On the Dominance of Truth-Telling in Gradual Mechanisms

Recent literature highlights the advantages of implementing social rules via dynamic game forms. We characterize when truth-telling remains a dominant strategy in gradual mechanisms implementing strategy-proof social rules, where agents gradually reveal their private information while acquiring information about others in the process. Our first characterization hinges on the incentive-preservation of a basic transformation on gradual mechanisms called illuminating that partitions information sets. The second relies on a single reaction-proofness condition. We demonstrate the usefulness of both characterizations through applications to second-price auctions and the top-trading cycles algorithm.