Examples of the redshift dependence of the dark energy equation of state in the three models considered in this work, for various choices of the free parameters in the models. Blue dashed, red dotted, and black solid lines correspond, respectively, to the Models B, C and L described in the text – cf. respectively, Eqs. (7), (9), and (11). The top left panel has w₀ = −0.9 and Δ = 0.2, the top right one has w₀ = −0.99 and Δ = 0.2, the bottom left one has w₀ = −0.9 and Δ = 0.8, and the bottom right one has w₀ = −0.99 and Δ = 0.8.