A.l Dynamical systemsA dynamical system is a mathematical object that corresponds to real sys tems (physical, chemical, biological, and others) whose evolution depends uniquely on the initial state. It is described by a system of equationsdifferential, difference, integral, etc. -which allow for the existence of a unique solution for each initial condition in an infinite period of time.The state of a dynamical system is described by a set of variables; there are different criteria for choosing a particular set of variables: symmetry and/or simplicity considerations, natural interpretation, etc. The set of states of a dynamical system forms a phase space. Each point in the phase space corresponds to a state of a dynamical system and temporal evolution of the system is depicted by phase trajectories. The location of the states relative to one another in the phase space of a dynamical system is described by the notion distance. The ensemble of states at a fixed moment of time is the phase volume of the system. The possibility to describe the behavior of a system by some determin istic equations (e.g. equations devoid of noisy terms) does not necessarily mean that the system is a dynamical system. For example, the equation dx/dt = x 2 does not describe a dynamical system because the solution