Inhomogeneous and anisotropic cosmologies
Although the purpose of this workshop is to discuss the structures in the universe, which are inhomogeneous, homogeneous models have been used in considering many of the cosmological issues raised in that discussion, so I have also included in this survey the anisotropic homogeneous models and their implications. Only exact solutions will be covered: other speakers at Pont d’Oye (e.g. Bardeen, Brandenberger, Dunsby and Ellis) gave very full discussions of perturbation theory. Here I continue my previous practice (MacCallum 1979, 1984), by using the mathematical classification of the solutions as an overall scheme of organization; the earlier reviews give additional details and references. (A survey organized by the nature of the applications is to appear in the proceedings of Dennis Sciama’s 65th birthday meeting.) Other useful reviews are: Ryan and Shepley (1975) on homogeneous anisotropic models; Krasinski (1990) on inhomogeneous models; and Verdaguer (1985, 1992) on models of solitonic character.