2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/57474Necessary and sufficient conditions for a dense subspace of a Hilbert space to be a linear Hilbertian manifold domain are given. Some relations between linear Hilbertian manifold domains and domains of self-adjoint operators are found.9 pages, LatexMathematical Physicstext