We present polynomial-time interior-point algorithms for solving the Fisher and Arrow-Debreu competitive market equilibrium problems with linear utilities and n players. Both of them have the arithmetic operation complexity bound of O(n 4 log(1/ɛ)) for computing an ɛ-equilibrium solution. If the problem data are rational numbers and their bit-length is L, then the bound to generate an exact solution is O(n 4 L) which is in line with the best complexity bound for linear programming of the same dimension and size. This is a significant improvement over the previously best bound O(n 8 log(1/ɛ)) for approximating the two problems using other methods. The key ingredient to derive these results is to show that these problems admit convex optimization formulations, efficient barrier functions and fast rounding techniques. We also present a continuous path leading to the set of the Arrow-Debreu equilibrium, similar to the central path developed for linear programming interior-point methods. This path is derived from the weighted logarithmic utility and barrier functions and the Brouwer fixed-point theorem. The defining equations are bilinear and possess some primal-dual structure for the application of the Newton-based path-following method.

This paper presents a dynamic, quantitative macro framework designed for the analysis of the impact of adjustment policies and external shocks on poverty and income distribution. It emphasizes the role of labor market segmentation, urban informal activities, the impact of the composition of public expenditure on supply and demand, and credit market imperfections. Numerical simulations for a prototype low-income country highlight the importance of accounting for the various channels through which poverty alleviation programs and debt relief may ultimately affect the poor.

IFPRI was established in 1975 to identify and analyze national and international strategies and policies for meeting the food needs of the developing world on a sustainable basis, with particular emphasis on low-income countries and poor people; to make the results of its research available to all those in a position to use them; and to help strengthen institutions conducting research and applying research results in developing countries. Future Harvest ™ and the Consultative Group on International Agricultural Research (CGIAR) IFPRI is one of 16 international food and environmental research organizations known as the Future Harvest Centers. The Centers are principally funded by governments, private foundations, and regional and international organizations, most of which are members of the CGIAR. About this Series Microcomputers in Policy Research represents IFPRI’s ongoing collective experience in adapting microcomputer technology for use in food policy analysis in developing countries. Designed to provide hands-on methods and clear instruction through the extensive use of examples, the primary purpose of the volumes in this series is to share IFPRI’s experience with potential developing

Arguing that food security management belongs to the core of government tasks and has been since Biblical times, we assess current practices in this domain and their effect on local governance, with special reference to the food aid operations of the World Food Program. Within the food security management task, we distinguish three basic elements: (i) entitlement: to provide income entitlements that enable the needy to acquire sufficient food, (ii) delivery: to ensure that the food physically gets within the reach of the needy, and (iii) taxation: to secure funding that covers the full cost of the operations. Our review of literature suggests that the taxation aspect is often neglected, and that little attention is paid to the weakening of respect for local authorities that inevitably results when they remain dependent on foreigners in fulfilling core security tasks, financially and otherwise, let alone when they no longer play any role in this sphere. Next, we present a theoretical framework that coherently deals with the three elements, and discuss its application through a spatially explicit model of optimal food aid provision for Sub Saharan Africa that is being developed within an ongoing joint research project between WFP and SOW-VU. Our main message is that foreign donors, when called upon to intervene during food crises, should always program for a post-emergency exit strategy that leaves behind local authorities with sufficient authority and means for food security management.

The paper describes how stochastic optimization techniques can be used to model profit maximizing producer behaviour in a spatial continuum. The main methodological issues to be addressed are, first, that the representation of optimal allocations in a spatial continuum naturally leads to models that contain integrals over space, and the second that the resulting model tends to have a multi-level structure, i.e. requires solving nested optimization problems because it should combine the profit maximization by individual producers with market clearing at regional level. We specify four regional models that may illustrate the approach. The first determines the optimal output level for factories that emit pollutants which reduce the crop output of neighboring farmers. The main issue is to compute the associated level of compensation to be paid by the factories to the farmers.

in 1975 to identify and analyze alternative national and international strategies and policies for meeting food needs of the developing world on a sustainable basis, with particular emphasis on low-income countries and on the poorer groups in those countries. While the research effort is geared to the pre-IFPRI cise objective of contributing to the reduction of hunger and malnutrition, the factors involved are many and wide-ranging, requiring analysis of underlying processes and extending beyond a narrowly defined food sector. The Institute’s research program reflects worldwide collaboration with governments and private and public institutions interested in increasing food production and improving the equity of its distribution. Research results are disseminated to policymakers, opinion formers, administrators, policy analysts, researchers, and others concerned with

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report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor UChicago Argonne, LLC, nor any of their employees or officers, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of document authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof,

A Proposal for the Attribution

In this paper an applied general equilibrium model for the Extremadura region is presented. Our aim is to show the importance of agricultural subsidies in this economy, that it is a distinctive characteristic of this region. To achieve this purpose, we analyse the effects of a supression of these subsidies, using different scenaries related to the labour market and tax compensation. Model parameters are mainly obtained from a Social Accounting Matrix built for this economy. The results clearly show the negative effects on important microeconomic variables (prices, activity levels or household welfare) and macroeconomic variables (unemployment rate).