A note on stability and Cauchy time functions

Abstract

Since the solution of the so-called folk problems of smoothability, there has been a special interest in the properties of classical time and volume functions of spacetimes. Here we supply some information that complements the one provided in arXiv:1108.5120v3 and arXiv:1301.2909v1, and discuss some results. As an illustration, we show that any Cauchy temporal function for a globally hyperbolic spacetime remains Cauchy temporal for close metrics ---which, in particular, implies stability for global hyperbolicity.