2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/184941There are investigated such cosmological models which instead of the usual spatial homogeneity property only fulfil the condition that in a certain synchronized system of reference all spacelike sections t = const. are homogeneous manifolds. This allows time-dependent changes of the BIANCHI type. Discussing differential geometrical theorems it is shown which of them are permitted. Besides the trivial case of changing into type I there exist some possible changes between other types. However, physical reasons like energy inequalities partially exclude them.10 pages, LaTeX, 1 figureGeneral Relativity and Quantum Cosmologytext