To investigate the relevance of chaos and/or stochasticity to
the evolution of the EOFs described by the PCs, as well as of
the solar cycle itself, we used the Lyapunov exponents. The
Lyapunov exponents are related to the exponential divergence
of nearby orbits in the phase space and give both qualitative
and quantitative information about the dynamical behavior of
the system. In particular, when at least one Lyapunov exponent