過去の記録 ~10/04本日 10/05 | 今後の予定 10/06~



17:00-18:00   数理科学研究科棟(駒場) 370号室
Oleg Emanouilov 氏 (Colorado State University)
Inverse boundary value problem for Schroedinger equation in two dimensions (ENGLISH)
[ 講演概要 ]
We relax the regularity condition on potentials of Schroedinger equations in uniqueness results on the inverse boundary value problem recently proved in A.Bukhgeim (2008) and O. Imanuvilov, G.Uhlmann and M. Yamamoto (2010).


15:00-16:00   数理科学研究科棟(駒場) 128号室
森洋一朗 氏 (ミネソタ大学)
電解質および浸透圧調節の細胞生理学とその数理モデル (JAPANESE)
[ 講演概要 ]
モデルはpump-leak model と呼ばれ、数学的には常微分方程式に
知られていなかった。本講演では、pump-leak model には熱力学的な
結果を紹介する。さらにpump-leak model を拡張して得られる偏微分


16:30-17:30   数理科学研究科棟(駒場) 128号室
Bernold Fiedler 氏 (Free University of Berlin)
Schoenflies spheres in Sturm attractors (ENGLISH)
[ 講演概要 ]
In gradient systems on compact manifolds the boundary of the unstable manifold of an equilibrium need not be homeomorphic to a sphere, or to any compact manifold.
For scalar parabolic equations in one space dimension, however, we can exlude complications like Reidemeister torsion and the Alexander horned sphere. Instead the boundary is a Schoenflies embedded sphere. This is due to Sturm nodal properties related to the Matano lap number.



18:00-19:00   数理科学研究科棟(駒場) 056号室
志甫 淳 氏 (東京大学数理科学研究科)
On extension and restriction of overconvergent isocrystals (ENGLISH)
[ 講演概要 ]
First we explain two theorems concerning (log) extension of overconvergent isocrystals. One is a p-adic analogue of the theorem of logarithmic extension of regular integrable connections, and the other is a p-adic analogue of Zariski-Nagata purity. Next we explain a theorem which says that we can check certain property of overconvergent isocrystals by restricting them to curves.




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
與倉 昭治 氏 (鹿児島大学)
Fiberwise bordism groups and related topics (JAPANESE)
[ 講演概要 ]
We have recently introduced the notion of fiberwise bordism. In this talk, after a quick review of some of the classical (co)bordism theories, we will explain motivations of considering fiberwise bordism and some results and connections with other known works, such as M. Kreck's bordism groups of orientation preserving diffeomorphisms and Emerson-Meyer's bivariant K-theory etc. An essential motivation is our recent work towards constructing a bivariant-theoretic analogue (in the sense of Fulton-MacPherson) of Levine-Morel's or Levine-Pandharipande's algebraic cobordism.


16:30-18:00   数理科学研究科棟(駒場) 128号室
寺澤 祐高 氏 (東京大数理(日本学術振興会特別研究員PD))
確率的摂動項を持つ冪乗法則流体方程式の弱解の存在と 一意性について (JAPANESE)
[ 講演概要 ]
偏微分方程式に加法的確率的摂動項を加えた確率偏微分方程式 の弱解
の存在と一意性について考察する。 非ニュートン流体としては、粘性
が変形速度テンソルの大きさの冪乗 の形で依存する冪乗法則流体を考
察し、確率的摂動項としては 有色雑音を考察する。 Necas-Malek-
Ruzicka('93)において、確率的外力項を伴わない、 決定方程式に関し
て示された弱解の存在と一意性の主張を、 確率的摂動項を持つ方程式
に対して示す。 解の存在の証明は、ガレルキン近似によって得られた
解の列に対して、 伊藤の公式、Birkholder-Davis-Gundyの不等式など
により、 解の列のコンパクト性を示すこと及び、解の部分列が収束し
、 その収束先が方程式を弱い意味で満たすことを示すことでなされる。


16:30-17:30   数理科学研究科棟(駒場) 052号室
Ralph Bruckschen 氏 (ベルリン工科大学、MATHEON)
Interactive Data Visualization challenges, approaches and examples (ENGLISH)
[ 講演概要 ]
Data visualization is probably the most important method to analyze scientific datasets. In the time of petaflop supercomputers and high resolution sensors, the visualization of such datasets became a challenge because of the sheer magnitude. Using the latest technology I will describe some of the challenges and approaches to visualize large and massive datasets. The main bottle necks will be explained, as some algorithms and data structures to widen them. Finally I will show some examples of data visualization using a CAVE environment and virtual prototyping from the 3D Labor at the Technical University of Berlin.



