Gianni Arioli, Hans Koch, Susanna Terracini
The Fermi-Pasta-Ulam Model: Periodic Solutions
(643K, TeX with EPS figures gzipped)

ABSTRACT.  We introduce two novel methods for studying periodic solutions of the FPU 
beta-model, both numerically and rigorously. 
One is a variational approach, based on the dual formulation of the problem, and the other involves computer-assisted proofs. 
These methods are used e.g. to construct a new type of solutions, whose energy is spread among several modes, associated with closely spaced resonances.