§a: Po>0, a<-1: phantom for r > rL; for r < rL recollapsing
flat and
cyclic closed models (around Einstein fixed point)
§b: Po>0,
-1<a<-1/3: similar to
lower part of a
§c: Po<0,
-1/3<a: phantom for r < rL,
de Sitter
attractor, closed
loitering models (close to
Einstein fixed point).