 Since player’s information varies as the game progresses, it is useful to think of moves of the game as indexed by times, and to introduce operators \(O\) and \(U\) from tense logic for ‘next’ and ‘until’. Then \(K_i OA \rightarrow OK_i A\) expresses that player \(i\) has “perfect recall”, that is, that when \(i\) knows that \(A\) happens next, then at the next moment \(i\) has not forgotten that \(A\) has happened. This illustrates how modal logics for games can reflect cognitive idealizations, and a player’s success (or failure) at living up to them.