Also known as CANDECOMP/PARAFAC (CP) decomposition, it expresses a tensor as a sum of rank-1 outer-product terms.
Introduced by Frank Lauren Hitchcock in 1927 in the Journal of Mathematics and Physics 6, pp. 164–189, and rediscovered several times, notably in psychometrics.
Contrary to the matrix case, computing the rank of a tensor is NP-hard.