Thermodynamics of dark energy interacting with dark matter and radiation
  We investigate the validity of the generalized second law of thermodynamics,
in the cosmological scenario where dark energy interacts with both dark matter
and radiation. Calculating separately the entropy variation for each fluid
component and for the apparent horizon itself, we show that the generalized
second law is always and generally valid, independently of the specific
interaction form, of the fluids equation-of-state parameters and of the
background geometry.
