We prove that group strategy-proofness and strategy-proofness are equivalent requirements on stable mechanisms in priority-based resource allocation problems with multi-unit demand. The result extends to the model with contracts

"Strategy-proofness" is one of the axioms that are most frequently used in the recent literature on social choice theory. It requires that by misrepresenting his preferences, no agent can manipulate the outcome of the social choice rule in his favor. The stronger requirement of "group...

A Principal appoints a committee of partially informed experts to choose a policy. The experts' preferences are aligned with each other but conflict with hers. We study whether she gains from banning committee members from communicating or \deliberating" before voting. Our main result is that if...