## 今後の予定

### 2022年10月04日(火)

#### トポロジー火曜セミナー

17:00-18:30   オンライン開催

Orientable rho-Q-manifolds and their modular classes (JAPANESE)
[ 講演概要 ]
A rho-commutative algebra, or an almost commutative algebra, is a graded algebra whose commutativity is given by a function called a commutation factor. It is one generalization of a commutative algebra or a superalgebra. We obtain a rho-Lie algebra, or an epsilon-Lie algebra, by a similar generalization of a Lie algebra. On the other hand, we have the modular class of an orientable Q-manifold. Here, a Q-manifold is a supermanifold with an odd vector field whose Lie bracket with itself vanishes, and its orientability is described in terms of the Berezinian bundle. In this talk, we introduce the concept of a rho-manifold, which is a graded manifold whose functional algebra is a rho-commutative algebra, then we show that we can define Q-structures, Berezinian bundle, volume forms, and modular classes of a rho-manifold with some examples.
[ 参考URL ]
https://park.itc.u-tokyo.ac.jp/MSF/topology/TuesdaySeminar/index_e.html

### 2022年10月05日(水)

#### 代数幾何学セミナー

13:00-14:00   数理科学研究科棟(駒場) 056号室

Yuri Tschinkel 氏 (Mathematics and Physical Sciences Division, Simons Foundation/ Courant Institute, New York University)
Equivariant birational geometry (joint with A. Kresch) (English)
[ 講演概要 ]
Ideas from motivic integration led to the introduction of new invariants in equivariant birational geometry, the study of actions of finite groups on algebraic varieties, up to equivariant birational transformations.
These invariants allow us to distinguish actions in many new cases, shedding light on the structure of the Cremona group. The structure of the invariants themselves is also interesting: there are unexpected connections to modular curves and cohomology of arithmetic groups.

### 2022年10月06日(木)

#### 情報数学セミナー

16:50-18:35   数理科学研究科棟(駒場) 123号室

[ 講演概要 ]

Tatsuaki Okamoto, ‘‘A New Quantitative Definition of the Complexity of Organized Matters,’’ Complexity, Volume 2022, Article ID 1889348 (2022)
https://www.hindawi.com/journals/complexity/2022/1889348/

### 2022年10月11日(火)

#### 作用素環セミナー

16:45-18:15   数理科学研究科棟(駒場) 128号室

Constructing number field isomorphisms from *-isomorphisms of certain crossed product C*-algebras
[ 参考URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm

#### トポロジー火曜セミナー

17:00-18:00   オンライン開催

Magnitude homology of graphs (JAPANESE)
[ 講演概要 ]
Magnitude is introduced by Leinster in 00’s as an Euler characteristic of metric spaces”. It is defined for the metric structure itself rather than the topology induced from the metric. Magnitude homology is a categorification of magnitude in a sense that ordinary homology categorifies the Euler characteristic. The speaker’s interest is in geometric meaning of this theory. In this talk, after an introduction to basic ideas, I will explain that magnitude truly extends the Euler characteristic. From this perspective, magnitude homology can be seen as one of the categorification of the Euler characteristic, and the path homology (Grigor’yan—Muranov—Lin—S-T. Yau et.al) appears as a part of another one. These structures are aggregated in a spectral sequence obtained from the classifying space of "filtered set enriched categories" which includes ordinary small categories and metric spaces.
[ 参考URL ]
https://park.itc.u-tokyo.ac.jp/MSF/topology/TuesdaySeminar/index_e.html

### 2022年10月12日(水)

#### 代数学コロキウム

17:00-18:00   ハイブリッド開催

Abhinandan 氏 (東京大学大学院数理科学研究科)
Syntomic complex with coefficients (English)
[ 講演概要 ]
In the proof of $p$-adic crystalline comparison theorem, one of the most important steps in the approach of Fontaine and Messing is to establish a comparison between syntomic cohomology and p-adic étale cohomology via (Fontaine-Messing) period map. This approach was successfully generalized to the semistable case by Kato and a complete proof of crystalline and semistable comparison theorems for schemes was given by Tsuji. Few years ago, Colmez and Nizioł gave a new interpretation of the (local) Fontaine-Messing period map in terms of complexes of $(\varphi,\Gamma)$-modules and used it to prove semistable comparison theorem for $p$-adic formal schemes. We will present a generalisation (of crystalline version of this interpretation by Colmez and Nizioł) to coefficients arising from relative Fontaine-Laffaille modules of Faltings (on syntomic side) and relative Wach modules introduced by the speaker (on $(\varphi,\Gamma)$-module side).

### 2022年10月13日(木)

#### 情報数学セミナー

16:50-18:20   数理科学研究科棟(駒場) 123号室

[ 講演概要 ]

### 2022年10月18日(火)

#### 作用素環セミナー

16:45-18:15   数理科学研究科棟(駒場) 128号室
Valerio Proietti 氏 (東大数理)

[ 参考URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm

### 2022年10月24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) 128号室

TBA (Japanese)
[ 講演概要 ]
TBA
[ 参考URL ]
https://forms.gle/hYT2hVhDE3q1wDSh6

### 2022年10月31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) 128号室

TBA (Japanese)
[ 講演概要 ]
TBA
[ 参考URL ]
https://forms.gle/hYT2hVhDE3q1wDSh6

### 2022年11月01日(火)

#### 作用素環セミナー

16:45-18:15   数理科学研究科棟(駒場) 128号室

Permutation stability of finitely generated free metabelian groups
[ 参考URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm

### 2022年11月08日(火)

#### 作用素環セミナー

16:45-18:15   数理科学研究科棟(駒場) 128号室

On the type of the von Neumann algebra of an open subgroup of the Neretin group
[ 参考URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm

### 2022年11月14日(月)

#### 複素解析幾何セミナー

15:00-16:30   オンライン開催
オンラインのみで、通常とは開始時間が異なっております。参加の際は参考URLからご登録ください。

TBA (Japanese)
[ 講演概要 ]
TBA
[ 参考URL ]
https://forms.gle/hYT2hVhDE3q1wDSh6

### 2022年11月21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) 128号室

Resolution of singularities for $C^{\infty}$ functions and meromorphy of local zeta functions (Japanese)
[ 講演概要 ]
In this talk, we attempt to resolve the singularities of the zero variety of a $C^{\infty}$ function of two variables as much as possible by using ordinary blowings up. As a result, we formulate an algorithm to locally express the zero variety in the “almost” normal crossings form, which is close to the normal crossings form but may include flat functions. As an application, we investigate analytic continuation of local zeta functions associated with  $C^{\infty}$ functions of two variables.
[ 参考URL ]
https://forms.gle/hYT2hVhDE3q1wDSh6

### 2022年11月22日(火)

#### 代数幾何学セミナー

10:30-12:00   数理科学研究科棟(駒場) 002号室
90分ハイブリッド開催です。

TBA (日本語)
[ 講演概要 ]
TBA

### 2022年12月05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) 128号室

TBA (Japanese)
[ 講演概要 ]
TBA
[ 参考URL ]
https://forms.gle/hYT2hVhDE3q1wDSh6

### 2023年01月10日(火)

#### 代数幾何学セミナー

10:30-11:30/12:00   数理科学研究科棟(駒場) 002号室

TAB (日本語)
[ 講演概要 ]
TBA