2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/130106The two-state vector formalism (TSVF), the time-symmetric description of the standard quantum mechanics originated by Aharonov, Bergmann and Lebowitz is reviewed. The TSVF describes a quantum system at a particular time by two quantum states: the usual one, evolving forward in time, defined by the results of a complete measurement at the earlier time, and by the quantum state evolving backward in time, defined by the results of a complete measurement at a later time.6 pages, entry for a forthcoming "Compendium of Quantum Physics"Quantum Physicstext