Seminar information archive

Seminar information archive ~08/17Today's seminar 08/18 | Future seminars 08/19~

FMSP Lectures

15:30-17:00   Room #Lecture Hall, Kavli IPMU (Graduate School of Math. Sci. Bldg.)
Alan Weinstein (University of California, Berkeley)
Lecture 1: Special subspaces in symplectic vector spaces (ENGLISH)
[ Reference URL ]
http://fmsp.ms.u-tokyo.ac.jp/FMSPLectures_Weinstein.pdf

Seminar on Geometric Complex Analysis

10:30-12:00   Room #128 (Graduate School of Math. Sci. Bldg.)
Taro Asuke (The University of Tokyo)
Defining the Julia sets on CP^2 (JAPANESE)
[ Abstract ]
The Julia sets play a central role in the study of complex dynamical systems as well as Kleinian groups where they appear as limit sets. They are also known to be meaningful for complex foliations without singularities, however still not defined for singular ones. In this talk, I will discuss some expected properties of the Julia sets for singular foliations and difficulties for defining them.

2016/04/08

Colloquium

15:30-16:30   Room #123 (Graduate School of Math. Sci. Bldg.)
François Apery (l'IRMA à Strasbourg)
Using mathematical objects (ENGLISH)
[ Abstract ]
Mathematical models are not only teaching tools or pieces of museum but can also have inspiring influence to discovering new truths in mathematics. Through some examples including the Boy surface we will show how models have played a major role in the emergence of new results.

2016/04/05

Tuesday Seminar on Topology

17:00-18:30   Room #056 (Graduate School of Math. Sci. Bldg.)
Takahiro Kitayama (The University of Tokyo)
Torsion invariants and representation varieties for non-positively curved cube complexes (JAPANESE)
[ Abstract ]
Applications of torsion invariants and representation varieties have been extensively studied for 3-manifolds. Twisted Alexander polynomials are known to detect the Thurston norm and fiberedness of a 3-manifold. Ideal points of character varieties are known to detect essential surfaces in a 3-manifold in a certain extension of Culler-Shalen theory. In view of cubulation of 3-manifolds one can expect that these results naturally extend to a wider framework and, in particular, the case of virtually special cube complexes. We formulate and discuss such analogous questions for non-positively curved cube complexes.

2016/04/04

Numerical Analysis Seminar

16:30-18:00   Room #056 (Graduate School of Math. Sci. Bldg.)
Eric Chung (Chinese University of Hong Kong)
Staggered discontinuous Galerkin methods for the incompressible Navier-Stokes equations (English)
[ Abstract ]
In this talk, we present a staggered discontinuous Galerkin method for the approximation of the incompressible Navier-Stokes equations. Our new method combines the advantages of discontinuous Galerkin methods and staggered meshes, and results in many good properties, namely local and global conservations, optimal convergence and superconvergence through the use of a local postprocessing technique. Another key feature is that our method provides a skew-symmetric discretization of the convection term, with the aim of giving a better conservation property compared with existing discretizations. We also analyze the stability and convergence of the method. In addition, we will present some numerical results to show the performance of the proposed method.

2016/03/29

Number Theory Seminar

17:30-18:30   Room #002 (Graduate School of Math. Sci. Bldg.)
Matthew Morrow (Universität Bonn)
Motivic cohomology of formal schemes in characteristic p
(English)
[ Abstract ]
The logarithmic Hodge-Witt sheaves of Illusie, Milne, Kato, et al. of a smooth variety in characteristic p provide a concrete realisation of its p-adic motivic cohomology, thanks to results of Geisser-Levine and Bloch-Kato-Gabber which link them to algebraic K-theory. I will explain an analogous theory for formal schemes, as well as applications to algebraic cycles, such as a weak Lefschetz theorem for formal Chow groups.

