# what is a folk theorem

In game theory, folk theorems are a class of theorems about possible Nash equilibrium payoff profiles in repeated games (Friedman 1971). The original Folk Theorem concerned the payoffs of all the Nash equilibria of an infinitely repeated game. This result was called the Folk Theorem because it was widely known among game theorists

Example: Repeated prisoner’s dilemma

Folk theorems are partially converse claims: they say that, under certain conditions (which are different in each folk theorem), every payoff that is both IR and feasible can be realized as a Nash equilibrium payoff profile in the repeated game.

In mathematics, the term folk theorem refers generally to any theorem that is believed and discussed, but has not been published. In order that the name of the theorem be more descriptive, Roger Myerson has recommended the phrase general feasibility theorem

Example: Repeated prisoner’s dilemma

Folk theorem may refer to: Folk theorem (game theory), a general feasibility theorem Ethnomathematics, the study of the relationship between mathematics and culture Mathematical folklore, theorems that are widely known to mathematicians but cannot be traced

Folk theorems are used in Economics specially in the field of game theory and specifically to repeated games. This theorem is said to be satisfactorily fulfilled when the equilibrium outcome in a game that is repeated an infinity number of times, is the same as the

Preliminaries

Ein Folk-Theorem beschreibt mögliche Gleichgewichte in wiederholten Spielen. Das Einsatzgebiet des Folk-Theorems ist die Modellierung von langfristigen Verträgen und Interaktionen von Menschen (zum Beispiel Kreditverträge, Gesellschaftsverträge, (implizite

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These findings are made precise in numerous folk theorems.8,9 Each folk theorem considers a class of games and identifies a set of payoff vectors each of which can

26/7/2019 · In 1995, when the US’ growth dipped from the previous year’s supercharged 4% to 2.7%, one of the finest macroeconomists of our time was the vice

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136 15. Repeated Games and the olkF Theorem es,gam dan ee eht extreme stimli of what ew can do whit ard-anrewd-punit tategies. 15.1 Finitlye Repaeedt Gasme A niytel repdeaet eamg s,i as sit name ,suggesst a eastg game thta si r epeated a nite breumn of

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Repeated Games and the Folk Theorem Lecture 9, Slide 10 RecapRepeated GamesIn nitely Repeated GamesFolk Theorem Finitely Repeated Games Everything is straightforward if we repeat a game a nite number of times we can write the whole thing as an

Folk theorem may refer to: Ethno-cultural studies of mathematics Mathematical folklore, theorems that are widely known to mathematicians but cannot be traced back to an individual In game theory, “the folk theorem” is a general feasibility theorem

Folk theorem may refer to: Folk theorem (game theory), a general feasibility theorem Ethnomathematics, the study of the relationship between mathematics and culture Mathematical folklore, theorems that are widely known to mathematicians but cannot be traced

Folk Theorem Folk Theorem è un teorema della teoria dei giochi. In un gioco ripetuto in un orizzonte temporale infinito, il teorema dimostra la convenienza ad adottare nel lungo periodo dei comportamenti che non sarebbero considerati ottimali nel breve periodo. In

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however, only established partial folk theorems in special restricted contexts, while the current paper presents a complete folk theorem with no restrictions on the underlying games. Next, we discuss commitments in real life and in some of the earlier theoretical

Folk theorem (game theory). Quite the same Wikipedia. Just better. Live Statistics English Articles Improved in 24 Hours Added in 24 Hours Languages Recent Deutsch Español עברית 日本語 中文 Show all languages What we do. Every page goes through

Das FOLK-Theorem besagt, dass jedes Auszahlungspaar in der »konvexen Hülle« P der Punkte (2, 2), (0, 3), (3, 0) und (1, 1) durch ein NASH-Gleichgewicht implementiert werden kann, wenn das Spiel mit unbegrenztem Zeithorizont wiederholt wird.

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deﬂnition of vi that allows randomizations, the Folk theorem would still hold, though proofs would become more involved. (Intuitively, randomization isn’t needed in the repeated setting, since we can simulate frequencies of play) . We say that a payoﬁ proﬂle (ri) is

The concept of folk psychology has played a significant role in philosophy of mind and cognitive science over the last half century. However, even a cursory examination of the literature reveals that there are at least three distinct senses in which the term “folk

17/5/2008 · A well-known result in game theory known as “the Folk Theorem” suggests that finding Nash equilibria in repeated games should be easier than in one-shot games. In contrast, we show that the problem of finding any (approximate) Nash equilibrium for a three-player

Sketch of proof The proof of the non-perfect folk theorem employs what is called a grim trigger strategy (Rubinstein 1979). All players start by playing the prescribed action and continue to do so until someone deviates. If player i deviates, all players switch to the

Why is the Folk Theorem of Repeated Prisoner’s Dilemma so important ? There are many analogies between Repeated Prisoner’s Dilemma (with an unknown end-round) and issues of competition, cooperation and coordination. Repeated/Iterated Prisoner’s dilemma

I take it that you have read and understood the Folk Theorem for repeated games. (Folk theorem (game theory)). The significance of it is that it allows for non-defection Nash equlibria in Prisoner’s Dilemma games which are infinitely repeated. T

In order that the name of the theorem be more descriptive, Roger Myerson has recommended the phrase general feasibility theorem in the place of folk theorem for describing theorems which are of this class. Sketch of proof Edit A commonly referenced proof of a.

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A Folk Theorem for One-Shot Bertrand Games Michael R. Baye Indiana University John Morgan Princeton University February 1999 Abstract We show that bounded monopoly proﬁts are essential for the uniqueness of the Bertrand paradox (zero proﬁt) outcome.

Folk theorem The theorem is that a Nash equilibrium exists in repeated games in which sufficiently patient players to reach Pareto optimal payoffs in a Nash equilibrium. (Fudenberg and Tirole, p 150, describes the achievable payoffs as the individually rational ones

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Concepts and Tools Finitely Repeated Prisoner’s Dilemma Inﬁnitely Repeated PD Folk Theorem Repeated games • Repeated games: given a simultaneous-move game G, a repeated game of G is an extensive game with perfect information and simultaneous moves

A commitment folk theorem shows that the potential of voluntary conditional commitments is essentially unlimited. All feasible and individually rational payoffs of a two-person strategic game can be attained at the equilibria of one (universal) commitment game

1/10/2011 · Human cognition is characterized by enormous variability and structured by universal psychological constraints. The focus of this chapter is on the development of knowledge acquisition because it provides important insight into how the mind interprets new

Econornetrica, Vol. 54, No. 3 (May, 1986), pp. 533-554 THE FOLK THEOREM IN REPEATED GAMES WITH DISCOUNTING OR WITH INCOMPLETE INFORMATION’ When either there are only two players or a “full dimensionality” condition holds, any

12/11/2013 · This video from Game Theory Online (http://www.game-theory-class.org) proves the Folk Theorem in the context of infinitely repeated games with discounted rewards