2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/72895We present an extension of Naimark's duality principle which states that complete systems in a Hilbert space are projections of $ω$-linearly independent systems of elements of an ambient Hilbert space. This result is presented in the context of other known extensions of Naimark's theorem.Functional Analysis42C40text