Three Lectures on the Walrasian Hypotheses for Exchange Economies

This paper discusses the testable implications of the Walrasian hypotheses: H1 Observed market demand is the sum of consumer's demands derived from utility maximization subject to budget constraints. H2 There exists an observable (locally) unique equilibrium price system such that the observable market demand is equal to the observable market supply in every market. H3 The observed equilibrium price system is a (locally) stable equilibrium of tƒtonnement price adjustment. The main results are the Brown Matzkin Theorem: H1 is testable, and the Brown Shannon Theorem: H2 and H3 are not testable.Exchange Economies, Testable Restrictions

Uniqueness, Stability, and Comparative Statics in Rationalizable Walrasian Markets

This paper studies the extent to which qualitative features of Walrasian equilibria are refutable given a finite data set. In particular, we consider the hypothesis that the observed data are Walrasian equilibria in which each price vector is locally stable under tatonnement. Our main result shows that a finite set of observations of prices, individual incomes and aggregate consumption vectors is rationalizable in an economy with smooth characteristics if and only if it is rationalizable in an economy in which each observed price vector is locally unique and stable under tatonnement. Moreover, the equilibrium correspondence is locally monotone in a neighborhood of each observed equilibrium in these economies. Thus the hypotheses that equilibria are locally stable under tatonnement, equilibrium prices are locally unique and equilibrium comparative statics are locally monotone are not refutable with a finite data set.

Competition, Consumer Welfare and Monopoly Power

An applied general equilibrium analysis of monopoly power is proposed as an alternative to the partial equilibrium analyses of monopoly pricing current in antitrust economics. This analysis introduces a new notion of market equilibrium where firms with monopoly power are cost-minimizing price-takers in competitive factor markets and make supracompetitive profits in equilibrium, i.e., the monopoly price exceeds the marginal cost of production. We assume that the primary goals of antitrust policy are the promotion of competition and the enhancement of consumer welfare. To that end, we use Debreu's coefficient of resource utilization to determine the counterfactual competitive price levels in monopolized markets and then impute the economic costs of monopolization.Monopoly power, Antitrust economics, Applied general equilibrium analysis

Sign Tests for Dependent Observations

The present paper introduces new sign tests for testing equality of conditional distributions of two (arbitrary) adapted processes as well as for testing conditionally symmetric martingale-difference assumptions. Our analysis is based on results that demonstrate randomization over ties in sign tests for equality of conditional distributions of two adapted sequences produces a stream of i. i. d. symmetric Bernoulli random variables. This reduces the problem of estimating the critical values of the tests to computing the quantiles or moments of Binomial or normal distributions. A similar proposition holds for randomization over zero values of three-valued random variables in a conditionally symmetric martyingale-difference sequence.

Affective Decision Making and the Ellsberg Paradox

We characterize, in the framework for variational preferences, the affective decision making model of choice under risk and uncertainty introduced by Bracha and Brown (2007). This characterization (i) provides a rigorus decision-theoretic foundation for affective decision making, (ii) offers an axiomatic explanation for ambiguity-seeking in the Ellsberg Paradox and (iii) suggests a dual representation of ADM games in terms of the Legendre-Fenchel conjugate.Ellsberg paradox, Schmeidler's axiom, Affective decision making, Variational preferences, Legendre-Fenchel conjugate

Two Algorithms for Solving the Walrasian Equilibrium Inequalities

We propose two algorithms for deciding if the Walrasian equilibrium inequalities are solvable. These algorithms may serve as nonparametric tests for multiple calibration of applied general equilibrium models or they can be used to compute counterfactual equilibria in applied general equilibrium models defined by the Walrasian equilibrium inequalities.Applied general equilibrium analysis, Walrasian equilibrium inequalities, Calibration

Rationalizing and Curve-Fitting Demand Data with Quasilinear Utilities

In the empirical and theoretical literature a consumer's utility function is often assumed to be quasilinear. In this paper we provide necessary and sufficient conditions for testing if the consumer acts as if she is maximizing a quasilinear utility function over her budget set. If the consumer's choices are inconsistent with maximizing a quasilinear utility function over her budget set, then we compute the "best" quasilinear rationalization of her choices.Quasilinear utilities, Afriat inequalities, Curve-fitting

The Strong Law of Demand

We show that a demand function is derived from maximizing a quasilinear utility function subject to a budget constraint if and only if the demand function is cyclically monotone. On finite data sets consisting of pairs of market prices and consumption vectors, this result is equivalent to a solution of the Afriat inequalities where all the marginal utilities of income are equal. We explore the implications of these results for maximization of a random quasilinear utility function subject to a budget constraint and for representative agent general equilibrium models. The duality theory for cyclically monotone demand is developed using the Legendre-Fenchel transform. In this setting, a consumer's surplus is measured by the conjugate of her utility function.Permanent income hypothesis, Afriat's theorem, Law of demand, Consumer's surplus, Testable restrictions

The Computation of Counterfactual Equilibria in Homothetic Walrasian Economies

We propose a nonparametric test for multiple calibration of numerical general equilibrium models, and we present an effective algorithm for computing counterfactual equilibria in homothetic Walrasian economies, where counterfactual equilibria are solutions to the Walrasian inequalities.Applied general equilibrium analysis, Walrasian inequalities, Calibration