Existence of a Pareto-optimal equilibrium in nearly-stationary overlapping-generations economies

Summary In overlapping-generations models of fiat money, the existence of a Pareto-optimal equilibrium — which defines an optimal quantity of money — is more general than well-known counter-examples suggest. Those examples, having no optimal equilibrium just because there are small variations in households' tastes and endowments across generations, are not typical. On the contrary: For an open-dense, full-measure subset of smooth stationary economies and an open-dense subset of continuous stationary economies, introducing small variations in tastes and endowments across generations preserves the existence of an optimal equilibrium. Put simply, optimal equilibria generically exist for nearly-stationary economies.I thank Scott Freeman, Katsuhiko Kawai, and two referees for proofreading this text; all lead to clarifications.     

A theory of sequential reciprocity

Many experimental studies indicate that people are motivated by reciprocity. Rabin [Amer. Econ. Rev. 83 (1993) 1281] develops techniques for incorporating such concerns into game theory and economics. His theory is developed for normal form games, and he abstracts from information about the sequential structure of a strategic situation. We develop a theory of reciprocity for extensive games in which the sequential structure of a strategic situation is made explicit, and propose a new solution concept—sequential reciprocity equilibrium—for which we prove an equilibrium existence result. The model is applied in several examples, and it is shown that it captures very well the intuitive meaning of reciprocity as well as certain qualitative features of experimental evidence.     

Uniqueness of equilibrium for smooth multistage concave games

Smooth, noncooperative, multistage, concave games are formulated so that a new uniqueness condition—based on the Poincaré-Hopf theorem—can be applied. The new condition is the weakest to appear in the uniqueness literature. The uniqueness subgame perfect equilibrium is obtained and examples are given.     

Counting combinatorial choice rules

I count the number of combinatorial choice rules that satisfy certain properties: Kelso–Crawford substitutability, and independence of irrelevant alternatives. The results are important for two-sided matching theory, where agents are modeled by combinatorial choice rules with these properties. The rules are a small, and asymptotically vanishing, fraction of all choice rules. But they are still exponentially more than the preference relations over individual agents—which has positive implications for the Gale–Shapley algorithm of matching theory.     

Extensive-form games and strategic complementarities

I prove the subgame-perfect equivalent of the basic result for Nash equilibria in normal-form games of strategic complements: the set of subgame-perfect equilibria is a nonempty, complete lattice—in particular, subgame-perfect Nash equilibria exist. For this purpose I introduce a device that allows the study of the set of subgame-perfect equilibria as the set of fixed points of a correspondence. My results are limited because extensive-form games of strategic complementarities turn out—surprisingly—to be a very restrictive class of games.     

Exploitation and Growth

I develop a model of exploitation—coercive wealthtransfer—and growth based on social importance. Exploitationreduces growth since the return to capital falls with exploitationcosts. Initial relative wealth across groups—the measureof social importance—determines which group is the exploiterand how costly exploitation will be. The exploiter selects anexploitation path that maintains its dominant position and rarelymaximizes current transfers. Productive minorities and fast-growinggroups are most prone to exploitation. International sanctions,if strong, end exploitation; otherwise they increase exploitationand reduce growth. Segregation and apartheid are broadly consistentwith the theory.     

Better technology forecasting using systematic innovation methods

An evolved version of the Soviet-originated Theory of Inventive Problem Solving, TRIZ, contains a series of generically predictable technology and business evolution trends uncovered from the systematic analysis of over 2 million patents, academic journals and business texts. The current state of the art—recorded for the first time together in this paper—now bring the total number of generic technical trends to over 30, and the number of business trends to over 20. The paper describes some of the newly discovered trends, and their incorporation into a design method that allows individuals and businesses to first establish the relative maturity of their current systems, and then, more importantly, to identify areas where ‘evolutionary potential’ exists. The paper introduces this concept of evolutionary potential—defined as the difference between the relative maturity of the current system, and the point where it has reached the limits of each of the evolution trends—through a number of case study examples focused on the design and evolution of complex systems.     

