Monday, April 13, 2015 - 11:00am
1 hour (actually 50 minutes)
We present a method to find KAM tori with fixed frequency in degenerate cases, in which the Birkhoff normal form is singular. The method provides a natural classification of KAM tori which is based on Singularity Theory. The method also leads to effective algorithms of computation, and we present some numerical results up to the verge of breakdown. This is a joint work with Alejandra Gonzalez and Rafael de la Llave.