In this paper, we show that in pure exchange economies where the number of goods equals or exceeds the number of agents, any Pareto-efficient and strategy-proof allocation mechanism always allocates the total endowment to some single agent even if the receivers vary.

Costless pre-play communication has been found to effectively facilitate coordination and enhance efficiency in games with Pareto-ranked equilibria. We report an experiment in which two groups compete in a weakest-link contest by expending costly efforts. Allowing intra-group communication leads...

We revisit Sen's (1970) Paradox in its formulation for collective choice rules. It is well-known that under unrestricted domain, binary liberalism (BL) and the global (resp. binary) Weak Pareto principle (GWP/BWP) are incompatible with binary rejection consistency (resp. binariness). We first...