Cauchy surfaces and diffeomorphism types of globally hyperbolic spacetimes

Chernov–Nemirovski observed that the existence of a globally hyperbolic Lorentzian metric on a (3+1)-spacetime pins down a smooth structure on the underlying four-manifold. In this paper, we point out that the diffeomorphism type of a globally hyperbolic (n+1)-spacetime is determined by the h-cobordism class of its Cauchy surface, hence extending Chernov–Nemirovski's observation to arbitrary dimensions. (paper)