Although we have restricted ourselves to the case of a vanishing cosmological constant this does not mean that other cases have not been analyzed. Friedrich  has shown the existence of asymptotically simple de Sitter type solutions of the Einstein-Maxwell–Yang–Mills equations and stability of de Sitter space. More recently , with the general version of his conformal field equations, he was able to demonstrate the existence of asymptotically simple anti-de Sitter type solutions.
It should also be mentioned that some work has gone into generalizing the Bondi–Sachs calculations to poly-homogeneous space-times [34, 160, 161].
The structure of space-like infinity has been discussed here only in a rather cursory way. A very recent account of the relationship between static solutions and the role they play can be found in . Readers who are interested in a more detailed treatment of the subject in general are referred to a recent review by Friedrich .
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