Stability of the de-Sitter spacetime. The anisotropic case.

We elaborate on the cosmological implications of the recently established non-perturbative O (D , D) -symmetric approach. Following the α ′ -complete Friedmann equations, we provide a qualitative description of the dynamics of anisotropy perturbations. We find that the spacetime stability depends on the sign of the generalized dilaton time derivative. We consider isotropic limits and find possible mechanism for pre-big bang cosmology, governed by the value of cosmological constant. [ABSTRACT FROM AUTHOR]