computational economics and economic theory substitutes or complements abstract this essay examines the idea and potential of a computational approach to theory discusses methodological issues raised by such computational methods and outlines the problems associated with the dissemination of computational methods and the exposition of computational results we argue that the study of a theory need not be confined to proving theorems that current and future computer technologies create new possibilities for theoretical analysis and that by resolving these issues we will create an intellectual atmosphere in which computational methods can make substantial contributions to economic analysis

rational expectations in microeconomic models an overview abstract this paper is an expository introduction to several topics of current research in the general equilibrium theory of rational expectations more specifically we discuss the existence of exact and approximate rational expectations equilibria the implementation of equilibria the behavior of learning and smoothing processes by which traders construct expectations from repeated observations of the market and the lagged use of the information revealed by prices in an intertemporal sequence of markets the purpose of this discussion is to introduce papers on these topics appearing in the journal of economic theory symposium on rational expectations in microeconomic models

strict rational expectations equilibria with diffuseness abstract for smooth static pure exchange economies under uncertainty it is shown that a diffuseness condition on the distribution of traders characteristics as the state of the world varies permits one to use only a weak dimensionality restriction in the proof of the genericity of existence of strict rational expectations equilibria a generic result on the amount of information conveyed by equilibrium price functions and comparisons with some examples of nonexistence are given

aggregate fluctuations as an information transmission mechanism a model is presented in which individuals attempt to track shocks with a capital like quantity that is costly to produce and to adjust the shocks have separate individual specific and economy wide components individuals do not have direct access to desired information about economy wide shocks the information is potentially available from the observation of endogenous aggregates but because the aggregates are endogenous there is an informational externality associated with them two polar cases are considered when the desired information is about economy wide real shocks as in townsend 1983 the externality is potentially completely internalized when the desired information is about purely nominal aggregates as in lucas 1973 1975 aggregate fluctuations are a necessary condition of equilibrium

photovoltaic electricity production in brazil a stochastic economic viability analysis for small systems in the face of net metering and tax incentives abstract currently in addition to the search for sustainable development there is increased pressure for a change in consumption and production of energy patterns in brazil in this scenario net metering is an important mechanism fostering dissemination of small photovoltaic pv solar systems as complementary support to net metering a tax exemption is currently being offered in some brazilian states thus the objective of the present study is to analyze the impact of tax exemption on the circulation of goods and services and the returns and risks of the pv microgeneration project in four cities located in different regions of brazil belem petrolina uberaba and uruguaiana the analysis is performed using the monte carlo simulation mcs wherein uncertainties related to the financial and environmental variables are considered the results of the stochastic economic viability analysis allowed us to conclude that the exemption of tax on circulation of goods and services icms is fundamental to make pv microgeneration viable in brazil in the cities analyzed pv microgeneration presented economic unfeasibility to the investor when the icms is charged when considering the icms exemption policy the cities of petrolina and belem obtained high probabilities of viability in relation to the risk analysis pv microgeneration obtained the best results in petrolina both in terms of the condition of collection and exemption of icms there is high potential for harness solar throughout the brazilian territory however due to the current evolution stage and the productive chain of the brazilian pv industry high costs limit the expansion of this clean energy generation technology the findings of this study could assist policymakers in evaluating this incentive program highlighting that this tax exemption directly meets one of the objectives for which the icms was created which is to encourage the development of productive sectors such as pv industry

aggregation determinacy and informational efficiency for a class of economies with asymmetric information abstract we identify and analyze a class of economies with asymmetric information that we call quasi complete for quasi complete economies we determine equilibrium trades show that the set of fully informative equilibria is a singleton and give necessary and sufficient conditions for the existence of partially informative equilibria besides unifying some familiar settings such as those of grossman 1976 and milgrom and stokey 1982 the following new results are proved a the same restrictions that deliver gorman aggregation under symmetric information are sufficient for gorman aggregation under asymmetric information even under partially informative prices b the traditional assumptions of quadratic utilities and endowment spanning that result in the capm under symmetric information deliver a conditional capm under asymmetric information with prices that need not be fully informative c the linear equilibrium in grossman s 1976 model is the only equilibrium linear or not while minor changes in the normality assumptions result in indeterminacy and partially informative equilibria and d if there is no aggregate endowment risk asymmetrically informed agents with common priors sell the risky part of their endowment in every equilibrium journal of economic literature classification numbers d82 g14 c62

