Tourists and traditional divers in a common fishing ground

We study socio-ecological models for a fishing ground open to tourists. On Jeju Island, Korea, women traditional divers called “Haenyeo” harvest resources in a common fishing ground. To investigate the impact of introducing tourists on the benefit to the fishing association and the resource level, we examine two models that differ in the way the number of tourists is controlled. In the first model, the fishing association charges an entrance fee to tourists and the level of the fee is chosen to regulate tourist number. In the second, only a part of the fishing ground is made open to tourists, and the fraction of the ground open is chosen to control the tourist number. In both models, the fishing association seeks to maximize its total benefit. Analysis shows that the way the number of tourists increases with the availability of resources strongly influences the distribution of benefits among the fishing ground stakeholders. Finally, we discuss policy implications of our results and how local government can reduce the risk of introducing tourism.     

Reflecting inequality of claims in gains and losses

We consider the problem of dividing a resource among a group of agents who have conflicting claims on it. We follow the axiomatic approach and investigate the class of rules satisfying claims-inequality and claims-order preservation in gains and losses. We show that these axioms single out the proportional rule when there are more than three agents. This result confirms the central role of this rule and furthers our understanding of it in claims problems.     

Secure implementation in Shapley–Scarf housing markets

This paper considers the object allocation problem introduced by Shapley and Scarf (J Math Econ 1:23–37, 1974). We study secure implementation (Saijo et al. in Theor Econ 2:203–229, 2007), that is, double implementation in dominant strategy and Nash equilibria. We prove that (1) an individually rational solution is securely implementable if and only if it is the no-trade solution, (2) a neutral solution is securely implementable if and only if it is a serial dictatorship, and (3) an efficient solution is securely implementable if and only if it is a sequential dictatorship. Furthermore, we provide a complete characterization of securely implementable solutions in the two-agent case: a solution is securely implementable if and only if it is either a constant solution or a serial dictatorship.     

A dynamic two country Heckscher–Ohlin model with non-homothetic preferences

We examine the properties of a two-country dynamic Heckscher–Ohlin model that allows for preferences to be non-homothetic. We show that the model has a continuum of steady state equilibria under free trade, with the initial conditions determining which equilibrium will be attained. We establish conditions under which a static Heckscher–Ohlin theorem will hold in the steady state, and also conditions for a dynamic Heckscher–Ohlin theorem to hold. If both goods are normal, each country will have a unique autarkic steady state, and all steady state equilibria are saddle points. We also consider the case in which one good is inferior, and show that this can lead to multiple autarkic steady states, violations of the static Heckscher–Ohlin theorem in the steady state. Furthermore, there may exist steady state equilibria that Pareto dominate other steady states. These steady states will be unstable if discount factors are the same in each country, although they may exhibit dynamic indeterminacy if discount factors differ.     

Strategic approximations of discontinuous games

An infinite game is approximated by restricting the players to finite subsets of their pure strategy spaces. A strategic approximationof an infinite game is a countable subset of pure strategies with the property that limits of all equilibria of all sequences of approximating games whose finite strategy sets eventually include each member of the countable set must be equilibria of the infinite game. We provide conditions under which infinite games admit strategic approximations.     

Equilibrium price formation in markets with differentially informed agents

We consider a pure exchange economy with a finite set of types of agents which have incomplete and asymmetric information on the states of nature. Our aim was to describe the equilibrium price formation and analyze how the lack of information may affect the allocation of resources. To do so, we adapt to an asymmetric information scenario a variant of the Shapley–Shubik game introduced by Dubey and Geanakoplos (J Math Econ 39:391–400, 2003 ).     

Compensating for unforeseeable damages in torts

The doctrine regarding unforeseeable damages in a contract was established in the well known case of Hadley vs. Baxendale. According to the judgement, a plaintiff cannot be compensated for unforeseeable damages in an incomplete contract unless he informs the defendant of the possible unforeseen contingency beforehand. In this paper, I extend the argument to the tort case in which it is hardly possible to communicate between a plaintiff and a defendant before an accident occurs. In the case of the sequential bilateral accident in which the victim’s care level is observable to the injurer, the victim’s care level can be a signal of the unforeseen contingency. I mainly discuss the implementability of the social optimum by the contributory negligence with dual standard of care enabling the communication between the parties.