Total destruction of invariant tori for the generalized   Frenkel-Kontorova model
  We consider generalized Frenkel-Kontorova models on higher dimensional lattices. We show that the invariant tori which are parameterized by continuous hull functions can be destroyed by small perturbations in the $C^r$ topology with $r<1$. 
Xifeng Su and Lin Wang
math.DS math-ph math.MP