§Why
quadratic, P=Po + ar + e r /rc ?
simplest
non-linear EoS, introduces energy scale(s);
Mostly in
general, energy scale -> effective cosmological constant rL;
qualitative
dynamics is representative of more general non-linear EoSÕs;
Parametrizes
a vast class of DE models: truncated Taylor expansion of any P(r)
(3 parameters);
explore
singularities and bounces or cyclic solutions (brane and pre-big bang inspired).