  Interactions between dark matter and dark energy which result in a power-law
behavior (with respect to the cosmic scale factor) of the ratio between the
energy densities of the dark components (thus generalizing the LCDM model) have
been considered as an attempt to alleviate the cosmic coincidence problem
phenomenologically. We generalize this approach by allowing for a variable
equation of state for the dark energy within the CPL-parametrization. Based on
analytic solutions for the Hubble rate and using the Constitution and Union2
SNIa sets, we present a statistical analysis and classify different interacting
and non-interacting models according to the Akaike (AIC) and the Bayesian (BIC)
information criteria. We do not find noticeable evidence for an alleviation of
the coincidence problem with the mentioned type of interaction.

Cosmology and Nongalactic Astrophysics;General Relativity and Quantum Cosmology;High Energy Physics - Theory