The emergence of cooperation in the random asynchronous prisoner’s dilemma

The iterated prisoners dilemma (IPD) is a simple model for the study of the emergence of cooperative behavior in populations of selfish individuals. In this work, we challenge the assumption that players move in synchrony, and develop a general Markovian model that allows the study of a wide spectrum of scenarios. Simulations show that the relative timing of player moves, and the reward for mutual cooperation, influences the strategy that eventually dominates the final population. For a synchronous environment, reciprocal behavior appears to be the key to the evolution of cooperation, while in an asynchronous environment, guarded generosity may be a route to the evolution of cooperation.     

Cooperation in the evolutionary iterated prisoner’s dilemma game with risk attitude adaptation

The Iterated Prisoner’s Dilemma (IPD) game has been commonly used to investigate the cooperation among competitors. However, most previous studies on the IPD focused solely on maximizing players’ average payoffs without considering their risk preferences. By introducing the concept of income stream risk into the IPD game, this paper presents a novel evolutionary IPD model with agents seeking to balance between average payoffs and risks with respect to their own risk attitudes. We build a new IPD model of multiple agents, in which agents interact with one another in the pair-wise IPD game while adapting their risk attitudes according to their received payoffs. Agents become more risk averse after their payoffs exceed their aspirations, or become more risk seeking after their payoffs fall short of their aspirations. The aspiration levels of agents are determined based on their historical self-payoff information or the payoff information of the agent population. Simulations are conducted to investigate the emergence of cooperation under these two comparison methods. Results indicate that agents can sustain a highly cooperative equilibrium when they consider only their own historical payoffs as aspirations (called historical comparison) in adjusting their risk attitudes. This holds true even for the IPD with a short game encounter, for which cooperation was previously demonstrated difficult. However, when agents evaluate their payoffs in comparison with the population average payoff (called social comparison), those agents with payoffs below the population average tend to be dissatisfied with the game outcomes. This dissatisfaction will induce more risk-seeking behavior of agents in the IPD game, which will constitute a strong deterrent to the emergence of mutual cooperation in the population.     

Flexible asynchronous simulation of iterated prisoner’s dilemma based on actor model

The wide range of applications of the Iterated prisoner’s dilemma (IPD) game made it a popular subject of study for the research community. As a consequence, numerous experiments have been conducted by researchers along the last decades. However, topics related with scaling simulation leveraging existing HPC infrastructure in the field of IPD did not always play a relevant role in such experimental work. The main contribution of this paper is a new simulation framework, based on asynchronous communication and its implementation oriented to distributed environments. Such framework is based on the modern Akka actor platform, that supports concurrent, distributed and resilient message-driven simulations; which are exemplified over the IPD game as a case study. We also present several interesting results regarding the introduction of asynchrony into the IPD simulation in order to obtain an efficient framework, so the whole simulation becomes scalable when using HPC facilities. The influence of asynchrony on the algorithm itself is also discussed, and the results show that it does not hamper the simulation.     

Effects of a membrane formation in the spatial prisoner’s dilemma

A cooperative relationship has been developed among individuals. However, altruistic behavior has little advantage against selfish behavior in the sense of rational terms. If each individual chooses selfish behavior pursuing their own payoff, then altruistic behavior will vanish. Earlier studies proposed mechanisms based on game theory which explained the problem of the difference between theoretical predictions and observation. Furthermore, those studies also considered the mechanisms of protecting a cooperator’s cluster in a spatial prisoner’s dilemma involving spatial strategies and spatial generosity, although they did not rigorously analyze the effects of the membrane for the cooperators. In this article, we report the quantitative effect of the membrane for protecting the cooperators from the exploitation of the defectors.     

Reverse engineering of spatiotemporal patterns in the spatial prisoner’s dilemma

Many complex patterns are produced by the spatial prisoner’s dilemma, such as spatial games (Nature 1992;359:826–829) and spatial strategies (Artif Life Robotics 2004;9:139–143). We have studied the inverse problem of identifying a game by estimating the parameters in the payoff of the game from spatiotemporal patterns.     

Evolution of cooperative behavior among heterogeneous agents with different strategy representations in an iterated prisoner’s dilemma game

The iterated prisoner’s dilemma (IPD) game has frequently been used to examine the evolution of cooperative behavior among agents. When the effect of representation schemes of IPD game strategies was examined, the same representation scheme was usually assigned to all agents. That is, in the literature, a population of homogeneous agents was usually used in computational experiments. In this article, we focus on a slightly different situation where every agent does not necessarily use the same representation scheme. That is, a population can be a mixture of heterogeneous agents with different representation schemes. In computational experiments, we used binary strings of different lengths (i.e., three-bit and five-bit strings) to represent IPD game strategies. We examined the evolution of cooperative behavior among heterogeneous agents in comparison with the case of homogeneous ones for the standard IPD game with typical payoff values of 0, 1, 3, and 5. Experimental results showed that the evolution of cooperative behavior was slowed down by the use of heterogeneous agents. It was also demonstrated that a faster evolution of cooperative behavior is achieved among majority agents than among minority ones in a heterogeneous population.     

On the effect of memory in a quantum prisoner’s dilemma cellular automaton

The disrupting effect of quantum memory on the dynamics of a spatial quantum formulation of the iterated prisoner’s dilemma game with variable entangling is studied. The game is played within a cellular automata framework, i.e., with local and synchronous interactions. The main findings of this work refer to the shrinking effect of memory on the disruption induced by noise.     

On the effect of quantum noise in a quantum prisoner’s dilemma cellular automaton

The disrupting effect of quantum noise on the dynamics of a spatial quantum formulation of the iterated prisoner’s dilemma game with variable entangling is studied in this work. The game is played in the cellular automata manner, i.e., with local and synchronous interaction. It is concluded in this article that quantum noise induces in fair games the need for higher entanglement in order to make possible the emergence of the strategy pair (Q, Q), which produces the same payoff of mutual cooperation. In unfair quantum versus classic player games, quantum noise delays the prevalence of the quantum player.     

