2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/98369These are notes of a talk given at the Mathematische Arbeitstagung 2005 in Bonn. Following ideas of Ozbagci-Stipsicz, a proof based on contact Dehn surgery is given of Eliashberg's concave filling theorem for contact 3-manifolds. The role of that theorem in the Kronheimer-Mrowka proof of property P for nontrivial knots is sketched.9 pagesSymplectic GeometryGeometric Topology57R17; 57R65, 53D35text