2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/138886It is shown that von Neumann-Landau equation for wave functions can present a mathematical formalism of motion of quantum mechanics. The wave functions of von Neumann-Landau equation for a single particle are `bipartite', in which the associated Schrödinger's wave functions correspond to those `bipartite' wave functions of product forms. This formalism establishes a mathematical expression of wave-particle duality and that von Neumann's entropy is a quantitative measure of complementarity between wave-like and particle-like behaviors. Furthermore, this extension of Schrödinger's form suggests that collapses of Schrödinger's wave functions can be regarded as the simultaneous transition of the particle from many levels to one.4 pagesQuantum Physicstext