AN ALGEBRAIC APPROACH TO THE KOLMOGOROV-SINAI ENTROPY

We revisit the notion of Kolmogorov-Sinai entropy for classical dynami cal systems in terms of an algebraic formalism. This is the starting p oint for defining the entropy for general non-commutative systems. Her eby typical quantum tools are introduced in the statistical descriptio n of classical dynamical systems. We illustrate the power of these tec hniques by providing a simple, self-contained proof of the entropy for mula for general automorphisms of n-dimensional tori.