Social Sorting

This paper is about the behaviour of a society in which learning individuals play a Prisoner’s Dilemma that guides social promotion and demotion. The direct effect of the payoff-based socialization that is implemented here is segregation. However, segregation permits the survival of cooperation as it (unintendedly) preserves cooperators from detrimental interactions with defectors. Very large amounts of cooperation can be observed in the long run.microeconomics ;

Equivariant absolute extensor property on hyperspaces of convex sets

Let G be a compact group acting on a Banach space L by means of linear isometries. The action of G on L induces a natural continuous action on cc(L), the hyperspace of all compact convex subsets of L endowed with the Hausdorff metric topology. The main result of this paper states that the G-space cc(L) is a G-AE. Under some extra assumptions, this result can be extended to CB(L), the hyperspace of all closed and bounded convex subsets of L.Comment: 8 page

Information Technology and the Dynamics of Joint Innovation

We develop a model of an innovative industry to examine how information technology, by both enhancing matching efficiency and knowledge sharing, can have an ambiguous effect on the total amount of innovation. We consider a population of firms holding different knowledge expertise, and forming partnerships to conduct joint R&D. We assume that bringing together different expertise has positive value for innovating but also that joint innovation implies a partial convergence of the partners'' expertise. We study how the distribution of firms changes and thus how the innovative potential of the economy evolves. We show that as heterogeneity is used as an input by the innovative process, the industry must eventually collapse to a unique expertise, but how fast this takes place depends on the quality of IT. As a result of falling dispersion, a tension arises between static and dynamic efficiency. JEL Classification Numbers: C78,O33,O38.mathematical economics and econometrics ;

A note on compatibility and entry in a circular model of product differentiation

Consider an industry in which network goods are supplied by two horizontally differentiated firms facing the threat of a potential entrant. Firms' dilemma is between occupying the product space by selling very differentiated (incompatible) goods, and supplying compatible goods that offer higher utilities hence can be charged a higher price to consumers but are also closer substitutes. The compatibility-entry-price game is solved backward when firms and consumers are located on a circular product space. It turns out that strong externalities can favour entry, as merging the networks and accommodating entry can be preferred by the incumbents.compatibility

Structural Holes, Innovation and the Distribution of Ideas

We model knowledge diffusion in a population of agents situated on a network, interacting only over direct ties. Some agents are by nature traders, others are by nature "givers": traders demand a quid pro quo for information transfer; givers do not. We are interested in efficiency of diffusion and explore the interplay between the structure of the population (proportion of traders), the network structure (clustering, path length and degree distribution), and the scarcity of knowledge. We find that at the global level, trading (as opposed to giving) reduces efficiency. At the individual level, highly connected agents do well when knowledge is scarce, agents in clustered neighbourhoods do well when it is abundant. The latter finding is connected to the debate on structural holes and social capital.Innovation, Diffusion of Innovations, Knowledge, Information, Networks

Fits and Misfits: Technological Matching and R&D Networks

This paper presents an economic model of R&D network formation through the creation of strategic alliances. Firms are randomly endowed with knowledge elements. They base their alliance decisions purely on the technological fit of potential partners, ignoring social capital considerations and indirect benefits on the network. This is sufficient to generate equilibrium networks with the small world properties of observed alliance networks, namely short pairwise distances and local clustering. The equilibrium networks are more clustered than "comparable" random graphs, while they have similar characteristic path length. Two extreme regimes of competition are examined, to show that while the competition has a quantitative effect on the equilibrium networks (density is lower with competition), the small world features of the equilibrium networks are preserved.network formation, small worlds, R&D networks, strategic alliances, business clusters

A duopoly Logit model with price competition and strategic compatibility

This paper provides an analysis of compatibility decisions with oligopolistic price setting in a duopoly logit model. We consider a sequential game in which firms first choose whether they supply compatible products and then set the price which is charged. The equilibrium compatibility configuration is the outcome of a trade-off between consumers valuation of compatibility and the loss of product differentiation which is associated with compatibility. Finally, it is shown that firms incentives towards compatibility tend to be socially insufficient.industrial organization ;