Sufficient condition for the hyperbolicity of mappings of the torus

Abstract

We consider mappings of the m-dimensional torus T^m (m ≥ 2) that are C¹-perturbations of linear hyperbolic automorphisms. We obtain sufficient conditions for such mappings to be one-to-one hyperbolic mappings (i.e., Anosov diffeomorphisms). These results are used to study the blue-sky catastrophe related to the vanishing of a saddle-node invariant torus with a quasiperiodic winding in a system of ordinary differential equations.