過去の記録 ~02/27本日 02/28 | 今後の予定 02/29~



16:30-18:00   数理科学研究科棟(駒場) 056号室
Tea: 16:00 - 16:30 コモンルーム
今城 洋亮 氏 (Kavli IPMU)
Singularities of special Lagrangian submanifolds (JAPANESE)
[ 講演概要 ]
There are interesting invariants defined by "counting" geometric
objects, such as instantons in dimension 4 and pseudo-holomorphic curves
in symplectic manifolds. To do the counting in a sensible way, however,
we have to care about singularities of the geometric objects. Special
Lagrangian submanifolds seem very difficult to "count" as their
singularities may be very complicated. I'll talk about simple
singularities for which we can make an analogy with instantons in
dimension 4 and pseudo-holomorphic curves in symplectic manifolds. To do
it I'll use some techniques from geometric measure theory and Lagrangian
Floer theory, and the Floer-theoretic part is a joint work with Dominic
Joyce and Oliveira dos Santos.


16:30-18:00   数理科学研究科棟(駒場) 126号室
Pablo Ramacher
(Marburg University)
[ 講演概要 ]
Let G be a connected reductive complex algebraic group with split real form $G^\\sigma$.
In this talk, we introduce a distribution character for the regular representation of $G^\\sigma$ on the real locus of a strict wonderful G-variety X, showing that on a certain open subset of $G^\\sigma$ of transversal elements it is locally integrable, and given by a sum over fixed points.



10:30-12:00   数理科学研究科棟(駒場) 126号室
小木曽啓示 氏 (大阪大学)
Primitive automorphisms of positive entropy of rational and Calabi-Yau threefolds (JAPANESE)


15:30-17:00   数理科学研究科棟(駒場) 122号室
三内顕義 氏 (東京大学数理科学研究科)
Invariant subrings of the Cox rings of K3surfaces by automorphism groups (JAPANESE)
[ 講演概要 ]
Cox rings were introduced by D.Cox and are important rings which appeared in algebraic geometry. One of the main topic related with Cox rings is the finite generation of them. In this talk, we consider the Cox rings of K3 surfaces and answer the following question asked by D. Huybrechts; Are the invariant subrings of the Cox rings of K3 surfaces by automorphism groups finitely generated in general?

Kavli IPMU Komaba Seminar

16:30-18:00   数理科学研究科棟(駒場) 002号室
Anatol Kirillov 氏 (RIMS, Kyoto University)
On some quadratic algebras with applications to Topology,
Algebra, Combinatorics, Schubert Calculus and Integrable Systems. (ENGLISH)
[ 講演概要 ]
The main purpose of my talk is to draw attention of the
participants of the seminar to a certain family of quadratic algebras
which has a wide range of applications to the subject mentioned in the
title of my talk.



13:30-17:00   数理科学研究科棟(駒場) 128号室
Neal Bez 氏 (埼玉大学) 13:30-15:00
On the multilinear restriction problem (ENGLISH)
[ 講演概要 ]
I will discuss the multilinear restriction problem for the Fourier transform. This will include an overview of the pioneering work of Bennett, Carbery and Tao on this problem and the very losely connected multilinear Kakeya problem. I will also discuss some of my own work in this area which is connected to nonlinear Brascamp-Lieb inequalities (joint work with Jonathan Bennett).
Hong Yue 氏 (Georgia College and State University) 15:30-17:00
John-Nirenberg lemmas for a doubling measure (ENGLISH)
[ 講演概要 ]
We study, in the context of doubling metric measure spaces, a class of BMO type functions defined by John and Nirenberg. In particular, we present a new version of the Calderon-Zygmund decomposition in metric spaces and use it to prove the corresponding John-Nirenberg inequality.



10:00-11:30   数理科学研究科棟(駒場) 122号室
開始時間と開催場所などは変更されることがあるので, セミナーごとにご確認ください.
桑田和正 氏 (東京工業大学)
Entropic curvature-dimension condition and Bochner’s inequality (JAPANESE)
[ 講演概要 ]
As a characterization of "lower Ricci curvature bound and upper dimension bound”, there appear several conditions which make sense even on singular spaces. In this talk we show the equivalence in complete generality between two major conditions: a reduced version of curvature-dimension bounds of Sturm-Lott-Villani via entropy and optimal transport and Bakry–¥'Emery's one via Markov generator or the associated heat semigroup. More precisely, it holds for metric measure spaces where Cheeger's L^2-energy functional is a quadratic form. In particular, we establish the full Bochner inequality, which originally comes from the Bochner-Weitzenb¥"ock formula, on such spaces. This talk is based on a joint work with M. Erbar and K.-T. Sturm (Bonn).



