Dynamical properties and predictability in a class of self-organized critical models

We consider a particular class of self-organized critical models. For these systems we show that the Lyapunov exponent is strictly lower than zero. That allows us to describe the dynamics in terms of a piecewise linear contractive map. We describe the physical mechanisms underlying the approach to the recurrent set in the configuration space and we discuss the structure of the attractor for the dynamics. Finally the problem of the chaoticity of these systems and the definition of a predictability are addressed.