Third-order explicit autonomous differential equations, commonly called jer
ky dynamics, constitute a powerful approach to understand the properties of
functionally very simple but nonlinear three-dimensional dynamical systems
that can exhibit chaotic longtime behavior. In this paper, we investigate
the dynamics that can be generated by the two simplest polynomial jerky dyn
amics that, up to these days, are known to show chaotic behavior in some pa
rameter range. After deriving several analytical properties of these system
s, we systematically determine the dependence of the long-time dynamical be
havior on the system parameters by numerical evaluation of Lyapunov spectra
. Some features of the systems that are related to the dependence on initia
l conditions are also addressed. The observed dynamical complexity of the t
wo systems is discussed in connection with the existence of homoclinic orbi
ts. (C) 2001 Elsevier Science Ltd. All rights reserved.