16:45-18:00   数理科学研究科棟(駒場) 122号室
守屋創 氏 (芝浦工大)
Supersymmetric C*-dynamical systems (JAPANESE)


14:50-16:20   数理科学研究科棟(駒場) 128号室
中岡 慎治 氏 (RIKEN Center for Integrative Medical Sciences)
T 細胞による腫瘍免疫の数理モデル (JAPANESE)
[ 講演概要 ]
ならず、癌の除去にも貢献している。T リンパ球の集団は非自己(外来抗原)と自
T 細胞による認識が充分でないと考えられる。また、免疫応答は複数段階の複雑

本講演では、T 細胞を体外で癌由来抗原を認識させて活性化してから体内に戻す
を攻撃する T 細胞の増殖を表す関数型を3タイプ想定し、それぞれに対して解
解釈が可能である。これまでに得られた数理解析結果を中心に報告する [1] 。時間が
てて、マルチスケール数理モデルを用いたアプローチ [2] について話題提供をして


16:40-17:40   数理科学研究科棟(駒場) 056号室
滝口 正彦 氏 (東京大学数理科学研究科)
Periods of some two dimensional reducible p-adic representations and non-de Rham B-pairs (JAPANESE)



10:30-11:30   数理科学研究科棟(駒場) 056号室
Piotr Rybka 氏 (University of Warsaw)
Sudden directional diffusion: counting and watching facets (ENGLISH)
[ 講演概要 ]
We study two examples of singular parabolic equations such that the diffusion is so strong that is leads to creation of facets. By facets we mean flat parts of the graphs of solutions with singular slopes. In one of the equations we study there are two singular slopes. The other equation has just one singular slope and the isotropic diffusion term. For both problems we watch and count facet.

For the system with two singular slopes a natural question arises if any solution may have an infinite number of oscillations. We also show that the solutions we constructed are viscosity solutions. This in turn gives estimates on the extinction time based on the comparison principle.


17:10-18:10   数理科学研究科棟(駒場) 056号室
Tea: 16:50 - 17:10 コモンルーム
野坂 武史 氏 (九州大学数理学研究院)
On third homologies of quandles and of groups via Inoue-Kabaya map (JAPANESE)
[ 講演概要 ]
In this talk, we demonstrate certain quandles, which are defined from a
group $G$ and an isomorphism $¥rho:G - G$, and introduce the following
results: First, "Inoue-Kabaya chain map" is formulated as a map from
quandle homology to group homology. For example, with respect to every
Alexander quandle over F_q, the all of Mochizuki 3-cocycle is derived
from some group 3-cocycle, and mostly interpreted by a Massey products.
In addition, for universal centrally extended quandles, the chain map
induces an isomorphism between the 3-rd homologies (up to certain
torsion parts).


16:00-17:30   数理科学研究科棟(駒場) 122号室
西岡斉治 氏 (山形大学)
[ 講演概要 ]



10:30-12:00   数理科学研究科棟(駒場) 126号室
野口潤次郎 氏 (東京大学)
岡の第1連接定理の証明に於ける割り算法についての一注意 (JAPANESE)
[ 講演概要 ]
The problem is the local finite generation of a relation sheaf $R(f_1, \ldots, f_q)$ in $\mathcal{O}_n=\mathcal{O}_{C^n}$. After $f_j$ reduced to Weierstrass' polynomials in $z_n$, it is the key to apply the induction in $n$ to show that elements of $R(f_1, \ldots, q)$ are expressed by $z_n$-polynomial-like elements of degree at most $p=\max_j\deg f_j$ over $\mathcal{O}_n$. In that proof one is used to use a divison by $f_j$ of $\deg f_j=p$ (Oka '48, Cartan '50, Hörmander, Demailly, . . .). In this talk we shall confirm that the division abve works by making use of $f_k$ of the minimum degree $\min_j \deg f_j$. This proof is natrually compatible with the simple case when some $f_j$ is a unit, and gives some improvement in the degree estimate of generators.



10:00-11:30   数理科学研究科棟(駒場) 122号室
開始時間と開催場所などは変更されることがあるので, セミナーごとにご確認ください.
酒井 高司 氏 (首都大学東京)
Antipodal structure of the intersection of real forms and its applications (JAPANESE)
[ 講演概要 ]
A subset A of a Riemannian symmetric space is called an antipodal set if the geodesic symmetry s_x fixes all points of A for each x in A. This notion was first introduced by Chen and Nagano. Tanaka and Tasaki proved that the intersection of two real forms L_1 and L_2 in a Hermitian symmetric space of compact type is an antipodal set of L_1 and L_2. As an application, we calculate the Lagrangian Floer homology of a pair of real forms in a monotone Hermitian symmetric space. Then we obtain a generalization of the Arnold-Givental inequality. We expect to generalize the above results to the case of complex flag manifolds. In fact, using the k-symmetric structure, we can describe an antipodal set of a complex flag manifold. Moreover we can observe the antipodal structure of the intersection of certain real forms in a complex flag manifold.

