TITLE: On the existence of doubly symmetric "Schubart-like" periodic orbits. 


AUTHORS: 
R. Martinez
Dept. de Matematiques, Univ. Autonoma de Barcelona
Barcelona, Catalunya, Spain 
E-mail:reginamb@mat.uab.cat


ABSTRACT:
We give sufficient conditions to ensure the existence of symmetrical
periodic orbits for a class of Hamiltonian systems having some singularities.
The results are applied to different subproblems of the gravitational
n-body problem where singularities appear due to collisions.


Preprint submitted to Discrete and Continuous Dynamical Systems, B, 11 July 2010.