  In a systematic study, we use an equivalent pair of improved numerical
relativity codes based on a tetrad-formulation of the classical Einstein-scalar
field equations to examine whether slow contraction or inflation (or both) can
resolve the homogeneity, isotropy and flatness problems. Our finding, based on
a set of gauge/frame invariant diagnostics, is that slow contraction robustly
and rapidly smooths and flattens spacetime beginning from initial conditions
that are outside the perturbative regime of the flat Friedmann-Robertson-Walker
metric, whereas inflation fails these tests. We present new numerical evidence
supporting the conjecture that the combination of ultralocal evolution and an
effective equation-of-state with pressure much greater than energy density is
the key to having robust and rapid smoothing. The opposite of ultralocality
occurs in expanding spacetimes, which is the leading obstruction to smoothing
following a big bang.