competitive auction mechanisms for the promotion renewable energy technologies the case of the 50 mw photovoltaics projects in cyprus abstract there are a range of policy frameworks and support mechanisms to promote the penetration of renewable energy technologies into the energy mix assembled by the governments and regulatory bodies around the world the three dominant and most common support schemes that have also been implemented within the eu and proven successful in the past include the competitive auctions the feed in tariff scheme fit and tradable green certificates tgcs this study reviews the use of the competitive auction mechanism for the promotion of power generation from renewable energy technologies the process of the specific policy instrument as well as its pros and cons are introduced successful and failed case studies from countries that have already incorporated this mechanism into their renewable energy technologies development policies are also presented among these cases is the cyprus auction procurement for the licensing of 50 mw of photovoltaic power plants conducted in january 2013 which is thoroughly elaborated in this paper the timeline of the bids is presented and the auction winner strategy is tracked and examined a discussion is also presented on the feasibility of the awarded projects eventually the entire auction procurement procedure is evaluated to expose the defects of the mechanism and to offer some recommendations for the viability of the process

tax reform theory and practice abstract the tax reform act of 1986 is the most significant piece of tax legislation enacted since the income tax was converted to a mass tax during world war ii after decades of erosion the indi

are shocks to renewable energy consumption permanent or transitory an empirical investigation for brazil china and india abstract this paper investigates whether there is a unit root in renewable energy consumption in three large developing economies brazil china and india over the period 1971 2014 to do so it uses four unit root tests assuming one structural break two structural breaks and more than two structural breaks it observes that renewable energy consumption is a unit root process in brazil but it is found as stationary in china and india the paper also tackles issues and challenges in the unit root test methodology in energy economics literature and provides implications for renewable energy consumption in three economies

corporate financial hedging with proprietary information abstract if a firm has information pertinent to its own dividend stream that is not made available to its shareholders it may be in the interests of the firm and its shareholders to adopt a financial hedging policy this is in contrast with the modigliani miller theorem which implies that with informational symmetry such financial hedging is irrelevant in certain cases hedging policies are identified that are unanimously supported by shareholders

a privately revealing rational expectations equilibrium for the futures market abstract this paper develops a model of the futures market with two types of participants farmers and speculators farmers undertake production decisions and face both output and spot price risk as opposed to speculators who face only spot price risk agents have constant absolute risk aversion von neumann morgenstern utility functions and form rational expectations about the future output shock and spot price we assume that traders specialize in information collection in our model the futures price is not a sufficient statistic for the market information we show that the rational expectations equilibrium ree futures price is privately revealing to traders who purchase costly information this ree is efficient in the sense that in equilibrium traders are in possession of all market information we demonstrate that traders a have an incentive to collect costly information and b are better off by specializing in collecting the information in which they have a comparative advantage in terms of the quality of the information that they can obtain finally we show that the futures market stabilizes the spot price

the generic existence of rational expectations equilibrium in the higher dimensional case abstract the study of the generic existence of rational expectations equilibrium has concentrated on three cases according to whether the space of states of private information has dimension less than equal to or greater than the price space previous results have shown that in the first case fully revealing equilibria exist generically and in the second case there are open sets of environments with no equilibrium this paper shows that in the third case there is a residual set of environments which permits equilibria which are arbitrarily close to fully revealing

