過去の記録 ~08/15本日 08/16 | 今後の予定 08/17~


16:00-17:30   数理科学研究科棟(駒場) 002号室
渡辺 達也 氏 (早稲田大学・理工学術院)
Two positive solutions for an inhomogeneous scalar field equation
[ 講演概要 ]
We consider the following nonlinear elliptic equation:
$$-\\Delta u+u=g(u)+f(x), x \\in R^N,$$
where $N\\ge 3$. When $f(x)\\equiv 0$, it is known that there is a nontrivial solution for a wide class of nonlinearities. Even though $f(x) \\not\\equiv 0$, we can expect the existence of a nontrivial solution if $f(x)$ is small in a suitable sense. Our purpose is to show the existence of two positive solutions via the variational approach when $\\| f\\|_{L^2}$ is small. The first solution is characterized as a local minimizer. The second solution will be obtained by the Mountain Pass Method. Since we do not impose any global condition on the nonlinearity, we will need a presice interaction estimate.


16:20-17:30   数理科学研究科棟(駒場) 126号室
吉田 亮 氏 (統計数理研究所)
Bayesian learning of biological pathways on genomic data assimilation
[ 講演概要 ]
States of living cells are controlled by networks of biochemical reactions, referred to as biological pathways, which comprise of, for instance, phosphorylation and binding of protein molecules, gene expressions mediated by transcription factor activities. In systems biology, mathematical modeling and simulation, based on biochemical rate equations, have proved to be a popular approach for unraveling complex machinery of cellular mechanisms. To proceed to simulations, however, it is vital to find the effective values of kinetic rate constants that are difficult to measure directly from in vivo and in vitro experiments. Furthermore, once a set of hypothetical models is given, a proper statistical criterion is needed to test the reliability of the constructed models in terms of predictability and biological robustness. The aim of this research is to present a new statistical technology, called Genomic Data Assimilation, for handling data-driven model construction of biological pathways. The method starts with a knowledge-based pathway modeling with hybrid functional Petri net. It then proceeds to the Bayesian learning of model parameters for which experimental data are available. This process uses time course measurements of biochemical reactants, e.g. gene expression profiles. Another important issue that we consider is statistical evaluation and comparison of the constructed hypothetical models. For this purpose, we developed a new Bayesian information-theoretic measure that assesses the predictability and the biological robustness of models. In this talk, I will detail mathematical aspects of the proposed method, and then, show some statistical issues to be addressed.
[ 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
Otto van Koert 氏 (北海道大学大学院理学研究科, JSPS)
Contact homology of left-handed stabilizations and connected sums
[ 講演概要 ]
In this talk, we will give a brief introduction to contact homology, an invariant of contact manifolds defined by counting holomorphic curves in the symplectization of a contact manifold. We shall show that certain left-handed stabilizations of contact open books have vanishing contact homology.
This is done by finding restrictions on the behavior of holomorphic curves in connected sums. An additional application of this behavior of holomorphic curves is a long exact sequence for linearized contact homology.


16:30-18:00   数理科学研究科棟(駒場) 126号室
直井 克之 氏 (東大数理)
construction of extended affine Lie algebras from multiloop Lie algebras
[ 講演概要 ]
affine Lie algebra の Kac-Moody Lie algebra とは異なる一般化として、extended affine Lie algebra と呼ばれる Lie algebra の class を考える。
ほとんどの extended affine Lie algebra は、有限次元 simple Lie algebra と、有限個の互いに可換な有限位数自己同型を用いて構成できることがすでに知られている。
この講演では、上の構成によって得られる extended affine Lie algebra がどのような場合に(適当な意味で)同型となるか、という問題に関する結果をお話ししたい。
[ 参考URL ]



10:30-12:00   数理科学研究科棟(駒場) 128号室
石井 豊 氏 (九大数理)
Henon 写像の複素力学系



16:20-17:30   数理科学研究科棟(駒場) 126号室
西山 陽一 氏 (統計数理研究所)
[ 講演概要 ]
独立同一分布に従う確率変数列に対する適合度検定問題を考えるとき, Kolmogorov-Smirnov 検定統計量が漸近的に分布不変であることはよく知られて いる.ところが,拡散過程モデルにおいて,例えばエルゴード性を仮定してその 不変分布の経験分布関数から Kolmogorov-Smirnov 型の検定統計量を構成しても, 漸近的分布不変にはならない.本報告では,この問題に対し,score marked empirical process に基づく新しいアプローチを用いて漸近的分布不変な検定統 計量を構成し,かつそれが一致性をもつことを紹介する.モデルとしては小拡散 過程とエルゴード的拡散過程を扱い,また連続観測・離散観測の双方を考察する ので,合計4通りの場合を調べ尽くす.同時期に提案された Dachian and Kutoyants (2008) の結果にも触れる.
本報告は Ilia Negri 氏と共同で執筆した3編の論文(うち1編は増田弘毅氏と も共同)にもとづくものであるが、概要は日本語によるサーベイ論文
[ 参考URL ]



