Two hypotheses concerning the Lagrange function postulating for a system with electromagnetic interactions: "vortex" (classic) and "gradient" (new) are compared. It is shown that the gradient hypothesis, unlike the vortex one, does not result in conflict between the Aharonov-Bohm (AB) effect and the locality principle. A modification of AB effect in Zero Magnetic (ZM) oscillation of potential around excited closed waveguide is predicted.