Seminar information archive
Seminar information archive ~02/12|Today's seminar 02/13 | Future seminars 02/14~
2022/03/08
Lie Groups and Representation Theory
Masatoshi Kitagawa (Waseda University)
On the structure of Hamiltonian G-varieties (Japanese)
I will talk about a result by I. Losev (Math. Z. 2009) on the structure of Hamiltonian G-varieties.
In particular, I will explain how to reduce the result to central-nilpotent cases.
I will give an application of the result to branching laws.
2022/02/22
Lie Groups and Representation Theory
Hiroyoshi Tamori (Hokkaido University)
On a long exact sequence of the Schwartz homology (Japanese)
For a smooth Fr\’{e}chet representation of moderate growth of an almost linear Nash group, Chen-Sun introduced a homology (called Schwartz homology) equipped with certain topology. Given a short exact sequence of such representations, we can construct a long exact sequence of Schwartz homology groups via the natural isomorphism with relative Lie algebra homology. We give an example of a long exact sequence where the connecting homomorphism is not continuous.
2022/02/16
Seminar on Probability and Statistics
Teppei Ogihara (University of Tokyo)
Efficient estimation for ergodic jump-diffusion processes
Asia-Pacific Seminar in Probability and Statistics (APSPS)
https://sites.google.com/view/apsps/home
We study the estimation problem of the parametric model for ergodic jump-diffusion processes. Shimizu and Yoshida (Stat. Inference Stoch. Process. 2006) proposed a quasi-maximum-likelihood estimator based on a thresholding likelihood function that detects the existence of jumps.
In this talk, we consider the efficiency of estimators by using local asymptotic normality (LAN). To show the LAN property, we need to specify the asymptotic behavior of log-likelihood ratios, which is complicated for the jump-diffusion model because the transition probability for no jump is quite different from that for the presence of jumps. We develop techniques to show the LAN property based on transition density approximation. By applying these techniques to the thresholding likelihood function, we obtain the LAN property for the jump-diffusion model. Moreover, we have the asymptotic efficiency of
the quasi-maximum-likelihood estimator in Shimizu and Yoshida (2006) and a Bayes-type estimator proposed in Ogihara and Yoshida (Stat.Inference Stoch. Process. 2011). This is a joint work with Yuma Uehara (Kansai University).
https://docs.google.com/forms/d/e/1FAIpQLSeRTEo19DJgFiVsEpLrRapqzkL6LZAiUMGdA0ezK-nWYSPrGg/viewform
2022/02/15
Lie Groups and Representation Theory
Kazuki Kannaka (RIKEN iTHEMS)
Deformations of standard compact Clifford-Klein forms (Japanese)
Let Γ be a discontinuous group for a homogeneous manifold G/H of reductive type.
The Clifford-Klein form Γ\G/H is standard if Γ is contained in a reductive subgroup of G acting properly on G/H.
For 12 series of standard compact Clifford-Klein forms given by Kobayashi-Yoshino, we discuss in this talk whether or not there exist (1) locally rigid ones, (2) non-standard deformations, and (3) Zariski-dense deformations in G.
After briefly explaining Kobayashi's work and Kassel's work on these
questions, we will explain the new results.
2022/01/28
thesis presentations
Xiaobing Sheng (Graduate School of Mathematical Sciences University of Tokyo)
Geometric and combinatorial properties of some generalisations of Thompson's groups
[ Reference URL ]
https://forms.gle/bdsntP4pZ4TMaehF9
thesis presentations
Erbol Zhanpeisov (Graduate School of Mathematical Sciences University of Tokyo)
Local existence and blow-up rate of solutions to nonlinear parabolic equations
[ Reference URL ]
https://forms.gle/bdsntP4pZ4TMaehF9
thesis presentations
Kentaro Kameoka (Graduate School of Mathematical Sciences University of Tokyo)
Studies on semiclassical analysis and resonance theory
[ Reference URL ]
https://forms.gle/bdsntP4pZ4TMaehF9
thesis presentations
Teppei Takamatsu (Graduate School of Mathematical Sciences University of Tokyo)
On the arithmetic finiteness of irreducible symplectic varieties
[ Reference URL ]
https://forms.gle/bdsntP4pZ4TMaehF9
thesis presentations
Yujiro Takeishi (Graduate School of Mathematical Sciences University of Tokyo)
Optimal decay estimates for Schrödinger heat semigroups with inverse square potential in Lorentz spaces
[ Reference URL ]
https://forms.gle/bdsntP4pZ4TMaehF9
thesis presentations
Kengo Takei (Graduate School of Mathematical Sciences University of Tokyo)
Some asymptotic problems for systems of Hamilton-Jacobi-Bellman equations
[ Reference URL ]
https://forms.gle/bdsntP4pZ4TMaehF9
thesis presentations
Shota Fukushima (Graduate School of Mathematical Sciences University of Tokyo)
Microlocal construction and analysis of the Schrödinger propagators on manifolds
[ Reference URL ]
https://forms.gle/bdsntP4pZ4TMaehF9
thesis presentations
Yuki Yamamoto (Graduate School of Mathematical Sciences University of Tokyo)
On the restrictions of supercuspidal representations for inner forms of GL_N
[ Reference URL ]
https://forms.gle/bdsntP4pZ4TMaehF9
2022/01/27
Information Mathematics Seminar
Yusuke Aikawa (Information Technology R&D Center, Mitsubishi Electric Co.)
