2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/168722We extend several results of the third author and C. Malvenuto on graph-different permutations to the case of directed graphs and introduce new open problems. Permutation capacity is a natural extension of Sperner capacity from finite directed graphs to infinite digraphs. Our subject is combinatorial in nature, but can be equally regarded as zero-error information theory.11 pages, no figuresCombinatoricsInformation Theory05D05; 05C69: 05C69; 94A24text