Isotropic singularities in cosmological models

摘要: Motivated by the ideas of quiescent cosmology and Penrose's Weyl tensor hypothesis concerning 'big bang', authors give a geometric (and hence coordinate-independent) definition concept 'isotropic singularity' in spacetime. The generalises previous work on 'quasi-isotropic' 'Friedman-like' singularities. They discuss simple consequences definition. In particular it is shown that an isotropic singularity scalar polynomial curvature at which dominated Ricci tensor. Finally they impose Einstein field equations with irrotational perfect fluid source. This enables them to detailed description structure singularity.