16:30-17:30   数理科学研究科棟(駒場) 117号室
近藤 智 氏 (東京大学数物連携宇宙研究機構)



16:30-18:00   数理科学研究科棟(駒場) 126号室
奥田 隆幸 氏 (東大数理)
[ 講演概要 ]
TypeIV extremal と呼ばれる不変式の無限列に対し、deg = 0 (mod 6) の場合には、対応する全ての zeta多項式の零点が同一円周上に乗るという事が証明されているが、deg = 2,4 (mod 6) の場合は未解決であった。
この講演では、不変式に対する微分作用素を用いて、deg = 4 (mod6) の場合にも全てのzeta多項式の零点が同一円周上に乗るということを示したい。


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
佐藤 隆夫 氏 (大阪大学大学院理学研究科, JSPS)
On the Johnson homomorphisms of the automorphism group of
a free metabelian group
[ 講演概要 ]
The main object of our research is the automorphism group of a
free group. To be brief, the Johnson homomorphisms are studied in order to
describe one by one approximations of the automorphism group of a free group
. They play important roles on the study of the homology groups of the autom
orphism group of a free group. In general, to determine their images are ver
y difficult problem. In this talk, we define the Johnson homomorphisms of th
e automorphism group of a free metabelian group, and determine their images.
Using these results, we can give a lower bound on the image of the Johnson
homomorphisms of the automorphism group of a free group.



10:30-12:00   数理科学研究科棟(駒場) 128号室
足助 太郎 氏 (東大数理)

Kavli IPMU Komaba Seminar

17:00-18:30   数理科学研究科棟(駒場) 002号室
J.Manuel Garcia-Islas 氏 (National Autonomous University of Mexico)
Quantum topological invariants and black hole entropy
[ 講演概要 ]
A type of topological invariants of three manifolds were
introduced by Turaev and Viro. We will define an invariant of graphs
embedded in a three dimensional manifold in a Turaev-Viro spirit.
The relation of these invariants to mathematical physics is
a really nice one. We will show how entropy of a three dimensional
black hole known as BTZ can be described using our formulation.



16:30-18:00   数理科学研究科棟(駒場) 056号室
酒匂宏樹 氏 (東大数理)
Solid groups and orbit equivalence rigidity


16:20-17:30   数理科学研究科棟(駒場) 126号室
日野 英逸 氏 (早稲田大学)
アイテムの選好度のモデルとパラメタ推定法 - Plackett-Luceモデルの一般化 -
[ 講演概要 ]
アイテムの比較やランキングデータが多数与えられたとき、一つ一つのアイテムが潜在的に持つ 価値を決定する問題は、心理学、経済学、政治学などの分野で古くから研究が行われているが、 近年機械学習の分野でも注目されている。 Plackett-Luceモデルはアイテムへのランキングの確率モデルであり、アイテム一つ一つに 多項分布のパラメタを割り当ててアイテム選択のプロセスを説明する。 本発表では、映画評の生成プロセスに注目し、Plackett-Luceの一般化として グループ化ランキングモデルを提案する。このモデルの尤度関数を直接評価することは 困難であるため、尤度関数の下界を与え、emアルゴリズムを用いて近似的に下界の 最大化を行うことでパラメタ推定を行う。 Toy exampleに対する実験結果と、映画評データに対する適用結果を紹介する。 時間が許せば、個人の嗜好に基づくパラメタの推定と、協調フィルタリングへの 応用についても言及する。
[ 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
Kenneth Shackleton 氏 (東京工業大学, JSPS)
On computing distances in the pants complex
[ 講演概要 ]
The pants complex is an accurate combinatorial
model for the Weil-Petersson metric (WP) on Teichmueller space
(Brock). One hopes that many of the geometric properties
of WP are accurately replicated in the pants complex, and
this is the source of many open questions. We compare these
in general, and then focus on the 5-holed sphere and the
2-holed torus, the first non-trivial surfaces. We arrive at
an algorithm for computing distances in the (1-skeleton of the)
pants complex of either surface.
[ 参考URL ]



10:30-12:00   数理科学研究科棟(駒場) 128号室
橋本 健治 氏 (東大数理)



16:30-17:30   数理科学研究科棟(駒場) 002号室
お茶&Coffee&お菓子: 16:00~16:30 (コモンルーム)
村山斉 氏 (数物連携宇宙研究機構)
IPMU, Mathematics, Physics, and me
[ 講演概要 ]
Institute for the Physics and Mathematics of the Universe (IPMU) was founded to promote synergy between mathematics and physics, and to address deep mysteries about the universe. In this colloquium, I will discuss the mysteries IPMU will address, and why the interaction between mathematicians and physicists are crucial for this purpose. I will also talk about my personal journey about mathematics and physics.



