  These 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.

Symplectic Geometry;Geometric Topology