= Perfect recall
A player has perfect recall when the <information sets> never erase that player's previously available information or earlier chosen actions. With perfect recall, randomizing once over complete <pure strategies> and using suitable independent randomizations at information sets can induce the same outcome distributions.
Without perfect recall, one <information set> may be encountered twice on the same play path. A <behavioural strategy> then uses the same probabilities with fresh draws at both encounters; its outcome distribution need not be attainable by any <mixed strategy> over deterministic plans.
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