for example, assume that, for each natural number formula_4 such that formula_48, a basis of formula_49 is formula_50, and assume that the tensor is expressed with respect to this basis as formula_51 where for each positive integer formula_4 such that formula_48, the notation formula_54 is meant to denote another positive integer formula_55, where formula_56 denotes the dimension of the vector space formula_49, or equivalently the number of elements in the basis formula_58 for formula_49.