Seminar information archive
Seminar information archive ~04/27|Today's seminar 04/28 | Future seminars 04/29~
thesis presentations
thesis presentations
thesis presentations
2018/02/01
thesis presentations
thesis presentations
thesis presentations
thesis presentations
thesis presentations
thesis presentations
thesis presentations
thesis presentations
thesis presentations
thesis presentations
thesis presentations
thesis presentations
thesis presentations
thesis presentations
2018/01/30
Tuesday Seminar on Topology
Yuichi Ike (The University of Tokyo)
Persistence-like distance on Tamarkin's category and symplectic displacement energy (JAPANESE)
The microlocal sheaf theory due to Kashiwara and Schapira can be regarded as Morse theory with sheaf coefficients. Recently it has been applied to symplectic geometry, after the pioneering work of Tamarkin. In this talk, I will propose a new sheaf-theoretic method to estimate the displacement energy of compact subsets in cotangent bundles. In the course of the proof, we introduce a persistence-like pseudo-distance on Tamarkin's sheaf category. This is a joint work with Tomohiro Asano.
2018/01/29
Operator Algebra Seminars
Michiya Mori (Univ. Tokyo)
Tingley's problem for operator algebras
Tokyo Probability Seminar
Kazuhiro Kuwae (Department of Applied Mathematics, Faculty of Science, Fukuoka University)
(JAPANESE)
2018/01/26
Colloquium
Yuta Koike (Univ. Tokyo)
(JAPANESE)
Algebraic Geometry Seminar
Hiromichi Takagi (The University of Tokyo)
On classification of prime Q-Fano 3-folds with only 1/2(1,1,1)-singularities and of genus less than 2
I classified prime Q-Fano threefolds with only 1/2(1,1,1)-singularities and of genus greater than 1 (2002, Nagoya Math. J.).
In this talk, I will explain how the method in that paper can be extended to the case of genus less than 2. The method is so called two ray game. By this method, I can classify the possibilities of such Q-Fano's. The classification is not yet completed since constructions of examples in certain cases are difficult. I will also explain some pretty examples in this talk.
2018/01/25
FMSP Lectures
Norbert A'Campo (University of Basel)
NUMERICAL ANALYSIS, COBORDISM OF MANIFOLDS AND MONODROMY. (ENGLISH)
http://fmsp.ms.u-tokyo.ac.jp/FMSPLectures_ACampo_abst.pdf
http://fmsp.ms.u-tokyo.ac.jp/FMSPLectures_ACampo.pdf
2018/01/23
Tuesday Seminar on Topology
Yuta Nozaki (The University of Tokyo)
An invariant of 3-manifolds via homology cobordisms (JAPANESE)
For a closed 3-manifold X, we consider the topological invariant defined as the minimal integer g such that X is obtained as the closure of a homology cobordism over a surface of genus g. We prove that the invariant equals one for every lens space, which is contrast to the fact that some lens spaces do not admit any open book decomposition whose page is a surface of genus one. The proof is based on the Chebotarev density theorem and binary quadratic forms in number theory.
Tuesday Seminar on Topology
Junha Tanaka (The University of Tokyo)
Wrapping projections and decompositions of Keinian groups (JAPANESE)
Let $S$ be a closed surface of genus $g ¥geq 2$. The deformation space $AH(S)$ consists of (conjugacy classes of) discrete faithful representations $\rho:\pi_{1}(S) \to PSL_{2}(\mathbb{C})$.
McMullen, and Bromberg and Holt showed that $AH(S)$ can self-bump, that is, the interior of $AH(S)$ has the self-intersecting closure.
Both of them demonstrated the existence of self-bumping under the exisetence of a non-trivial wrapping projections from an algebraic limits to a geometric limits which wraps an annulus cusp into a torus cusp.
In this talk, given a representation $\rho$ at the boundary of $AH(S)$, we characterize a wrapping projection to a geometric limit associated to $\rho$, by the information of the actions of decomposed Kleinian groups of the image of $\rho$.
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