rational behavior and rational expectations abstract this paper presents a new definition of rational expectations equilibrium in security markets characterized by a rigorous treatment of the decision problem facing each agent a rational expectations equilibrium is one in which it is common knowledge among the agents that all of them are rational and that the price observed is the market clearing price the paper shows that such equilibria always exist and that they need not have the property that for generic economies the equilibrium price reveals all economically relevant information the paper also shows that the new definition generalizes existing definitions of rational expectations equilibrium

expectations equilibria with dispersed information existence with approximate rationality in a model with a continuum of agents and finitely many states of the world a model of a large economy in which prices transmit information about the state of the world which is an argument in consumers utility functions from more informed to less informed agents is analysed the basic hypothesis is that the forecast functions of imperfectly informed agents are suitably dispersed for any such distribution of forecasts market clearing prices exist moreover there is always an equilibrium in which each agent s expectations are approximately rational

the renewable energy market in brazil current status and potential abstract renewable energy offers a range of options with which to meet the growing demand for energy particularly in the context of the pursuit especially in developing countries of economic development which takes into account social and environmental issues brazil has abundant natural sources of renewable energy such as wind and solar power hydraulic energy small hydroelectric plants ethanol and bio diesel these sources form part of the brazilian strategy aimed at satisfying the demand for 6300 mw of fresh capacity per year arising out of projected economic growth of 5 1 per year over the next 10 years renewable energy sources currently provide 47 2 of the internal supply of primary energy in brazil brazil has been pursuing a strategy of maintaining its renewable energy matrix and developing and providing incentives for further low carbon initiatives in this study we set out an overview of the renewable energy options available in brazil their current status the main positive results obtained to date and future potential we describe the market for renewable energy in brazil and examine specific public policies aimed at overcoming barriers to this market thereby promoting its consolidation and expansion

the existence of fully rational expectations approximate equilibria with noisy price observations abstract nonrevealing fully rational expectations approximate equilibria exist in microeconomic pure exchange economies in which uninformed agents have suitably dispersed noisy price observations such traders maximize a state dependent expected utility conditional on the price vector they observe the distributions of noisy price observations and the correct equilibrium relationship between states of the world and prices in equilibrium aggregate excess demand is small with high probability in every state of the world and its expectation is also small this magnitude diminishes as the noisy price observations become more accurate equilibria are obtained by applying a fixed point argument to state dependent excess demand functions which are smooth because of the noisy price observations

information aggregation and policy the function of monetary policy to alter the informational content of money price signals is examined in a model where traders can observe an economy wide financial signal and a local commodity price under a passive policy money demand disturbances which are not directly observable are shown to be confused with real productivity shocks and thereby preclude prices from fully reflecting all information even when the policy authority has no informational advantage prospective money growth feedback rules can improve the structure of available information applications of the rational expectations hypothesis to monetary theory have focused on the informational aspects of money price signals a key element of the models of lucas 1972 1975 barro 1976 and sargent and wallace 1975 is that agents have limited powers of information acquisition and use prices as imperfect summaries from the rest of the world those works have suggested that monetary policy can affect the informational content of observed price signals and thereby affect real variables in weiss 1980a it was shown systematic money growth feedback rules can contribute to economic efficiency when the money demands of one group are based on factors not directly observed by all in this context monetary policy can alter the information content transmitted from the informed to the uninformed through observation of nominal price signals a limitation of these analyses is the omission of economy wide financial signals clearly stock and bond prices are observed accurately and costlessly empirically there are strong comovements between financial signals and economic activity traditional keynesian theory argues that financial signals exert an important influence on output by affecting the demand for new capital goods understanding the informational role of such signals is crucial to any theory which explains fluctuations as arising from incomplete information the present analysis investigates the structure of available information with its implications for real variables in a model where agents trade on both an economy wide capital market and a local commodity market the model has positive implications for the comovements of money demand disturbances aggregate investment expected and realized returns as well as normative implications for the conduct of policy the structure of exogenous information in the model differs from that of my earlier paper rather than assuming two types of traders informed and uninformed the model considers traders to have symmetric although noisy exogenous private information in this framework the economy wide market both aggregates and transmits individuals information about an aggregate structural variable this modification is both analytically convenient and illustrates how noise in the price system alters the importance of public relative to private sources of information the idea that prices aggregate individual information was first formalized in grossman 1976 in that paper a non monetary model of a speculative market was developed in which the price system conveyed all relevant information so as to yield an efficient allocation however this feature was also shown to break down if prices are influenced by

