ABSTRACT
In other words, G is impartial only if every option of G is also impartial, and the collection of Left options coincides with the collection of Right ones.
Recall the convention {A, B,C, . . . } = {A, B, C, . . . I A, B, C, ...}. In view of this convention, it is natural to use G', rather than G*~ or G*, for the typical option of G, and to write G' e G to mean that G' is an option of G. So we identify each game with the set of all its options.
