Intrinsic irreversibility in classical and quantum mechanics

Intrinsically Irreversible Dynamical Systems allow for an exact passage to Irreversible Evolution through appropriate non-Unitary change of Representation. The property which characterises such systems is Dynamical Instability expressed by the Kolmogorov Partition and Internal Time or by the non-vanishing of the asymptotic Collision Operator. This leads to an extension of both Classical and Quantum Mechanics. Certain implications of the Kolmogorov Instability and Internal Time for Relativistic Systems as well as of the non-vanishing of the asymptotic Collision Operator for Unstable quantum systems are discussed.NOTXT