な部分は、完全に理解されていると思っている(若い)研究者が多いと思われる。しかし、最近発見された「外接半径条件」(circumradius condition)は、この認識に修正が必要なことを強く示唆している。

[ 参考URL ]



16:30-18:00   数理科学研究科棟(駒場) 126号室
松本久義 氏 (東京大学大学院数理科学研究科)
The homomorphisms between scalar generalized Verma modules of gl(n,C) with regular infinitesimal characters (JAPANESE)
[ 講演概要 ]
We will explain the classification of the homomorphisms between scalar generalized Verma modules of gl(n,C) with regular infinitesimal characters. In fact, they are compositions of elementary homomorphisms. The main ingredient of our proof is the translation principle in the mediocre region.


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
Francis Sergeraert 氏 (L'Institut Fourier, Univ. de Grenoble)
Discrete vector fields and fundamental algebraic topology.
[ 講演概要 ]
Robin Forman invented the notion of Discrete Vector Field in 1997.
A recent common work with Ana Romero allowed us to discover the notion
of Eilenberg-Zilber discrete vector field. Giving the topologist a
totally new understanding of the fundamental tools of combinatorial
algebraic topology: Eilenberg-Zilber theorem, twisted Eilenberg-Zilber
theorem, Serre and Eilenberg-Moore spectral sequences,
Eilenberg-MacLane correspondence between topological and algebraic
classifying spaces. Gives also new efficient algorithms for Algebraic
Topology, considerably improving our computer program Kenzo, devoted
to Constructive Algebraic Topology. The talk is devoted to an
introduction to discrete vector fields, the very simple definition of
the Eilenberg-Zilber vector field, and how it can be used in various



17:30-18:30   数理科学研究科棟(駒場) 056号室
今井直毅 氏 (東京大学数理科学研究科)
Good reduction of ramified affinoids in the Lubin-Tate perfectoid space (ENGLISH)
[ 講演概要 ]
Recently, Weinstein finds some affinoids in the Lubin-Tate perfectoid space and computes their reduction in equal characteristic case. The cohomology of the reduction realizes the local Langlands correspondence for some representations of GL_h, which are unramified in some sense. In this talk, we introduce other affinoids in the Lubin-Tate perfectoid space in equal characteristic case, whose reduction realizes "ramified" representations of conductor exponent h+1. We call them ramified affinoids. We study the cohomology of the reduction and its relation with the local Langlands correspondence. This is a joint work with Takahiro Tsushima.

(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.)

Kavli IPMU Komaba Seminar

17:00-18:30   数理科学研究科棟(駒場) 002号室
金沢 篤 氏 (University of British Columbia)
Calabi-Yau threefolds of Type K (ENGLISH)
[ 講演概要 ]
We will provide a full classification of Calabi-Yau threefolds of Type
K studied by Oguiso and Sakurai. Our study completes the
classification of Calabi-Yau threefolds with infinite fundamental
group. I will then discuss special Lagrangian T3-fibrations of
Calabi-Yau threefolds of type K. This talk is based on a joint work
with Kenji Hashimoto.



16:30-18:00   数理科学研究科棟(駒場) 002号室
野津裕史 氏 (早稲田大学高等研究所)
流れ問題のための圧力安定化特性曲線有限要素スキーム (JAPANESE)
[ 講演概要 ]
特性曲線法は流体粒子の軌跡に沿った離散化手法であり,上流化のアイデアが自然に入るため流れ問題に強靭である.さらに,大規模連立一次方程式の係数行列が対称という固有の長所をもつ.特性曲線法と有限要素法を組み合わせた特性曲線有限要素法は,それぞれの特徴を併せ持っており流れ問題の有力な数値解法である.我々は3次元問題をより簡便に行うことを念頭に圧力安定化特性曲線有限要素スキームを開発した.その理論解析および 2,3 次元数値計算の結果を示す.本講演では理論面に重点をおく予定である.特に,安定性評価における定数の拡散係数(Reynolds 数)依存性に注目して話したい.
[ 参考URL ]


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
Andrei Pajitnov 氏 (Univ. de Nantes)
Twisted Novikov homology and jump loci in formal and hyperformal spaces (ENGLISH)
[ 講演概要 ]
Let X be a CW-complex, G its fundamental group, and R a repesentation of G.
Any element of the first cohomology group of X gives rise to an exponential
deformation of R, which can be considered as a curve in the space of
representations. We show that the cohomology of X with local coefficients
corresponding to the generic point of this curve is computable from a spectral
sequence starting from the cohomology of X with R-twisted coefficients. We
compute the differentials of the spectral sequence in terms of Massey products,
and discuss some particular cases arising in Kaehler geometry when the spectral
sequence degenerates. We explain the relation of these invariants and the
twisted Novikov homology. This is a joint work with Toshitake Kohno.



16:45-18:15   数理科学研究科棟(駒場) 126号室
Stefano Olla 氏 (Univ. Paris-Dauphine)
Thermal conductivity and weak coupling (ENGLISH)
[ 講演概要 ]
We investigate the macroscopic thermal conductivity of a chain of anharmonic oscillators and more general systems, under weak coupling limits and energy conserving stochastic perturbations of the dynamics. In particular we establish a series expansion in the coupling parameter.


