2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/33382We corrected a few errors in the previous submission. These do not affect any of the topological conclusions of the earlier version. We have also included a few observations about the Casson invariant of the Brieskorn homology spheres.Latex 2.09 with macros diagram.sty and auxdefs.sty; several errors corrected, new results includedDifferential Geometrytext