Publication Type
Working Paper
Version
publishedVersion
Publication Date
3-2024
Abstract
A social choice function (SCF) is robustly implementable in rationalizable strate-gies if every rationalizable strategy profile on every type space results in outcomes consistent with it. First, we establish an equivalence between robust implementation in rationalizable strategies and “weak rationalizable implementation”. Second, using the equivalence result, we identify weak robust monotonicity as a necessary and al-most sufficient condition for robust implementation in rationalizable strategies. This exhibits a contrast with robust implementation in interim equilibria, i.e., every equilib-rium on every type space achieves outcomes consistent with the SCF. Bergemann and Morris (2011) show that strict robust monotonicity is a necessary and almost sufficient condition for robust implementation in interim equilibria. We argue that strict robust monotonicity is strictly stronger than weak robust monotonicity, which further implies that, within general mechanisms, robust implementation in rationalizable strategies is more permissive than robust implementation in interim equilibria. The gap between robust implementation in rationalizable strategies and that in interim equilibria stems from the strictly stronger nonemptiness requirement inherent in the latter concept.
Keywords
Ex post incentive compatibility, rationalizability, interim equilibrium, robust implementation, weak rationalizable implementation, weak robust monotonicity
Discipline
Economic Theory
Research Areas
Economic Theory
First Page
1
Last Page
75
Publisher
SMU Economics and Statistics Working Paper Series, Paper No. 10-2020
Citation
KUNIMOTO, Takashi and SARAN, Rene.
Robust implementation in rationalizable strategies in general mechanisms. (2024). 1-75.
Available at: https://ink.library.smu.edu.sg/soe_research/2373
Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-No Derivative Works 4.0 International License.