16:30-18:00   数理科学研究科棟(駒場) 118号室
Professor Igor Reider 氏 (Universite d'Angers / RIMS)
Kodaira-Spencer classes, geometry of surfaces of general type and Torelli
theorem (ENGLISH)
[ 講演概要 ]
In this talk I will explain a geometric interpretation of Kodaira-Spencer classes and apply
it to the study of the differential of the period map of weight 2 Hodge structures for surfaces
of general type.
My approach is based on interpreting Kodaira-Spencer classes as higher rank bundles and
then studing their stability. This naturally leads to two parts:
1) unstable case
2) stable case.
I will give a geometric characterization of the first case and show how to relate the second
case to a special family of vector bundles giving rise to a family of rational curves. This family
of rational curves is used to recover the surface in question.


10:30-12:00   数理科学研究科棟(駒場) 126号室
千葉 優作 氏 (東京工業大学)
Kobayashi hyperbolic imbeddings into low degree surfaces in three dimensional projective spaces (JAPANESE)
[ 講演概要 ]
We construct smooth irreducible curves of the lowest possible degree in quadric and cubic surfaces whose complements are Kobayashi hyperbolically imbedded into those surfaces. This is a joint work with Atsushi Ito.



13:00-18:00   数理科学研究科棟(駒場) 128号室
斉藤 洋樹 氏 (首都大学東京) 13:30-15:00
Directional maximal operators and radial weights on the plane
[ 講演概要 ]
Let $\\Omega$ be a set of unit vectors and $w$ be a radial weight on the plane. We consider the weighted directional maximal operator defined by
$M_{\\Omega,w}f(x):=\\sup_{x\\in R\\in \\cB_{\\Omega}}\\frac{1}{w(R)}\\int_{R}|f(y)|w(y)dy$,
where $\\cB_{\\Omega}$ denotes the all rectangles on the plane whose longest side is parallel to some unit vector in $\\Omega$ and $w(R)$ denotes $\\int_{R}w$.
In this talk we give a sufficient condition of the weight
for an almost-orthogonality principle related to these maximal operators to hold. The condition allows us to get weighted norm inequality
$\\|M_{\\Omega,w}f\\|_{L^2(w)}\\le C \\log N \\|f\\|_{L^2(w)}$,
when $w(x)=|x|^a$, $a>0$, and $\\Omega$ is a set of unit vectors on the plane with cardinality $N\\gg 1$.
野井 貴弘 氏 (中央大学) 15:30-17:00
変動指数ベゾフ空間におけるトレース作用素の有界性について (JAPANESE)
[ 講演概要 ]
変動指数ベゾフ空間はAlmeidaとHasto(2010, J.Funct.Anal)により導入された関数空間であり, ベゾフ空間の可積分指数, 数列指数, 滑らかさを表す指数をlog-Holder連続な関数に置き換えた関数空間である. (可積分指数, 数列指数に対しては, さらに値域が[1, $\\infty$)に含まれる条件を課す. )変動指数トリーベル-リゾルキン空間についてはDiening, HastoとRoudenko(2009, J.Funct.Anal)により導入され, 原子分解によりトレース作用素の有界性を示した. 変動指数ベゾフ空間に関するトレース作用素の結果については, 数列指数が定数である場合のみAlmeidaとHastoにより2011年に開催された国際研究集会(2nd International workshop on Interpolation Theory, Function spaces and Related Topics)で実補間を応用することにより得られている.
本発表では, クォーク分解を用いることにより, 数列指数も変動指数である変動指数ベゾフ空間におけるトレース作用素の有界性を示していきたい.



10:30-11:30   数理科学研究科棟(駒場) 056号室
石井 克幸 氏 (神戸大学)
An approximation scheme for the anisotropic and the planar crystalline curvature flow (JAPANESE)
[ 講演概要 ]
In 2004 Chambolle proposed an algorithm for the mean curvature flow based on a variational problem. Since then, some extensions of his algorithm have been studied.
In this talk we would like to discuss the convergence of the anisotropic variant of his algorithm by use of the anisotropic signed distance function. An application to the approximation for the planar motion by crystalline curvature is also discussed.



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.
長友康行 氏 (明治大学)
Harmonic maps into Grassmannian manifolds (JAPANESE)
[ 講演概要 ]
A harmonic map from a Riemannian manifold into a Grassmannian manifold is characterized by a vector bundle, a space of sections of the bundle and the Laplace operator. This characterization can be considered as a generalization of Theorem of Takahashi on minimal immersions into a sphere (J.Math.Soc.Japan 18 (1966)) and implies the well-known fact that the Kodaira embedding is a harmonic map.

We apply the main result to generalize a Theorem of do Carmo and Wallach (Ann.of Math. 93 (1971)) and describe a moduli space of harmonic maps with constant energy densities and some properties about pull-back bundles and connections from a Riemannian homogeneous space into a Grassmannian. We give some applications including a rigidity of minimal immersions from the complex projective line to complex projective spaces (S.Bando and Y.Ohnita, J. Math. Soc. Japan 39 (1987)).

The ADHM-construction of instantons gives a family of maps into Grassmannians via monad theory on the twistor space. These maps are, in general, not harmonic maps, but are similar to maps obtained in our generalized do Carmo-Wallach theorem. We compare these two constructions of moduli spaces.



16:30-18:00   数理科学研究科棟(駒場) 118号室
Tamar Friedmann 氏 (Univ. Rochester)
Singularities, algebras, and the string landscape (ENGLISH)

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