Recent techniques and results on the Erd\H{o}s-P\'osa property
  Several min-max relations in graph theory can be expressed in the framework of the Erd\H{o}s-P\'osa property. Typically, this property reveals a connection between packing and covering problems on graphs. We describe some recent techniques for proving this property that are related to tree-like decompositions. We also provide an unified presentation of the current state of the art on this topic. 
Jean-Florent Raymond and Dimitrios M. Thilikos
cs.DM math.CO