0
Tensor calculus Einstein was non that good at mathematics.
R=0
where
Rici curvature tensor=0
Einstein states that Rici tensor is identically 0 which probably means space-time is non curved
A first rank tensor is called a vector.
A massless spin-2 field would be indistinguishable from, or it would describe gravity, if its equations of motions are the Einstein field equations.
A zero tensor is a tensor with all entries equal to zero.
tensor.