This talk is based on a joint work with Hiroshi Iriyeh and Hiroyuki Tasaki.



16:30-18:00   数理科学研究科棟(駒場) 122号室
荒野悠輝 氏 (東大数理)
Toward the classification of irreducible unitary spherical representations of the Drinfeld double of $SU_q(3)$ (ENGLISH)



16:30-18:00   数理科学研究科棟(駒場) 002号室
Tea: 16:00 - 16:30 コモンルーム
松田 能文 氏 (青山学院大学)
2次元軌道体群の円周への作用の有界オイラー数 (JAPANESE)
[ 講演概要 ]


17:30-18:30   数理科学研究科棟(駒場) 056号室
Bao Châu Ngô 氏 (University of Chicago, VIASM)
Vinberg's monoid and automorphic L-functions (ENGLISH)
[ 講演概要 ]
We will explain a generalisation of the construction of the local factors of Godement-Jacquet's L-functions, based on Vinberg's monoid.

(本講演は「東京北京パリ数論幾何セミナー」として, インターネットによる東大数理, Morningside Center of MathematicsとIHESの双方向同時中継で行います.)


16:30-18:00   数理科学研究科棟(駒場) 126号室
Pablo Ramacher 氏 (Marburg University)
[ 講演概要 ]
Let M be a smooth manifold and G a compact connected Lie group acting on M by isometries. In this talk, we study the equivariant cohomology of the cotangent bundle of M, and relate it to the cohomology of the Marsden-Weinstein reduced space via certain residue formulae. In case of compact symplectic manifolds with a Hamiltonian G-action, similar residue formulae were derived by Jeffrey, Kirwan et al..



10:30-12:00   数理科学研究科棟(駒場) 126号室
伊師英之 氏 (名古屋大学)
非等質ジーゲル領域の荷重ベルグマン核の新しい例 (JAPANESE)

Kavli IPMU Komaba Seminar

16:30-18:00   数理科学研究科棟(駒場) 002号室
A.P. Veselov 氏 (Loughborough, UK and Tokyo)
Universal formulae for Lie groups and Chern-Simons theory (ENGLISH)
[ 講演概要 ]
In 1990s Vogel introduced an interesting parametrization of simple
Lie algebras by 3 parameters defined up to a common multiple and
permutations. Numerical characteristic is called universal if it can be
expressed in terms of Vogel's parameters (example - the dimension of Lie
algebra). I will discuss some universal formulae for Lie groups
and Chern-Simons theory on 3D sphere.
The talk is based on joint work with R.L. Mkrtchyan and A.N. Sergeev.



16:30-18:00   数理科学研究科棟(駒場) 118号室
窪田陽介 氏 (東大数理)
Finiteness of K-area and the dual of the Baum-Connes conjecture (ENGLISH)


14:50-16:20   数理科学研究科棟(駒場) 128号室
小林 徹也 氏 (東京大学生産技術研究所 統合バイオメディカル国際研究センター)
個体群ダイナミクスの経路積分表現と変分構造 (JAPANESE)
[ 講演概要 ]
本研究は、杉山 友規氏との共同研究である。



14:40-16:10   数理科学研究科棟(駒場) 056号室
Sergei Duzhin 氏 (Steklov Institute of Mathematics)
Bipartite knots (ENGLISH)
[ 講演概要 ]
We give a solution to a part of Problem 1.60 in Kirby's list of open
problems in topology thus proving a conjecture raised in 1987 by
J.Przytycki. A knot is said to be bipartite if it has a "matched" diagram,
that is, a plane diagram that has an even number of crossings which can be
split into pairs that look like a simple braid on two strands with two
crossings. The conjecture was that there exist knots that do not have such
diagrams. I will prove this fact using higher Alexander ideals.
This talk is based on a joint work with my student M.Shkolnikov


10:30-11:30   数理科学研究科棟(駒場) 056号室
木村 芳文 氏 (名古屋大学多元数理科学研究科)
The self-similar collapse solution of a point vortex system and complex time singularities (JAPANESE)
[ 講演概要 ]
A system of N point vortices is a Hamiltonian dynamical system with N degrees of freedom,and it is known that under certain parameter and initial conditions, there are self-similar collapse solutions for which N vortices collide at a point while rotating without changing the initial shape of configuration. In this talk, I will introduce such collision solutions and discuss some properties of complex time singularities in relation with those solutions.

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