2016/03/22

Colloquium

16:50-17:50   Room #大講義室 (Graduate School of Math. Sci. Bldg.)
Shihoko Ishii  (Graduate School of Mathematical Sciences, University of Tokyo)
Singularities and Jet schemes (JAPANESE)
[ Reference URL ]
http://faculty.ms.u-tokyo.ac.jp/~shihoko/

FMSP Lectures

10:00-11:00   Room #118 (Graduate School of Math. Sci. Bldg.)
Fatiha Alabau (Université de Lorraine)
Control and stabilization of degenerate wave equations (ENGLISH)
[ Abstract ]
The control of degenerate PDE's arise in many applications such as cloaking, climatology, population genetics, and vision.
For such models, the diffusion operator degenerates on some subset of the spatial domain. We present some recent results on observability, control and stabilization of these equations.
This is a joint work with Piermarco Cannarsa (University di Roma Tor Vergata, Italy) and G\"unter Leugering (Friedrich-Alexander-Universit\"at Erlangen-N\"urnberg, Erlangen, Germany).
[ Reference URL ]
http://fmsp.ms.u-tokyo.ac.jp/FMSPLectures_Alabau.pdf

FMSP Lectures

11:00-12:00   Room #118 (Graduate School of Math. Sci. Bldg.)
Mourad Bellassoued (Université de Tunis El Manar)
Stable determination of coefficients in the dynamical Schrödinger equation in a magnetic field (ENGLISH)
[ Reference URL ]
http://fmsp.ms.u-tokyo.ac.jp/FMSPLectures_Bellassoued.pdf

2016/03/19

FMSP Lectures

11:00-12:00   Room #370 (Graduate School of Math. Sci. Bldg.)
Oleg Emanouilov (Colorado State Univ.)
About the Landis conjecture (ENGLISH)
[ Reference URL ]
http://fmsp.ms.u-tokyo.ac.jp/FMSPLectures_Emanouilov160319.pdf

2016/03/18

FMSP Lectures

14:30-15:30   Room #118 (Graduate School of Math. Sci. Bldg.)
Piermarco Cannarsa (Università degli Studi di Roma Tor Vergata)
Control of degenerate parabolic equations: old and new (ENGLISH)
[ Abstract ]
This talk will survey the main results obtained in the last fifteen years or so for the null controllability of degenerate parabolic operators.
We shall describe the state of the art for operators which degenerate at the boundary as well as for certain classes of interior degeneracy of hypoelliptic type.
[ Reference URL ]
http://fmsp.ms.u-tokyo.ac.jp/FMSPLectures_Cannarsa.pdf

2016/03/16

PDE Real Analysis Seminar

16:00-17:00   Room #056 (Graduate School of Math. Sci. Bldg.)
Boris Khesin (University of Toronto)
Fluids, vortex membranes, and skew-mean-curvature flows (English)
[ Abstract ]
We show that an approximation of the hydrodynamical Euler equation describes the skew-mean-curvature flow on vortex membranes in any dimension. This generalizes the classical binormal, or vortex filament, equation in 3D. We present a Hamiltonian framework for dynamics of higher-dimensional vortex filaments and vortex sheets as singular 2-forms (Green currents) with support of codimensions 2 and 1, respectively.

2016/03/11

Operator Algebra Seminars

16:45-18:15   Room #118 (Graduate School of Math. Sci. Bldg.)
Bas Jordans (Univ. Oslo)
Convergence to the boundary for random walks on discrete quantum groups
(English)

2016/03/08

Operator Algebra Seminars

16:45-18:15   Room #118 (Graduate School of Math. Sci. Bldg.)
Roberto Longo (Univ. Rome "Tor Vergata")
Equilibrium and non-equilibrium states in Conformal Field Theory (英語)

2016/02/22

FMSP Lectures

17:00-18:00   Room #118 (Graduate School of Math. Sci. Bldg.)
Michel Cristofol (Aix-Marseille Univ.)
Inverse problems for parabolic operators : comparison of three different approaches (ENGLISH)
[ Abstract ]
Basing my talk around a toy problem : reconstruction of the potential for a linear parabolic problem, I will recall the two main classical following methods : Dirichlet to Neumann map and Carleman estimates. Then I will present a different and recent approach based on pointwise observations and I will underline some points to be improved for each method. Then, I will finish my talk by a review of some results related to this technic of pointwise observations.
[ Reference URL ]
http://fmsp.ms.u-tokyo.ac.jp/FMSPLectures_Cristofol.pdf

