iTHEMS Math Seminar
An introduction to modular functions, conformal field theories, and moonshine phenomena
July 2 at 16:00 - 18:10, 2021
Mr. Mizuki Oikawa (Junior Research Associate, iTHEMS)
Moonshine phenomena are certain mysterious connections between modular functions and finite groups. The first example is the celebrated monstrous moonshine, which connects the J-invariant and the Mons...more
Venue: via Zoom
Event Official Language: English
Stable eigenvalues of compact anti-de Sitter 3-manifolds
June 18 at 16:00 - 18:10, 2021
Dr. Kazuki Kannaka (Special Postdoctoral Researcher, iTHEMS)
Geometric objects that have been investigated in detail so far, such as closed Riemann surfaces, are sometimes locally homogeneous. Loosely speaking, their infinitesimal behavior is the same at each p...more
Venue: via Zoom
Event Official Language: English
Loewner's theorem for maps on operator domains / The structure of maps on the space of all quantum pure states that preserve a fixed quantum angle
May 24 at 16:00 - 18:10, 2021
Dr. Michiya Mori (Special Postdoctoral Researcher, iTHEMS)
This talk is divided into two independent topics. In the first part of my talk we consider the order structure of hermitian matrices. Given two matrix domains (open connected sets of n-by-n hermitia...more
Venue: via Zoom
Event Official Language: English
Geometry of canonical metrics on Kähler manifolds
May 14 at 16:00 - 18:10, 2021
Dr. Eiji Inoue (Special Postdoctoral Researcher, iTHEMS)
The aim of this talk is to report recent trends in Kähler geometry. Kähler geometry consists of two aspects: the one is algebraic geometry and the other is metric geometry.The first one hour is an int...more
Venue: via Zoom
Event Official Language: English
Alternative tsunami observing and forecasting systems
April 22 at 16:00 - 18:10, 2021
Dr. Iyan Mulia (Research Scientist, Prediction Science Laboratory, RIKEN CPR)
Dedicated tsunami observing systems are mostly expensive and are often not sustainable. Therefore, alternative approaches should be implemented to overcome the issues. We introduced innovative ways to...more
Venue: via Zoom
Event Official Language: English
Long-time behavior of moving solids in a fluid and the kinetic theory of gases
April 7 at 16:00 - 18:10, 2021
Dr. Kai Koike (JSPS Fellow, Graduate School of Engineering, Kyoto University)
Understanding dynamics of solids in a fluid is a fundamental problem in fluid dynamics. Due to the growing interest in engineering in out-of-equilibrium situations, moving boundary problems for kineti...more
Venue: via Zoom
Event Official Language: English
The Green-Tao theorem for number fields
March 22 at 16:00 - 18:10, 2021
Dr. Wataru Kai (Assistant professor, Mathematical Institute, Tohoku University)
5, 11, 17, 23, 29 are prime numbers which form an arithmetic progression of length 5. A famous theorem of Ben Green and Terence Tao in 2008 says there are arbitrarily long arithmetic progressions of p...more
Venue: via Zoom
Event Official Language: English
Scattering theory for half-line Schrödinger operators: analytic and topological results
December 7 at 16:00 - 18:10, 2020
Dr. Hideki Inoue (Nagoya University)
Levinson’s theorem is a surprising result in quantum scattering theory, which relates the number of bound states and the scattering part of the underlying quantum system. For the last about ten years,...more
Venue: via Zoom
Event Official Language: English
Flat and spherical surface approximations
November 30 at 16:00 - 17:30, 2020
Dr. Martin Skrodzki (Visiting Researcher, iTHEMS / Fellow, German Academic Scholarship Foundation)
State-of-the-art acquisition devices produce surface representations of increasingly high resolution. While these detailed representations are important for production, they are problematic e.g. when ...more
Venue: via Zoom
Event Official Language: English
Representations of fundamental groups and 3-manifold topology
November 16 at 16:00 - 18:10, 2020
Dr. Takahiro Kitayama (Associate Professor, Graduate School of Mathematical Sciences, The university of Tokyo)
In 3-dimensional topology the great progress during the last two decades revealed that various properties of 3-manifolds are well understood from their fundamental groups. I will give an introduction ...more
Venue: via Zoom
Event Official Language: English
Efficient probabilistic assessment of building performance: sequential Monte Carlo and decomposition methods
