2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/93213A recent result about measurability of a quantum state of a single quantum system is generalized to the case of a single pre- and post-selected quantum system described by a two-state vector. The protection required for such measurement is achieved by coupling the quantum system to a pre- and post-selected protected device yielding a nonhermitian effective Hamiltonian.TeX, 11 pagesQuantum Physicstext