2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/171682We construct the moduli spaces of stable maps, \bar M_g,n(P^r,d), via geometric invariant theory (GIT). This construction is only valid over Spec C, but a special case is a GIT presentation of the moduli space of stable curves of genus g with n marked points, \bar M_g,n; this is valid over Spec Z. Our method follows that used in the case n=0 by Gieseker to construct \bar M_g, though our proof that the semistable set is nonempty is entirely different.75 pages LaTeX; the GIT construction of moduli spaces of stable n-pointed curves is now given over the integersAlgebraic Geometry14H10 (Primary); 14D22, 14N35 (Secondary)text