2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/154380For a quantum Hamiltonian H =H(p) the observability of the energies E may be robust (whenever all E are real at all p) or, otherwise, conditional. Using a pseudo-Hermitian family of N-state chain models H we discuss some generic properties of conditionally observable spectra.21 pp incl. 10 figMathematical Physicstext