Before revision:  These restrictions are inspired by the idea that trembles correspond to deliberate experiments by inexperienced agents who are unsure of the prevailing distribution of play in opponent populations, and that different players' relative "compatibilities" with various strategies determine the relative frequencies of their experiments.
After revision:  These restrictions are inspired by the idea that trembles correspond to deliberate experiments by agents who are unsure of the prevailing distribution of play in opponent populations, and that different players' relative "compatibilities" with various strategies determine the relative frequencies of their experiments.