17:00-18:00   数理科学研究科棟(駒場) 470号室
Oleg Emanouilov 氏 (Colorado State University)
Inverse boundary value problem for Schroedinger equation in two dimensions (ENGLISH)
[ 講演概要 ]
We relax the regularity condition on potentials of Schroedinger equations in uniqueness results on the inverse boundary value problem recently proved in A.Bukhgeim (2008) and O. Imanuvilov, G.Uhlmann and M. Yamamoto (2010).


15:30-17:00   数理科学研究科棟(駒場) 122号室
伊藤 敦 氏 (東京大学数理科学研究科)
Okounkov bodies and Seshadri constants (JAPANESE)
[ 講演概要 ]
Okounkov bodies, which are convex bodies associated to big line bundles, have rich information of the line bundles. On the other hand, Seshadri constants are invariants which measure the positivities of line bundles. In this talk, I will explain a relation between Okounkov bodies and Seshadri constants.


10:30-12:00   数理科学研究科棟(駒場) 128号室
野口潤次郎 氏 (東大数理)
岡の余零問題と関連する話題について (JAPANESE)
[ 講演概要 ]
The main part of this talk is a joint work with my colleagues, M. Abe and S. Hamano. After the solution of Cousin II problem by K. Oka III in 1939, he thought an extra-zero problem in 1945 (his posthumous paper) asking if it is possible to solve an arbitrarily given Cousin II problem adding some extra-zeros whose support is disjoint from the given one. Some special case was affirmatively confirmed in dimension two and a counter-example in dimension three or more was obtained. We will give a complete solution of this problem with examples and to discuss some new questions. An example on a toric variety of which idea is based on K. Stein's paper in 1941 has some special interest and will be discussed. I would like also to discuss some analytic intersections form the viewpoint of Nevanlinna theory.



16:30-17:30   数理科学研究科棟(駒場) 123号室
お茶&Coffee&お菓子: 16:00~16:30 (コモンルーム)。

金井 雅彦 氏 (東京大学・数理科学研究科)
複比を巡って (JAPANESE)
[ 講演概要 ]
複比 (cross ratio) は二千年にもおよぶ歴史を有すると言われているが,



16:30-17:30   数理科学研究科棟(駒場) 056号室
金城 謙作 氏 (東京大学数理科学研究科)
Hypergeometric series and arithmetic-geometric mean over 2-adic fields (JAPANESE)
[ 講演概要 ]
Dwork proved that the Gaussian hypergeometric function on p-adic numbers
can be extended to a function which takes values of the unit roots of
ordinary elliptic curves over a finite field of characteristic p>2.
We present an analogous theory in the case p=2.
As an application, we give a relation between the canonical lift
and the unit root of an elliptic curve over a finite field of
characteristic 2
by using the 2-adic arithmetic-geometric mean.



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
竹内 潔 氏 (筑波大学)
Motivic Milnor fibers and Jordan normal forms of monodromies (JAPANESE)
[ 講演概要 ]
We introduce a method to calculate the equivariant
Hodge-Deligne numbers of toric hypersurfaces.
Then we apply it to motivic Milnor
fibers introduced by Denef-Loeser and study the Jordan
normal forms of the local and global monodromies
of polynomials maps in various situations.
Especially we focus our attention on monodromies
at infinity studied by many people. The results will be
explicitly described by the ``convexity" of
the Newton polyhedra of polynomials. This is a joint work
with Y. Matsui and A. Esterov.



15:30-17:00   数理科学研究科棟(駒場) 122号室
藤野 修 氏 (京都大学理学系研究科)
Minimal model theory for log surfaces (JAPANESE)
[ 講演概要 ]
We discuss the log minimal model theory for log sur- faces. We show that the log minimal model program, the finite generation of log canonical rings, and the log abundance theorem for log surfaces hold true under assumptions weaker than the usual framework of the log minimal model theory.


