Rational blow-downs in Heegaard-Floer homology
  The paper describes how known results in Heegaard-Floer homology apply to all known examples of rational blow-downs, and provides several new four dimensional pieces which could be exchanged while preserving some of the Ozsv\'ath-Szab\'o four manifold invariants, when one of these pieces is found embedded in a smooth four manifold. 
Lawrence Roberts