The Lost Decades: Developing Countries' Stagnation in Spite of Policy Reform 1980–1998

I document in this paper a puzzle thathas not received previous attention in the literature. In 1980–98,median per capita income growth in developing countries was 0.0percent, as compared to 2.5 percent in 1960–79. Yet I documentin this paper that variables that are standard in growth regressions—policieslike financial depth and real overvaluation, and initial conditionslike health, education, fertility, and infrastructure generallyimproved from 1960–79 to 1980–98. Developing countrygrowth should have increased instead of decreased according tothe standard growth regression determinants of growth. The stagnationseems to represent a disappointing outcome to the movement towardsthe ``Washington Consensus' by developing countries. I speculatethat worldwide factors like the increase in world interest rates,the increased debt burden of developing countries, the growthslowdown in the industrial world, and skill-biased technicalchange may have contributed to the developing countries' stagnation,although I am not able to establish decisive evidence for thesehypotheses. I also document that many growth regressions aremis-specified in a way similar to the Jones (1995) critique thata stationary variable (growth) is being regressed on non-stationaryvariables like policies and initial conditions. It may be thatthe 1960–1979 period was the unusual period for LDC growth,and the 1980–98 stagnation of poor countries representsa return to the historical pattern of divergence between richand poor countries.     

An elephantine theory of depressions

In microeconomics a theory is thought to be, if not inadequate, then incomplete unless it can be interpreted as “telling a story.” Beavers and deers, perpetual plants, aging wine—these and other homely examples play a larger role in our assessment of the validity of theories than economists might want to admit. If we cannot find a plausible story, then the theory itself is often suspect. This criterion may be applied to macroeconomics too…     

Consumption dynamics under information processing constraints

This paper studies how “rational inattention” (RI)—a type of information processing constraint proposed by Sims [Sims, C.A., 2003. Implications of rational inattention, Journal of Monetary Economics 50 (3), 665–690]—affects the joint dynamics of consumption and income in a permanent income model with general income processes. Specifically, I propose an analytical approach to solve the multivariate permanent income model with RI and examine its implications for optimal consumption, saving, and welfare. It is shown that RI can affect the relative volatility of consumption and provide an endogenous propagation mechanism that disentangles the short-run and long-run responses of consumption to exogenous income shocks. I also explore how aggregation reduces the impact of the RI-induced endogenous noise on consumption and thus increases the smoothness of aggregate consumption. Finally, I compare RI with four alternative hypotheses (habit formation, signal extraction, robustness, and inattentiveness) by examining their implications for the joint behavior of consumption and income.     

On Hayek's road to serfdom: 60 years later

Stimulated by recent work of Levy–Peart–Ferrant, Rosser and McPhail, I read The Road to Serfdom by projecting it onto four registers—security and freedom, impersonal forces and the market, rules and the rule of law, and language and education—and identify in each the need for judgement, hopefully balanced but inevitably arbitrary beyond an analytical threshold, a need exacerbated by incomplete and dispersed knowledge. My larger project is to understand the role of the expert, theoretician if one prefers, in a ‘free’ society.     

Using Random nth Price Auctions to Value Non-Market Goods and Services

Public policy decision making often requires balancing the benefits of a policy with the costs. While regulators in the United States and abroad rely heavily on benefit-cost analysis, critics contend that hypothetical bias precludes one of the most popular benefit estimation techniques—contingent surveys—from providing reliable economic values for nonmarket goods and services. This paper explores a new methodology to obtain the total value of nonmarket goods and services—random nth price auctions. The empirical work revolves around examining behavior of 360 participants in a competitive marketplace, where subjects naturally buy, sell, and trade commodities. The field experiment provides some preliminary evidence that hypothetical random nth price auctions can, in certain situations, reveal demand truthfully.     

Monetary policy in Germany: A cointegration analysis on the relevance of interest rate rules

The paper attempts to identify an empirical relationship that characterizes the way the Bundesbank adjusted its short-term rate with respect to various objectives. By building on a careful exploration of the properties of the variables involved, it is established that interest rate rules —often remarkably similar to the Taylor rule— remain valid and relevant in a Vector Error Correction framework, and thereby proposing a distinctive interpretation of German monetary policy during the period 1975–1998.     

