2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/29918The validity of Bethe ansatz wave function without the backward scattering for the problem of impurity in correlated hosts with periodic boundary condition is illustrated by a simple example of quantum mechanics. An long being overlooked point in solving Hubbard model by means of Bethe ansatz is indicated. A possible repairing on the Hamiltonian is suggested so that the well known solution is still valid.Revtex, 2 pages, 1 figureCondensed Mattertext