Seminar information archive

2006/07/10

Seminar on Geometric Complex Analysis

10:30-12:00   Room #128 (Graduate School of Math. Sci. Bldg.)
Do Duc Thai (Hanoi教育大)
Characterization of domains in $C^n$ by their noncompact automorphism groups
[ Abstract ]
In this talk, the characterization of domains in $C^n$ by their noncompact automorphism groups are given. By this characterization, the Bedford-Pinchuk theorem is true for any domain (not necessary bounded) in $C^n$.

2006/07/08

Monthly Seminar on Arithmetic of Automorphic Forms

13:30-15:45   Room #123 (Graduate School of Math. Sci. Bldg.)

Rankin-Cohen-Ibukiyama operators for holomorphic automorphic forms on type I symmetric domains

On Dirichlet series counting cubic alegebras

2006/07/07

Colloquium

16:30-17:30   Room #123 (Graduate School of Math. Sci. Bldg.)

[ Abstract ]

2006/07/06

Seminar for Mathematical Past of Asia

17:00-18:30   Room #123 (Graduate School of Math. Sci. Bldg.)

ユークリッドをめぐる最新の研究動向
[ Reference URL ]
http://www.ms.u-tokyo.ac.jp/~kawazumi/asia.html

Operator Algebra Seminars

16:30-18:00   Room #052 (Graduate School of Math. Sci. Bldg.)
Rolf Dyre Svegstrup (東大数理)
Endomorphisms of half-sided modular inclusions

2006/07/05

Seminar on Mathematics for various disciplines

10:30-11:30   Room #056 (Graduate School of Math. Sci. Bldg.)
Y. H. Richard Tsai (University of Texas)
Level Set Methods and Multi-valued solutions
[ Abstract ]
We review the level set methods for computing multi-valued
solutions to a class of nonlinear first order partial differential
equations, including Hamilton-Jacobi equations, quasi-linear
hyperbolic equations, and conservative transport equations with
multi-valued transport speeds.
The multivalued solutions are embedded as the zeros of a set of scalar functions that solve the initial value problems of a time dependent partial differential equation in an augmented space.
We discuss the essential ideas behind the techniques, the coupling of these techniques to the projection of the interaction of zero level sets and a collection of applications including the omputation of the semiclassical limit for Schr\\"{o}dinger quations and the high frequency geometrical optics limits of linear wave equations.
[ Reference URL ]
http://coe.math.sci.hokudai.ac.jp/sympo/various/index.html

2006/07/04

Tuesday Seminar on Topology

16:30-18:00   Room #056 (Graduate School of Math. Sci. Bldg.)
Alexander A. Ivanov (Imperial College (London))
Amalgams: a machinery of the modern theory of finite groups
[ Reference URL ]
http://faculty.ms.u-tokyo.ac.jp/~topology/

2006/07/03

Seminar on Geometric Complex Analysis

14:00-15:30   Room #128 (Graduate School of Math. Sci. Bldg.)
Jörg Winkelmann (Université Henri Poincaré Nancy)
Complex Semi-Abelian Varieties II --- Compactifications and etc.

2006/06/28

Number Theory Seminar

16:30-17:30   Room #117 (Graduate School of Math. Sci. Bldg.)

Configuration of the central streams in the moduli of abelian varieties

Mathematical Finance

17:30-19:00   Room #118 (Graduate School of Math. Sci. Bldg.)

PDE Real Analysis Seminar

10:30-11:30   Room #056 (Graduate School of Math. Sci. Bldg.)
Jian Zhai (Zhejiang University)
Uniqueness of Constant Anisotropic Mean Curvature Immersion of Sphere $S^2$ In $\\Bbb E^3$
[ Abstract ]
We prove that the constant anisotropic mean curvature immersion of sphere $S^2$ in $\\Bbb E^3$ is unique, provided that the energy density function $\\gamma$ satisfies some reasonable assumptions.

