Decentralized evolutionary mechanisms for intertemporal economies: A possibility result

We consider a stationary, infinite horizon aggregative model with one consumer and one producer living in each period. A decentralized intertemporal mechanism, satisfying the following evolutionary property, is constructed: if the current period's producer and consumer verify their equilibrium conditions, then the allocation is actually executed, without further verification by future agents. The mechanism is based on the idea of continual planning revision. It is shown that the outcome is an intertemporally efficient allocation which maximizes the long run average of one period utilities from consumption.We would like to thank L. Hurwicz, E. Malinvaud, and R. Radner for valuable discussions, and two referees for helpful comments. Research on this project was partially supported by a National Science Foundation Grant.     

Reconstructing dynamics from intertemporal economic data

Summary This paper is concerned with the relationship between a continuous dynamical system and the trajectory generated by such a system. The main result provides necessary and sufficient conditions for an infinite data stream to be rationalized as the output of a continuous law of motion. The paper develops concepts of informativeness of a given set of intertemporal data and shows that informativeness is maximal when the data is chaotic. It also demonstrates that with probability one the sample paths from a non-trivial independent and identically distributed stochastic process cannot be rationalized as the output of a continuous deterministic system. Two impossibility results are discussed which show that even with an infinite amount of data the hypothesis that the data has been generated by a non-monotonic function cannot be ruled out. An application concerning the recovery of the excess demand function from a sequence of price observations from the tatonnement process is also given.I would like to thank Professors Bent Christensen and Mukul Majumdar for valuable discussions and an anonymous referee for helpful comments. Financial support from SSHRC and Quebec's Fonds FCAR is gratefully acknowledged.     

Chaotic tatonnement

Summary Debreu's theorem on excess demand functions is used to demonstrate the possibilities of ergodic and topological chaos in a discrete-time tatonnement process with only two goods. The result is in sharp contrast with the well-known result of Arrow and Hurwicz on system stability in a continuous time model of price adjustment with two commodities.We would like to thank Professors Jess Benhabib, Richard Day, John Guckenheimer, Philip Holmes, Nicholas Kiefer and Tapan Mitra.     

A pitchfork bifurcation in the tatonnement process★

Summary . This note extends the example of Gale (1963) by considering the continuous time tatonnement process for a class of two agent, two commodity exchange economies, parametrized by a number μ∈(0,1). We demonstrate that as the parameter passes a threshold value μ^* the unique, globally stable competitive equilibrium loses local stability while two new locally stable equilibria appear. Intuitively, as μ increases the income effect become increasingly more important relative to substitution effect, and eventually overwhelms the latter. As the parameter μ approaches 1, the economy tends to the example considered by Gale, as does the limiting behavior of the tatonnement. Received: February 28, 1996; revised version August 5, 1996     

Network effects and competition: an empirical analysis of the home video game industry

Building on the resource‐based view of the firm, we advance the idea that a firm's customer network can be a strategic asset. We suggest that network effects are a function of network size (i.e., installed customer base) and network strength (i.e., the marginal impact of a unit increase in network size on demand). We empirically study these network effects in the 16‐bit home video game industry in which the dominant competitors were Nintendo and Sega. In the spirit of the new empirical IO framework, we estimate a structural econometric model assuming the data are equilibrium outcomes of the best fitting noncooperative game in price and advertising. After controlling for other effects, we find strong evidence that network effects are asymmetric between the competitors in the home video game industry. Specifically, we find that the firm with a smaller customer network (Nintendo) has higher network strength than the firm with the larger customer base (Sega). Thus, our results provide a possible explanation for this situation in which the firm with a smaller customer network (Nintendo) was able to overtake the sales of a firm with a larger network size (Sega). Copyright © 2002 John Wiley & Sons, Ltd.     

Migrant farmworkers: Resisting and organising before,during and after COVID-19

Migrant farmworkers are a ubiquitous but invisibilised, expropriated and exploited component of the global agricultural economy. Their conditions took centre-stage during the COVID-19 pandemic. Fear of production disruption in the migrant labour-intensive sectors led to foreign workers being deemed ‘essential’ in many countries, and exceptional procedures and regulations were instituted that further increased their exploitation, illnesses and deaths. However, the pandemic has not merely exposed the long-established structures of racialised exploitation and expropriation in the domain of farm work. Although it exacerbated the precariousness of the living and working conditions defining the reality of migrant farm workers, there is evidence that the pandemic also strengthened farmworkers' individual and collective consciousness, along with forms of organisation and resistance. The symposium ‘Migrant Farmworkers: Resisting and Organizing before, during and after COVID-19’ explores two dimensions reflected in migrant farmworkers' realities during the pandemic. First, the contributions look at the general conditions defining power structures and material outcomes within the political economy of agriculture before and during the pandemic. Second, they explore the conditions under which resistance and solidarity emerged to question established structures of exploitation.     

Managing the retail operations in the COVID-19 pandemic: Evidence from Morocco

Novel coronavirus disease (COVID-19) and resulting lockdowns have contributed to major retail operational disturbances around the globe, forcing retail organizations to manage their operations effectively. The impact can be measured as a black swan event (BSE). Therefore, to understand its impact on retail operations and enhance operational performance, the study attempts to evaluate retail operations and develop a decision-making model for disruptive events in Morocco. The study develops a three-phase evaluation approach. The approach involves fuzzy logic (to measure the current performance of retail operations), graph theory (to develop an exit strategy for retail operations based on different scenarios), and ANN and random forest-based prediction model with K-cross validation (to predict customer retention for retail operations). This methodology is preferred to develop a unique decision-making model for BSE. From the analysis, the current retail performance index has been computed as “Average” level and the graph-theoretic approach highlighted the critical attributes of retail operations. Further, the study identified triggering attributes for customer retention using machine learning-based prediction models (MLBPM) and develops a contactless payment system for customers' safety and hygiene. The framework can be used on a periodic basis to help retail managers to improve their operational performance level for disruptive events.