Chaotic systems arise naturally in Statistical Mechanics and in Fluid
Dynamics. A paradigm for their modelization are smooth hyperbolic systems. Are
there consequences that can be drawn simply by assuming that a system is
hyperbolic? here we present a few model independent general consequences which
may have some relevance for the Physics of chaotic systems. Expanded version of
a talk at ICM98, Berlin.Comment: 29 pages: Plain-TeX, 1 figur