16:30-18:00   数理科学研究科棟(駒場) 056号室
David Kerr 氏 (Texas A&M University)
Turbulence, representations, and trace-preserving actions


16:00-17:30   数理科学研究科棟(駒場) 002号室
谷口 雅治 氏 (東京工業大学大学院情報理工学研究科)
(The uniqueness and asymptotic stability of pyramidal traveling fronts in the Allen-Cahn equations)

[ 講演概要 ]
We study the uniqueness and the asymptotic stability of a pyramidal traveling front in the three-dimensional whole space. For a given admissible pyramid we prove that a pyramidal traveling front is uniquely determined and that it is asymptotically stable under the condition that given perturbations decay at infinity. For this purpose we characterize the pyramidal traveling front as a combination of planar fronts on the lateral surfaces. Moreover we characterize the pyramidal traveling front in another way, that is, we write it as a combination of two-dimensional V-form waves on the edges. This characterization also uniquely determines a pyramidal traveling front.


16:20-17:50   数理科学研究科棟(駒場) 052号室
伊藤 高一 氏 (IRI-DNL)
[ 講演概要 ]
[ 参考URL ]



16:30-18:45   数理科学研究科棟(駒場) 117号室
服部 新 氏 (北海道大学大学院理学研究院) 16:30-17:30
On a ramification bound of semi-stable torsion representations over a local field
朝倉 政典 氏 (北海道大学大学院理学研究院) 17:45-18:45
[ 講演概要 ]


17:30-19:00   数理科学研究科棟(駒場) 122号室
塩谷 匡介 氏 (日本銀行)
経済学と金融工学 ―Financial Economics入門―」(講義)
+M. Piazzesi and E. Swanson, "Futures Prices as Risk-Adjusted Forecasts
of Monetary Policy", Journal of Monetary Economics (2008)



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
佐野 友二 氏 (東京大学IPMU)
Multiplier ideal sheaves and Futaki invariant on toric Fano manifolds.
[ 講演概要 ]
I would like to discuss the subvarieties cut off by the multiplier
ideal sheaves (MIS) and Futaki invariant on toric Fano manifolds.
Futaki invariant is one of the necessary conditions for the existence
of Kahler-Einstein metrics on Fano manifolds,
on the other hand MIS is one of the sufficient conditions introduced by Nadel.
Especially I would like to focus on the MIS related to the Monge-Ampere equation
for Kahler-Einstein metrics on non-KE toric Fano manifolds.
The motivation of this work comes from the investigation of the
relationship with slope stability
of polarized manifolds introduced by Ross and Thomas.
This talk will be based on a part of the joint work with Akito Futaki



10:30-12:00   数理科学研究科棟(駒場) 128号室
山ノ井 克俊 氏 (熊本大自然)



13:30-16:00   数理科学研究科棟(駒場) 117号室
孫 娟娟 氏 (東大数理) 13:30-14:30
Confluent KZ equations for $sl_2$ and quantization of monodromy preserving deformation
[ 講演概要 ]
We obtain a system of confluent Knizhnik-Zamolodchikov (KZ) equations which generalizes that of KZ equations for $sl_2$,
and give integral solutions of the system. We also study the relation between the system and monodromy preserving deformation theory,
and recover quantizations of Painlev\\'e equations P_I-P_V with affine Weyl group symmetry which are introduced by H.Nagoya.
Paul A. Pearce 氏 (Univ. of Melbourne) 15:00-16:00
Exact Solution and Physical Combinatorics of Critical Dense
[ 講演概要 ]
A Yang-Baxter integrable model of critical dense polymers on the
square lattice
is introduced corresponding to the first member ${\\cal LM}(1,2)$ of a
family of logarithmic
minimal models. The model has no local degrees of freedom, only non-
local degrees
of freedom in the form of extended polymers. The model is built
diagrammatically using the
planar Temperley-Lieb algebra and solved exactly on finite width
strips using transfer matrix
techniques. The bulk and boundary free energies and finite-size
corrections are
obtained from the Euler-Maclaurin formula. The spectra are classified
by selection rules and
the physical combinatorics of the eigenvalue patterns of zeros in the
spectral-parameter plane. This yields explicit finitized conformal
In particular, in the scaling limit, we confirm the central charge
$c=-2$ and conformal weights
$\\Delta_{1,s}=\\frac{(2-s)^2-1}{8}$ for $s=1,2,3,\\ldots$ where $s-1$ is
the number
of defects.



16:30-18:00   数理科学研究科棟(駒場) 156号室
見村万佐人 氏 (東大数理)
On Lubotzky's property $(\\tau)$ and expander graphs

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