## 過去の記録

### 2013年12月02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
Anne-Katrin Herbig 氏 (名古屋大学)
A smoothing property of the Bergman projection (ENGLISH)
[ 講演概要 ]
Let $D$ be a bounded domain with smooth boundary in complex space of dimension $n$. Suppose its Bergman projection $B$ maps the Sobolev space of order $k$ continuously into the one of order $m$. Then the following smoothing result holds: the full Sobolev norm of $Bf$ of order $k$ is controlled by $L^2$-derivatives of $f$ taken along a single, distinguished direction (of order up to $m$). This talk is based on joint work with J. D. McNeal and E. J. Straube.

### 2013年11月29日(金)

#### FMSPレクチャーズ

10:40-12:10   数理科学研究科棟(駒場) 126号室

Erwin Bolthausen 氏 (University of Zurich)
Random walks in random environments (ENGLISH)
[ 講演参考URL ]
http://fmsp.ms.u-tokyo.ac.jp/FMSPLectures_Bolthausen.pdf

#### FMSPレクチャーズ

14:50-16:20   数理科学研究科棟(駒場) 126号室

Erwin Bolthausen 氏 (University of Zurich)
Random walks in random environments (ENGLISH)
[ 講演参考URL ]
http://fmsp.ms.u-tokyo.ac.jp/FMSPLectures_Bolthausen.pdf

### 2013年11月28日(木)

#### 幾何コロキウム

10:00-11:30   数理科学研究科棟(駒場) 122号室

[ 講演概要 ]
スカラー曲率函数に対する逆問題は微分幾何における基本問題である.すなわち,閉多様体に滑らかな函数が与えられたとき,その函数をスカラー曲率とする計量の存在を問う.この問題はKazdan-Warnerにより解決した.

#### GCOEセミナー

17:00-18:00   数理科学研究科棟(駒場) 470号室
Oleg Emanouilov 氏 (Colorado State Univ.)
Inverse problem for the Maxwell equations (ENGLISH)
[ 講演概要 ]
We consider an analog of Caderon's problem for the system of Maxwell equations in a cylindrical domain.
Under some geometrical assumptions on domain we show that from the partial data one can recover the complete set of parameters.

### 2013年11月27日(水)

#### 統計数学セミナー

13:30-14:40   数理科学研究科棟(駒場) 052号室

Density of solutions to stochastic functional differential equations (JAPANESE)
[ 講演概要 ]

[ 講演参考URL ]
http://www.sigmath.es.osaka-u.ac.jp/~kamatani/statseminar/2013/08.html

### 2013年11月26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

[ 講演概要 ]
Sは有理楕円曲面とする.Sの生成ファイバーは
1変数有理函数体上の楕円曲線であり,楕円曲線の

C_2を構成することできる.本講演では,このアイ
デアに基づいて得られるある7次のline-conic
arrangementsについて解説する.

#### 諸分野のための数学研究会

10:30-11:30   数理科学研究科棟(駒場) 056号室

Huaxiong Huang 氏 (York University)
An immersed boundary method for mass transfer across permeable moving interfaces (ENGLISH)
[ 講演概要 ]
In this talk, we present an immersed boundary method for mass transfer across permeable deformable moving interfaces interacting with the surrounding fluids. One of the key features of our method is the introduction of the mass flux as an independent variable, governed by a non-standard vector transport equation. The flux equation, coupled with the mass transport and the fluid flow equations, allows for a natural implementation of an immersed boundary algorithm when the flux across the interfaces is proportional to the jump in concentration. As an example, the oxygen transfer from red blood cells in a capillary to its wall is used to illustrate the applicability of the proposed method. We show that our method is capable of handling multi-physics problems involving fluid- structure interaction with multiple deformable moving interfaces and (interfacial) mass transfer simultaneously.
This is joint work with X. Gong and Z. Gong.

#### 解析学火曜セミナー

16:30-18:00   数理科学研究科棟(駒場) 128号室

Global Strichartz estimates for Schr\\"odinger equations with long range metrics (JAPANESE)
[ 講演概要 ]
We consider Schr\\"odinger equations on the asymptotically Euclidean space
with the long-range condition on the metric.
We show that if the high energy resolvent has at most polynomial growth with respect to the energy,
then global-in-time Strichartz estimates, outside a large compact set, hold.
Under the non-trapping condition we also discuss global-in-space Strichartz estimates.
This talk is based on a joint work with J.-M. Bouclet (Toulouse University).

