2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/199585We propose an action for a sine-Gordon-like theory, which reproduces the classical equations of motion of the Green-Schwarz-Metsaev-Tseytlin superstring on AdS(5) x S(5). The action is relativistically invariant. It is a mass-deformed gauged WZW model for SO(4,1) x SO(5) / SO(4) x SO(4) interacting with fermions.19 pages, LaTeX; v2: added discussion of zero modes in Section 3; v3: improved presentationHigh Energy Physics - Theorytext