The UDM plane with the most important areas, (see [44]). The dashed line represents the line; the dash-dotted line represents the line, the boundary between the decelerated expansion phase of the Universe and the accelerated one; the dotted line represents a fictitious boundary, above which the CDM-like behaviour of the UDM fluid dominates. The pressure and the energy density are normalised to (where ). The CDM model is represented here by the solid horizontal line , while the line represents an EdS model, that is, pure CDM.
