Text only print
Full screen print
Future seminars
Seminar information archive ～03/16｜Today's seminar 03/17 | Future seminars 03/18～
2026/03/18
FJ-LMI Seminar
13:30-14:15 Room #056 (Graduate School of Math. Sci. Bldg.)
Amaury HAYAT (ENPC, Paris)
Stabilization of PDEs and AI for mathematics (英語)
https://fj-lmi.cnrs.fr/seminars/
Amaury HAYAT (ENPC, Paris)
Stabilization of PDEs and AI for mathematics (英語)
[ Abstract ]
Control theory consists in asking: if we can act on a system, what can we make it do? One of the main problems is the stabilization problem: how can we act on a system to guarantee the long-term behavior of its solutions? In this presentation, we will examine this problem from several angles. First, we will look at the problem of stabilizing PDEs from an abstract perspective and present a recent approach called F-equivalence (or sometimes Fredholm backstepping). The principle is simple: instead of trying to find a control that makes the system stable, we look at another problem: we try find a control that renders the PDE system dynamically equivalent to a simpler system for which stability is already known. Besides being interesting in itself, this approach has also resulted in new results in control theory, and we will review the progress that has been made in the last three years. In a second part, we will focus on a more concrete problem: the stabilization of hyperbolic equations modeling road traffic. We will show how abstract mathematical concepts, such as entropic solutions, can have tangible impacts in real-world scenarios, and we will discuss their application to traffic regulation and the reduction of traffic jams.
[ Reference URL ]Control theory consists in asking: if we can act on a system, what can we make it do? One of the main problems is the stabilization problem: how can we act on a system to guarantee the long-term behavior of its solutions? In this presentation, we will examine this problem from several angles. First, we will look at the problem of stabilizing PDEs from an abstract perspective and present a recent approach called F-equivalence (or sometimes Fredholm backstepping). The principle is simple: instead of trying to find a control that makes the system stable, we look at another problem: we try find a control that renders the PDE system dynamically equivalent to a simpler system for which stability is already known. Besides being interesting in itself, this approach has also resulted in new results in control theory, and we will review the progress that has been made in the last three years. In a second part, we will focus on a more concrete problem: the stabilization of hyperbolic equations modeling road traffic. We will show how abstract mathematical concepts, such as entropic solutions, can have tangible impacts in real-world scenarios, and we will discuss their application to traffic regulation and the reduction of traffic jams.
https://fj-lmi.cnrs.fr/seminars/
Applied Analysis
16:00-17:30 Room #128 (Graduate School of Math. Sci. Bldg.)
Dietmar Hoemberg (Weierstrass Institute, Berlin)
A phasefield approach to two-scale topology optimization (English)
Dietmar Hoemberg (Weierstrass Institute, Berlin)
A phasefield approach to two-scale topology optimization (English)
[ Abstract ]
Subject of my presentation is a novel approach for optimizing both the macroscopic shape and the porous mesoscopic structure of components. In the first part of my presentation I will introduce the concept of phasefield based topology optimization. The second part of my presentation is devoted to two-scale topology optimization. The key feature here is the introduction of an additional local volume control (LVC), which allows to adjust the desired spatial scales. The main novelty is that the radius of the LVC may depend both on space and a local stress measure. This allows for creating optimal topologies with heterogeneous mesostructures enforcing any desired spatial grading and accommodating stress concentrations by stress dependent pore size. I will present some analytical results for the resulting optimal control problem and conclude with numerical results showing the versatility of our approach for creating optimal macroscopic designs with tailored mesostructures.
Subject of my presentation is a novel approach for optimizing both the macroscopic shape and the porous mesoscopic structure of components. In the first part of my presentation I will introduce the concept of phasefield based topology optimization. The second part of my presentation is devoted to two-scale topology optimization. The key feature here is the introduction of an additional local volume control (LVC), which allows to adjust the desired spatial scales. The main novelty is that the radius of the LVC may depend both on space and a local stress measure. This allows for creating optimal topologies with heterogeneous mesostructures enforcing any desired spatial grading and accommodating stress concentrations by stress dependent pore size. I will present some analytical results for the resulting optimal control problem and conclude with numerical results showing the versatility of our approach for creating optimal macroscopic designs with tailored mesostructures.
2026/03/19
FJ-LMI Seminar
13:30-14:15 Room #056 (Graduate School of Math. Sci. Bldg.)
