Phantom Energy with Variable G and Λ

We investigate a cosmological model of a phantom energy with a variable cosmological constant (Λ) depending on the energy density (ρ) as Λ∝ρ^-α, α=const and a variable gravitational constant G. The model requires α<0 and a negative gravitational constant. The cosmological constant evolves with time as Λ∝t^-2. For Ω>-1 and α<-1 the cosmological constant Λ<0, G>0 and ρ decrease with cosmic expansion. For ordinary energy (or dark energy), i.e.~ω>-1, we have -1<α<0 and β>0 so that G>0 increases with time and ρ decreases with time. Cosmic acceleration with dust particles is granted, provided -2/3<α<0 and Λ>0.