Sets closed under rational behavior were introduced by Basu and Weibull (1991) as subsets of the strategy space that contain all best replies to all strategy profiles in the set. We here consider a more restrictive notion of closure under rational behavior: a subset of the strategy space is...

This paper provides two conditions of epistemic robustness, robustness to alternative best replies and robustness to non-best replies, and uses them to characterize variants of curb sets in finite games, including the set of rationalizable strategies.