2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/64391We construct a subcrystal of the Littelmann's path crystal whose formal character coincides with that of a certain simple integrable module of level zero over the untwisted affine Lie algebra associated to sl_n. We also establish an analogue of the Littlewood-Richardson rule for the tensor product of that crystal with a highest weight crystal.25 pages, AMSLaTeX; to appear in the "Journal of Algebra"Quantum Algebratext