2016/02/19

FMSP Lectures

10:30-11:30   Room #118 (Graduate School of Math. Sci. Bldg.)
Olivier Poisson (Aix-Marseille University)
Recovering time-dependent inclusion in heat conductive bodies by a dynamical probe method (ENGLISH)
[ Abstract ]
Many articles solve a version of the Calder'on inverse problem for the heat equation. The biggest part of them assume that the unknown conductivity do not depend on time t. But they are very few results concerning the time de- pendent situation, and they are based on the computation of an ansatz for the parabolic equation:
- A reconstruction method of an unknown moving inclusion by a dynamical probe method was performed by Daido-Kang-Nakamura in 2007, but it works for the one dimensional spatial space only,
- An energy estimate for x-multidimensional convex inclusions.
In the talk I will present a dynamical probe method based on special fundamental solutions of the heat equation and basic inequalities :
this approach is very close to the probe method for the elliptic Calderon inverse problem, and does not require regularity of the inclusion.
[ Reference URL ]
http://fmsp.ms.u-tokyo.ac.jp/FMSPLectures_Poisson.pdf

2016/02/18

FMSP Lectures

10:00-11:00   Room #002 (Graduate School of Math. Sci. Bldg.)
Dror Varolin (Stony Brook)
L^2 Extension and its applications: A survey (3) (ENGLISH)
[ Abstract ]
We discuss certain aspects of the theory of L^2 extension, going back to the famous and fundamental work of Ohsawa and Takegoshi, and even further back to work of Donnelly and Fefferman.
The first of three lectures will recall a number of L^2 extension theorems, to some extent following an incomplete history (as I see it), and ending with a sketch of a proof of one of these theorems.
The second lecture will discuss a number of my favorite applications of L^2 extension, from Bergman kernels to deformation invariance of plurigenera.
The third lecture will discuss a new proof of the extension theorem, due to Berndtsson and Lempert. The key tool is a theorem of Berndtsson on the positivity of direct images, which we will review. Berndtsson's theorem permits the introduction of degeneration techniques, whose surprising application to L^2 extension represents one of the most beautiful and fundamental recent breakthroughs in the subject.
[ Reference URL ]
http://fmsp.ms.u-tokyo.ac.jp/FMSPLectures_Varolin.pdf

FMSP Lectures

10:30-11:30   Room #118 (Graduate School of Math. Sci. Bldg.)
Michel Cristofol (Aix-Marseille Univ.)
Inverse boundary value problem for a hyperbolic equation in an infinite guide (ENGLISH)
[ Abstract ]
We consider the multidimensional inverse problem of determining the conductivity coefficient of a hyperbolic equation in an infinite cylindrical domain, from a single boundary observation of the solution. We prove Holder stability with the aid of a Carleman estimate specially designed for hyperbolic waveguides. I will provide numerical simulations in multiple backgrounds.
[ Reference URL ]
http://fmsp.ms.u-tokyo.ac.jp/FMSPLectures_Cristofol.pdf

2016/02/17

FMSP Lectures

10:00-11:00   Room #002 (Graduate School of Math. Sci. Bldg.)
Dror Varolin (Stony Brook)
L^2 Extension and its applications: A survey (2) (ENGLISH)
[ Abstract ]
We discuss certain aspects of the theory of L^2 extension, going back to the famous and fundamental work of Ohsawa and Takegoshi, and even further back to work of Donnelly and Fefferman.
The first of three lectures will recall a number of L^2 extension theorems, to some extent following an incomplete history (as I see it), and ending with a sketch of a proof of one of these theorems.
The second lecture will discuss a number of my favorite applications of L^2 extension, from Bergman kernels to deformation invariance of plurigenera.
The third lecture will discuss a new proof of the extension theorem, due to Berndtsson and Lempert. The key tool is a theorem of Berndtsson on the positivity of direct images, which we will review. Berndtsson's theorem permits the introduction of degeneration techniques, whose surprising application to L^2 extension represents one of the most beautiful and fundamental recent breakthroughs in the subject.
[ Reference URL ]
http://fmsp.ms.u-tokyo.ac.jp/FMSPLectures_Varolin.pdf

