Property rights and investments: An evolutionary approach

When contracts are not enforceable, or property rights are not clearly defined, individuals may lack an incentive to carry out costly investments even when they are socially efficient. Some recent contributions such as Ellingsen and Robles (2002) prove that this problem may be less dramatic than standard economic models would suggest. They propose evolutionary models in which only efficient equilibria can be (stochastically) stable. In this paper we show that these results are not robust with respect to the introduction of individual heterogeneity. When individuals have different cost functions, stochastically stable states may be inefficient, even when they induce a positive (suboptimal) level of investment.     

Relaxing the substitutes condition in matching markets with contracts

In the many-to-one matching model with contracts, I provide new necessary and new sufficient conditions for the existence of a stable allocation. These new conditions exploit the fact that one side of the market has strict preferences over individual contracts.     

Contracting with externalities and outside options

This paper proposes a model of multilateral contracting where players are engaged in two parallel interactions: they dynamically form coalitions and play a repeated normal form game with temporary and permanent decisions. We show that when outside options are independent of the actions of other players all Markov perfect equilibrium without coordination failures are efficient, regardless of externalities created by interim actions. Otherwise, in the presence of externalities on outside options, all Markov perfect equilibrium may be inefficient. This formulation encompasses many economic models, and we analyze the distribution of coalitional gains and the dynamics of coalition formation in four illustrative applications.     

Subcontractors for tractors: Theory and evidence on flexible specialization,supplier selection,and contracting

Buyer–Seller networks are pervasive in developing economies yet remain relatively understudied. Using primary data on contracts between the largest tractor assembler in Pakistan and its suppliers we find large variations in prices and quantities across suppliers of the same product. Surprisingly, “tied” suppliers – those that choose higher levels of specific investments – receive lower and more unstable orders and lower prices. These results are explained by developing a simple model of flexible specialization under demand uncertainty. A buyer faces multiple suppliers with heterogeneous types to supply customized parts. Specific investments raise surplus within the relationship but lower the seller's flexibility to cater to the outside market. Higher quality suppliers have a greater likelihood of selling outside and so this cost is greater for them. Therefore even if a buyer typically prefers high types, some low type suppliers might be kept as marginal suppliers because of their greater willingness to invest more in buyer-specific assets. Further empirical examination shows that the more tied suppliers are indeed of lower quality.     

Stochastic stability for roommate markets

We show that for any roommate market the set of stochastically stable matchings coincides with the set of absorbing matchings. This implies that whenever the core is non-empty (e.g., for marriage markets), a matching is in the core if and only if it is stochastically stable, i.e., stochastic stability is a characteristic of the core. Several solution concepts have been proposed to extend the core to all roommate markets (including those with an empty core). An important implication of our results is that the set of absorbing matchings is the only solution concept that is core consistent and shares the stochastic stability characteristic with the core.     

Electoral manipulation via voter-friendly spending: Theory and evidence

We present a model of the political budget cycle in which incumbents try to influence voters by changing the composition of government spending, rather than overall spending or revenues. Rational voters may support an incumbent who targets them with spending before the election even though such spending may be due to opportunistic manipulation, because it may also reflect sincere preference of the incumbent for types of spending voters favor. Classifying expenditures into those which are likely targeted to voters and those that are not, we provide evidence supporting our model in data on local public finances for all Colombian municipalities. Our findings indicate both a pre-electoral increase in targeted expenditures, combined with a contraction of other types of expenditure, and a voter response to targeting.     

Groundwater and ecosystems damages: Questioning the Gisser-Sánchez effect

Gisser and Sánchez (1980a) state the conditions under which welfare gains from policy intervention are negligible in aquifer management, when compared with non-regulation or “free market” outcomes. This is the so-called Gisser-Sánchez effect (GSE), which has been supported by the ensuing literature during recent decades. The GSE requires a number of assumptions, among which is the disregard for aquatic ecosystems linked and dependent on aquifer systems. The depletion of aquifer systems in arid and semiarid regions worldwide is causing acute water scarcity and quality degradation, and leading to extensive ecosystem damages. This study shows that by including environmental damages into the analytical model, results can change substantially. The analysis highlights both theoretically and empirically the importance of policies in groundwater management, as well as the potential role for stakeholders' cooperation. The empirical application deals with two large aquifers in Spain, the Western La Mancha aquifer which is grossly mismanaged, and the Eastern La Mancha aquifer, which is moving towards sustainable management. Western and Eastern La Mancha aquifers illustrate that policies and institutions are essential to avoid the current global aquifer mismanagement.     

