Tensor

What is a tensor?

In a spacetime, the Riemann curvature tensor has 256 components, but fortunately they don't all have to be directly calculated thanks to some symmetries.

The tensor #92;alpha#95;#123;ij#125; should really be called a “tensor of second rank,” because it has two indexes. A vector—with one index—is a tensor of the first rank, and a scalar—with no index—is a tensor of zero rank.