For a club such as the European Union, an important question is when, and under which conditions, a subset of the members should be allowed to form "inner clubs" and enhance cooperation. Flexible cooperation allows members to participate if and only if they benefit, but it generates a freerider...

Does European economic integration create more inequality between domestic regions, or is the opposite true? We show that a general answer to this question does not exist, and that the outcome depends on the liberalisation scenario. In order to examine the impact of European and international...