Non-density of hyperbolicity in complex dynamics in several variables

Sébastien Biebler (Université Paris Cité)

One of the main goals in the theory of dynamical systems is to describe the dynamics of a “typical” map. For instance, in the case of diffeomorphisms of a given manifold, it was conjectured by Smale in the 60s that uniform hyperbolicity was generically satisfied. This hope was however fast discouraged by exhibiting dynamical systems displaying in a robust way dynamical configurations which are obstructions to hyperbolicity: robust homoclinic tangencies (this is the so-called Newhouse phenomenon) and robust heterodimensional cycles. In this talk, I will explain these phenomena and their extensions to the complex setting. In particular, I will show how to construct robust heterodimensional cycles in the family of polynomial automorphisms of C3. The main tool is the notion of blender coming from real dynamics.