Symbolic dynamics for certain non-invertible $C^{1+{\hat{I}}^2}$ maps

Abstract

Let $f$ be a non-invertible $C^{1+{\hat{I}}^2}({\hat{I}}^2>0)$ map with zero Lyapunov exponents and singularities on a closed Riemannian manifold $M$. We consider the symbolic dynamics of $f$. Combining the techniques in recent works of Sarig, Ovadia and Araujo-Lima-Poletti, we construct a countable Markov partition for the invariant set consisting of summable points of the inverse limit space of $(M,f)$ and show that there exists a finite-to-one symbolic extension for $f$ on the corresponding subset of $M$.