generic existence of completely revealing equilibria for economies with uncertainty when prices convey information conditions which imply the existence of strict rational expectations equilibria for most static pure exchange economies where prices convey information about the state of the world are analyzed information is aggregated and transmitted by prices because agents have different initial information and maximize the conditional expectation of state dependent utility functions major results state that if with probability one agents characteristics do not vary too much as the state of the world varies then generically there exist equilibrium price functions which reveal all initial information more precisely if the support of the image measure is contained in a compact c1 manifold satisfying some technical conditions which is of sufficiently low dimension relative to the number of commodities then existence of completely revealing equilibria is generic any economy satisfying these assumptions can be approximated by a sequence of economies which also obey these assumptions and have completely revealing equilibrium price functions slight perturbations do not destroy the existence property

rural electrification and energy poverty empirical evidences from brazil the aim of this article is to evaluate the impact of rural electrification on the reduction of energy poverty in brazil through the analysis of 23 000 rural domiciles or rural properties between the years 2000 and 2004 the results indicate a fast change in the profile of energy consumption and a reduction of energy poverty this new approach works as a complement among other variables to analyze and quantify the real economic social and energy impacts in rural electrification programs generally applied in developing countries

on endogenous formation of price expectations abstract we study a two period exchange economy with complete financial markets and endogenous borrowing constraints contrary to perfect foresight paradigm we assume that agents are heterogeneous in their ability to forecast future prices we introduce a new equilibrium concept called informationally constrained equilibrium where the formation of price expectations is endogenous and reflects the revelation of information from observing bounds on liabilities designed to ensure solvency at any contingency we prove that under standard assumptions an equilibrium always exists and we characterize the degree of information revealed by the endogenous debt limits

approximate equilibria in microeconomic rational expectations models abstract for general equilibrium models in which prices transmit information among asymmetrically informed traders strict rational expectations approximate equilibria are defined a state dependent price function is an e equilibrium if when agents use their own information and that conveyed by prices aggregate excess demand in each state of the world does not exceed e for any positive e existence requires only very mild assumptions continuity and compact support moreover there are revealing e equilibria for all smooth economies satisfying a dimensionality condition in an open neighborhood of this case existence of maximally revealing e equilibria holds

wind power generation an impact analysis of incentive strategies for cleaner energy provision in brazil brazil has adopted various strategies to encourage alternative renewable energy sources in pursuit of cleaner and sustainable energy production to this end strategies should support the reduction of the financial risk for potential investors in the renewable energy market therefore this study aims to analyze the impact of incentive strategies on the financial risk of wind power generation projects in brazil in different marketing environments from a quantitative approach using monte carlo simulation in three scenarios we evaluate the impact of funding from the national development bank and participation in the clean development mechanism in the financial returns of the investor in a regulated contracting environment and free contracting environment measured by the net present value we conduct a statistical analysis to find out if there were statistically significant differences in investor risk in each scenario the main results of the study are as follows the wind speed the selling price of energy and disbursement for the investment have the most significant impact on the financial return the project viability probability is greater than 85 in all scenarios regardless of the marketing environment the regulated market is less risky for the producer than the free market since there is a statistically significant difference in net present value variances for all scenarios in the regulated contracting environment funding is critical to reducing risk and carbon credit trading is not a suitable policy for providing financial security to renewable energy producers thus we conclude that in brazil the contracting of projects from auctions in the regulated contracting environment with the support of the national development bank has been important for neutralizing the producer s financial risks

