Stability of stochastic optimal growth models: a new approach

The paper proposes an Euler equation technique for analyzing the stability of differentiable stochastic programs. The main innovation is to use marginal reward directly as a Foster-Lyapunov function. This allows us to extend known stability results for stochastic optimal growth models, both weakening hypotheses and strengthening conclusions.     

Trade and Indeterminacy in a Dynamic General Equilibrium Model

This paper introduces sector-specific externalities in the Heckscher-Ohlin two-country dynamic general equilibrium model to show that indeterminacy of the equilibrium path in the world market can occur. Under certain conditions in terms of factor intensities, there are multiple equilibrium paths from the same initial distribution of capital in the world market, and the distribution of capital in the limit differs among equilibrium paths. One equilibrium path converges to a long-run equilibrium in which the international ranking of factor endowment ratios differs from the initial ranking; another equilibrium path maintains the initial ranking and converges to another long-run equilibrium. Since the path realized is indeterminate, so is the long-run trade pattern. Therefore, the Long-Run Heckscher-Ohlin prediction is vulnerable to the introduction of externality. Journal of Economic Literature Classification Numbers: E13, E32, F11, F43.     

Long-Run Effects of Monetary Expansion in a Two-Sector Model of Endogenous Growth

This paper explores the long-run effects of monetary expansion by introducing a cash-in-advance constraint into one of the basic models of endogenous growth. In our model, the real side of the economy consists of two production sectors, one of which produces a final good that can be used either for consumption or for investment and the other produces new human capital. Both sectors use physical and human capital under constant returns to scale technologies. We first characterize the balanced-growth equilibrium and then examine how a rise in money growth affects the relevant variables, such as the long-term growth rate and the relative prices.     

Pairs trading under transaction costs using model predictive control

Model predictive control with proportional transactions costs provides a good approximation to the optimal trading strategy     

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.     

Expectation-driven fluctuations and welfare loss under free trade in two-country models

This paper investigates the interlinkage in the business cycles based on expectation-driven fluctuations of large-country economies in a free-trade equilibrium. We consider a two-country, two-good, two-factor general equilibrium model with sector-specific externalities. We show that some country's expectation-driven fluctuations can spread throughout the world once trade opens even if the other country has determinacy under autarky. We thus prove that under free trade, globalization and market integration can have destabilizing effects on a country's competitive equilibrium. Finally, we characterize a configuration in which opening to international trade improves the stationary welfare at the world level but deteriorates the stationary welfare of the country that imports investment goods and exports consumption goods. We conclude that in opposition to the standard belief, international trade might not be beneficial to all trading partners in the long run.     

Non‐compliance with the Minimum Wage Law when Completely New Minimum Wage Laws Are Established: The Case of South Africa

Abstract: Using the case of South Africa, we study compliance with the minimum wage law when completely new minimum wage levels are established. By even the best estimate, the compliance rate in South Africa would not exceed 40 per cent for the agricultural sector and 30 per cent for the domestic worker sector. The compliance rates by subpopulation groups reveal that the compliance rate is low where the cost to comply with the minimum wage law is high, implying that government inspections are not done where they are likely to have the highest payoff. However, if the government tries to enforce the policy more strictly, the poor/less skilled would be adversely affected.     

On the shape of the single-country and world commodity-substitution and factor-substitution surfaces under conditions of joint production

In recent years trade theorists have completed the task of specifying necessary and sufficient conditions for the single-country and world transformation surfaces to be locally of any assigned degree of flatness. However those conditions are relevant only if the technology is of the no-joint-products type. In the present note we derive necessary and sufficient conditions for the single-country and world transformation surfaces to be of any assigned degree of flatness under conditions of joint production; and we also obtain, as a by-product, necessary and sufficient conditions for the single-country and world equal-product surfaces to be of any assigned degree of flatness.     

Factor-Market Distortions, Dynamic Stability, and Paradoxical Comparative Statics

In the late 1960s and early 1970s there was a strong revival of interest in the role of factor-market distortions in those branches of our subject which rely on the Lerner–Samuelson two-by-two model of production. Among the legacies from that period were several comparative statical propositions which seemed counterintuitive or paradoxical. However, the revival lost momentum when confronted with Neary's observation that the major paradoxes are associated with unstable equilibria and therefore rarely observed. On the other hand, there are now seen to be several errors in Neary's analysis. For example, in the important case of a closed economy (and, by interpretation, in the case of a large open economy) he overlooked the fact that paradoxes can be associated with stable equilibria.