2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/91647We investigate the canonical forms of positive partial transposition (PPT) density matrices in ${\cal C}^2 \otimes {\cal C}^M \otimes {\cal C}^N$ composite quantum systems with rank $N$. A general expression for these PPT states are explicitly obtained. From this canonical form a sufficient separability condition is presented.11 pages, LatexQuantum Physicstext