### 2013年11月25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

On hyperkaehler metrics on holomorphic cotangent bundles on complex reductive Lie groups (JAPANESE)
[ 講演概要 ]
There exists a complete hyperkaehler metric on the holomorphic cotangent bundle on each complex reductive Lie group. It was constructed by Kronheimer, using hyperkaehler quotient method. In this talk I explain how to describe the Kaehler potentials of these metrics.

#### 代数幾何学セミナー

15:30-17:00   数理科学研究科棟(駒場) 122号室

Minimal singular metrics of some line bundles with infinitely generated section rings (JAPANESE)
[ 講演概要 ]
We consider Hermitian metrics of pseudo-effective line bundles on smooth
projective varieties defined over $\\mathbb{C}$.
Especially we are interested in (possibly singular) Hermitian metrics
with semi-positive curvatures when the section rings are not finitely generated.
We study where and how minimal singular metrics, special Hermitian
metrics with semi-positive curvatures, diverges in the following two situations;
a line bundle admitting no Zariski decomposition even after any
modifications (Nakayama example)
and a nef line bundle $L$ on $X$ satisfying $D \\subset |mL|$ and $|mL-D| = \\emptyset$ for some divisor $D \\subset X$ and for all $m \\geq 1$ (
Zariski example).

### 2013年11月22日(金)

#### FMSPレクチャーズ

10:40-11:40   数理科学研究科棟(駒場) 123号室
Alfred RAMANI 氏 (École polytechnique)
Integrable discrete systems, an introduction Pt. 2 (ENGLISH)
[ 講演概要 ]
The second part will mostly be devoted to the various integrability detectors (singularity confinement, algebraic entropy) for integrability of discrete systems, in one or more dimensions. The most important systems identified through these detectors, namely the discrete Painlev¥'e equations, will be presented in detail, through a geometric approach.

### 2013年11月21日(木)

#### GCOEセミナー

15:30-17:00   数理科学研究科棟(駒場) 056号室
この講義はMini workshop on birational geometryの一環として行われます
Florin Ambro 氏 (IMAR)
Cyclic covers and toroidal embeddings (ENGLISH)
[ 講演参考URL ]
http://www.ms.u-tokyo.ac.jp/documents/miniworkshop.pdf

### 2013年11月20日(水)

#### 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
Valentina Di Proietto 氏 (東京大学数理科学研究科)
On the homotopy exact sequence for the logarithmic de Rham fundamental group (ENGLISH)
[ 講演概要 ]
Let K be a field of characteristic 0 and let X* be a quasi-projective simple normal crossing log variety over the log point K* associated to K. We construct a log de Rham version of the homotopy sequence \\pi_1(X*/K*)-->\\pi_1(X*/K)--\\pi_1(K*/K)-->1 and prove that it is exact. Moreover we show the injectivity of the first map for certain quotients of the groups. Our proofs are purely algebraic. This is a joint work with A. Shiho.

#### 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
Camille Male 氏 (Univ. Paris VII)
The spectrum of large random matrices, the non commutative random variables and the distribution of traffics (ENGLISH)

#### 統計数学セミナー

13:30-14:40   数理科学研究科棟(駒場) 052号室

TD法における価値関数への収束アルゴリズム (JAPANESE)
[ 講演概要 ]
マルコフ過程に従い状態遷移が行われ、状態に応じた報酬が支 払われるモデルにおいて、その報酬の累積和の期待値、価値関数を推定する問題 を考える。線形関数近似を用いたTD法において、真の価値関数が特徴量の線形結 合で表されない場合であっても収束することは知られているが、特徴量の選択に よって性能に大きな差が出てしまう。そこで、得られた極限を真の価値関数へ補 正するように特徴量を構成することによって、真の価値関数に収束するアルゴリ ズムを提案し、その効率を上げる手法について説明する。
[ 講演参考URL ]
http://www.sigmath.es.osaka-u.ac.jp/~kamatani/statseminar/2013/07.html

### 2013年11月19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

[ 講演概要 ]

これは松元重則氏(日本大学)との共同研究である。

#### 解析学火曜セミナー

16:30-18:00   数理科学研究科棟(駒場) 128号室
Alexander Pushnitski 氏 (King's Colledge London)
Inverse spectral problem for positive Hankel operators (ENGLISH)
[ 講演概要 ]
Hankel operators are given by (infinite) matrices with entries
$a_{n+m}$ in $\\ell^2$. We consider inverse spectral problem
for bounded self-adjoint positive Hankel operators.
A famous theorem due to Megretskii, Peller and Treil asserts
that such operators may have any continuous spectrum of
multiplicity one or two and any set of eigenvalues of multiplicity
one. However, more detailed questions of inverse spectral
problem, such as the description of isospectral sets, have never
been addressed. In this talk I will describe in detail the
direct and inverse spectral problem for a particular sub-class
of positive Hankel operators. The talk is based on joint work
with Patrick Gerard (Paris, Orsay).

