Bartnik's cosmological splitting conjecture in terms of Lorentz-distance families

Let (M,g)(M,g) be a globally hyperbolic, timelike geodesically complete spacetime with compact Cauchy surfaces satisfying the strong energy condition. For a Cauchy temporal function τa\tau a and its level sets

Σt:={τ=t},\Sigma_t:=\{\tau=t\},

consider the families of Lorentz distances {(,Σt)}t>0\{\ell(\cdot,\Sigma_t)\}_{t>0} and {(Σt,)}t>0\{\ell(\Sigma_{-t},\cdot)\}_{t>0}. Bartnik's cosmological splitting conjecture. There exists a Cauchy temporal function τC(M)\tau\in C^\infty(M) such that one of these two families is locally equi-Lipschitz. This formulation is stated as equivalent to Bartnik's cosmological splitting conjecture; the paper's counterexamples show that compactness of Cauchy surfaces and the strong energy condition cannot independently be omitted, so the conjecture is refuted by the counterexamples discussed in the paper.

Sources & referencesView supporting material

Primary source

Gregory J. Galloway, Robert J. McCann and Argam Ohanyan, “Failure of local equi-Lipschitzness for families of Lorentz distances to Cauchy surface foliations”, arXiv:2606.21997 (2026).

Additional references

10 papers in this index state this conjecture (2007–2026). The statement above is taken from the most recent of them; the others are arXiv:2410.16619, arXiv:2407.21524, arXiv:2311.13715, arXiv:1902.08803, arXiv:1810.03183, arXiv:1809.02071, arXiv:1712.00785, arXiv:1608.06353, arXiv:0712.1321.

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