an introduction to the theory of rational expectations under asymmetric information every good economics textbook contains the cliche that market prices provide signals which facilitate the allocation of resources to their best use in a world not subject to random shocks consumers and producers when faced with competitive prices need look no further than their own preferences or production technology to be able to make a decision they need give no thought to the tastes endowments or technology of other agents however in a world subject to random shocks this is no longer the case agents are faced with the problem of forecasting future states of nature and more importantly of forecasting the impact of these states on the actions of other agents rational expectations theories provide a model of how agents make those forecasts in a world subject to random shocks it will be the case that agents acquire or at least attempt to acquire information about the future realization of the shocks it will in general be the case that different agents have access to different information the fact that information is dispersed throughout the economy has the potential to cause a misallocation of resources relative to what would be the case if all agents knew everything an efficient allocation of resources will in general require the transfer of information from consumers who have some information about their future demands to producers who can take current actions to mitigate avoidable scarcities or surpluses though many classical and neo classical writers emphasize the informational role of prices the standard marshallian or walrasian model of competitive equilibrium does not involve prices transferring information across traders the purpose of this paper is to show that rational expectations models are radically different from walrasian models in an economy where traders have diverse information this is demonstrated by showing that unlike what occurs in a walrasian equilibrium of an economy with heterogeneous information if there is a complete set of insurance markets and utility is additively separable over time then there exists a rational expectations equilibrium which gives consumers the same allocation as if each consumer has access to all of the economy s information this implies that under the above assumptions a central planner with all the economy s information could not pareto dominate the competitive allocation achieved when traders have diverse information and rational expectations this paper makes no attempt to survey the literature on rational expectations the reader is referred to shiller 1978 barro 1981 for a survey of macroeconomics and rational expectations and radner 1980 for a survey of the microeconomics and mathematical theory of rational expectations this paper will however try to outline the evolution of the rational expectations concept from a notion of optimal forecasting to a virtually complete departure from the walrasian model of equilibrium the rest of this section is devoted to a discussion of pre rational expectations ideas

on the existence of rational expectations equilibrium abstract we prove a theorem on the existence of rational expectations general economic equilibrium when agents condition on prices as well as on private information and maximize the expectation of a state dependent utility function the key to the result is a new idealization of what it means for a set of empirical distributions to support agents expectations this idealization depends on the notion that agents compare their expectations with continuous versions of the random empirical distributions that are generated by the workings of the economy the existence theorem covers all strictly concave utility functions arbitrary distributions of the state variable and situations in which the dimension of the state variable is large relative to the number of commodities

the revelation of information and self fulfilling beliefs abstract at a rational expectations equilibrium ree individuals are assumed to know the map from states to prices this hypothesis has two components that agents agree consensus and that they have point expectations degeneracy we consider economies where agents beliefs are described by a joint distribution on states and prices and these beliefs are fulfilled at equilibrium beliefs are self fulfilling if every price in the support of the distribution is an equilibrium price the corresponding equilibria are beliefs equilibria be the further restriction that agents have the same beliefs results in common beliefs equilibria cbe we study the relationship between be cbe and ree thus isolating the role of consensus and of degeneracy in achieving rational expectations journal of economic literatureclassification numbers d51 d82

partially revealing rational expectations equilibrium in a competitive economy abstract a class of pure exchange economies is considered in which some agents are informed of private information and others are uninformed existence of a partially revealing rational expectations equilibrium ree is proved without restricting attention to particular functional forms for utility functions and probability distributions without introducing noise into the model and without departing from the standard definition of ree the equilibrium is robust in the sense that if the primitives of the economy are slightly perturbed the economy continues to have a qualitatively similar ree with somewhat stronger assumptions placed on the economy the equilibrium is also the unique measurable ree

information aggregation in a noisy rational expectations economy abstract this paper analyzes a general equilibrium model of a competitive security market in which traders possess independent pieces of information about the return of a risky asset each trader conditions his estimate of the return both on his own private source of information and price which in equilibrium serves as a noisy aggregator of the total information observed by all traders a closed form characterization of the rational expectations equilibrium is presented a counter example to the existence of fully revealing equilibrium is developed