Ana Mauleon

Rationalizability for social environments

Social environments constitute a framework in which it is possible to study how groups of agents interact in a society. The framework is general enough to analyze both non-cooperative and cooperative games. In order to remedy the shortcomings of existing solution concepts and to identify the consequences of common knowledge of rationality and farsightedness, we propose to apply extensive-form rationalizability to the framework of social environments. For us, the social environment is a primitive. On this social environment is defined a multistage game. An outcome of the social environment is socially rationalizable if and only if it is rationalizable in the multistage game. The set of socially rationalizable outcomes is shown to be non-empty for all social environments and it can be computed by an iterative reduction procedure. We introduce a definition of coalitional rationality for social environments and show that it is satisfied by social rationalizability.

von Neumann–Morgenstern farsightedly stable sets in two-sided matching

We adopt the notion of von Neumann–Morgenstern (vNM) farsightedly stable sets to determine which matchings are possibly stable when agents are farsighted in one-to-one matching problems. We provide the characterization of vNM farsightedly stable sets: a set of matchings is a vNM farsightedly stable set if and only if it is a singleton subset of the core. Thus, contrary to the vNM (myopically) stable sets (Ehlers 2007), vNM farsightedly stable sets cannot include matchings that are not in the core. Moreover, we show that our main result is robust to many-to-one matching problems with substitutable preferences: a set of matchings is a vNM farsightedly stable set if and only if it is a singleton set and its element is in the strong core.

Networks of manufacturers and retailers

We study the endogenous formation of networks between manufacturers of differentiated goods and multi-product retailers who interact in a successive duopoly. Joint consent is needed to establish and/or maintain a costly link between a manufacturer anda retailer. We find that only three distribution networks are stable for particular values of the degree of product differentiation and link costs: (i) the non-exclusive distribution & non-exclusive dealing network in which both retailers distribute both products is stable for intermediate degree of product differentiation and small link costs; (ii) the exclusive distribution & exclusive dealing network in which each retailer distributes a different product is stable for low degrees of product differentiation; (iii) the mixed distribution network in which one retailer distributes both products while the other retailer sells only one is stable for high degrees of product differentiation and large link costs. We show that the distribution networks that maximize social welfare are not necessarily stable. Thus, a conflict between stability and social welfare is likely to occur, even more if the degree of product differentiation is either low or high.

Allocation Rules for Coalitional Network Games

Coalitional network games are real-valued functions defined on a set of players organized into a network and a coalition structure. We adopt a flexible approach assuming that players organize themselves the best way possible by forming the efficient coalitional network structure. We propose two allocation rules that distribute the value of the efficient coalitional network structure: the atom-based flexible coalitional network allocation rule and the player-based flexible coalitional network allocation rule.

Myopic or Farsighted? An Experiment on Network Formation

Pairwise stability (Jackson and Wolinsky, 1996) is the standard stability concept in network formation. It assumes myopic behavior of the agents in the sense that they do not forecast how others might react to their actions. Assuming that agents are farsighted, related stability concepts have been proposed. We design a simple network formation experiment to test these theories. Our results provide support for farsighted stability and strongly reject the idea of myopic behavior.

Strategic union delegation and incentives for merger

A unionized duopoly model to analyse how unions affect the incentives for merger is considered. It is found that both firms will merge if and only if unions are weak. However, once surplus-maximizing unions have the option to delegate the wage bargaining to wage-maximizing delegates (such as senior union members), both firms may have incentives to merge even if the union bargaining power is strong. Moreover, the option of strategic delegation may harm both the unions and the firms.

Farsightedness and Cautiousness in Coalition Formation

We adopt the largest consistent set defined by Chwe [J. of Econ. Theory 63 (1994), 299-235] to predict which coalition structures are possibly stable when players are farsighted. We also introduce a refinement, the largest cautious consistent set, based on the assumption that players are cautious. For games with positive spillovers, many coalition structures may belong to the largest consistent set. The grand coalition, which is the efficient coalition structure, always belongs to the largest consistent set and is the unique one to belong to the largest cautious consistent set.

Market competition and strike activity

We develop a model of wage bargaining with private information in a duopoly. We investigate how product differentiation and market competition (Bertrand vs. Cournot competition) affect wages and strikes. If bargaining takes place at the industry-level, then both the wage outcome and the strike activity do not depend on the degree of product differentiation whatever the type of market competition. However, if bargaining takes place at the firm-level, then wages and strikes are increasing with the degree of product differentiation, and the strike activity is smaller under Bertrand than under Cournot competition.

Networks of Free Trade Agreements among Heterogeneous Countries

The paper examnes the formation of free trade agreements as a network formation game. We consider a three-country model in which international trade occurs between economies with imperfectly competitive product markets. Labor markets can be unionized and non-unionized in each country. We show that if all countries are of the same type (all of them are either unionized or non-unionized), the global free trade network is both the unique pairwise stable network and the unique efficient network. If some countries are unionized while others are non-unionized, other networks apart from the global free trade network are likely to be pariwise stable. however the efficient network is always the global free trade network. Thus, a conflict between stability and efficiency may occur. Moreover, starting from the network in which no country has signed a free trade agreement, all sequences of networks due to continuously profitable deviations to do not lead (in most cases) to the global free trade network, even when global free trade is stable

Stability of networks under level-k farsightedness

We provide a tractable concept that can be used to study the influence of the degree of farsightedness on network stability. A set of networks GK is a level-K farsightedly stable set if three conditions are satisfied. First, external deviations should be deterred. Second, from any network outside of GK there is a sequence of farsighted improving paths of length smaller than or equal to K leading to some network in GK. Third, there is no proper subset of GK satisfying the first two conditions. We show that a level-K farsightedly stable set always exists and we provide a sufficient condition for the uniqueness of a level-K farsightedly stable set. There is a unique level-1 farsightedly stable set G1 consisting of all networks that belong to closed cycles. Level-K farsighted stability leads to a refinement of G1 for generic allocation rules. We then provide easy to verify conditions for a set to be level-K farsightedly stable and we consider the relationship between level-K farsighted stability and efficiency of networks. We show the tractability of the concept by applying it to a model of criminal networks.