13:30-14:30   数理科学研究科棟(駒場) 056号室
Horst Heck
(Technische Universität Darmstadt)
Stationary Weak Solutions of the Navier-Stokes Equations Past an Obstacle (ENGLISH)
[ 講演概要 ]
Consider the stationary Navier-Stokes equations in an exterior smooth domain $\\Omega$. If the flow condition $u_\\infty$ for $u$ at infinity is non-zero and the external force $f\\in \\dot H^{-1}_2(\\Omega)$ is given Leray constructed a weak solution $u\\in \\dot H^1_2(\\Omega)$, the homogeneous Sobolev space, with $u-u_\\infty\\in L^6(\\Omega)$.
We show that if in addition $f\\in \\dot H^{-1}_q(\\Omega)$ for some $q\\in (4/3,4)$ then the weak solution has the property $u-u_\\infty\\in L^{4q/(4-q)}(\\Omega)$.
This additional integrability implies that $u$ satisfies the energy identity. Further consequences are uniqueness results for small $u_\\infty$ and $f$ and continuous dependence of the solution with respect to $u_\\infty$.
The presented results are joint work with Hyunseok Kim and Hideo Kozono.


10:30-12:00   数理科学研究科棟(駒場) 128号室
本多宣博 氏 (東北大学)
Classification of Moishezon twistor spaces on 4CP^2 (JAPANESE)



11:00-14:30   数理科学研究科棟(駒場) 117号室
Alexander Orlov 氏 (Nonlinear Wave Processes Laboratory, Oceanology Institute (Moscow)) 11:00-12:00
CKP Hierarchy, Bosonic Tau Function, Bosonization Formulae and Orthogonal Polynomials both in Odd and Even Variables
(based on a joint work with Johan van de Leur and Takahiro Shiota) (ENGLISH)
[ 講演概要 ]
We develop the theory of CKP hierarchy introduced in the papers of Kyoto school where the CKP tau function is written as a vacuum expectation value in terms of free bosons. We show that a sort of odd currents naturaly appear. We consider bosonization formulae which relate bosonic Fock vectors to polynomials in even and odd Grassmannian variables, where both sets play a role of higher times.
増田恭穂 氏 (神戸大学) 13:30-14:30
van Diejenの$q$差分作用素に対する核関係式と
多重$q$超幾何級数の変換公式 (JAPANESE)
[ 講演概要 ]
$BC$型のCauchy型核関数がKoornwinderの$q$差分作用素に対して, ある関係式を満たすことが知られている. 本講演ではこの結果を一般化して, 核関数とvan Diejenの$q$差分作用素族との関係を述べる. また,この関係式から現れる2種類の多重$q$超幾何級数の変換公式を紹介する.



15:00-16:10   数理科学研究科棟(駒場) 000号室
本セミナーはITスタジオで開かれます.参加希望の方は事前に東大数理 鎌谷研吾( kengok at ms.u-tokyo.ac.jp)までお問い合わせください.
清 智也 氏 (慶應義塾大学 理工学部 数理科学科)
定常な最適輸送写像から作られる統計モデル (JAPANESE)
[ 講演概要 ]
輸送コストの定義が Gray, Neuhoff and Shields (1975) によって与えられている.
本研究の一部は,Ludger Rueschendorf 教授との共同研究である
[ 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, Univ. of Tokyo)
Circle-valued Morse theory for complex hyperplane arrangements (ENGLISH)
[ 講演概要 ]
Let A be a complex hyperplane arrangement
in an n-dimensional complex vector space V.
Denote by H the union of the hyperplanes
and by M the complement to H in V.

We develop the real-valued and circle-valued Morse
theory on M. We prove that if A is essential then
M has the homotopy type of a space
obtained from a finite n-dimensional
CW complex fibered over a circle,
by attaching several cells of dimension n.

We compute the Novikov homology of M and show
that its structure is similar to the
homology with generic local coefficients:
it vanishes for all dimensions except n.

This is a joint work with Toshitake Kohno.


