In their most general and abstract definitions as Mathematical Objects :
- A Scalar is an element of a field used to define Vector Spaces
- A Vector is an element of a Vector Space.
Since a Scalar is a Tensor of rank-0 and a Vector is a Tensor of rank-1, then what Space are Tensors an element of?
Can you even think of Tensors abstractly as elements of a Mathematical Space?
Rank one tensors, on a vector space $V$ over the scalar field $\Bbb F$, are linear maps $$V\to\Bbb F$$ and $$V^*\to\Bbb F,$$ where $V^*$ is the dual space of $V$.
Rank two tensors are bilinear maps $$V\times V\to\Bbb F,$$ $$V^*\times V\to\Bbb F,$$ $$V^*\times V^*\to\Bbb F.$$
Rank three tensors are trilinear maps $$V\times V\times V\to\Bbb F,$$ $$V^*\times V\times V\to\Bbb F,$$ $$V^*\times V^*\times V\to\Bbb F,$$ $$V^*\times V^*\times V^*\to\Bbb F,$$ and so on.