Poverty Traps

no abstract given.Poverty

A strategic model of complex networks formation.

This paper introduces a spatialized variation of the Connections model of Jackson and Wolinski (1996). Agents benefit from their direct and indirect connections in a communication network. They are arranged on a circle and bear costs for maintaining direct connections which are linearly increasing with geographic distance. In a dynamic setting, this model is shown to generate networks that exhibit the small world properties shared by many real social and economic networks.Strategic Network Formation, Pairwise Stability, Small World, Monte Carlo.

Path dependence, its critics and the quest for ‘historical economics’

The concept of path dependence refers to a property of contingent, non- reversible dynamical processes, including a wide array of biological and social processes that can properly be described as 'evolutionary.' To dispell existing confusions in the literature, and clarify the meaning and significance of path dependence for economists, the paper formulates definitions that relate the phenomenon to the property of non-ergodicity in stochastic processes; it examines the nature of the relationship between between path dependence and 'market failure,' and discusses the meaning of 'lock-in.' Unlike tests for the presence of non-ergodicity, assessments of the economic significance of path dependence are shown to involve difficult issues of counterfactual specification, and the welfare evaluation of alternative dynamic paths rather than terminal states. The policy implications of the existence of path dependence are shown to be more subtle and, as a rule, quite different from those which have been presumed by critics of the concept. A concluding section applies the notion of 'lock-in' reflexively to the evolution of economic analysis, suggesting that resistence to historical economics is a manifestation of 'sunk cost hysteresis' in the sphere of human cognitive development.path dependence, non-ergodicity, irreversibility, lock-in, counterfactual analysis

Coordination failures in network formation.

In this paper, we make an exploratory use of numerical techniques (genetic algorithms and Monte Carlo simulations) to compute efficient and emergent networks in a spatialized version of the connections model of Jackson and Wolinski (1996). This approach allows us to observe and discuss the coordination failures that arise in a strategic network formation context with link-mediated positive externalities to connections and geographically based connection costs. Our results highlight that, depending on the strength of the externalities, emergent and efficient networks may share several structural properties. Nevertheless, emergent networks have too few local and distant connections and are also too less “coordinated” around some central agents than they should.Strategic Network Formation; Efficiency; Stability; Coordination; Small Worlds; Genetic Algorithms; Monte Carlo Simulations.

Markets and Jungles

Economic institutions determine prospects for growth and development. This paper examines necessary conditions for an economy to support institutions that implement markets. Agents differ in land holdings, skill, and power. A competitive market assigns land to the skilled, not necessarily to the powerful. Therefore a market allocation needs to be robust to coalitional expropriation. In a dynamic setting, market payoffs may induce sufficient inequality in next period's endowments for markets to alternate with expropriation in a limit cycle, decreasing efficiency and amplifying macroeconomic fluctuations. Long run stability of markets is favored by higher social mobility, more initial equality, and less mismatch between demand and supply. --Expropriation,market institutions,inequality,fluctuations,coalition formation

Memory, multiple equilibria and emerging market crises

We present a new Generalized Markov Equilibrium (GME) approach to studying sudden stops and financial crises in emerging countries in the canonical small open economy model with equilibrium price-dependent collateral constraints. Our approach to characterizing and computing stochastic equilibrium dynamics is global, encompasses recursive equilibrium as a special case, yet allows for a much more flexible approach to modeling memory in such models that are known to have multiple equilibrium. We prove the existence of ergodic GME selections from the set of sequential competitive equilibrium, and show that at the same time ergodic GME selectors can replicate all the observed phases of the macro crises associated with a sudden stop (boom, collapse, spiralized recession, recovery) while still being able to capture the long-run stylized behavior of the data. We also compute stochastic equilibrium dynamics associated with stationary and nonstationary GME selections, and we find that a) the ergodic GME selectors generate stochastic dynamics that are less financially constrained with respect to stationary non-ergodic paths, b) non-stationary GME selections exhibit a great range of fluctuations in macroeconomic aggregates compared to the stationary selections. From a theoretical perspective, we prove the existence of both sequential competitive equilibrium and (minimal state space) recursive equilibrium, as well as provide a complete theory of robust recursive equilibrium comparative statics in deep parameters. Consistent with recent results in the literature, relative to the set of recursive equilibrium, we find 2 stationary equilibrium: one with high/over borrowing, the other with low/under borrowing. These equilibrium are extremal and “selffulfilling” under rational expectations. The selection among these equilibria depend on observable variables and not on sunspots

