The Experts below are selected from a list of 5976 Experts worldwide ranked by ideXlab platform
Zhihai Rong - One of the best experts on this subject based on the ideXlab platform.
-
timescale diversity facilitates the emergence of cooperation Extortion alliances in networked systems
2019Co-Authors: Zhihai Rong, Zhihong TianAbstract:Abstract Extortion strategies, which can unilaterally guarantee the Extortionate agent’s payoff not less than its opponent, have attracted lots of attention. It has been found that Extortion plays a nontrivial role in the evolution of unconditional cooperation in networked systems. In this paper, we investigate the influence of timescale diversity on the evolution of three strategies, i.e., unconditional cooperation, unconditional defection, and Extortion. It is shown that diversifying the timescales can significantly promote the emergence of unconditional cooperation. Particularly, with the diversity of timescales, cooperators can slow down their update speed while obtaining high payoffs. Therefore, they are able to form stable alliances with Extortioners, which helps them to resist the invasion of defectors. Eventually, the cooperation-Extortion alliance can eliminate defection in the networked system.
-
the emergence of cooperation Extortion alliance on scale free networks with normalized payoff
2018Co-Authors: Yajun Mao, Zhihai RongAbstract:Based on the Prisoner's Dilemma game, this paper investigates the evolution of Extortion behavior with cooperation and defection strategies on the Barabasi-Albert (BA) scale-free network under the normalized payoff framework. Using Monte Carlo simulations, we show that the cooperation-Extortion alliance emerges, and Extortioners can act as catalysts to help cooperators survive on the scale-free network. Moreover, we find the non-trivial influence of the Extortion factor on the evolution of cooperation, which implies that there exists an optimal value of the Extortion factor with which the cooperation-Extortion alliance is mostly favored and may defeat defectors on the networks with the normalized payoff framework.
-
Extortion provides alternative routes to the evolution of cooperation in structured populations
2017Co-Authors: Zhihai Rong, Tao Zhou, Chi K TseAbstract:In this paper, we study the evolution of cooperation in structured populations (individuals are located on either a regular lattice or a scale-free network) in the context of repeated games by involving three types of strategies, namely, unconditional cooperation, unconditional defection, and Extortion. The strategy updating of the players is ruled by the replicator-like dynamics. We find that Extortion strategies can act as catalysts to promote the emergence of cooperation in structured populations via different mechanisms. Specifically, on regular lattice, Extortioners behave as both a shield, which can enwrap cooperators inside and keep them away from defectors, and a spear, which can defeat those surrounding defectors with the help of the neighboring cooperators. Particularly, the enhancement of cooperation displays a resonance-like behavior, suggesting the existence of optimal Extortion strength mostly favoring the evolution of cooperation, which is in good agreement with the predictions from the generalized mean-field approximation theory. On scale-free network, the hubs, who are likely occupied by Extortioners or defectors at the very beginning, are then prone to be conquered by cooperators on small-degree nodes as time elapses, thus establishing a bottom-up mechanism for the emergence and maintenance of cooperation.
-
The influence of Extortion diversity on the evolution of cooperation in scale-free networks
2016Co-Authors: Zhihai Rong, Xiongrui XuAbstract:Extortion strategies, which can let an individual's surplus exceed her opponent's by a fixed percentage, have played an important role in the understanding of the evolution of cooperation in the Prisoner's Dilemma game. In this paper, we combine individuals' Extortion ability with their degrees, and study the influence of Extortion diversity in the heterogeneous scale-free network. Our investigation shows that, when individuals' Extortion factors are negative correlation with their degrees, these Extortionate hubs play as catalysts to enhance the emergence of cooperative behavior. However, when the Extortion factors are positively correlated with degrees, the effect of hub's catalyst is weaken.
-
Extortion under uncertainty zero determinant strategies in noisy games
2015Co-Authors: Dong Hao, Zhihai Rong, Tao ZhouAbstract:Repeated game theory has been one of the most prevailing tools for understanding long-running relationships, which are the foundation in building human society. Recent works have revealed a new set of "zero-determinant" (ZD) strategies, which is an important advance in repeated games. A ZD strategy player can exert unilateral control on two players' payoffs. In particular, he can deterministically set the opponent's payoff or enforce an unfair linear relationship between the players' payoffs, thereby always seizing an advantageous share of payoffs. One of the limitations of the original ZD strategy, however, is that it does not capture the notion of robustness when the game is subjected to stochastic errors. In this paper, we propose a general model of ZD strategies for noisy repeated games and find that ZD strategies have high robustness against errors. We further derive the pinning strategy under noise, by which the ZD strategy player coercively sets the opponent's expected payoff to his desired level, although his payoff control ability declines with the increase of noise strength. Due to the uncertainty caused by noise, the ZD strategy player cannot ensure his payoff to be permanently higher than the opponent's, which implies dominant Extortions do not exist even under low noise. While we show that the ZD strategy player can still establish a novel kind of Extortions, named contingent Extortions, where any increase of his own payoff always exceeds that of the opponent's by a fixed percentage, and the conditions under which the contingent Extortions can be realized are more stringent as the noise becomes stronger.