16:30-18:00   数理科学研究科棟(駒場) 126号室
大島芳樹 氏 (東京大学大学院数理科学研究科)
コホモロジカル誘導の局所化 (ENGLISH)
[ 講演概要 ]
コホモロジカル誘導は(g,K)-加群に対して代数的に定義され、半単純リー群の離散系列表現、主系列表現(のHarish-Chandra加 群)、Zuckerman加群などを生成する。
Borel部分代数の1次元表現からの誘導の場合、誘導された表現は旗多様体のD加群を用いて実現できることが,Hecht, Milicic, Schmid, Wolfにより示されている。



13:30-16:00   数理科学研究科棟(駒場) 117号室
Leonid Rybnikov 氏 (IITP, and State University Higher School of Economics,
Department of Mathematics) 13:30-14:30
Quantization of Quasimaps' Spaces (joint work with M. Finkelberg) (ENGLISH)
[ 講演概要 ]
Quasimaps' space Z_d (also known as Drinfeld's Zastava space) is a
remarkable compactification of the space of based degree d maps from
the projective line to the flag variety of type A. The space Z_d has a
natural Poisson structure,
which goes back to Atiyah and Hitchin. We describe
the Quasimaps' space as some quiver variety, and define the
Atiyah-Hitchin Poisson structure in quiver terms.
This gives a natural way to quantize this Poisson structure.
The quantization of the coordinate ring of the Quasimaps' space turns
to be some natural subquotient of the Yangian of type A.
I will also discuss some generalization of this result to the BCD types.
Anton Zabrodin 氏 (
Instituteof Biochemical Physics) 15:00-16:00
Quantum integrable models with elliptic R-matrices
and elliptic hypergeometric series (ENGLISH)
[ 講演概要 ]
Intertwining operators for infinite-dimensional representations of the
Sklyanin algebra with spins l and -l-1 are constructed using the technique of
intertwining vectors for elliptic L-operator. They are expressed in
terms of
elliptic hypergeometric series with operator argument. The intertwining
operators obtained (W-operators) serve as building blocks for the
elliptic R-matrix
which intertwines tensor product of two L-operators taken in
representations of the Sklyanin algebra with arbitrary spin. The
Yang-Baxter equation
for this R-matrix follows from simpler equations of the star-triangle
type for the
W-operators. A natural graphic representation of the objects and
equations involved
in the construction is used.



16:30-18:00   数理科学研究科棟(駒場) 270号室
O. Emanouilov 氏 (Colorado State University)
On reconstruction of Lame coefficients from partial Cauchy data (ENGLISH)
[ 講演概要 ]
For the isotropic Lame system, we prove that if the Lame coefficient ¥mu is a positive constant, then both Lame coefficients can be recovered from the partial Cauchy data.



17:30-18:30   数理科学研究科棟(駒場) 056号室
Andrei Suslin 氏 (Northwestern University)
K_2 of the biquaternion algebra (ENGLISH)
[ 参考URL ]



10:30-12:00   数理科学研究科棟(駒場) 128号室
神島 芳宣 氏 (首都大学東京)
Compact locally homogeneous Kähler manifolds $\Gamma\backslash G/K$ (JAPANESE)



15:00-16:10   数理科学研究科棟(駒場) 000号室
本セミナーはITスタジオで開かれます.参加希望の方は事前に東大数理 鎌谷研吾( kengok at ms.u-tokyo.ac.jp) までお問い合わせください.
鈴木 大慈 氏 (東京大学情報理工学系研究科)
On Convergence Rate of Multiple Kernel Learning with Various Regularization Types (JAPANESE)
[ 講演概要 ]
本発表ではMultiple Kernel Learning (MKL) の統計的な収束レートを様々な正則化項に関して議論する. 近年の数値実験によると,スパースなL1正則化は必ずしもデンスな正則化よりも良い性能を示すとは限らない. そこで,我々はエラスティックネットやLpノルムを含む様々な正則化に関して収束レートを議論する.そのため, 二つの状況(真がスパースな状況および真がデンスな状況)に分けて議論を進める. スパースな状況ではエラスティックネットが真の滑らかさを適切に捉える事が出来ることを示す.デンスな状況では, 再生核ヒルベルト空間の複雑さのばらけ具合が最適な正則化項の決定に影響することを示す. すなわち,複雑さが一様な場合はL1が,非一様な場合はデンスな正則化が好ましいことが示される.
[ 参考URL ]

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