In the 1950s and 60s, Japanese and US antitrust authorities occassionally used the degree of concentration to regulate industries. Does regulating firms based on their market shares make theoretical sense? We set up a simple duopoly model with stochastic R&D activities to evaluate market share...

We consider a (pure) public goods provision problem with voluntary participation in a quasi-linear economy. We propose a new hybrid solution concept, the free-riding-proof core (FRP-Core), which endogenously determines a contribution group, public good provision level, and its cost-sharing. The...

We consider a (pure) public goods provision problem with voluntary participation in a quasi-linear economy. We propose a new hybrid solution concept, the free-riding-proof core (FRP-Core), which endogenously determines a contribution group, public goods provision level, and how to share the...

We study international free-riding-proof coalitions to solve trans-boundary environmental problems such as global warming. We show that the free-riding problem is rather serious so that a free-riding-proof coalition can consist of only a small number of countries. In the optimal coalitional...