Qualitative analysis of anisotropic and curved string cosmologies

A complete qualitative study of the dynamics of string cosmologies is prese nted for the class of isotopic curvature universes. These models are of Bia nchi types I, V and IX and reduce to the general class of Friedmann-Roberts on-Walker universes in the limit of vanishing shear isotropy. A non-trivial 2-form potential and cosmological constant terms are included in the syste m. In general, the 2-form potential and spatial curvature terms are only dy namically important at intermediate stages of the evolution. In many of the models, the cosmological constant is important asymptotically and anisotro py becomes dynamically negligible. There also exist bouncing cosmologies.