#### Lie群論・表現論セミナー

16:30-17:30   数理科学研究科棟(駒場) 126号室
Simon Gindikin 氏 (Rutgers University (USA))
Horospheres, wonderfull compactification and c-function (JAPANESE)
[ 講演概要 ]
I will discuss what is closures of horospheres at the wonderfull compactification and how does it connected with horospherical transforms, c-functions and product-formulas

### 2013年11月18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

[ 講演概要 ]

#### FMSPレクチャーズ

15:30-16:30   数理科学研究科棟(駒場) 056号室
Alfred RAMANI 氏 (École polytechnique)
Integrable discrete systems, an introduction Pt.1 (ENGLISH)
[ 講演概要 ]
The first part will contain a general overview of the notion of integrability, starting from continuous systems with or without physical applications. The Painlev¥'e property will be discussed as an integrability detector for integrability of continuous systems. The notion of integrability of discrete systems will be introduced next. One dimensional systems will be presented as well as multidimensional ones.

#### Kavli IPMU Komaba Seminar

17:00-18:30   数理科学研究科棟(駒場) 002号室
Mauricio Romo 氏 (Kavli IPMU)
Exact Results In Two-Dimensional (2,2) Supersymmetric Gauge Theories With Boundary
(ENGLISH)
[ 講演概要 ]
I will talk about the recent computation, done in joint work with Prof. K. Hori, of the partition function on the hemisphere of a class of two-dimensional (2,2) supersymmetric field theories including gauged linear sigma models (GLSM). The result provides a general exact formula for the central charge of the D-branes placed at the boundary. From the mathematical point of view, for the case of GLSMs that admit a geometrical interpretation, this formula provides an expression for the central charge of objects in the derived category at any point of the stringy Kahler moduli space. I will describe how this formula arises from physics and give simple, yet important, examples that supports its validity. If time allows, I will also explain some of its consequences such as how it can be used to obtain the grade restriction rule for branes near phase boundaries.

#### 代数幾何学セミナー

15:30-17:00   数理科学研究科棟(駒場) 122号室
この講演はGCOEレクチャーズとの共同セミナーになります
Florin Ambro 氏 (IMAR)
An injectivity theorem (ENGLISH)
[ 講演概要 ]
I will discuss a generalization of the injectivity theorem of Esnault-Viehweg, and an
application to the problem of lifting sections from the non-log canonical locus of a log variety.

### 2013年11月16日(土)

#### 保型形式の整数論月例セミナー

13:30-16:00   数理科学研究科棟(駒場) 123号室

Pair correlation of low lying zeros of quadratic L-functions (JAPANESE)
[ 講演概要 ]
In this talk, we give certain asymptotic formula involving non-trivial zeros of L-functions associated to Knonecker symbol under the assumption of the Generalized Riemann Hypothesis. From this formula, we obtain several results on non-trivial zeros of quadratic L-functions near the real axis.

σ関数と空間曲線 (JAPANESE)
[ 講演概要 ]
In this talk, I show that Kleinian sigma function, which is a generalization of Weierstrass elliptic sigma function, is extended to space curves, (3,4,5), (3,7,8) and (6,13,14,15,16) type. In terms of the function, the Jacob inversion formula is also generalized, in which the affine coordinates are given as functions of strata of Jacobi variety associated with these curves.

#### 調和解析駒場セミナー

13:00-18:00   数理科学研究科棟(駒場) 128号室
このセミナーは,月に1度程度,不定期に開催されます.

Besov and Triebel-Lizorkin spaces associated with
(ENGLISH)
[ 講演概要 ]
Let $(X,d)$ be a locally compact metric space
endowed with a doubling measure $¥mu$, and
let $L$ be a non-negative self-adjoint operator on $L^{2}(X,d¥mu)$.
Assume that the semigroup
$P_{t}=e^{-tL}$
generated by $L$ consists of integral operators with (heat) kernel
$p_{t}(x,y)$
enjoying Gaussian upper bound but having no information on the
regularity in the variables $x$ and $y$.
In this talk, we shall introduce Besov and Triebel-Lizorkin spaces associated
with $L$, and
present an atomic decomposition of these function spaces.

[ 講演概要 ]

そこで、Galilei変換の生成作用素を修正したものと、