2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/31434In this paper we propose a simple and efficient data structure yielding a perfect hashing of quite general arrays. The data structure is named phorma, which is an acronym for perfectly hashable order restricted multidimensional array. Keywords: Perfect hash function, Digraph, Implicit enumeration, Nijenhuis-Wilf combinatorial family.12 pages, 4 figures, 2 tables. Revised version. Submitted to Discrete Applied MathematicsData Structures and AlgorithmsE.2;E.1text