, etc., vanish in this case, the contribution to the energy tensor must be of the form
. We must therefore put
At rest, the density of the matter, or the energy per unit volume, is in this case, not
but
. For
, etc., vanish in this case, the contribution to the energy tensor must be of the form
. We must therefore put
At rest, the density of the matter, or the energy per unit volume, is in this case, not
but
. For