•and
hence

•

•

•

•In a
homogeneous model the conservation equation yields the

•Chaplygin
gas density as a function of the scale factor *a
*

•

where *B* is an integration constant.The Chaplygin gas thus
interpolates

•between
dust (*ρ**~**a *-3 ) at large redshifts and a cosmological constant

(*ρ**~ A*½) today and hence yields a correct homogeneous
cosmology