Daniel Traca - One of the best experts on this subject based on the ideXlab platform.
-
corruption and bilateral trade flows Extortion or evasion
2010Co-Authors: Pushan Dutt, Daniel TracaAbstract:Abstract We analyze the impact of corruption on bilateral trade, highlighting its dual role in terms of Extortion and evasion. Corruption taxes trade, when corrupt customs officials in the importing country extort bribes from exporters (Extortion effect); however, with high tariffs, corruption may be trade enhancing when corrupt officials allow exporters to evade tariff barriers (evasion effect). We derive and estimate a corruption-augmented gravity model, where the effect of corruption on trade flows is ambiguous and contingent on tariffs. Empirically, corruption taxes trade in the majority of cases, but in high-tariff environments (covering 5% to 14% of the observations) their marginal effect is trade enhancing.
-
corruption and bilateral trade flows Extortion or evasion
2007Co-Authors: Pushan Dutt, Daniel TracaAbstract:This paper analyzes the impact of corruption on bilateral trade flows, highlighting the dual role of corruption in terms of Extortion and evasion. On one hand, corruption taxes trade, when corrupt customs officials in the importing country extort bribes from exporters (the Extortion effect); on the other, if tariffs are high, corruption may be trade enhancing, when the corrupt officials allow exporters to evade tariff barriers (the evasion effect). The paper derives and estimates a corruption-augmented gravity model that shows that the effect of corruption on trade flows is ambiguous and is contingent on the level of tariffs. The predictions are borne out in the data: corruption taxes trade in the majority of cases, but in high tariff environments (covering 5-14% of the observations,) its marginal effect is trade-enhancing.
Tao Zhou - One of the best experts on this subject based on the ideXlab platform.
-
Extortion provides alternative routes to the evolution of cooperation in structured populations
2017Co-Authors: Zhihai Rong, Tao Zhou, Chi K TseAbstract:In this paper, we study the evolution of cooperation in structured populations (individuals are located on either a regular lattice or a scale-free network) in the context of repeated games by involving three types of strategies, namely, unconditional cooperation, unconditional defection, and Extortion. The strategy updating of the players is ruled by the replicator-like dynamics. We find that Extortion strategies can act as catalysts to promote the emergence of cooperation in structured populations via different mechanisms. Specifically, on regular lattice, Extortioners behave as both a shield, which can enwrap cooperators inside and keep them away from defectors, and a spear, which can defeat those surrounding defectors with the help of the neighboring cooperators. Particularly, the enhancement of cooperation displays a resonance-like behavior, suggesting the existence of optimal Extortion strength mostly favoring the evolution of cooperation, which is in good agreement with the predictions from the generalized mean-field approximation theory. On scale-free network, the hubs, who are likely occupied by Extortioners or defectors at the very beginning, are then prone to be conquered by cooperators on small-degree nodes as time elapses, thus establishing a bottom-up mechanism for the emergence and maintenance of cooperation.
-
Extortion under uncertainty zero determinant strategies in noisy games
2015Co-Authors: Dong Hao, Zhihai Rong, Tao ZhouAbstract:Repeated game theory has been one of the most prevailing tools for understanding long-running relationships, which are the foundation in building human society. Recent works have revealed a new set of "zero-determinant" (ZD) strategies, which is an important advance in repeated games. A ZD strategy player can exert unilateral control on two players' payoffs. In particular, he can deterministically set the opponent's payoff or enforce an unfair linear relationship between the players' payoffs, thereby always seizing an advantageous share of payoffs. One of the limitations of the original ZD strategy, however, is that it does not capture the notion of robustness when the game is subjected to stochastic errors. In this paper, we propose a general model of ZD strategies for noisy repeated games and find that ZD strategies have high robustness against errors. We further derive the pinning strategy under noise, by which the ZD strategy player coercively sets the opponent's expected payoff to his desired level, although his payoff control ability declines with the increase of noise strength. Due to the uncertainty caused by noise, the ZD strategy player cannot ensure his payoff to be permanently higher than the opponent's, which implies dominant Extortions do not exist even under low noise. While we show that the ZD strategy player can still establish a novel kind of Extortions, named contingent Extortions, where any increase of his own payoff always exceeds that of the opponent's by a fixed percentage, and the conditions under which the contingent Extortions can be realized are more stringent as the noise becomes stronger.
