What upper limit is placed on Ω(tP) by the requirement that the universe not end in a Big Crunch between the Planck time, tP≈5×10−44 s, and the start of the inflationary epoch at ti? Compute the maximum permissible value of Ω(tP), first assuming ti≈10−36 s, then assuming ti≈10−26 s. (Hint: prior to inflation, the Friedmann equation will be dominated by the radiation term and the curvature term.)