Amaury HAYAT (ENPC, Paris)
How can AI Help Mathematicians? (英語)
https://fj-lmi.cnrs.fr/seminars/
Amaury HAYAT (ENPC, Paris)
How can AI Help Mathematicians? (英語)
[ Abstract ]
The advent of artificial intelligence raises an important question: can AI assist mathematicians in solving open problems in mathematics? This talk explores this question from multiple perspectives. We will explore how different types of AI models can be trained to provide valuable insights into mathematical questions from different areas of mathematics and applied mathematics. We will also present recent works on AI models specifically designed for automated theorem proving.
[ Reference URL ]The advent of artificial intelligence raises an important question: can AI assist mathematicians in solving open problems in mathematics? This talk explores this question from multiple perspectives. We will explore how different types of AI models can be trained to provide valuable insights into mathematical questions from different areas of mathematics and applied mathematics. We will also present recent works on AI models specifically designed for automated theorem proving.
https://fj-lmi.cnrs.fr/seminars/
2026/03/27
Colloquium
16:00-17:00 Room #NISSAY Lecture Hall(大講義室) (Graduate School of Math. Sci. Bldg.)
Nakahiro Yoshida (Graduate School of Mathematical Sciences, The University of Tokyo)
A study of chance and randomness: a personal history with selection bias (日本語)
Nakahiro Yoshida (Graduate School of Mathematical Sciences, The University of Tokyo)
A study of chance and randomness: a personal history with selection bias (日本語)
[ Abstract ]
My studies in probability and statistics have been guided by numerous coincidences, even though my direction has at times been seemingly random. Aware of the bias inherent in my selection of topics and retrospective evaluation of events, I reflect on the trajectory that has brought me to the present.
My studies in probability and statistics have been guided by numerous coincidences, even though my direction has at times been seemingly random. Aware of the bias inherent in my selection of topics and retrospective evaluation of events, I reflect on the trajectory that has brought me to the present.
2026/04/10
Geometric Analysis Seminar
16:00-17:00 Room # (Graduate School of Math. Sci. Bldg.)
Shinichiroh Matsuo (Nagoya University)
Discretization of Dirac operators and lattice gauge theory (日本語)
https://sites.google.com/g.ecc.u-tokyo.ac.jp/geometricanalysisseminar/
Shinichiroh Matsuo (Nagoya University)
Discretization of Dirac operators and lattice gauge theory (日本語)
[ Abstract ]
Our ultimate goal is to discretize Seiberg-Witten theory.
Considering PL = DIFF in dimension four, we would like to construct something like PL Seiberg-Witten theory.
As a first step towards this goal, we study the discretization of the analytic index of Dirac operators.
However, the analytic index of Fredholm operators is an essentially infinite-dimensional phenomenon, while the index theory of finite-dimensional self-adjoint operators is trivial.
Thus, a naive discretization of Dirac operators does not work.
In this talk, I will explain how the “Wilson-Dirac operator” from lattice gauge theory provides a correct discretization, at least from the viewpoint of the analytic index.
This talk is based on a joint work with Shoto Aoki, Hidenori Fukaya, Mikio Furuta, Tetsuya Oonogi, and Satoshi Yamaguchi.
https://arxiv.org/abs/2602.12576
https://arxiv.org/abs/2407.17708
[ Reference URL ]Our ultimate goal is to discretize Seiberg-Witten theory.
Considering PL = DIFF in dimension four, we would like to construct something like PL Seiberg-Witten theory.
As a first step towards this goal, we study the discretization of the analytic index of Dirac operators.
However, the analytic index of Fredholm operators is an essentially infinite-dimensional phenomenon, while the index theory of finite-dimensional self-adjoint operators is trivial.
Thus, a naive discretization of Dirac operators does not work.
In this talk, I will explain how the “Wilson-Dirac operator” from lattice gauge theory provides a correct discretization, at least from the viewpoint of the analytic index.
This talk is based on a joint work with Shoto Aoki, Hidenori Fukaya, Mikio Furuta, Tetsuya Oonogi, and Satoshi Yamaguchi.
https://arxiv.org/abs/2602.12576
https://arxiv.org/abs/2407.17708
https://sites.google.com/g.ecc.u-tokyo.ac.jp/geometricanalysisseminar/
2026/04/22
Seminar on Mathematics for various disciplines
10:30-11:30 Room #056 (Graduate School of Math. Sci. Bldg.)
Hidekazu Yoshioka (Japan Advanced Institute of Science and Technology)
Non-standard mathematical models for a deeper understanding of aquatic environments (日本語)
Hidekazu Yoshioka (Japan Advanced Institute of Science and Technology)
Non-standard mathematical models for a deeper understanding of aquatic environments (日本語)
