The origin of a classical background geometry in the quantum vacuum in
homogeneous master model is investigated. It is shown that the backgro
und appears at the moment when the horizon size has the order of the c
haracteristic scale of the inhomogeneity of the universe and that the
local anisotropy can be described by small perturbations. (C) 1997 Ame
rican Institute of Physics. [S0021-3640(97)00119-9].