International agreements on product standard: an incomplete contracting theory

We propose a theory of international agreements on product standards. The key feature of the model is that agreements are viewed as incomplete contracts. In particular, these do not specify standards for products that may arise in the future. One potential remedy to contractual incompleteness is a dispute settlement procedure (DSP) that provides arbitration in states of the world that are not covered by the ex ante agreement. We identify conditions under which a DSP can provide ex-ante efficiency gains, and examine how these gains depend on the fundamentals of the problem. Another potential remedy to contractual incompleteness is given by rigid rules, i.e. rules that are not product-specific. We argue that the nondiscrimination rule is the only rule of this kind that increases ex ante efficiency for any probability distribution over potential products. Finally we show that, under relatively weak conditions, the optimal ex-ante agreement is structured in three parts: (i) a set of clauses that specify standards for existing products; (ii) a rigid nondiscrimination rule, and (iii) a dispute settlement procedure. Although the model focuses on the case of product standards, the analysis suggests a more general incomplete-contracting theory of trade agreements.

THE LOGIC OF BELIEF PERSISTENCY

The interaction bietween knowledge and belief in a temporal context is analyzed. An axiomatic formulation and semantic characterization of the principle of belief persistency implied by the standard conditionalization rule are provided. This principle says that an individual does not change her mind unless new evidence forces her to do so. It is shown that if beliefs are conscious (or stateindependent) and satisfy negative introspection then the principle of persistency of beliefs is characterized by the following axiom schema: the individual believes that 9 at date t if and orilly if she believes at date t that she will believe that 4 at date t+l.

An Epistemic Characterisation of Extensive Form Rationalisability

We use an extensive form, universal type space to provide the following epistemic characterisation of extensive form rationalisability. Say that player i strongly believes event E if i is certain of E conditional on each of her information sets consistent with E. Our main contribution is to show that a strategy profile s is extensive form rationalisable if and only if there is a state in which s is played and (0) everybody is rational, (1) everybody strongly believes (0), (2) everybody strongly believes (0) & (1), (3) everybody strongly believes (0) & (1) & (2), .... This result also allows us to provide sufficient epistemic conditions for the backward induction outcome and to relate extensive form rationalisability and conditional common certainty of rationality.Rationalisability, Extensive Form Games

An Epistemic Characterization of Extensive Form Rationalizability

We use an extensive form, universal type space to provide the following epistemic characterisation of extensive form rationalisability. Say that player i strongly believes event E if i is certain of E conditional on each of her information sets consistent with E. Our main contribution is to show that a strategy profile s is extensive form rationalisable if and only if there is a state in which s is played and (0) everybody is rational, (1) everybody strongly believes (0), (2) everybody strongly believes (0) & (1), (3) everybody strongly believes (0) & (1) & (2), .... This result also allows us to provide sufficient epistemic conditions for the backward induction outcome and to relate extensive form rationalisability and conditional common certainty of rationality

Costly Contracting in a Long-Term Relationship

We examine a model of contracting where parties interact repeatedly and can contract at any point in time, but writing enforceable contracts is costly. A contract can describe contingencies and actions at a more or less detailed level, and the cost of writing a contract is proportional to the amount of detail. We consider both formal (externally enforced) and informal (self-enforcing) contracts. The presence of writing costs has important implications both for the optimal structure of formal contracts, particularly the tradeoff between contingent and spot contracts, and for the interaction between formal and informal contracting. Our model sheds light on these implications and generates a rich set of predictions about the determinants of the optimal mode of contracting

RECENT RESULTS ON BELIEF, KNOWLEDGE AND THE EPISTEMIC FOUNDATIONS OF GAME THEORY

We provide a self-contained, selective overview of the literature on the role of knowledge and beliefs in game theory. We focus on recent results on the epistemic foundations of solution concepts, including correlated equilibrium, rationalizability in dynamic games, forward and backward induction.

PUTTING THINGS IN ORDER: PATTERNS OF TRADE DYNAMICS AND GROWTH

We develop a procedure to rank-order countries and commodities using dis-aggregated American imports data. We find strong evidence that both countries and commodities can be ranked, consistent with the ""produce cycle"" hypothesis. Countries habitually begin to export goods to the United States according to an ordering; goods are also exported in order. We estimate these orderings using a semi-parametric methodology which takes account of the fact that most goods are not exported by most countries in our sample. Our orderings seem sensible, robust and intuitive. For instance, our country rankings derived from dis-aggregated trade data, turn out to be highly correlated with macroeconomic phenomenon such as national productivity levels and growth rates.

Learning and Selfconfirming Equilibria in Network Games

Consider a set of agents who play a network game repeatedly. Agents may not know the network. They may even be unaware that they are interacting with other agents in a network. Possibly, they just understand that their payoffs depend on an unknown state that in reality is an aggregate of the actions of their neighbors. Each time, every agent chooses an action that maximizes her subjective expected payoff and then updates her beliefs according to what she observes. In particular, we assume that each agent only observes her realized payoff. A steady state of such dynamic is a selfconfirming equilibrium given the assumed feedback. We characterize the structure of the set of selfconfirming equilibria in network games and we relate selfconfirming and Nash equilibria. Thus, we provide conditions on the network under which the Nash equilibrium concept has a learning foundation, despite the fact that agents may have incomplete information. In particular, we show that the choice of being active or inactive in a network is crucial to determine whether agents can make correct inferences about the payoff state and hence play the best reply to the truth in a selfconfirming equilibrium. We also study learning dynamics and show how agents can get stuck in non--Nash selfconfirming equilibria. In such dynamics, the set of inactive agents can only increase in time, because once an agent finds it optimal to be inactive, she gets no feedback about the payoff state, hence she does not change her beliefs and remains inactive