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
Next year I’ll come to Sanya, Hainan, China to attend “GAP XII”, an international conference on geometry and physics.
The organizers said they would have money to cover local expenses for a number of participants, so if anyone is interested in visiting Sanya, please contact them (or contact me if you don’t know them)
. . . → Read More: Geometry and Physics XII, Hainan (China), 10-14/03/2014
There seems to be a lot of confusion (among my colleagues, and also of myself) concerning the relationships between singular foliations and integrable p-vector fields (a.k.a. Nambu structures). The aim of this note is to make some clarifications.
1) How to construct a singular foliation from an integrable p-vector field ?
The obvious (but . . . → Read More: Integrable p-vector fields and singular foliations
This week I’m at the AlanFest in EPFL, Switzerland, on the occasion of Alan Weinstein’s 70th birthday. I gave a talk on Thursday entitled:
A normalization toolbox, with applications to singular foliations
Here are the slides of my talks (with some typographical errors), for people who might be interested:
. . . → Read More: Talk at AlanFest 07/2013
I’m writing down here the ideas for proving that smooth nondegenerate integrable dynamical systems are smoothly linearizable. The analytic case can be proved using analytic torus actions (my paper about that will appear in Ergodic Th Dyn Sys). I think the smooth case is also true, but the proof is much more complicated than . . . → Read More: Linearization of smooth integrable systems
Take a singular foliation say of dimension k.
Locally at each point there exists $k$ vector fields X1, …, Xk which are tangent to the foliation and which are linearly independent almost everywhere (we will only consider foliations which satisfy this property)
The wedge product L = X1…Xk is a Nambu structure tangent to . . . → Read More: Anti-canonical bundle of singular foliations
This is the topic that I want to talk about in the conference in honor of Alan Weinstein’s 70th birthday in EPFL (Lausanne) in July. This post is the place in keep the preparation for my talk.
A work of mine on the linearization of proper Lie groupoids was directly influenced by Alan (it . . . → Read More: Linearization and stability of singular foliations
Me giving the last lecture of my minicourse, Friday 07/June/2013, GESTA
The “tail of the cat”, which was drawn 3 times there on the blackboard, was an example (of an exotic symplectic R^2n) that intrigued many people
Thanks to Truong Hong Minh for the picture, that he shot using his . . . → Read More: A picture from GESTA 2013
Ok, đây là tôi tự bổ túc văn hóa về complexity thôi.
Trong lý thuyết complexity, người ta nói đến các oracle, tức là các “hộp đen” để tính các hàm (hay trả lời các câu hỏi) nào đó, chỉ cần cho input (thuộc loại nào đó) vào đấy thì sẽ ra ngay output, . . . → Read More: Oracle phổ quát bậc 2 ?
An activity in mathematical biology “Multiscale Modeling”:
we are very pleased to announce the ESMTB-EMS Spring School
“Multiscale modeling in the life sciences”, Lyon, May 27-31 2013
Courses will be given by distinguished specialists in the field of Mathematical Biology.
Pierre Degond (Université Paul Sabatier, Toulouse) Dirk Drasdo (INRIA Rocquencourt) Bard . . . → Read More: Mathematical Biology Activity
Got an ad from Regular and Chaotic Dynamics:
The following RCD articles on non-holonomic systems, contact mechanics and applications will be available on free access at http://ics.org.ru/journals/rcd till March 1, 2013.
V.V. Kozlov, On Invariant Manifolds of Nonholonomic Systems http://ics.org.ru/eng?menu=mi_pubs&abstract=1985
A.V. Borisov, A.A. Kilin, I.S. Mamaev, How to Control Chaplygin’s Sphere Using Rotors http://ics.org.ru/eng?menu=mi_pubs&abstract=2011
. . . → Read More: Free online articles on (integrable) nonholonomic systems
An international conference to celebrate the 70th birthday of Alan Weinstein (one of the founders of symplectic and Poisson geometry) will take place at EPFL (Lausanne) from 22 to 26 July 2013. A-priori, I’ll be in Lausanne for 4 weeks in July, and will take part in this conference.
. . . → Read More: Weinstein Conference 07/2013