Development economics is a branch of economics which deals with economic aspects of the development process in low income countries. Its focus is not only on methods of promoting economic development, economic growth and structural change but on improving the potential for the mass of the population, for example, through health and workplace conditions, whether through public or private channels. Development economics involves the creation of theories and methods that aid in the determination of policies and practices and can be implemented at either the domestic or international level; this may involve restructuring market incentives or using mathematical methods such as intertemporal optimization for project analysis, or it may involve a mixture of quantitative and qualitative methods. Unlike in many other fields of economics, approaches in development economics may incorporate social and political factors to devise particular plans. Unlike many other fields of economics, there is no consensus on what students should know.
Different approaches may consider the factors that contribute to economic convergence or non-convergence across households and countries. The earliest Western theory of development economics was mercantilism, which developed in the 17th century, paralleling the rise of the nation state. Earlier theories had given little attention to development. For example, the dominant school of thought during medieval feudalism, emphasized reconciliation with Christian theology and ethics, rather than development; the 16th- and 17th-century School of Salamanca, credited as the earliest modern school of economics did not address development specifically. Major European nations in the 17th and 18th century all adopted mercantilist ideals to varying degrees, the influence only ebbing with the 18th-century development of physiocrats in France and classical economics in Britain. Mercantilism held that a nation's prosperity depended on its supply of capital, represented by bullion held by the state, it emphasised the maintenance of a high positive trade balance as a means of accumulating this bullion.
To achieve a positive trade balance, protectionist measures such as tariffs and subsidies to home industries were advocated. Mercantilist development theory advocated colonialism. Theorists most associated with mercantilism include Philipp von Hörnigk, who in his Austria Over All, If She Only Will of 1684 gave the only comprehensive statement of mercantilist theory, emphasizing production and an export-led economy. In France, mercantilist policy is most associated with 17th-century finance minister Jean-Baptiste Colbert, whose policies proved influential in American development. Mercantilist ideas continue in the theories of economic neomercantilism. Following mercantilism was the related theory of economic nationalism, promulgated in the 19th century related to the development and industrialization of the United States and Germany, notably in the policies of the American System in America and the Zollverein in Germany. A significant difference from mercantilism was the de-emphasis on colonies, in favor of a focus on domestic production.
The names most associated with 19th-century economic nationalism are the American Alexander Hamilton, the German-American Friedrich List, the American Henry Clay. Hamilton's 1791 Report on Manufactures, his magnum opus, is the founding text of the American System, drew from the mercantilist economies of Britain under Elizabeth I and France under Colbert. List's 1841 Das Nationale System der Politischen Ökonomie, which emphasized stages of growth, proved influential in the US and Germany, nationalist policies were pursued by politician Henry Clay, by Abraham Lincoln, under the influence of economist Henry Charles Carey. Forms of economic nationalism and neomercantilism have been key in Japan's development in the 19th and 20th centuries, the more recent development of the Four Asian Tigers, most China. Following Brexit and the United States presidential election, 2016, some experts have argued a new kind of "self-seeking capitalism" popularly known as Trumponomics could have a considerable impact on cross-border investment flows and long-term capital allocation The origins of modern development economics are traced to the need for, problems with the industrialization of eastern Europe in the aftermath of World War II.
The key authors are Paul Rosenstein-Rodan, Kurt Mandelbaum, Ragnar Nurkse, Sir Hans Wolfgang Singer. Only after the war did economists turn their concerns towards Asia and Latin America. At the heart of these studies, by authors such as Simon Kuznets and W. Arthur Lewis was an analysis of not only economic growth but structural transformation. An early theory of development economics, the linear-stages-of-growth model was first formulated in the 1950s by W. W. Rostow in The Stages of Growth: A Non-Communist Manifesto, following work of Marx and List; this theory modifies Marx's stages theory of development and focuses on the accelerated accumulation of capital, through the utilization of both domestic and international savings as a means of spurring investment, as the primary means of promoting economic growth and, development. The linear-stages-of-growth model posits that there are a series of five consecutive stages of development which all countries must go through during the process of development.
These stages are "the traditional society, the pre-conditions for take-off, the take-off, the drive to maturity, the age of high mass-consumption" Simple versi
Welfare is a type of government support for the citizens of that society. Welfare may be provided to people of any income level, as with social security, but it is intended to ensure that the poor can meet their basic human needs such as food and shelter. Welfare attempts to provide poor people with a minimal level of well-being either a free- or a subsidized-supply of certain goods and social services, such as healthcare and vocational training. A welfare state is a political system wherein the State assumes responsibility for the health and welfare of society; the system of social security in a welfare state provides social services, such as universal medical care, unemployment insurance for workers, financial aid, free post-secondary education for students, subsidized public housing, pensions, etc. In 1952, with the Social Security Convention, the International Labour Organization formally defined the social contingencies covered by social security; the first welfare state was Imperial Germany, where the Bismarck government introduced social security in the late 19th century.
In the early 20th century, Great Britain introduced social security around 1913, adopted the welfare state with the National Insurance Act 1946, during the Attlee government. In the countries of western Europe and Australasia, social welfare is provided by the government out of the national tax revenues, to a lesser extent by non-government organizations, charities. In the U. S. welfare program is the general term for government support of the well-being of poor people, the term social security refers to the US social insurance program for retired and disabled people. In other countries, the term social security has a broader definition, which refers to the economic security that a society offers when people are sick and unemployed. In the U. K. government use of the term welfare includes help for poor people and benefits, including specific social services such as help in finding employment. In the Roman Empire, the first emperor Augustus provided the Cura Annonae or grain dole for citizens who could not afford to buy food every month.
