- Cite this article as:
- Bellon, M. & Viallet, CM. Comm Math Phys (1999) 204: 425. doi:10.1007/s002200050652
For any discrete time dynamical system with a rational evolution, we define an entropy, which is a global index of complexity for the evolution map. We analyze its basic properties and its relations to the singularities and the irreversibility of the map. We indicate how it can be exactly calculated.