2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/67700We prove the uniqueness of crepant resolutions for some quotient singularities and for some nilpotent orbits. The finiteness of non-isomorphic symplectic resolutions for 4-dimenensional symplectic singularities is proved. We also give an example of symplectic singularity which admits two non-equivalent symplectic resolutions.This is an extended and revised versionAlgebraic Geometrytext