Harsanyi
John Charles Harsanyi (May 29, 1920 – August 9, 2000) was a Hungarian-American economist and Nobel Laureate in Economics. He is best known for his contributions to game theory, particularly his work on games of incomplete information and the use of Bayesian games to model these situations.
Harsanyi's key contributions include:
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Incomplete Information: He developed a rigorous mathematical framework for analyzing games where players do not have perfect information about each other's preferences, beliefs, or strategies. This framework, known as Bayesian game theory, revolutionized the field by allowing economists and social scientists to model real-world situations where uncertainty and asymmetric information are prevalent.
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Harsanyi Doctrine: This doctrine states that when modeling games with incomplete information, seemingly different private information that players might have must be represented as different "types" of players drawn from a common prior distribution. This ensures that all players ultimately share a common understanding of the underlying possibilities, even if they have different private information.
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Utilitarianism: Harsanyi was a prominent advocate of utilitarianism, arguing that social welfare should be maximized by summing the utilities of all individuals in society. He provided formal justifications for this ethical position based on considerations of impartiality and rationality.
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Nash Bargaining Solution: He offered a non-cooperative game-theoretic foundation for the Nash bargaining solution, showing how it could be derived from a limiting case of a non-cooperative game with a small amount of incomplete information.
Harsanyi's work has had a profound impact on economics, political science, philosophy, and other social sciences. His development of Bayesian game theory provided a powerful tool for analyzing a wide range of strategic interactions, from auctions and bargaining to voting and political competition. He shared the 1994 Nobel Memorial Prize in Economic Sciences with John Nash and Reinhard Selten for their pioneering work in game theory.