2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/152089We prove that every suitable $4$-manifold with $b_1=0$ and with an embedded Riemann surface of genus $2$ is of simple type. We find a relationship between the basic classes of two of these $4$-manifolds and those of the connected sum along the Riemann surface.AMSLaTeX, 18 pages, no figuresDifferential Geometrytext