2006/06/27

Tuesday Seminar on Topology

16:30-18:00   Room #056 (Graduate School of Math. Sci. Bldg.)
Cedric Tarquini (Ecole Nomale Superieure of Lyon)
Lorentzian foliations on 3-manifolds
[ Abstract ]
a joint work with C. Boubel (Ecole Nomale Superieure of Lyon) and P. Mounoud (University of Bordeaux 1 sciences and technologies)

The aim of this work is to give a classification of transversely Lorentzian one dimensional foliations on compact manifolds of dimension three. There are the foliations which admit a transverse pseudo-Riemanniann metric of index one. It is the Lorentzian analogue of the better known Riemannian foliations and they still have rigid transverse geometry.

The Riemannian case was listed by Y. Carriere and we will see that the Lorentzian one is very different and much more complicated to classify. The difference comes form the fact that the completness of the transverse structure, which is automatic in the Riemannian case, is a very strong hypothesis for a transverse Lorentzian foliation.

We will give a classification of complete Lorentzian foliations and some examples which are not complete. As a natural corollary of this classification we will list the codimension one timelike geodesically complete totally geodesic foliations of Lorentzian compact three manifolds.

2006/06/26

Seminar on Geometric Complex Analysis

10:30-12:00   Room #128 (Graduate School of Math. Sci. Bldg.)

Toward construction of Green current for modular cycles in modular varieties

2006/06/23

Colloquium

17:00-18:00   Room #123 (Graduate School of Math. Sci. Bldg.)
Robert Gompf (University of Texas at Austin)
25 years of exotic $\\mathbb{R}^4s$
[ Abstract ]
A quarter century ago, 4-manifold theory was revolutionized by the Fields-Medal winning breakthroughs of Freedman and Donaldson, with Freedman showing that topological 4-manifolds behave like their higher dimensional counterparts, but Donaldson showing that smooth 4-manifolds behave in a completely different way. The interplay between these theories produces results unique to dimension 4: A fixed topological 4-manifold often admits infinitely many distinct smooth structures, for which no classification scheme is yet available. The quintessential example is that in contrast with other dimensions, Euclidean 4-space admits exotic smooth structures. That is, there are "exotic R^4s" homeomorphic to R4 but not diffeomorphic to it. We will survey what has been learned about these strange creatures in the last quarter century, and exhibit an explicit example.

2006/06/22

Operator Algebra Seminars

16:30-18:00   Room #052 (Graduate School of Math. Sci. Bldg.)
Detlev Buchholz (Univ. Göttingen)
Integrable models and operator algebras
[ Abstract ]
Recently, it has been possible to establish rigorously the existence of an abundance of 1+1-dimensional local nets of von Neumann algebras describing an interacting massive particle with factorizing scattering matrix. This novel approach is based on structural results in algebraic quantum field theory concerning the modular structure of such theories. It is thus complementary to the older methods of constructive quantum field theory and settles some longstanding questions in the context of integrable models (form-factor program). In this talk, a survey is given on basic ideas, results and perspectives of this promising new approach.

2006/06/21

Seminar on Probability and Statistics

16:20-17:30   Room #128 (Graduate School of Math. Sci. Bldg.)

Malliavin calculus applied to mathematical finance and a new formulation of the intgration-by-parts
[ Reference URL ]
http://www.ms.u-tokyo.ac.jp/~kengok/statseminar/2006/05.html

2006/06/19

Seminar on Geometric Complex Analysis

10:30-12:00   Room #128 (Graduate School of Math. Sci. Bldg.)

Deformations and smoothing of (generalized) holomorphic symplectic structures

2006/06/15

Applied Analysis

16:00-17:30   Room #056 (Graduate School of Math. Sci. Bldg.)
Mark Bowen (東京大学大学院数理科学研究科/日本学術振興会)
Spreading and draining in thin fluid films
[ Abstract ]
The surface tension driven flow of a thin fluid film arises in a number of contexts. In this talk, we will begin with an overview of thin film theory and present a number of examples from the natural sciences and industrial process engineering. Similarity solutions play an important role in understanding the dynamics of general thin film motion and we shall use them to investigate the dynamics of an archetypal (degenerate high-order parabolic) thin film equation. In this context, we will encounter self-similarity of the first and second kind, undertake an investigation of a four-dimensional phase space and discover a surprisingly rich set of stable sign-changing solutions for the intermediate asymptotics of a generalised problem.