Implementation of college admission rules

Summary We consider both Nash and strong Nash implementation of various matching rules for college admissions problems. We show that all such rules are supersolutions of the stable rule. Among these rules the lower bound stable rule is implementable in both senses. The upper bound Pareto and individually rational rule is strong Nash implementable yet it is not Nash implementable. Two corollaries of interest are the stable rule is the minimal (Nash or strong Nash) implementable solution that is Pareto optimal and individually rational, and the stable rule is the minimal (Nash or strong Nash) implementable extension of any of its subsolutions.We wish to thank Professor William Thomson for his efforts in supervision as well as his useful suggestions. We are grateful to the participants in his reading class, workshops at Bilkent University, University of Rochester, and in particular Jeffrey Banks, Stephen Ching, Bhaskar Dutta, Rangarajan Sundaram and an anonymous referee for their helpful comments.     

The dynamics of a differentiated duopoly with quantity competition

We analyse the dynamics of a Cournot duopoly with heterogeneous players to investigate the effects of micro-founded differentiated products demand on stability. The present study, which indeed modifies and extends Zhang et al. (2007) (Zhang, J., Da, Q., Wang, Y., 2007. Analysis of nonlinear duopoly game with heterogeneous players. Economic Modelling 24, 138–148) and Tramontana, F., (2010) (Tramontana, F., 2010. Heterogeneous duopoly with isoelastic demand function. Economic Modelling 27, 350–357), reveals that a higher degree of product differentiation may destabilise the market equilibrium. Moreover, we show that a cascade of flip bifurcations may lead to periodic cycles and ultimately chaotic behaviours. Since a higher degree of product differentiation implies weaker competition, then a theoretical implication of our findings, that also constitute a policy warning, is that a fiercer (weaker) competition tends to stabilise (destabilise) the unique positive Cournot–Nash equilibrium.     

Comparative statics for oligopoly: A generalized result

We perform comparative statics for a general model of asymmetric oligopoly and derive a concise formula for the response of one firm to a marginal change in its rival’s strategic variable, taking into account the responses of all other firms. We obtain the conditions under which the sign of this response coincides with that of the mixed second-order partial derivative of the firm’s payoff function. We then propose a distinction between gross and net strategic relationships (i.e., strategic substitute and complement).     

Exchange in a general market with indivisible goods

We show how to restrict trades in exchange markets with heterogeneous indivisible goods so that the resulting restricted exchange markets, the fixed deal exchange markets, have a unique core allocation. Our results on fixed deal exchange markets generalize classical results on the Shapley-Scarf housing market, in which each agent owns one good only. Furthermore, we define the class of fixed deal exchange rules for general exchange markets, and prove that these are the only exchange rules that satisfy strategyproofness, individual rationality, and a weak form of efficiency.     

A solution to the hold-up problem involving gradual investment

We consider a setting in which the buyer's ability to hold up a seller's investment is so severe that there is no investment in equilibrium of the static game typically analyzed. We show that there exists an equilibrium of a related dynamic game generating positive investment. The seller makes a sequence of gradually smaller investments, each repaid by the buyer under the threat of losing further seller investment. As modeled frictions converge to zero, the equilibrium outcome converges to the first best. We draw connections between our work and the growing literature on gradualism in public good contribution games and bargaining games.     

The effect of corruption on bidding behavior in first-price auctions

When the owner of an object sells it through an auction run by an agent of hers, corruption may appear. In a first-price auction, corruption can make honest bidders more or less aggressive, or their behavior can remain unchanged. We identify sufficient conditions for each of the three possibilities. We analyze the effects of corruption on efficiency, bidders’ welfare and expected revenue. Our results apply as well to the situation—unrelated to corruption—where one of the bidders is granted a right of first refusal.