Cosmology with a time-variable cosmological 'constant'

If the potential V(φ) of the scalar field that drove inflation had a power-law tail at large φ, V ~ φ^{-aplpha}^, the mass density, ρ<SUB>phi</SUB>_, associated with φ would act like a cosmological constant that decreases with time less rapidly than the mass densities of matter and radiation. If ρ<SUB>phi</SUB>_ were appreciable at the present epoch it could help reconcile the low dynamical estimates of the mean mass density with the negligibly small space curvature preferred by inflation.