A comparison of diffusion approximations and actual limits in birth and death processes of noisy evolution

The stationary distribution of a birth and death process may not be approximated by a diffusion. The general situation is illustrated on the “musical chairs” model by Binmore et al. (1995). This model is shown to generate outcomes which are not captured by the concept of the ultralong run equilibrium selection introduced in Binmore et al. (1995).     

Employment and hours of work

This paper develops a dynamic model of the labor market in which the degree of substitution between employment and hours of work is determined as part of a search equilibrium. Each firm chooses its demand for working hours and number of vacancies, and the earnings profile is determined by Nash bargaining. The earnings profile is generally nonlinear in hours of work, and defines the trade-off between employment and hours of work. Concave production technology induces firms to overemploy and, as a result, hours of work are below their optimal level. The Hosios condition is not sufficient for efficiency. When there are two industries, workers employed by firms with higher recruitment costs work longer and earn more. That is, “good jobs” require longer hours of work. Interestingly, technology differentials cannot account for working hours differentials.     

Learning Dynamics in Games with Stochastic Perturbations

Consider a generalization of fictitious play in which agents′ choices are perturbed by incomplete information about what the other side has done, variability in their payoffs, and unexplained trembles. These perturbed best reply dynamics define a nonstationary Markov process on an infinite state space. It is shown, using results from stochastic approximation theory, that for 2 × 2 games it converges almost surely to a point that lies close to a stable Nash equilibrium, whether pure or mixed. This generalizes a result of Fudenherg and Kreps, who demonstrate convergence when the game has a unique mixed equilibrium. Journal of Economic Literature Classification Numbers: 000, 000, 000.     

The historical significance of the revaluation of fixed assets in Japan's state-owned railway system, 1955-6

The Government Railways of Japan (GRJ) established a fixed assets accounting system on the accruals basis after the Second World War. The revaluation of tangible fixed assets was indispensable for GRJ's introduction of depreciation in 1948. GRJ scheduled the revaluation to secure a reasonable depreciation expense, because the company had applied the replacement method to all tangible fixed assets since its foundation in 1869. At the same time, GRJ assumed the balance of the revaluation reserve account to be a means of dealing with possible future accumulated losses.     

Evolutionary game dynamics and distributed recency-weighted learning

This paper presents a relationship between evolutionary game dynamics and distributed recency-weighted Monte Carlo learning. After reviewing some existing theories of replicator dynamics and agent-based Monte Carlo learning, we provide proofs of the formulation-level equivalence between these two models. The relationship will be revealed not only from a theoretical viewpoint, but also by computational simulations of the models. As a consequence, macro dynamic patterns generated by distributed micro-decisions can be explained by parameters defined at an individual level. In particular, given the equivalent formulations, we investigate how the rate of agents’ recency weighting in learning affects the emergent evolutionary game dynamic patterns. An increase in this rate negatively affects the inertia, making the evolutionary stability condition more strict, and positively affecting the evolutionary speed toward equilibrium.JEL Classification: C63, C73Supervisions and advice given by Arthur J. Caplan have greatly contributed to this paper. I am also grateful to the anonymous reviewers for their valuable comments redirecting my presentation to a more appropriate one.     

Determinants of interregional mobility in Russia

The paper studies the determinants of internal migration in Russia. Using panel data on gross region‐to‐region migration flows in 1992–99, we estimate the effect of economic, political and social factors. Although overall migration is rather low, it turns out that its intensity does depend on economic factors even controlling for fixed effects for each origin–destination pair. People move from poorer and job scarce regions with worse public good provision to those which are richer and prospering better both in terms of employment prospects and public goods. Migration is, however, constrained by the lack of liquidity; for the poorest regions, an increase in income raises rather than decreases outmigration. Our estimates imply that up to a third of Russian regions are locked in poverty traps.     

Is living in African cities expensive?

Although several studies have examined why overall price levels are higher in richer countries, little is known about whether there is a similar relationship at the urban and city level across countries. This paper compares the price levels of cities in Sub-Saharan Africa with those of other regions by analyzing price information collected for the purpose of calculating official purchasing power parities. The approach of the paper is to readjust the calculated price levels from national to urban levels, using known price-level ratios between those areas. The results indicate that African cities are relatively more expensive, despite having lower income levels. The price levels of goods and services consumed by households are 25 to 28 percent higher in Sub-Saharan Africa than in other low- and middle-income countries, relative to their income levels. Such high costs of living could constrain livelihood of low-income urban residents, as well as the development of Africa’s urban economies.     

Ukrainian gas transit game

This paper investigates the origins and reasons for the termination of the Russian natural gas flow from Russia to Europe through Ukraine in January 2009. It discusses the strategic interaction of the three players (Russia, Ukraine and the European Union) based on the dynamics of losses from confrontation. The objective is to interpret the situation in a stylized way and to derive outcomes using calibrated parameters for costs and benefits of the players. We show that the stakes are high for both Russia and Ukraine in choosing to follow their preferred strategies, as both countries would sustain moderate losses during the initial period of conflict. Meanwhile, Europe’s lack of reserves makes it less prepared for the energy deficit than Ukraine and Russia, causing wider and earlier suffering for European countries dependent on Russian gas. Therefore, the European Union has a strong incentive to intervene in the conflict. Its actions during the January confrontation between Ukraine and Russia included extortion and bribery, all of which affected the outcome of the conflict.