2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/150030In this paper we introduce a surgical procedure, called a rational blowdown, for a smooth 4-manifold X and determine how this procedure affects both the Donaldson and Seiberg-Witten invariants of X.34 pages with 14 figures (author-supplied), AMSLaTeXAlgebraic Geometry57N13 (Primary) 57R55 57R57 (Secondary)text