Monotone methods for equilibrium selection under perfect foresight dynamics

This paper studies equilibrium selection in supermodular games based on perfect foresight dynamics. A normal form game is played repeatedly in a large society of rational agents. There are frictions: opportunities to revise actions follow independent Poisson processes. Each agent forms his belief about the future evolution of action distribution in the society to take an action that maximizes his expected discounted payo�. A perfect foresight path is de�ned to be a feasible path of the action distribution along which every agent with a revision opportunity takes a best response to this path itself. A Nash equilibrium is said to be absorbing if there exists no perfect foresight path escaping from a neighborhood of this equilibrium; a Nash equilibrium is said to be globally accessible if for each initial distribution, there exists a perfect foresight path converging to this equilibrium. By exploiting the monotone structure of the dynamics, a unique Nash equilibrium that is absorbing and globally accessible for any small degree of friction is identi�ed for certain classes of supermodular games. For games with monotone potentials, the selection of the monotone potential maximizer is obtained. Complete characterizations of absorbing equilibrium and globally accessible equilibrium are given for binary supermodular games. An example demonstrates that unanimity games may have multiple globally accessible equilibria for a small friction

Monotone Methods for Equilibrium Selection under Perfect Foresight Dynamics

This paper studies equilibrium selection in supermodular games based on perfect foresight dynamics. A normal form game is played repeatedly in a large society of rational agents. There are frictions: opportunities to revise actions follow independent Poison processes. Each agent forms his belief about the future evolution of the action distribution in the society, and takes an action that maximizes his expected discounted payoff. A perfect foresight path is defined to be a feasible path of the action distribution along which every agent with a revision opportunity takes a best response to this path itself. A Nash equilibrium is said to be absorbing if any perfect foresight path converges to this equilibrium whenever the initial distribution is suffciently close to the equilibrium; a Nash equilibrium is said to be globally accessible if for each initial distribution, there exists a perfect foresight path converging to this equilibrium. By exploiting the monotone structure of the dynamics, the unique Nash equilibrium that is absorbing and globally accessible for any small degree of friction is identified for certain classes of supermodular games. For games with monotone potentials, the selection of the monotone potential maximizer is obtained. Complete characterizations for absorption and global accessibiltiy are given for binary supermodular games. An example demonstrates that unanimity games may have multiple globally accessible equilibria for a small friction.

Monotone methods for equilibrium selection under perfect foresight dynamics

This paper studies a dynamic adjustment process in a large society of forward-looking agents where payoffs are given by a normal form supermodular game. The stationary states of the dynamics correspond to the Nash equilibria of the stage game. It is shown that if the stage game has a monotone potential maximizer, then the corresponding stationary state is uniquely linearly absorbing and globally accessible for any small degree of friction. A simple example of a unanimity game with three players is provided where there are multiple globally accessible states for a small friction.Equilibrium selection, perfect foresight dynamics, supermodular game, strategic complementarity, stochastic dominance, potential, monotone potential

Are the anti-globalists right? Gains-from-trade without a Walrasian auctioneer

We examine whether the "fear" of globalisation can be rationalised by economic theory. To do so, we depart from the standard AD/AS (partial) equilibrium model where the coordinational role of the Auctioneer is substituted by an implementation device based on learning (Guesnerie, 1992). By endowing producers with a learning ability to forecast market prices, individual profit-maximizing production decisions become interdependent in a strategic sense (strategic substitutes). Performing basic comparative statics exercises, we show that "competitiveness" matters in a precise sense: as foreign producers gain access to the home market, home producers' ability to forecast market prices is undermined, so being their ability to forecast the profit consequences of their production decisions. When performing a standard open economy exercise in such a framework, we show that the existence of standard efficiency gains - due to the increase in competition (or spatial price stabilization) - is traded-off against coordination upon the welfare enhancing free-trade equilibrium (stabilizing price expectations). Therefore, we identify a new rationale for an exogenous price intervention in open economy targeting coordination, to allow trading countries to fully reap the benefits from trade. We illustrate this point showing that classical measures evaluating ex-ante the desirability of economic integration (net welfare gains) do not always advice integration between two expectationally stable economies

Are the antiglobalists right? Gains-from-trade without a walrasian auctioneer

We examine whether the "fear" of globalisation can be rationalised by economic theory. To do so, we depart from the standard AD/AS (partial) equilibrium model where the coordinational role of the Auctioneer is substituted by an implementation device based on learning (Guesnerie, 1992). By endowing producers with a learning ability to forecast market prices, individual profit-maximizing production decisions become interdependent in a strategic sense (strategic substitutes). Performing basic comparative statics exercises, we show that "competitiveness" matters in a precise sense: as foreign producers gain access to the home market, home producers' ability to forecast market prices is undermined, so being their ability to forecast the profit consequences of their production decisions. When performing a standard open economy exercise in such a framework, we show that the existence of standard efficiency gains - due to the increase in competition (or spatial price stabilization) - is traded-off against coordination upon the welfare enhancing free-trade equilibrium (stabilizing price expectations). Therefore, we identify a new rationale for an exogenous price intervention in open economy targeting coordination, to allow trading countries to fully reap the benefits from trade. We illustrate this point showing that classical measures evaluating ex-ante the desirability of economic integration (net welfare gains) do not always advice integration between two expectationally stable economies.open economy ; rational expectations ; coordination ; common knowledge