2016/02/16

Tuesday Seminar on Topology

17:00-18:30   Room #056 (Graduate School of Math. Sci. Bldg.)
Luc Menichi (University of Angers)
String Topology, Euler Class and TNCZ free loop fibrations (ENGLISH)
[ Abstract ]
Let $M$ be a connected, closed oriented manifold.
Chas and Sullivan have defined a loop product and a loop coproduct on
$H_*(LM;¥mathbb{F})$, the homology of the
free loops on $M$ with coefficients in the field $¥mathbb{F}$.
By studying this loop coproduct, I will show that if the free loop
fibration
$¥Omega M¥buildrel{i}¥over¥hookrightarrow
LM¥buildrel{ev}¥over¥twoheadrightarrow M$
is homologically trivial, i.e. $i^*:H^*(LM;¥mathbb{F})¥twoheadrightarrow
H^*(¥Omega M;¥mathbb{F})$ is onto,
then the Euler characteristic of $M$ is divisible by the characteristic
of the field $¥mathbb{F}$
(or $M$ is a point).

FMSP Lectures

10:00-11:00   Room #002 (Graduate School of Math. Sci. Bldg.)
Dror Varolin (Stony Brook)
L^2 Extension and its applications: A survey (1) (ENGLISH)
[ Abstract ]
We discuss certain aspects of the theory of L^2 extension, going back to the famous and fundamental work of Ohsawa and Takegoshi, and even further back to work of Donnelly and Fefferman.
The first of three lectures will recall a number of L^2 extension theorems, to some extent following an incomplete history (as I see it), and ending with a sketch of a proof of one of these theorems.
The second lecture will discuss a number of my favorite applications of L^2 extension, from Bergman kernels to deformation invariance of plurigenera.
The third lecture will discuss a new proof of the extension theorem, due to Berndtsson and Lempert. The key tool is a theorem of Berndtsson on the positivity of direct images, which we will review. Berndtsson's theorem permits the introduction of degeneration techniques, whose surprising application to L^2 extension represents one of the most beautiful and fundamental recent breakthroughs in the subject.
[ Reference URL ]
http://fmsp.ms.u-tokyo.ac.jp/FMSPLectures_Varolin.pdf

FMSP Lectures

16:00-17:00   Room #270 (Graduate School of Math. Sci. Bldg.)
Patricia Gaitan (Aix-Marseille University)
Inverse Problem for an Hyperbolic-Parabolic System and Perspectives (ENGLISH)
[ Reference URL ]
http://fmsp.ms.u-tokyo.ac.jp/FMSPLectures_Gaitan160216.pdf

2016/02/15

FMSP Lectures

17:00-18:00   Room #118 (Graduate School of Math. Sci. Bldg.)
Patricia Gaitan (Aix-Marseille University)
Probing for inclusions for heat conductive bodies time independent and time dependent cases (ENGLISH)
[ Reference URL ]
http://fmsp.ms.u-tokyo.ac.jp/FMSPLectures_Gaitan.pdf

2016/02/08

Tokyo Probability Seminar

16:50-18:20   Room #128 (Graduate School of Math. Sci. Bldg.)
Hirofumi Osada (Graduate School of Mathematics, Kyushu University)
Dynamical rigidity of stochastic Coulomb systems

Infinite Analysis Seminar Tokyo

13:30-15:00   Room #002 (Graduate School of Math. Sci. Bldg.)
Vincent Pasquier (IPhT Saclay)
q-Bosons, Toda lattice and Baxter Q-Operator (ENGLISH)
[ Abstract ]
I will use the Pieri rules of the Hall Littlewood polynomials to construct some
lattice models, namely the q-Boson model and the Toda Lattice Q matrix.
I will identify the semi infinite chain transfer matrix of these models with well known
half vertex operators. Finally, I will explain how the Gaudin determinant appears in the evaluation
of the semi infine chain scalar products for an arbitrary spin and is related to the Macdonald polynomials.

< Previous 123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138 Next >