November 13 at 16:00 - 18:10, 2020
Dr. Tianfeng Hou (Postdoctoral Researcher, iTHEMS / Postdoctoral Researcher, Prediction Science Laboratory, RIKEN Cluster for Pioneering Research / Postdoctoral Researcher, Data Assimilation Research Team, RIKEN Center for Computational Science)
The use of numerical simulations for complex systems is common. However, significant uncertainties may exist for many of the involved variables, and in order to ensure the reliability of our simulatio...more
Venue: via Zoom
Event Official Language: English
Mathematical aspects of quasi-Monte Carlo integration
November 5 at 16:00 - 18:10, 2020
Dr. Kosuke Suzuki (Assistant Professor, Graduate School of Advanced Science and Engineering, Hiroshima University)
In this talk, I will introduce mathematical aspects of quasi-Monte Carlo (QMC) integration. We aim to approximate the integral of a function on the d-dimensional hypercube [0,1]^d. A useful approach i...more
Venue: via Zoom
Event Official Language: English
Math Seminars by Dr. Genki Ouchi and Dr. Kenta Sato
September 24 at 16:00 - 18:10, 2020
Dr. Genki Ouchi
(Special Postdoctoral Researcher, iTHEMS)
Dr. Kenta Sato
(Special Postdoctoral Researcher, iTHEMS)
[Talk 1] (16:00 - 17:00) Dr. Genki Ouchi Automorphism groups of cubic fourfolds and K3 categories In this talk, I would like to talk about symmetries of algebraic varieties, especially cubic fou...more
Venue: via Zoom
Event Official Language: English
Maximal Regularity and Partial Differential Equations.
September 8 at 16:00 - 18:10, 2020
The theory of maximal regularity is a powerful tool to get solutions having the best regularity to linear partial differential equations (PDEs) of parabolic type. The theory is also applicable to show...more
Venue: via Zoom
Event Official Language: English
Stability of ferromagnetism in many-electron systems
July 31 at 16:00 - 18:10, 2020
Prof. Tadahiro Miyao (Associate Professor, Department of Mathematics, Faculty of Science, Hokkaido University)
First part Title: Stability of ferromagnetism in many-electron systems Abstract: I construct a model-independent framework describing stabilities of ferromagnetism in strongly correlated electron...more
Venue: via Zoom
Event Official Language: English
Topological data analysis from a practical and mathematical perspective
July 15 at 16:00 - 18:10, 2020
Dr. Yuichi Ike (Researcher, Artificial Intelligence, FUJITSU LABORATORIES LTD.)
1. Topological data analysis and its applications In this talk, I will explain some methods in topological data analysis (TDA) and their applications. First I recall persistent homology, which is a ...more
Venue: via Zoom
Event Official Language: English
Universal Error Bound for Constrained Quantum Dynamics
June 24 at 16:00 - 18:10, 2020
Dr. Ryusuke Hamazaki (Senior Research Scientist, iTHEMS / RIKEN Hakubi Team Leader, Nonequilibrium Quantum Statistical Mechanics RIKEN Hakubi Research Team, RIKEN Cluster for Pioneering Research)
In quantum mechanics, the existence of large energy gaps allows us to trace out the degrees of freedom of irrelevant energy scale. Consequently, we can treat a system within a constrained subspace obt...more
Venue: via Zoom
Event Official Language: English
Information geometry of operator scaling
June 17 at 16:00 - 18:10, 2020
Dr. Tasuku Soma (Research Associate, Graduate School of Information Science and Technology, The University of Tokyo)
Matrix scaling is a classical problem with a wide range of applications. It is known that the Sinkhorn algorithm for matrix scaling is interpreted as alternating e-projections from the viewpoint of cl...more
Venue: via Zoom
Event Official Language: English
Knotted 2-spheres in the 4-space and Yang-Mills gauge theory
May 27 at 16:00 - 18:10, 2020
Dr. Masaki Taniguchi (Special Postdoctoral Researcher, iTHEMS)
The classification problem of knots is one of the central topics in a study of topology. In the first part, we review classical knot theory and theory of 2-dimensional knots in the 4-dimensional space...more
Venue: via Zoom
Event Official Language: English
How many electrons can atoms bind?
May 13 at 16:00 - 18:10, 2020
Dr. Yukimi Goto (Special Postdoctoral Researcher, iTHEMS)
In this talk, I will introduce the mathematical studies on the ionization problem. Some experimental & numerical evidences say that any doubly charged atomic ion X^{2-} is not stable. This 'fact' is c...more
Venue: via Zoom
Event Official Language: English