ABSTRACT
The problem of absolute stability of nonlinear control systems has been formulated more than 50 years ago. If some physical system is described by the evolution of the deviations with respect to a steady state (equilibrium), its equations have the origin of the coordinates as equilibrium. If this zero equilibrium is stable, then the considered steady state (with respect to which the deviations are written) is also stable. If the zero equilibrium is globally asymptotically stable, there are no other stable equilibria and from the stability point of view the considered system while nonlinear is much like the linear one.
