Liên đoàn bố già Việt Nam chuẩn bị tổ chức đại hội thường kỳ, với sự tham dự của tất cả các bố già. Quy định của liên đoàn là địa điểm tổ chức phải ở một thành phố sao cho tổng độ dài các quãng đường của các bố già từ các thành . . . → Read More: Đại hội bố già tổ chức ở đâu (bài toán vui)?
Here is the new version of my invited talk
“A general approach to the problem of action-angle variables” (PDF File: AATalk2014, version 26/10/2014)
to be presented et the conference in honour of Charles Michel Marle’s 70th birthday in November 2014 in Paris.
Here is the website of the conference: http://www.imcce.fr/Equipes/ASD/person/albouy/Marle2014.html
Just submitted a joint paper with my student today, “only” 4 months behind schedule:
Reduction and Integrability of stochastic dynamical systems (PDF file)
This paper is devoted to the study of qualitative geometrical properties of stochastic dynamical systems, namely their symmetries, reduction and integrability. In particular, we show that an SDS which is . . . → Read More: Reduction and integrability of stochastic dynamical systems
These are the slides (preliminary version, to be revised) for a talk that I’ll give in Paris (24/11/2014) in the Conference in honour of the 80th birthday of C-M Marle. It contains a conceptual approach to the problem of action-angle variables, with some new results (a paper is in preparation based on an old . . . → Read More: A general approach to the problem of action-angle variables
Just finished my chapter for a book on integrable systems. In case anyone is interested, here is the PDF file:
These are quick notes for a joint work with Ch. Wacheux
Here, by an affine manifold, we mean a paracompact manifold with a locally flat affine structure. If the manifold is of dimension n, then near each point we have a chart whose coordinate functions are affine functions, and any local affine function is . . . → Read More: Stratified affine spaces
For those who might be interested: This PDF file contains the slides of my 3-hour minicourse on singular foliations, given in the Workshop “GAP XII: Geometric Mechanics”, Internatinal Mathematical Forum of Tsing Hua University, Sanya, 10-14/March/2014:
The main topic of this minicourse is the correspondence Singular Foliations <–> Nambu structures, and how . . . → Read More: Three lectures on singular foliations
Extension of Liouville’s theorem to the case of RDS
The case without first integrals:
X_1, …, X_p are p generators of RDS on a compact manifold M of dimension p, which commute with each other, and whose deterministic parts are linearly independent everwhere. Then M is a p-dimensional torus T^p with a periodic coordinate . . . → Read More: Notes on random systems 3: Liouville theorem for RDS
What is a random fixed point ?
A reference: Ochs – Oseledets: Examples of RDS on a closed unit ball without random fixed points. (So the topological fixed point theorem is NOT valid for RDS)
Definition. A random fixed point of a RDS \Phi over noise space (\Omega, \theta) (theta is the dynamics in . . . → Read More: Notes on random systems 2
These series of notes are for a research project that I’m doing with a student of mine. Some of what I write here will look quite stupid, because I myself know little about random dynamical systems.
I’ll explain why we’re interested in these systems later. But first, here . . . → Read More: Notes on random systems 1: RDS vs NDS
We just got a rather surprising result in our joint research project with Christophe Wacheux (currently post-doc at EPFL) about the intrinstic convexity of singular affine spaces.
The problem is to study the intrinsic local and global convexity of the affine structure of the base space of integrable Hamiltonian systems whose singularities are nondegenerate . . . → Read More: Monodromy can kill global convexity!
Có một bài toán “khá đơn giản” sau về vấn đề thuật toán, tôi biết chắc chắn là giải được (vì có định lý về vấn đề này), có điều tôi thử tự tìm lời giải mà loay hoay mãi chưa ra:
Có một người ở một làng bị mất trí và được cho . . . → Read More: Thuật toán của người mất trí nhớ
Our paper with Truong Hong Minh entitled “Commuting Foliations” has been accepted for publication in a special isue dedicated to Alain Chenciner in the journal Regular and Chaotic Dynamics
The most imporant part of this paper is actually the exposition of the relationship between singular foliations and Nambu structures: how to go from a . . . → Read More: Commuting Foliations