Volume comparison for Lorentzian warped products with integral curvature bounds
The author associates in a sophisticated way to every globally hyperbolic \(n\)-dimensional space-time \((M,g)\) a Robertson-Walker space-time \((\overline M,\overline g)\). Here \(\overline g\) is built from the Riemannian metric \(h\) induced by \(g\) on space-like spheres and from a warping function \(f\) which satisfies a Jacobi differential equation. The volume of compact sets with respect to \(g\) and with respect to \(\overline g\) is compared in the spirit of Bishop-Gromov.
scientific article; zbMATH DE number 5125276