Memoria, equilibrios múltiples y crisis en países emergentes

We present a new Generalized Markov Equilibrium (GME) approach to studying sudden stops and financial crises in emerging countries in the canonical small open economy model with equilib-rium price-dependent collateral constraints. Our approach to characterizing and computing stochastic equilibrium dynamics is global, encompasses recursive equilibrium as a special case, yet allows for a much more flexible approach to modeling memory in such models that are known to have multiple equilibrium. We prove the existence of ergodic GME selections from the set of sequential competitive equilibrium, and show that at the same time ergodic GME selectors can replicate all the observed phases of the macro crises associated with a sudden stop (boom, collapse, spiralized recession, recov-ery) while still being able to capture the long-run stylized behavior of the data. We also compute stochastic equilibrium dynamics associated with stationary and nonstationary GME selections, and we find that: a) the ergodic GME selectors generate stochastic dynamics that are less financially constrained with respect to stationary non-ergodic paths; and, b) non-stationary GME selections ex-hibit a great range of fluctuations in macroeconomic aggregates compared to the stationary selections. From a theoretical perspective, we prove the existence of both sequential competitive equilibrium and (minimal state space) recursive equilibrium, as well as provide a complete theory of robust recursive equilibrium comparative statics in deep parameters. Consistent with recent results in the literature, relative to the set of recursive equilibrium, we find 2 stationary equilibrium: one with high/over borrowing, the other with low/under borrowing. These equilibrium are extremal and “self-fulfilling” under rational expectations. The selection among these equilibria depend on observable variables and not on sunspots.Presentamos un nuevo equilibrio generalizado de Markov (GME) para estudiar crisis de balanza de pagos en economías emergentes que sufren fricciones financieras en la forma de restricciones de colateral. Nuestro enfoque permite caracterizar y computar los equilibrios dinámicos y estocásticos en forma global, comprende a otros equilibrios recursivos (como los de espacio de esta mínimo) y representa una forma flexible de modelar “memoria” en estas economías que suelen tener equilibrios múltiples. Probamos la existencia de un GME ergódico cómo una selección del equilibrio secuencial el cual a su vez puede replicar tanto todas las fases de una crisis de balanza de pagos cómo los hechos estilizados de largo plazo. Computamos el equilibrio ergódico, estacionario y no estacionario. Encontramos que el equilibrio ergódico tiene trayectorias del consumo más suaves y que el no estacionario puede replicar un gran rango de crisis de balanza de pagos. Desde una perspectiva teórica, probamos la existencia del equilibrio secuencial y recursivo en espacio de estados mínimos, como así también resultados de estática comparativa robusta. En línea con la literatura, encontramos 2 tipos de equilibrios estacionarios: uno con alto y el otro con bajo endeudamiento. Estos equilibrios son auto-validantes en expectativas racionales y no requieren de manchas solares para su coordinación

The Foundations of the Economics of Innovation

During the last forty years, economics of innovation has emerged as a distinct area of enquiry at the crossing of the economics of growth, industrial organization, regional economics and the theory of the firm, becoming a well identified area of competence in economics specializing not only in the analysis of the effects of the introduction of new technologies, but also and mainly in understanding technological change as an endogenous process. As the result of the interpretation, elaboration and evolution of different fields of analysis in economie theory, innovation is viewed as a complex, path dependent process characterized by the interdependence and interaction of a variety of heterogeneous agents, able to learn and react creatively with subjective and procedural rationality.