2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/75676Motivated by Stipsicz and Szabó's exotic 4-manifolds with b_2^+=3 and b_2^-=8, we construct a family of simply connected smooth 4-manifolds with b_2^+=3 and b_2^-=8. As a corollary, we conclude that the topological 4-manifold 3{CP}^2#8{-CP}^2 admits infinitely many distinct smooth structures.Minor errors are correctedGeometric Topology57R17, 57R57, 57N13text