1,461 research outputs found
Unbeatable Imitation
We show that for many classes of symmetric two-player games, the simple
decision rule "imitate-the-best" can hardly be beaten by any other decision
rule. We provide necessary and sufficient conditions for imitation to be
unbeatable and show that it can only be beaten by much in games that are of the
rock-scissors-paper variety. Thus, in many interesting examples, like 2x2
games, Cournot duopoly, price competition, rent seeking, public goods games,
common pool resource games, minimum effort coordination games, arms race,
search, bargaining, etc., imitation cannot be beaten by much even by a very
clever opponent
Unbeatable Imitation
We show that for many classes of symmetric two-player games, the simple decision rule "imitate-the-best" can hardly be beaten by any other decision rule. We provide necessary and sufficient conditions for imitation to be unbeatable and show that it can only be beaten by much in games that are of the rock-scissors-paper variety. Thus, in many interesting examples, like 2x2 games, Cournot duopoly, price competition, rent seeking, public goods games, common pool resource games, minimum effort coordination games, arms race, search, bargaining, etc., imitation cannot be beaten by much even by a very clever opponent.Imitate-the-best, learning, symmetric games, relative payoffs, zero-sum games, rock-paper-scissors, finite population ESS, potential games, quasisubmodular games, quasisupermodular games, quasiconcave games, aggregative games
Unbeatable Imitation
We show that for many classes of symmetric two-player games, the simple decision rule "imitate-the-best" can hardly be beaten by any other decision rule. We provide necessary and sufficient conditions for imitation to be unbeatable in the sense that, even against a very clever opponent, imitation is subject to a money pump if and only if the relative payoff function of the game is of the rock-scissors-paper variety. For many interesting classes of games including examples like 2x2 games, Cournot duopoly, price competition, public goods games, common pool resource games, and minimum effort coordination games, we obtain an even stronger notion of the unbeatability of imitation.imitate-the-best, learning, symmetric games, relative payoffs, zero-sum games, rock-paper-scissors, finite population ESS, potential games, quasisubmodular games, quasisupermodular games, quasiconcave games, aggregative games
Unexploitable games and unbeatable strategies
Imitation is a simple behavior which uses successful actions of others in
order to handle one's tasks. Because success of imitation generally depends on
whether profit of an imitating agent coincides with those of other agents or
not, game theory is suitable for specifying situations where imitation can be
successful. One of the concepts describing successfulness of imitation in
repeated two-player symmetric games is unbeatability. For infinitely repeated
two-player symmetric games, a necessary and sufficient condition for some
imitation strategy to be unbeatable was specified. However, situations where
imitation can be unbeatable in multi-player games are still not clear. In order
to analyze successfulness of imitation in multi-player situations, here we
introduce a class of totally symmetric games called unexploitable games, which
is a natural extension of two-player symmetric games without exploitation
cycles. We then prove that, for infinitely repeated unexploitable games, there
exist unbeatable imitation strategies. Furthermore, we also prove that, for
infinitely repeated non-trivial unexploitable games, there exist unbeatable
zero-determinant strategies, which unilaterally enforce some relationships on
payoffs of players. These claims are demonstrated in the public goods game,
which is the simplest unexploitable game. These results show that there are
situations where imitation can be unbeatable even in multi-player games.Comment: 6 page
Once Beaten, Never Again: Imitation in Two-Player Potential Games
We show that in symmetric two-player exact potential games, the simple decision rule "imitate-if-better" cannot be beaten by any strategy in a repeated game by more than the maximal payoff difference of the one-period game. Our results apply to many interesting games including examples like 2x2 games, Cournot duopoly, price competition, public goods games, common pool resource games, and minimum effort coordination games.Imitate-the-best, learning, exact potential games, symmetric games, relative payoffs, zero-sum games
Once Beaten, Never Again: Imitation in Two-Player Potential Games
We show that in symmetric two-player exact potential games, the simple decision rule "imitate-if-better" cannot be beaten by any strategy in a repeated game by more than the maximal payoff difference of the one-period game. Our results apply to many interesting games including examples like 2x2 games, Cournot duopoly, price competition, public goods games, common pool resource games, and minimum effort coordination games
Social Network Reciprocity as a Phase Transition in Evolutionary Cooperation
In Evolutionary Dynamics the understanding of cooperative phenomena in
natural and social systems has been the subject of intense research during
decades. We focus attention here on the so-called "Lattice Reciprocity"
mechanisms that enhance evolutionary survival of the cooperative phenotype in
the Prisoner's Dilemma game when the population of darwinian replicators
interact through a fixed network of social contacts. Exact results on a "Dipole
Model" are presented, along with a mean-field analysis as well as results from
extensive numerical Monte Carlo simulations. The theoretical framework used is
that of standard Statistical Mechanics of macroscopic systems, but with no
energy considerations. We illustrate the power of this perspective on social
modeling, by consistently interpreting the onset of lattice reciprocity as a
thermodynamical phase transition that, moreover, cannot be captured by a purely
mean-field approach.Comment: 10 pages. APS styl
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