What is cmfr: Definition and 1 Discussions

Dirac ("GTR" p. 47) makes an interesting observation immediately after obtaining Einstein's field equations with the simple energy-momentum tensor ##T^{\mu\nu}=\rho v^\mu v^\nu##. (##v^\mu## is the four-velocity.) First, the conservation of matter ##\left( \rho v^\mu \sqrt{-g}...