# Uniqueness and non-uniqueness results for spacetime extensions

@inproceedings{Sbierski2022UniquenessAN, title={Uniqueness and non-uniqueness results for spacetime extensions}, author={Jan Sbierski}, year={2022} }

Given a function f : A → R n of a certain regularity deﬁned on some open subset A ⊆ R m , it is a classical problem of analysis to investigate whether the function can be extended to all of R m in a certain regularity class. If an extension exists and is continuous, then certainly it is uniquely determined on the closure of A . A similar problem arises in general relativity for Lorentzian manifolds instead of functions on R m . It is well-known, however, that even if the extension of a…

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