Generally speaking relativity, a vanishing pressure–energy tensor implies, by Einstein area equations, the vanishing of all of the components on the Ricci tensor. Vacuum won't suggest the curvature of House-time is automatically flat: the gravitational industry can however produce curvature in a very vacuum in the form of tidal forces http://arvadavacuum32197.qowap.com/52853468/everything-about-vacuum-arvada