Recent development of post-quantum cryptography from supersingular elliptic curves (Japanese)
Explanation on recent development of post-quantum cryptography from supersingular elliptic curves
https://docs.google.com/forms/d/1WLEbsA2aQTXgdE2ynrumJOG-Z4AVWqcOLC-z42B4nPY
thesis presentations
Masaru Miyashita (Graduate School of Mathematical Sciences University of Tokyo)
Some new approaches to the finite element method for digital twins of plasma
[ Reference URL ]
https://forms.gle/bdsntP4pZ4TMaehF9
thesis presentations
Keiichi Maeta (Graduate School of Mathematical Sciences University of Tokyo)
On the existence problem of compact Clifford-Klein forms of indecomposable pseudo-Riemannian symmetric spaces with signature (n, 2)
[ Reference URL ]
https://forms.gle/bdsntP4pZ4TMaehF9
thesis presentations
Nobuo Iida (Graduate School of Mathematical Sciences University of Tokyo)
A stable homotopy version of monopole contact invariant
[ Reference URL ]
https://forms.gle/bdsntP4pZ4TMaehF9
thesis presentations
Jun Okamoto (Graduate School of Mathematical Sciences University of Tokyo)
Convergence of some non-convex energies under various topology
[ Reference URL ]
https://forms.gle/bdsntP4pZ4TMaehF9
thesis presentations
Yasuhiro Oki (Graduate School of Mathematical Sciences University of Tokyo)
On the connected components of Shimura varieties for CM unitary groups in odd variables
[ Reference URL ]
https://forms.gle/bdsntP4pZ4TMaehF9
thesis presentations
Tatsuro Kawakami (Graduate School of Mathematical Sciences University of Tokyo)
Studies on the Bogomolov-Sommese vanishing theorem and Du Val del Pezzo surfaces in positive characteristic
[ Reference URL ]
https://forms.gle/bdsntP4pZ4TMaehF9
thesis presentations
Cyuyou Ko (Graduate School of Mathematical Sciences University of Tokyo)
On the Helmholtz decomposition of vector fields with bounded mean oscillation in various domains
[ Reference URL ]
https://forms.gle/bdsntP4pZ4TMaehF9
thesis presentations
Masatoshi Goda (Graduate School of Mathematical Sciences University of Tokyo)
Statistical inference for Hawkes processes
[ Reference URL ]
https://forms.gle/bdsntP4pZ4TMaehF9
thesis presentations
Yusuke Sato (Graduate School of Mathematical Sciences University of Tokyo)
Multidimensional continued fractions and Fujiki-Oka resolutions of cyclic quotient singularities
[ Reference URL ]
https://forms.gle/bdsntP4pZ4TMaehF9
thesis presentations
Taketo Sano (Graduate School of Mathematical Sciences University of Tokyo)
On functoriality and spatial refinements of Khovanov homology and its variants
[ Reference URL ]
https://forms.gle/bdsntP4pZ4TMaehF9
thesis presentations
Hiroshi Takase (Graduate School of Mathematical Sciences University of Tokyo)
Inverse problems for hyperbolic partial differential equations with time-dependent coefficients
[ Reference URL ]
https://forms.gle/bdsntP4pZ4TMaehF9
thesis presentations
Mayuko Yamashita (RIMS, Kyoto University)
Differential models for the Anderson dual to bordism theories and invertible QFT’s
[ Reference URL ]
https://forms.gle/bdsntP4pZ4TMaehF9
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