Geometry and Dynamics of Singular Symplectic manifolds

Henan University by Eva Miranda

 

Public Lecture takes place on October 11 at 13h CET, 19h Kaifeng time

 

Connecting data for Public Lecture:

Zoom Id: 5673065241

password: 123456

Undecidability of certain fluid paths, the Navier-Stokes problem and 29000 rubber ducks lost in the ocean

 

 

 

This course is part of the Overseas Distinguished Lectureship Program at the University of Henan in Kaifeng

NEW CONNECTION DATA!

New Zoom ID: 815 7127 3363

Code: 123456

 

 

Problem sessions by Joaquim Brugues joaquim.brugues@upc.edu  and Pau Mir pau.mir.garcia@upc.edu

Figure on the top: Image of the moment map of a b-torus (courtesy of Pablo Nicolás, a student of the course). Observe that this b-moment map is circle valued. Figure on the bottom representation of a b-map on a b-sphere.

Summary: b-Calculus was introduced by Richard Melrose when considering pseudodifferential operators on manifolds with boundary. Later on, Ryszard Nest and Boris Tsygan applied these ideas to study the deformation quantization of symplectic manifolds with boundary.

The purpose of this minicourse is to unravel the geometrical structures (b-symplectic structures) behind this picture and describe some applications to Dynamical systems. b-Symplectic manifolds are Poisson manifolds which are symplectic away from an hypersurface and satisfy some transversality condition. b-Symplectic manifolds lie "close enough" to the symplectic category and indeed their study can be addressed using an "extended" De Rham complex. In particular many peculiarities from Symplectic manifolds are shared with b-symplectic manifolds. Using these ideas, we will study normal form theorems, action-angle theorems, toric actions and applications to KAM theory. At the end of the minicourse we present other singular symplectic structures such as folded symplectic structures and b^m-symplectic structures (for which the transversality condition is relaxed) and explain how they are related to b-symplectic and symplectic structures.

We will give a general overview of the theory using some examples in celestial mechanics as leitmotiv. For some of them (like double collision), we can even construct b^m-symplectic structures and m-folded structures. This apparent "duality" will be used as an excuse to closely explore the relation between the $b^m$-symplectic category with the symplectic and folded symplectic category. This relation depends surprisingly on the parity of m and is given by a desingularization procedure called deblogging. Time permitting, several applications of deblogging to dynamics and quantization will be presented.

Syllabus/Scheme of the lectures

The planning of the lectures would be the following one:

 
Title: Geometry and Dynamics of Singular Symplectic Manifolds
Summary: We will describe a novel geometrical approach to classical problems in Celestial Mechanics concerning collisions. The upshot of our methods is that the singularities (collisions, infinity line) are included in the geometrical techniques(as b-symplectic manifolds, b-contact manifolds). We will focus on the geometry and Dynamics of these manifolds and describe several techniques such as desingularization, normal forms, action-angle coordinates and perturbation theory used in this study.
 

 
Planning with description of contents per day.

 
September 7 Overture: Introduction to the course. Basic definitions in Symplectic Geometry and motivation for b-symplectic geometry. B-symplectic manifolds as Poisson manifolds.
 
September 9 Melrose language of b-forms. b-symplectic forms on b-Poisson manifolds. The geometry of the critical set. More degenerate forms b^m-symplectic forms and b^m contact forms. Desingularization of b^m-forms.
 
September 14  The path method for b^m-symplectic structures. Local normal form (b^m-Darboux theorem) and extension theorems. b^m-Structures to the test: Examples in Fluid Dynamics and Celestial Mechanics. The b-symplectic and b-contact geometry of the restricted three body problem and of Beltrami fields. Application: Finding periodic orbits for trajectories of a satellite in the restricted three body problem.
 
September 16 Exercise session
 
September 21 (POSTPONED DUE TO NATIONAL FESTIVITY IN CHINA)
 
September 23  More symmetries: Toric actions, action-angle coordinates and Integrable systems on b^m-symplectic manifolds. Applications: Perturbations of integrable systems and KAM theory.
 
September 28: Exercise session
 
September 30:  Some classical problems for b^m-symplectic and b^m-contact manifolds. Examples in Celestial Mechanics. Periodic Orbits. The (singular) Weinstein conjecture.

October 5: Finale: A magic mirror between singular contact geometry and singular Fluid Dynamics. Applying Uhlenbeck's results to find escape orbits in Celestial Mechanics. Open problems.

Material:

https://us02web.zoom.us/rec/share/g5BKbJ8ocAnuUJRqy2qvYD01VeEUWmcTrBSInq7Rpa9FJYDHXGfl5b40-Znu3_-V.Yv9HUZDrN4DIAKbq 
(passcode: KO8i^i77)

Videos of the course :

https://zoom.com.cn/rec/share/HIjqT2fTv1xNQTn2maZ_yZXGWROfqUer4n8D_K11S4zXwIiw3fxESA4sAYOyr2HR.3kpmBm8U-Crf2hy- Passcode: $4P2gh2V

https://us02web.zoom.us/rec/share/g5BKbJ8ocAnuUJRqy2qvYD01VeEUWmcTrBSInq7Rpa9FJYDHXGfl5b40-Znu3_-V.Yv9HUZDrN4DIAKbq  (passcode: KO8i^i77)

https://us02web.zoom.us/rec/share/xgSqJfHB6AITUK65jif8JhSapWdGLP8PymaX9FJ6mImufXbnsQdP53SyTQAgmQYJ.cbyPhSGPytNxWOZl   Passcode: e0Z?Dd@9
https://zoom.com.cn/rec/share/B3Ej7QL4RP0XtU1uPXS3q-pAMov5kz1UNpoAjl1-wkkSI8kicoGMI6XRe5YidHfj.GjThWbIPdLB4Hfex Passcode: *?c8Nv6a

https://us02web.zoom.us/rec/share/PR4vY2voJQ6c-hz6V5fh7jgzCER3_vT_aB2JKGZg_j8nagpupffcV4VU3bvgq2oE.qwON6FdeJCb66Tn6 Access Passcode: z61X@x*D

https://us02web.zoom.us/rec/share/bgtS_c67oYQNAXMXEnDnQOox_rUTR_ZIuiXCztLBrLb51J3nUKSGxMOckht3zs5j.bHqHMwstDYF2aVOL Passcode: C%7.0Mb$

 

Videos of the course  (Direct access to youtubechannel) :

https://www.youtube.com/playlist?list=PLl0M1BS0QQhEGV3bUnmKBK2h8IlaFBF8a

 

Bibliography: