The initial fate of an anisotropic JBD universe

Abstract

The dynamical effects on the scale factors due to the scalar $ϕ$-field at the early stages of a supposedly anisotropic Universe expansion in the scalar-tensor cosmology of Jordan-Brans and Dicke is studied. This universe shows an {\sl isotropic} evolution and, depending on the value of the theorie&#39;s coupling parameter $ω$, it can begin from a singularity if $ω>0$ and after expanding shrink to another one; or, if $ω<0$ and $-3/2< ω\leq -4/3$, it can evolve from a flat spatially-infinite state to a non extended singularity; or, if $ -4/3 < ω< 0$, evolve from an extended singularity to a non singular state and, at last, proceed towards a singularity.