-
diversity of timescale promotes the maintenance of Extortioners in a spatial prisoner s dilemma game
2015Co-Authors: Zhihai Rong, Zhixi Wu, Michael Z Q Chen, Tao ZhouAbstract:Recently, a class of interesting strategies, named Extortion strategies, has attracted considerable attention since such Extortion strategies can dominate any opponent in a repeated prisoner's dilemma game. In this paper, we investigate the influence of the strategy-selection timescale on the evolution of Extortion and cooperation in networked systems. Through connecting the lifetime of individuals' strategies with their fitness, we find that Extortioners can form long-term stable relationships with cooperative neighbors, whereas the lifetime of a defection strategy is short according to the myopic best response rule. With the separation of interaction and strategy-updating timescales, the Extortioners in a square lattice are able to form stable, cross-like structures with cooperators due to the snowdrift-like relation. In scale-free networks the hubs are most likely occupied by Extortioners, who furthermore induce their low-degree neighbors to behave as cooperators. Since Extortioners in scale-free networks can meet more cooperators than their counterparts in the square lattice, the latter results in higher average fitness of the whole population than the former. The Extortioners play the role of a catalyst for the evolution of cooperation, and the diversity of strategy-selection timescale furthermore promotes the maintenance of Extortioners with cooperators in networked systems.
Pushan Dutt - One of the best experts on this subject based on the ideXlab platform.
-
corruption and bilateral trade flows Extortion or evasion
2010Co-Authors: Pushan Dutt, Daniel TracaAbstract:Abstract We analyze the impact of corruption on bilateral trade, highlighting its dual role in terms of Extortion and evasion. Corruption taxes trade, when corrupt customs officials in the importing country extort bribes from exporters (Extortion effect); however, with high tariffs, corruption may be trade enhancing when corrupt officials allow exporters to evade tariff barriers (evasion effect). We derive and estimate a corruption-augmented gravity model, where the effect of corruption on trade flows is ambiguous and contingent on tariffs. Empirically, corruption taxes trade in the majority of cases, but in high-tariff environments (covering 5% to 14% of the observations) their marginal effect is trade enhancing.
-
corruption and bilateral trade flows Extortion or evasion
2007Co-Authors: Pushan Dutt, Daniel TracaAbstract:This paper analyzes the impact of corruption on bilateral trade flows, highlighting the dual role of corruption in terms of Extortion and evasion. On one hand, corruption taxes trade, when corrupt customs officials in the importing country extort bribes from exporters (the Extortion effect); on the other, if tariffs are high, corruption may be trade enhancing, when the corrupt officials allow exporters to evade tariff barriers (the evasion effect). The paper derives and estimates a corruption-augmented gravity model that shows that the effect of corruption on trade flows is ambiguous and is contingent on the level of tariffs. The predictions are borne out in the data: corruption taxes trade in the majority of cases, but in high tariff environments (covering 5-14% of the observations,) its marginal effect is trade-enhancing.
Fuhai Hong - One of the best experts on this subject based on the ideXlab platform.
-
collusion Extortion and the government s organizational structure
2020Co-Authors: Fuhai Hong, Zhendong YinAbstract:Abstract This paper studies the government’s organizational structure with petty corruption. We investigate whether the government should centralize or separate the power of granting business permits if bureaucrats may engage in collusion or/and Extortion. Centralization dominates when the bureaucrats engage in Extortion only, while separation dominates when the bureaucrats can collude with unqualified firms. Our analysis thus sheds some light on the debate over the “single window” policy, a proposed governmental reform for curbing corruption. We also find that, given multiple bureaucrats, fragmenting the bureaucrats’ responsibility in checking firms’ production eligibility can be welfare decreasing.
-
collusion Extortion and the government s organizational structure
2018Co-Authors: Fuhai Hong, Zhendong YinAbstract:This paper studies the government's organizational structure with petty corruption. We investigate whether the government should centralize or separate the power of granting business permits if bureaucrats may engage in collusion or/and Extortion. Centralization dominates when the bureaucrats engage in Extortion only, while separation dominates when the bureaucrats could collude with unqualified firms. We also find that, given multiple bureaucrats, fragmenting the bureaucrats' responsibility in checking firms' production eligibility can be welfare decreasing. Our analysis draws some implications for anti-corruption policies.
