2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/167357The determination of the maximal ranks of a set of a given type of tensors is a basic problem both in theory and application. In statistical applications, the maximal rank is related to the number of necessary parameters to be built in a tensor model. Based on this classical theorem by Bosch we will show the tight bound for 2 x n x n tensors by simple row and column operations, symmetrization and mathematical induction, which has been given by several authors based on eigenvalue theories.17 pages, no figuresRings and Algebras15A69; 15A72; 14Q99; 14M12; 14M99text