A seller sells a good of unknown quality to a buyer. He may certify his product , that is, announce that quality is at least equal to a certification level. If he doesn't observe himself the quality, he must first investigate to discover the quality before taking his certification decision. The...

We examine, in a network market open to competition, various mechanisms of allocation and funding for "universal service obligations". The obligations we consider are geographic "ubiquity" and non discrimination. We analyze, both from an efficiency and an equity point of views the respective...