“…A further important aspect is the effect of a cross-diffusion term, which arises for instance by the modelling of interaction between species [21]. As already mentioned in [1,22], this may lead to unexpected behaviour, e.g., in our case the cross-diffusion term δ∆u, δ ≥ 0 requires that the growth exponent p(x, t) ≥ 2. Only if δ = 0 we may assume that 2n n+2 < p(x, t), n ≥ 2.…”