2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/62030In this paper we demonstrate the existence of Sasakian-Einstein structures on certain 2-connected rational homology 7-spheres. These appear to be the first non-regular examples of Sasakian-Einstein metrics on simply connected rational homology spheres. We also briefly describe the rational homology 7-spheres that admit regular positive Sasakian structures.19 pagesDifferential GeometryAlgebraic Geometry53C25, 53C12, 14E30text