A quantum prisoner’s dilemma cellular automaton with probabilistic updating

The effect of variable entangling on the dynamics of a spatial quantum formulation of the iterated prisoner’s dilemma game is studied in this work. The game is played in the cellular automata manner, i.e. with local and synchronous interaction. The effect of probabilistic updating is assessed in fair and unfair contests, both in the two and three parameter strategy spaces.     

The Interplay Between the Speaker’s and the Hearer’s Perspective

The neutralization of contrasts in form or meaning that is sometimes observed in language production and comprehension is at odds with the classical view that language is a systematic one-to-one pairing of forms and meanings. This special issue is concerned with patterns of forms and meanings in language. The papers in this special issue arose from a series of workshops that were organized to explore variants of bidirectional Optimality Theory and Game Theory as models of the interplay between the speaker’s and the hearer’s perspective.     

Note on the Carleman’s inequality and Hardy’s inequality

In this article, using the properties of power mean and induction, new strengthened Carleman’s inequality and Hardy’s inequality are obtained. We also give an answer to the conjectures proposed by X. Yang in the literature Yang (2001) [5].     

Risk aversion and agents’ survivability in a financial market

Considering the effect of economic agents’ preferences on their actions, the relationships between conventional summary statistics and forecast profits are investigated. An analytical examination of loss function families demonstrates that investors’ utility maximisation is determined by their risk attitudes. In computational settings, stock traders’ fitness is assessed in response to a slow step increase in the value of the risk aversion coefficient. The experiment rejects the claims that the accuracy of the forecast does not depend upon which error-criteria are used and that none of them is related to the profitability of the forecast. The profitability of networks trained with L ₆ loss function appeared to be statistically significant and stable, although links between the loss functions and the accuracy of forecasts were less conclusive.     

Deferring to expertise versus the prima donna syndrome: a manager’s dilemma

Deference to operational or engineering expertise is considered critical for maintaining safety in many industries. At the same time, legitimating specialized knowledge can help create “prima donnas,” expert operators who attain considerable organizational status and informal power. Safety can be used as a lever to gain industrial advantage or maintain inequitable perquisites. This paper first considers the common consensus about the need to defer to expertise in safety–critical organizations and industries and assesses available research on the relationship between deference to expertise and safety. Then, it reviews two psychological literatures that illuminate some of the cognitions, behaviors and organizational dynamics behind a prima donna syndrome: one on entitlement and another on organizational narcissism. Conclusions and recommendations center on how to defer to expertise (not necessarily experts) while dealing with “prima donnas.”     

Grover’s algorithm and the secant varieties

In this paper we investigate the entanglement nature of quantum states generated by Grover’s search algorithm by means of algebraic geometry. More precisely we establish a link between entanglement of states generated by the algorithm and auxiliary algebraic varieties built from the set of separable states. This new perspective enables us to propose qualitative interpretations of earlier numerical results obtained by M. Rossi et al. We also illustrate our purpose with a couple of examples investigated in details.     

The machine’s role in human’s service automation and knowledge sharing

The possibility of interacting with remote services in natural language opens up new opportunities for sharing knowledge and for automating services. Easy-to-use, text-based interfaces might provide more democratic access to legal information, government services, and everyday knowledge as well. However, the methodology of engineering robust natural language interfaces is very diverse, and widely deployed solutions are still yet to come. The main contribution is a detailed problem analysis on the theoretical level, which reveals that a text-based interface is best understood as an artificial agent that represents the interests of the remote party who is separated in time and space from the client. A possible ethical issue about the development of such an agent is also discussed.     

Efficient approach and application of the Green’s functions in spatial domain in multilayered media

Based on the dipole source method, all components of the Green＇s functions in spectral domain are restructured concisely by four basis functions, and in terms of the two-level discrete complex image method （DCIM） with the high order Sommerfeld identities, an efficient algorithm for closed-form Green＇s functions in spatial domain in multilayered media is presented. This new work enjoys the advantages of the surface wave pole extraction directly carried out by the generalized integral path without troubles of that all components of Green＇s function in spectral domain should be reformed respectively in transmission line network analogy, and then the Green＇s functions for mixed-potential integral equation （MPIE） analysis in both near-field and far-field in multilayered media are obtained. In addition, the curl operator for coupled field in MPIE is avoided conveniently. It is especially applicable and useful to characterize the electromagnetic scattering by, and radiation in the presence of, the electrically large 3-D objects in multilayered media. The numerical results of the S-parameters of a microstrip periodic bandgap （PBG） filter, the radar cross section （RCS） of a large microstrip antenna array, the characteristics of scattering, and radiation from the three-dimensional （3-D） targets in multilayered media are obtained, to demonstrate better effectiveness and accuracy of this technique.     

Zipf’s and Bradford’s laws and universal models

Zipf’s and Bradford’s laws are empirical laws that were derived by the processing and analysis of so-called rank distributions. In this paper, they are treated as special cases of generalized (universal) continuous distributions that can accurately describe a wide variety of statistical distributions, including rank. We present the universal laws of the diffusion and aging of publications.     

Noether’s charge in the super-group field cosmology

We analyze the third quantization of a model of supergroup field cosmology with gauge symmetry. The effect of creation and annihilation of bosonic and fermionic universes in the multiverse is also analyzed. We also construct a third-quantized Noether charge which is conserved even if the number of universes is not conserved. Finally, we construct both the third-quantized BRST and the third-quantized anti-BRST charges for this theory and use them to show that creation and annihilation of universes is a unitary process.