Vittorio Coti Zelati

Periodic solutions for the N-body problem: a variational approach

Abstract:

The purpose of the lectures is to introduce to the variational approach to the search of periodic solutions for the N-body problems.  Such an approach has recently lead to the discovery of some new periodic solutions (see, for example, the paper A. Chenciner and 
R. Montgomery, A remarkable periodic solution of the three-body problem in the case of equal masses, Ann.  of Math.  (2), 152
(2000), 881--901). 

 
1. Introduction, central configurations. 
2. The variational approach and the minimizing properties of the solutions of the 2-body problem and of the central configurations.
3. The lack of compactness of the variational formulation for the 2 and the N-body problem.  Symmetry and topological constrains.
4. Collisions, strong and weak forces.
5. Existence of periodic non-collision solutions via
variational methods for perturbed N-body problems.
6. Existence of periodic solutions for the N-body problem: symmetry and variational constrains.