## 今後の予定

### 2018年01月23日(火)

#### トポロジー火曜セミナー

17:00-18:00   数理科学研究科棟(駒場) 056号室
Tea: Common Room 16:30-17:00

An invariant of 3-manifolds via homology cobordisms (JAPANESE)
[ 講演概要 ]
For a closed 3-manifold X, we consider the topological invariant defined as the minimal integer g such that X is obtained as the closure of a homology cobordism over a surface of genus g. We prove that the invariant equals one for every lens space, which is contrast to the fact that some lens spaces do not admit any open book decomposition whose page is a surface of genus one. The proof is based on the Chebotarev density theorem and binary quadratic forms in number theory.

#### トポロジー火曜セミナー

18:00-19:00   数理科学研究科棟(駒場) 056号室

Wrapping projections and decompositions of Keinian groups (JAPANESE)
[ 講演概要 ]
Let $S$ be a closed surface of genus $g ¥geq 2$. The deformation space $AH(S)$ consists of (conjugacy classes of) discrete faithful representations $\rho:\pi_{1}(S) \to PSL_{2}(\mathbb{C})$.
McMullen, and Bromberg and Holt showed that $AH(S)$ can self-bump, that is, the interior of $AH(S)$ has the self-intersecting closure.
Both of them demonstrated the existence of self-bumping under the exisetence of a non-trivial wrapping projections from an algebraic limits to a geometric limits which wraps an annulus cusp into a torus cusp.
In this talk, given a representation $\rho$ at the boundary of $AH(S)$, we characterize a wrapping projection to a geometric limit associated to $\rho$, by the information of the actions of decomposed Kleinian groups of the image of $\rho$.

### 2018年01月25日(木)

#### FMSPレクチャーズ

15:00-16:30   数理科学研究科棟(駒場) 002号室
Norbert A'Campo 氏 (University of Basel)
NUMERICAL ANALYSIS, COBORDISM OF MANIFOLDS AND MONODROMY. (ENGLISH)
[ 講演概要 ]
http://fmsp.ms.u-tokyo.ac.jp/FMSPLectures_ACampo_abst.pdf
[ 講演参考URL ]
http://fmsp.ms.u-tokyo.ac.jp/FMSPLectures_ACampo.pdf

### 2018年01月26日(金)

#### 談話会・数理科学講演会

15:30-16:30   数理科学研究科棟(駒場) 002号室

Wiener汎関数ベクトルの最大値のGauss型近似とその高頻度データ解析への応用 (JAPANESE)
[ 講演概要 ]

の最大値の分布の間のKolmogorov距離を評価する問題を考える. 特に, 最近数理統計学
の分野におけるChernozhukov, Chetverikov & Katoによる一連の研究で発展した,

Wiener汎関数からなるベクトルへと拡張することを試みる. 本報告では, Chernozhukov,
Chetverikov & Kato (2015, PTRF)の結果のWiener汎関数からなるベクトルへの一般化
が可能であることを示す. さらに, 特別な場合として, (同じ次数をもつ)多重Wiener-伊藤積分
のベクトルの最大値の分布とGauss型ベクトルの最大値の分布の間のKolmogorov距離が0に

phenomenonが起きることを示す. 最後に, 高頻度データ解析への応用例を与え、理論の

#### 代数幾何学セミナー

16:30-18:00   数理科学研究科棟(駒場) 122号室

On classification of prime Q-Fano 3-folds with only 1/2(1,1,1)-singularities and of genus less than 2
[ 講演概要 ]
I classified prime Q-Fano threefolds with only 1/2(1,1,1)-singularities and of genus greater than 1 (2002, Nagoya Math. J.).
In this talk, I will explain how the method in that paper can be extended to the case of genus less than 2. The method is so called two ray game. By this method, I can classify the possibilities of such Q-Fano's. The classification is not yet completed since constructions of examples in certain cases are difficult. I will also explain some pretty examples in this talk.

