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–Nemirovskiʼs observation to arbitrary dimensions.