In general partition function form games, the recursive core coalition structure may be either coarser or finer than the one that maximizes the social surplus. Moreover, the recursive core structure is typically different from the one predicted by the α-core. We fully implement the recursive core for general games, including non-superadditive games where the grand coalition does not form in equ...

Galeotti et al. (2006, [2]) show that all minimal networks can be strict Nash in two-way flow models with full parameter heterogeneity while only inward pointing stars and the empty network can be strict Nash in the homogeneous parameter model of Bala and Goyal (2000, [1]). In this note we show that the introduction of partner heterogeneity plays a major role in substantially increasing the set...

Drawing a conclusion from recent insights in evolutionary game theory, we show that a so-called spite e!ect implies that there is an essential di!erence between individual and social learning. We illustrate its consequences for the choice of computational tools in economics and social settings in general by analyzing two variants of a Genetic Algorithm. ( 2000 Elsevier Science B.V. All rights r...

We report a framed field experiment, in which we study the effectiveness of punishment and reward in sustaining cooperation in a social dilemma. Punishments tend to be directed at non-cooperators and rewards are assigned by those who are relatively cooperative. In contrast to the results typically found in laboratory experiments, however, we find that punishments and rewards fail to increase co...

The minority game is a simple congestion game in which the players’ main goal is to choose among two options the one that is adopted by the smallest number of players. We characterize the set of Nash equilibria and the limiting behavior of several well-known learning processes in the minority game with an arbitrary odd number of players. Interestingly, different learning processes provide consi...

We explore the scientific potential of virtual worlds for experimental economists. In particular, we report the results of a series of virtual world experiments designed to examine the suitability of (a) users as subjects and (b) the computer interface as an experimental platform. Formal results and informal observations from the sessions are discussed in terms of the methodological opportuniti...

Ever since the seminal work by Rothschild and Stiglitz (1976) on competitive insurance markets under adverse selection the equilibrium-non-existence problem has been one of the major puzzles in insurance economics. We extend the original analysis by considering firms which face capacity constraints, which might be due to limited capital. We show that under mild assumptions a pure strategy equil...

We extend Armstrong’s [1] result on exclusion in multi-dimensional screening models providing support for the view that the result holds true in a large class of models. We first relax some of the strong technical assumptions he imposed and provide alternative su cient conditions for exclusion not relying on any form of convexity. We then proceed to show that exclusion obtains generically. We i...

In this paper we first explore the predictive power of the solution notion called conservative stable standard of behaviour (CSSB), introduced by Greenberg (1990) in environments with farsighted players (as modelled in Xue (1998)) as intuitively it is quite nice. Unfortunately, we find that CSSB has a number of undesirable properties. Therefore, we introduce a refinement of this which we call c...

In this paper, we examine the role played by heterogeneity in the connection model. In sharp contrast to the homogeneous cases we show that under heterogeneity involving only two degrees of freedom, all networks can be supported as Nash or efficient. Moreover, we show that there does not always exist Nash networks. However, we show that on reducing heterogeneity, both the earlier “anything goes...