特異点セミナー( Singularity Theory) 2010-2011

Seminars in past: 2006-2007 , 2008-2009 2009-2010
Access to the University from Narita Airport: Take JR (Narita Express) to Tokyo station, then take a Chuo line train to Ochanomizu (2nd station from Tokyo), then change to the Sobu line on the other side of the platform to get off at 2nd station, Iidabshi, at west exit

Tokyo University of Science, Department of Mathematics

特異点と幾何学 Singularity theory, geometry and related topics.
世話人: 岡、 oka at rs.kagu.tus.ac.jp

Feburuary（2月）

日時、場所講演者、題目

26日（金曜　Friday）
15:30-17:00
W23
Nguyen Van Chau (Hanoi Institute of Math.)
RATIONAL POLYNOMIALS AND PLANE JACOBIAN PROBLEM

March Mini Workshop

March 13（土曜　Saturday） place: Tokyo University of Science, W25 (Wakamiya Build.) (13th)

10:00-11:00 M. Kawashima (Tokyo Univ. of Science)
On $(2, 3)$ torus decompositions of QL-configurations,(A3)

11:10-12:10 T. Ohmoto (Hokkaido Univ.)
Equivariant singular Chern class and ICIS (A4)

14:00-15:00: M. Namba (Ohtemon Univ.)
Pfaffian systems with given monodromy (abstract:A2)

15:10-16:10 H. Terao(Hokkaido Univ.)
Mathematics related to hyperplane arrangements (in retrospect)

16:40-17:40 T.K. Vu (Hanoi Inst. Math.)
On Turaev's theorem about Dijkgraaf-Witten invariants of surfaces (astract:A1)

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March 14 (Sunday): Build.3, Room 352 (土曜日と建物が 違います )

10:00-11:00 E. Artal Bartolo (Zaragoza Univ.)
Bestvina-Brady groups and pencil maps

11:10-12:10 H. Tokunaga (Tokyo Metroplitan Univ.)
Splitting curves and dihedral covers

14:00-15:00 M. Oka (Tokyo Univ. of Science)
Mixed curves with embedding degree 1 with an arbitrary genus

15:10-16:10 T. Ashikaga (Tohoku Gakuin Univ.)
Toric resolution of a certain non-normal singularity

Abstracts:

A1: Vu The Khoi
Abstract: Turaev proves a formula for the Dijkgraaf-Witten invariants of surfaces in terms of projective representations by using the state sum invariant technique from quantum topology. In this paper, we present another proof of Turaev's theorem by using classical method of characters and representation theory. A version of Turaev's formula for surfaces with boundary is also given.

A2: Namba:
Short abstract: We discuss a method to get Pfaffian systems ( simultaneous homogeneous linear differential equations) with given monodromy.

A3: Kawashima: Let $Q$ be a certain affine quartic which does not intersect transversely with the line at infinity. In this talk, we show the existence of a $(2, 3)$ torus decomposition of $Q$ and its uniqueness except for one class.

A4: Ohmoto: I will talk about equivariant Chern classes of singular G-varieties. (Chern-Schwartz-MacPherson class, Fulton class, Milnor class). As a concrete application, I will deal with weighted homogeneous ICS and toric varieites. If time remains, I will speak about the functorial theory of CSM class for algebraic stacks (DM, Artin stacks).

April（4月）

日時、場所講演者、題目

9日（金曜　Friday）
16:00-17:30 (変更)
7号館 5階 751セミナー室 (数学教室が7号館に移転しました)
Alex Dimca (Univ. Nice)
Monodromy of homogeneous polynomials

June（6月）

日時、場所講演者、題目

24日（木曜　Thursday）　　　　　　　　
16:15-17:45

7号館 5階 751セミナー室 　　　　

　　　　　　 		Kiyoshi TAKEUCHI (Univ. of Tsukuba)
Milnor fibers over toric varieties and their applications to A-discriminants and monodromies at infinity
Abstract: We study Milnor fibers by using nearby cycle sheaves and mixed Hodge modules.
　　　　　　As a byproduct, a geometric degree formula for A-dicriminants will be obtained.
　　　　　　We also discuss applications to Jordan normal forms of monodromies in various situations.

July（7月）

日時、場所講演者、題目

2日（金曜　Friday）　　　　　　　　
7号館 3階 731セミナー室 　

16:30-18:00

　

 Tadashi Ishibe (Hiroshima Univ. )
On the fundamental groups of the complement of complexified real line arrangement.
Abstract: 平行な２本を含まない実ラインアレンジメントの複素化 の補集合の基本群についてお話します。 Zariski-van Kampenの方法で表示すると、経験的には 関係式は正に表示されて、その両辺の長さはn本の直線配置に 対してn以下になる。 この表示を利用して、いくつかの基本群の 語の問題を解くということをお話しします。

September（9月）

日時、場所講演者、題目

24日（金曜　Friday）　　　　　　　　　　　
16:30-18:00
7号館 3階 731セミナー室
Andras　Nemethi (Alfred Renyi Institute of Mathematics)
The Seiberg-Witten invariants of negative definite plumbed 3-manifolds

Abstract: Assume that M is the link of a normal surface singularity and it is a rational homology sphere. We provide a new combinatorial formula for the Seiberg-Witten invariants of M (in terms of the resolution graph) as the constant term of a multivariable Hilbert polynomial. This formula reflects in a conceptual way the graph, and also emphasizes the subtle parallelism between the topological and analytic invariants of singularities.


27日（月曜　Monday）　　　　　　　　　　
16:00-17:30
7号館 3階 751セミナー室
Oswald Riemenschneider (Univ. of Hamburg)
Toric duality for deformations of the cyclic quotient singularities $A_{n,q}$ and $A_{n,n-q}$.
参考講義録1 参考講義録2

October（10月）

日時、場所講演者、題目

25日（月曜　Monday）　　　　　　　　
16:10-17:40

7号館 5階 751セミナー室 　　　　

　　　　　　 		Le Dung Trang (University of Provence)
Topology of algebraic varieties　I
Abstract: "In these lectures we shall speak on the topology of complex algebraic varieties.
　　　　　　　We shall indicate basic problems and basic methods to study complex algebraic varieties"

November（11月）

日時、場所講演者、題目

1日, 8日, 15日（月曜　Monday）　　　
16:10-17:40

7号館 5階 751セミナー室 　　　　

　　　　　　 		Le Dung Trang (University of Provence)
Topology of algebraic varieties　II, III, IV
Abstract: "In these lectures we shall speak on the topology of complex algebraic varieties.
　　　　　　　We shall indicate basic problems and basic methods to study complex algebraic varieties"