M. Novello et al., Minimal closed set of observables in the theory of cosmological perturbations. IV. The anisotropic paradigm - art. no. 124025, PHYS REV D, 6112(12), 2000, pp. 4025
Following the analysis started in the Friedmann-Robertson-Walker framework,
we apply the method of constructing a minimal closed set of gauge-independ
ent observables to Kasner universes, which constitute a paradigm of type Bi
anchi-type I anisotropic spacetimes. An adequate basis is built for this sp
ecific background, and subsequently employed in a dynamical system that is
written in the framework of the quasi-Maxwellian equations. It is then foun
d that the method can be carried out to its end and a closed dynamical syst
em obtained. All three types of perturbation are presented and discussed in
the same way, but the scalar perturbation case is only partially solved.