In interactive contexts such as games and economies, it is important to take account not only of what the players believe about substantive matters (such as payoffs), but also of what they believe about the beliefs of other players. Two different but equivalent ways of dealing with this matter,...

In [1], it was shown that in games of perfect information, common knowledge of rationality entails that the backward induction outcome is reached, and is consistent (for short, entails BI). That work has been criticized because it assumes that a player chooses rationally at all his nodes, even...

Define the riskiness of a gamble as the reciprocal of the absolute risk aversion (ARA) of an individual with constant ARA who is indifferent between taking and not taking that gamble. We characterize this index by axioms, chief among them a "duality" axiom that, roughly speaking, asserts that...

This groundbreaking series brings together a critical selection of key papers by the Nobel Memorial Laureates in Economics that have helped shape the development and present state of economics. The editors have organised this comprehensive series by theme and each volume focuses on those...