Preprint A126/2002
Chaotic and complex systems

Jacob Palis

**Keywords: **
Chaotic | complex systems | exponential and non-exponential growth of distances

We discuss the concepts of chaotic and complex systems, much in vogue these days, due to the potentiality of a wide spectrum of applications to natural phenomena in terms of mathematical modelling and a better prediction of future behaviour. Actually, the theory of chaotic systems is in an increasingly more solid basis and we can now present a possible global and universal scenario for them, in terms of conjectures that have been partially fulfilled. The situation concerning complex systems is much more delicated: They seem to be dynamical systems that are in the border of the former, to depend on a large number of parameters and to be in constant evolution. Some of the possible features of complex systems are presented as well as some of the basic references on applications.