2006/06/14

PDE Real Analysis Seminar

10:30-11:30   Room #056 (Graduate School of Math. Sci. Bldg.)
Qing-Ming Cheng (Saga University)
Bounds on eigenvalues of Dirichlet aplacian
[ Abstract ]
In this talk, I shall consider the eigenvalue problem of the Dirichlet Laplacian. I shall mention the Weyl asymptotic formula,
Polya conjecture and its partial solution. Furthermore, I shall talk about Bochner-Kac problem.
For universal inequalities for eigenvalues, I shall consider
conjectures of Payne, Polya and Weinberger and their development. In the final, I shall talk the universal bounds for eigenvalues as main part of my talk, which is my recent joint work with rofessor Yang.
[ Reference URL ]
http://coe.math.sci.hokudai.ac.jp/sympo/pde_ra/index.html

2006/06/13

Tuesday Seminar on Topology

16:30-18:00   Room #056 (Graduate School of Math. Sci. Bldg.)

A note on C1-moves
[ Abstract ]

Lie Groups and Representation Theory

16:30-18:00   Room #126 (Graduate School of Math. Sci. Bldg.)

[ Abstract ]

(1) 各λに対する $M_Θ(λ)$ の最小多項式の明示公式
(2) $M_Θ(λ)= M(λ)/I_Θ(λ)M(λ)$ が成り立つためのλの 必要十分条件

が得られた(これらは大島により g = gln の場合には既に得られている).セミナーでは(2)を示すための q(F) の各成分の Harish-Chandra 準同型像の計算法を主に説明する.

2006/06/12

Seminar on Geometric Complex Analysis

10:30-12:00   Room #128 (Graduate School of Math. Sci. Bldg.)

The Rumin complex and Hamiltonian mechanism
[ Reference URL ]
http://www.ms.u-tokyo.ac.jp/~hirachi/scv/akahori.pdf

2006/06/10

Infinite Analysis Seminar Tokyo

13:30-16:00   Room #117 (Graduate School of Math. Sci. Bldg.)
Boris Feigin (Landau Institute for Theoretical Physics) 13:30-14:30
"Critical" level for Vertex Algebras
[ Abstract ]
In the talk I present the construction of "VOA" on a critical level using fermionic screenings.Then I discuss the geometric background behind such algebras and applications - Langlands correspondence and related things

[ Abstract ]

2006/06/07

Infinite Analysis Seminar Tokyo

14:00-15:00   Room #270 (Graduate School of Math. Sci. Bldg.)
Youjin Zhang (Tsinghua Univ.)
On deformations of bihamiltonian structures of hydrodynamic type
[ Abstract ]
I will talk about the properties of deformations bihamiltonian structures of hydrodynamic type and the related integrable hierarchies, and the problem of classification of such deformations.

PDE Real Analysis Seminar

10:30-11:30   Room #056 (Graduate School of Math. Sci. Bldg.)

On phase boundary motion by surface diffusion with triple junction
[ Abstract ]
The phase boundary motion by a geometrical evolution law in a bounded domain is studied in this talk. We consider the surface diffusion flow equation, which has the gradient flow structure with respect to $H^{-1}$-inner product and the area-preserving property. This equation was derived by Mullins to model the motion of interfaces in the case that the motion of interfaces is governed purely by mass diffusion within the interfaces. We study the three-phase problem with triple junction in a bounded domain and analyze the stability of the stationary solutions for this problem.
[ Reference URL ]
http://coe.math.sci.hokudai.ac.jp/sympo/pde_ra/022.html