Muñoz, VicenteTralle, Aleksy2023-06-192023-06-1920150025-587410.1007/s00209-015-1494-8https://hdl.handle.net/20.500.14352/34868We construct a compact simply-connected 7-dimensional manifold admitting a K-contact structure but not a Sasakian structure. We also study rational homotopy properties of such manifolds, proving in particular that a simply-connected 7-dimensional Sasakian manifold has vanishing cup-product on the second cohomology and that it is formal if and only if all its triple Massey products vanish.engjournal articlehttp://link.springer.com/article/10.1007%2Fs00209-015-1494-8http://arxiv.org/pdf/1408.2496v2.pdfopen access514515.1Contact structureFormalitySasakian manifoldSymplectic manifoldGeometríaTopología1204 Geometría1210 Topología