CSMA Local Area Networking under Dynamic Altruism

In this paper, we consider medium access control of local area networks (LANs) under limited-information conditions as befits a distributed system. Rather than assuming "by rule" conformance to a protocol designed to regulate packet-flow rates (e.g., CSMA windowing), we begin with a non-cooperative game framework and build a dynamic altruism term into the net utility. The effects of altruism are analyzed at Nash equilibrium for both the ALOHA and CSMA frameworks in the quasistationary (fictitious play) regime. We consider either power or throughput based costs of networking, and the cases of identical or heterogeneous (independent) users/players. In a numerical study we consider diverse players, and we see that the effects of altruism for similar players can be beneficial in the presence of significant congestion, but excessive altruism may lead to underuse of the channel when demand is low

Vengefulness Evolves in Small Groups

We discuss how small group interactions overcome evolutionary problems that might otherwise erode vengefulness as a preference trait. The basic viability problem is that the fitness benefits of vengeance often do not cover its personal cost. Even when a sufficiently high level of vengefulness brings increased fitness, at lower levels, vengefulness has a negative fitness gradient. This leads to the threshold problem: how can vengefulness become established in the first place? If it somehow becomes established at a high level, vengefulness creates an attractive niche for cheap imitators, those who look like highly vengeful types but do not bear the costs. This is the mimicry problem, and unchecked it could eliminate vengeful traits. We show how within-group social norms can solve these problems even when encounters with outsiders are also important.

Reputation effects drive the joint evolution of cooperation and social rewarding

People routinely cooperate with each other, even when cooperation is costly. To further encourage such pro-social behaviors, recipients often respond by providing additional incentives, for example by offering rewards. Although such incentives facilitate cooperation, the question remains how these incentivizing behaviors themselves evolve, and whether they would always be used responsibly. Herein, we consider a simple model to systematically study the co-evolution of cooperation and different rewarding policies. In our model, both social and antisocial behaviors can be rewarded, but individuals gain a reputation for how they reward others. By characterizing the game’s equilibria and by simulating evolutionary learning processes, we find that reputation effects systematically favor cooperation and social rewarding. While our baseline model applies to pairwise interactions in well-mixed populations, we obtain similar conclusions under assortment, or when individuals interact in larger groups. According to our model, rewards are most effective when they sway others to cooperate. This view is consistent with empirical observations suggesting that people reward others to ultimately benefit themselves

Learning and evolution in games and oligopoly models

Dynamic models of adjustment, as well as static models of equilibrium, are important to understand economic reality. This thesis considers such dynamic models applied to economic games. The models can broadly be divided into two categories: learning and evolution. This thesis analyzes reinforcement learning and imitation dynamic on the learning side and the indirect evolution approach on the evolution side. It demonstrates the relation between the concept of Nash equilibrium and the long run outcome of the namic processes. The applications of the dynamic models to economic games include, among others, Cournot oligopoly and merger games.

Product differentiation and welfare in a mixed duopoly with regulated prices: the case of a public and a private hospital

Hospital markets are often characterised by price regulation and the existence of different ownership types. Using a Hotelling framework, this paper analyses the effect of different objectives of the hospitals on quality, profits, and overall welfare in a price regulated duopoly with symmetric locations. In contrast to other studies on mixed oligopolies, this paper shows that in a duopoly with regulated prices privatisation of the public hospital may increase overall welfare depending on the difference of the hospitals' marginal costs and the weight of the additional public hospital's motive. --mixed oligopoly,price regulation,quality,hospital competition

Game Theory Relaunched

The game is on. Do you know how to play? Game theory sets out to explore what can be said about making decisions which go beyond accepting the rules of a game. Since 1942, a well elaborated mathematical apparatus has been developed to do so; but there is more. During the last three decades game theoretic reasoning has popped up in many other fields as well - from engineering to biology and psychology. New simulation tools and network analysis have made game theory omnipresent these days. This book collects recent research papers in game theory, which come from diverse scientific communities all across the world; they combine many different fields like economics, politics, history, engineering, mathematics, physics, and psychology. All of them have as a common denominator some method of game theory. Enjoy