Stable accelerating universe with no hair
  After reviewing the main characteristics of the spacetime of accelerating universes driven by a quintessence scalar field with constant equation of state $\omega$, we investigate in this paper the classical stability of such spaces to cosmological perturbations, particularizing in the case of a closed geometry and equation of state $\omega=-2/3$. We conclude that this space is classically stable and conjecture that accelerating universes driven by quintessential fields have "no-hair". 
Pedro F. Gonzalez-Diaz (IMAFF, CSIC, Madrid)