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(Wald's GR book) Isotropy implying constant curvature
Context
In Wald's GR book, p. 94 of chapter 5, he gives an argument for why isotropy and homogeneity implies constant curvature.
In summary, it goes like this: We can take the induced metric, $h_{ab}$,...
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Topology in cosmology
Usually in cosmology, we make the hypothesis that the universe is isotropic.
Which conditions does this hypothesis impose on the topology of the universe? Does it fix completely the topology? Are all ...
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Canonical form of structure constants and mutually orthogonal triad on the orbits of Bianchi cosmologies
In Class. Quant. Grav. 28 (2011) 185007: "Linearization of homogeneous, nearly-isotropic cosmological models" at the start of section 2.3 the authors (Andrew Pontzen and Anthony Challinor) claim that ...
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