2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/127663The support of a matrix M is the (0,1)-matrix with ij-th entry equal to 1 if the ij-th entry of M is non-zero, and equal to 0, otherwise. The digraph whose adjacency matrix is the support of M is said to be the digraph of M. This paper observes some structural properties of digraphs of unitary matrices.19 pages. Accepted for publication in Ars CombinatoriaCombinatoricsQuantum PhysicsPrimary 05C50; Secondary 05C25text