Editing Index notation (section)

===Multi-dimensional arrays===

{{main|Tensors}}
{{see also|Classical treatment of tensors}}

The notation allows a clear generalization to multi-dimensional arrays of elements: tensors. For example,

:<math> A_{i_1 i_2 \cdots } + B_{i_1 i_2 \cdots} = C_{i_1 i_2 \cdots} </math>

representing a set of many equations.

In tensor analysis, superscripts are used instead of subscripts to distinguish covariant from contravariant entities, see [[covariance and contravariance of vectors]] and [[raising and lowering indices]].