Polynomial innovation diffusion models

In an earlier paper [42] the authors presented a comprehensive evaluation and extensions of available causal models of “binomial type” for describing the time pattern of the innovation diffusion processes. The binomial models are based on the assumption that the entire population can be divided into two groups—adopters of an innovation and the potential adopters—such that eventually everyone adopts the innovation and an innovation once adopted is never rejected. However, many examples can be cited where this assumption is unrealistic. Therefore this paper presents some polynomial innovation diffusion models that are less restrictive compared with the binomial models. The paper also shows the link between the polynomial diffusion process and the multilevel technological substitution process.     

Theorie der Spiele und ökonomische Entscheidungsprozesse

Ohne ZusammenfassungBesprechungsaufsatz übera) E. Burger: Einführung in die Theorie der Spiele. — Mit Anwendungsbeispielen, insbesondere aus Wirtschaftslehre und Soziologie. 169 S. Berlin: Walter de Gruyter & Co. 1959. DM 28,—.b) R. D. Luce und H. Raiffa: Games and Decisions. Introduction and Critical Survey. 509 S. New York: John Wiley & Sons, Inc. — London: Chapman & Hall Ltd. 1957. $ 8,75.c) M. Shubik: Strategy and Market Structure. Competition, Oligopoly and the Theory of Games. X, 387 S. New York: John Wiley & Sons, Inc. — London: Chapman & Hall Ltd. 1959. $ 8,—.d) S. Karlin: Mathematical Methods and Theory in Games, Programming, and Economics. Vol. I: Matrix Games, Programming, and Mathematical Economics. X, 427 S. Vol. II: The Theory of Infinite Games. XI, 386 S. Reading, Mass. — London: Addison-Wesley Publishing Company, Inc. 1959. — Je Band $ 10,75. Diesererste Teil behandelt zunächst das Lehrbuch von Burger.     

Gender Equality and Long-Run Growth

This research suggests that long-run economic and demographic development in Europe can be better understood when related to long-term trends in gender equality, dating back to the spread of Christianity. We set up a growth model where gaps in female-to-male human capital arise at equilibrium through a coordination process. An economy which over a long stretch of time re-coordinates on continuously more equal equilibria—as one could argue happened in Europe—exhibits growth patterns qualitatively similar to that of Europe.     

Ex post implementation

We analyze the problem of fully implementing a social choice set in ex post equilibrium. We identify an ex post monotonicity condition that is necessary and—in economic environments—sufficient for full implementation in ex post equilibrium. We also identify an ex post monotonicity no veto condition that is sufficient. Ex post monotonicity is satisfied in all single crossing environments with strict ex post incentive constraints.We show by means of two classic examples that ex post monotonicity does not imply nor is it implied by Maskin monotonicity. The single unit auction with interdependent valuations is shown to satisfy ex post monotonicity but not Maskin monotonicity. We further describe a Pareto correspondence that fails ex post monotonicity but satisfies Maskin monotonicity.     

Melioration learning in games with constant and frequency-dependent pay-offs

The paper explores the implications of melioration learning—an empirically significant variant of reinforcement learning—for game theory. We show that in games with invariable pay-offs melioration learning converges to Nash equilibria in a way similar to the replicator dynamics. Since melioration learning is known to deviate from optimizing behavior when an action’s rewards decrease with increasing relative frequency of that action, we also investigate an example of a game with frequency-dependent pay-offs. Interactive melioration learning is then still appropriately described by the replicator dynamics, but it indeed deviates from rational choice behavior in such a game.     

Finding invariant structures in Forrester's world dynamics—An analysis by simulation

The authors investigated Forrester's World Dynamics for properties which are invariant with respect to the model, i.e., properties of the prediction curves which are only dependent on the variables inherent in the model. The suspicion that invariant properties exist is confirmable, for example, by making significant changes in the initial conditions and by observing the resulting prediction curves for their qualitative behavior. In the course of extensive investigations carried out on the ICL-1909 computer of the Technical University of Berlin, several examples were encountered which prove certain invariants in Forrester's model. A one-year iteration interval was selected for the simulations that were carried out. Other step-lengths, it turned out, yielded appreciable alterations in Forrester's results. Further, the authors investigated if and when certain limiting values are approached after the year 2100. This is clearly exhibited in the case of some variables. Even for simulations with changed initial values, limiting values result which are similar to those in runs with the original initial values. Simulations with altered Table Functions show that some model variables are impacted by those changes while others are at least qualitatively in accord with their behavior in the original runs.