A Note on Invariant Temporal Functions

The purpose of this article is to present a result on the existence of Cauchy temporal functions invariant by the action of a compact group of conformal transformations in arbitrary globally hyperbolic manifolds. Moreover, the previous results about the existence of Cauchy temporal functions with additional properties on arbitrary globally hyperbolic manifolds are unified in a very general theorem. To make the article more accessible for non-experts, and in the lack of an appropriate single reference for the Lorentzian geometry background of the result, the latter is provided in an introductory section.