Are the anti-globalists right? Gains-from-trade without a Walrasian auctioneer

We examine whether the "fear" of globalisation can be rationalised by economic theory. To do so, we depart from the standard AD/AS (partial) equilibrium model where the coordinational role of the Auctioneer is substituted by an implementation device based on learning (Guesnerie, 1992). By endowing producers with a learning ability to forecast market prices, individual profit-maximizing production decisions become interdependent in a strategic sense (strategic substitutes). Performing basic comparative statics exercises, we show that "competitiveness" matters in a precise sense: as foreign producers gain access to the home market, home producers' ability to forecast market prices is undermined, so being their ability to forecast the profit consequences of their production decisions. When performing a standard open economy exercise in such a framework, we show that the existence of standard efficiency gains - due to the increase in competition (or spatial price stabilization) - is traded-off against coordination upon the welfare enhancing free-trade equilibrium (stabilizing price expectations). Therefore, we identify a new rationale for an exogenous price intervention in open economy targeting coordination, to allow trading countries to fully reap the benefits from trade. We illustrate this point showing that classical measures evaluating ex-ante the desirability of economic integration (net welfare gains) do not always advice integration between two expectationally stable economies. <br><br> Keywords; globalisation, rational expectations, coordination, common knowledge

Macroeconomic and monetary policies from the "eductive" viewpoint

The "eductive" viewpoint provides a theoretically sophisticated analysis as well as an intuitively plausible shortcut to the study of expectational coordination in economic models. From the review of expectational criteria in a class of dynamical models of macroeconomic theory, the paper shows how such an "eductive" viewpoint completes and deepens rather than contradicts standard analysis. It however argues that the "eductive" approach, when correctly implemented, challenges the conditions of learning in infinite-horizon models with infinitely-lived agents. In particular, in a simple monetary model adopting such a framework, Taylor rules may be stabilizing, in the demanding sense under scrutiny, but only within a small window for the reaction coefficient.expectational coordination ; dynamical models ; infinitely lived agents ; cashless economy ; inflation ; adaptive and "eductive" learning ; Taylor rules ; central banks

Commitment in intertemporal household consumption: a revealed preference analysis

We present a revealed preference methodology for analyzing intertemporal household consumption behavior. In doing so, we follow a collective approach, which explicitly recognizes that multi-member households consist of multiple decision makers with their own rational preferences. Following original work of Mazzocco (2007), we develop tests that can empirically verify whether observed consumption behavior is consistent with (varying degrees of) intrahousehold commitment. In our set-up, commitment means that households choose consumption allocations on the ex ante Pareto frontier. The distinguishing feature of our tests is that they are entirely nonparametric, i.e. their implementation does not require an a priori (typically non-verifiable) specification of the intrahousehold decision process (e.g. individual utilities). We demonstrate the practical usefulness of our methodology by means of an empirical application. For the data at hand, our results suggest using a so-called limited commitment model that allows for household-specific commitment patterns. Importantly, our application also shows that bringing intertemporal dynamics in the empirical analysis can substantially increases the discriminatory power of the revealed preference methodology.

Are the antiglobalists right? Gains-from-trade without a walrasian auctioneer

We examine whether the "fear" of globalisation can be rationalised by economic theory. To do so, we depart from the standard AD/AS (partial) equilibrium model where the coordinational role of the Auctioneer is substituted by an implementation device based on learning (Guesnerie, 1992). By endowing producers with a learning ability to forecast market prices, individual profit-maximizing production decisions become interdependent in a strategic sense (strategic substitutes). Performing basic comparative statics exercises, we show that "competitiveness" matters in a precise sense: as foreign producers gain access to the home market, home producers' ability to forecast market prices is undermined, so being their ability to forecast the profit consequences of their production decisions. When performing a standard open economy exercise in such a framework, we show that the existence of standard efficiency gains - due to the increase in competition (or spatial price stabilization) - is traded-off against coordination upon the welfare enhancing free-trade equilibrium (stabilizing price expectations). Therefore, we identify a new rationale for an exogenous price intervention in open economy targeting coordination, to allow trading countries to fully reap the benefits from trade. We illustrate this point showing that classical measures evaluating ex-ante the desirability of economic integration (net welfare gains) do not always advice integration between two expectationally stable economies.A l'aide de la théorie économique, on examine si la peur du libre-échange peut être rationalisée. Pour ce faire, on substitue l'élément de coordination implicite présent dans le modèle DA/OA de la macroéconomie standard (commissaire priseur "walrasien") par un mécanisme de "concrétisation" de l'équilibre fondé sur l'apprentissage (Guesnerie, 1992). Doués de cette capacité individuelle d'apprentissage, les producteurs vont former des anticipations sur le prix apurant le marché, et de ce fait reconnaître que leurs décisions de production dépendent des décisions de production des autres. Un exercice de statique comparée simple montre que la "compétitivité" est rationnelle dans un sens très précis : dès lors que les producteurs étrangers écoulent leur production dans le marché national, les producteurs nationaux voient leur capacité de prévoir les conséquences en termes de profit de leurs décisions de production diminuée, du fait de leur difficulté accrue de prévoir le prix de marché toute chose égale par ailleurs. Dans ce cadre, un exercice standard d'intégration économique révèle l'existence d'une tension entre les gains à l'échange (stabilité "spatiale" des prix d'autarcie) et la capacité des producteurs à apprendre l'équilibre de l'économie intégrée ("stabilité" de leurs anticipations du prix). C'est ainsi qu'on justifie la pertinence d'une intervention exogène qui, favorisant la coordination, permettrait aux pays matérialiser les gains à l'échange de l'intégration. Ce point est illustré à l'aide d'un exemple où ex-ante, l'évaluation classique des gains à l'ouverture ne "conseille" pas toujours l'intégration entre des économies "stables" à l'autarcie