### 2018年01月29日(月)

#### 作用素環セミナー

16:45-18:15   数理科学研究科棟(駒場) 126号室

Tingley's problem for operator algebras

#### 東京確率論セミナー

16:00-17:30   数理科学研究科棟(駒場) 128号室

Radial processes on RCD${}^*(K,N)$-spaces (JAPANESE)
[ 講演概要 ]

この講演は東北大学の桑田和正氏との共同研究に基づく。

### 2018年01月30日(火)

#### トポロジー火曜セミナー

17:00-18:00   数理科学研究科棟(駒場) 056号室
Tea: Common Room 16:30-17:00

Persistence-like distance on Tamarkin's category and symplectic displacement energy (JAPANESE)
[ 講演概要 ]
The microlocal sheaf theory due to Kashiwara and Schapira can be regarded as Morse theory with sheaf coefficients. Recently it has been applied to symplectic geometry, after the pioneering work of Tamarkin. In this talk, I will propose a new sheaf-theoretic method to estimate the displacement energy of compact subsets in cotangent bundles. In the course of the proof, we introduce a persistence-like pseudo-distance on Tamarkin's sheaf category. This is a joint work with Tomohiro Asano.

### 2018年02月14日(水)

#### 作用素環セミナー

16:45-18:15   数理科学研究科棟(駒場) 126号室
Valerio Proietti 氏 (Copenhagen Univ.)

### 2018年02月21日(水)

#### FMSPレクチャーズ

15:00-16:30   数理科学研究科棟(駒場) 117号室

Etienne Ghys 氏 (ENS de Lyon)
The topology of singular points of real analytic curves (ENGLISH)
[ 講演概要 ]
In the neighborhood of a singular point, a germ of real analytic curve in the plane consists of a finite number of branches. Each of these branches intersects a small circle around the singular point in two points. Therefore, the local topology is described by a chord diagram : an even number of points on a circle paired two by two. Not all chord diagrams come from a singular point. The main purpose of this mini course is to give an complete description of those ‘’analytic ? chord diagrams. On our way, we shall meet some interesting concepts from computer science, graph theory and operads.
[ 講演参考URL ]
http://fmsp.ms.u-tokyo.ac.jp/FMSPLectures_Ghys.pdf

### 2018年02月22日(木)

#### FMSPレクチャーズ

15:00-16:30   数理科学研究科棟(駒場) 117号室

Etienne Ghys 氏 (ENS de Lyon)
The topology of singular points of real analytic curves (ENGLISH)
[ 講演概要 ]
In the neighborhood of a singular point, a germ of real analytic curve in the plane consists of a finite number of branches. Each of these branches intersects a small circle around the singular point in two points. Therefore, the local topology is described by a chord diagram : an even number of points on a circle paired two by two. Not all chord diagrams come from a singular point. The main purpose of this mini course is to give an complete description of those ‘’analytic ? chord diagrams. On our way, we shall meet some interesting concepts from computer science, graph theory and operads.
[ 講演参考URL ]
http://fmsp.ms.u-tokyo.ac.jp/FMSPLectures_Ghys.pdf

### 2018年02月23日(金)

#### 談話会・数理科学講演会

15:30-16:30   数理科学研究科棟(駒場) 002号室

[ 講演概要 ]

ても大きく進展している。本講演では、極小モデル理論について概説した後、時

#### FMSPレクチャーズ

13:30-15:00   数理科学研究科棟(駒場) 002号室

Etienne Ghys 氏 (ENS de Lyon)
The topology of singular points of real analytic curves (ENGLISH)
[ 講演概要 ]
In the neighborhood of a singular point, a germ of real analytic curve in the plane consists of a finite number of branches. Each of these branches intersects a small circle around the singular point in two points. Therefore, the local topology is described by a chord diagram : an even number of points on a circle paired two by two. Not all chord diagrams come from a singular point. The main purpose of this mini course is to give an complete description of those ‘’analytic ? chord diagrams. On our way, we shall meet some interesting concepts from computer science, graph theory and operads.
[ 講演参考URL ]
http://fmsp.ms.u-tokyo.ac.jp/FMSPLectures_Ghys.pdf