The clear definition of property rights is not a sufficient condition to prevent congestion effects in commons. In this paper we present how interesting can be the coordination among owners in the preservation of the common good. Our approach takes into account economic dynamics and incentive...

Ce papier aborde la question de la subsidiarité dans le cadre de la Politique Agricole Commune. L'instrument privilégié est ici un contrat de gel de terre dont la définition relève soit directement des instances de l'Union Européenne, soit des instances nationales. Dans ce dernier cas, dit...

Nitrate pollution from agriculture is an important environmental problem, caused bythe excessive use of inorganic fertilizers. The internalization of this externality, via a tax onmineral nitrogen, could lead to a second best solution, reducing nitrate emissions. Severalauthors suggest that a...