Some spaces are more equal than others
  It has generally been thought that in perturbed
Friedmann-Lemaitre-Robertson-Walker models of the Universe, global topology
should not have any feedback effects on dynamics. However, a weak-field limit
heuristical argument, assuming a finite particle horizon for the transmission
of gravitational signals, shows that a residual acceleration effect can occur.
The nature of this effect differs algebraically between different constant
curvature 3-manifolds. This potentially provides a selection mechanism for the
3-manifold of comoving space.
