  The two-dimensional renormalization group acting as the Ricci flow
$\Lambda\frac{\partial}{\partial\Lambda} g_{\mu\nu} = R_{\mu\nu}$ produces a
specific 1+3 dimensional space-time metric which describes an expanding
universe that starts with a big bang $a \sim t^{\scriptscriptstyle 1/\sqrt3}$
then decelerates until $z=0.2$ then accelerates until ending at
$t_{\max}=1.6\,t_{H}$ with a big blowup $a \sim
(t_{\max}-t)^{\scriptscriptstyle -1/\sqrt3}$. The only free parameters are the
overall time scale and the value of the present time $t_{0}$. These are fixed
by the Hubble constant $H_{0}=t_{H}^{-1}$ and the present deceleration
parameter $q(t_{0})$. This crude calculation of cosmology omits all but the
gravitational field. The only energy-momentum is purely gravitational dark
matter and energy. This is a preliminary exploration towards a specific,
comprehensive, testable calculation of cosmology from a fundamental theory in
which physics is produced by a quantum version of the two-dimensional
renormalization group.