Social welfare was enlarged by the Emperor Trajan. Trajan's program brought acclaim including Pliny the Younger; the Song dynasty government supported multiple programs which could be classified as social welfare, including the establishment of retirement homes, public clinics, paupers' graveyards. According to economist Robert Henry Nelson, "The medieval Roman Catholic Church operated a far-reaching and comprehensive welfare system for the poor..."Early welfare programs in Europe included the English Poor Law of 1601, which gave parishes the responsibility for providing welfare payments to the poor. This system was modified by the 19th-century Poor Law Amendment Act, which introduced the system of workhouses. Public assistance programs were not called welfare until the early 20th century when the term was adopted to avoid the negative connotations that had become associated with older terms such as charity, it was predominantly in the late 19th and early 20th centuries that an organized system of state welfare provision was introduced in many countries.
Otto von Bismarck, Chancellor of Germany, introduced one of the first welfare systems for the working classes. In Great Britain the Liberal government of Henry Campbell-Bannerman and David Lloyd George introduced the National Insurance system in 1911, a system expanded by Clement Attlee; the United States inherited England's poor house laws and has had a form of welfare since before it won its independence. During the Great Depression, when emergency relief measures were introduced under President Franklin D. Roosevelt, Roosevelt's New Deal focused predominantly on a program of providing work and stimulating the economy through public spending on projects, rather than on cash payment. Modern welfare states include Germany, the Netherlands, as well as the Nordic countries, such as Iceland, Norway and Finland which employ a system known as the Nordic model. Esping-Andersen classified the most developed welfare state systems into three categories. In the Islamic world, one of the Five Pillars of Islam, has been collected by the government since the time of the Rashidun caliph Umar in the 7th century.
The taxes were used to provide income for the needy, including the poor, orphans and the disabled. According to the Islamic jurist Al-Ghazali, the government was expected to store up food supplies in every region in case a disaster or famine occurred; the World Bank's 2019 World Development Report on The Changing Nature of Work considers whether traditional social assistance models continue to be appropriate given that, in 2018, 8 in 10 people in developing countries still receive no social assistance while 6 in 10 work informally beyond the government's reach. Welfare can take a variety of forms, such as monetary payments and vouchers, or housing assistance. Welfare systems differ from country to country, but welfare is provided to individuals who are unemployed, those with illness or disability, the elderly, those with dependent children, veterans. A person's eligibility for welfare may be constrained by means testing or other conditions. Welfare is provided by governments or their agencies, by private organizations, or a combination of both.
Funding for welfare comes from general government revenue, but when d
Labour economics seeks to understand the functioning and dynamics of the markets for wage labour. Labour markets or job markets function through the interaction of employers. Labour economics looks at the suppliers of labour services and the demanders of labour services, attempts to understand the resulting pattern of wages and income. Labour is a measure of the work done by human beings, it is conventionally contrasted with such other factors of production as capital. Some theories focus on human capital. There are two sides to labour economics. Labour economics can be seen as the application of microeconomic or macroeconomic techniques to the labour market. Microeconomic techniques study individual firms in the labour market. Macroeconomic techniques look at the interrelations between the labour market, the goods market, the money market, the foreign trade market, it looks at how these interactions influence macro variables such as employment levels, participation rates, aggregate income and gross domestic product.
The labour force is defined as the number of people of working age, who are either employed or looking for work. The participation rate is the number of people in the labour force divided by the size of the adult civilian noninstitutional population; the non-labour force includes those who are not looking for work, those who are institutionalised such as in prisons or psychiatric wards, stay-at home spouses and those serving in the military. The unemployment level is defined as the labour force minus the number of people employed; the unemployment rate is defined as the level of unemployment divided by the labour force. The employment rate is defined as the number of people employed divided by the adult population. In these statistics, self-employed people are counted as employed. Variables like employment level, unemployment level, labour force, unfilled vacancies are called stock variables because they measure a quantity at a point in time, they can be contrasted with flow variables. Changes in the labour force are due to flow variables such as natural population growth, net immigration, new entrants, retirements from the labour force.
Changes in unemployment depend on inflows made up of non-employed people starting to look for jobs and of employed people who lose their jobs and look for new ones, outflows of people who find new employment and of people who stop looking for employment. When looking at the overall macroeconomy, several types of unemployment have been identified, including: Frictional unemployment – This reflects the fact that it takes time for people to find and settle into new jobs. Technological advancement reduces frictional unemployment. Structural unemployment – This reflects a mismatch between the skills and other attributes of the labour force and those demanded by employers. Rapid industry changes of a technical and/or economic nature will increase levels of structural unemployment; the process of globalization has contributed to structural changes in labour markets. Natural rate of unemployment – This is the summation of frictional and structural unemployment, that excludes cyclical contributions of unemployment.
It is the lowest rate of unemployment that a stable economy can expect to achieve, given that some frictional and structural unemployment is inevitable. Economists do not agree on the level of the natural rate, with estimates ranging from 1% to 5%, or on its meaning – some associate it with "non-accelerating inflation"; the estimated rate varies from country from time to time. Demand deficient unemployment – In Keynesian economics, any level of unemployment beyond the natural rate is due to insufficient goods demand in the overall economy. During a recession, aggregate expenditure is deficient causing the underutilisation of inputs. Aggregate expenditure can be increased, according to Keynes, by increasing consumption spending, increasing investment spending, increasing government spending, or increasing the net of exports minus imports, since AE = C + I + G +. Neoclassical economists view the labour market as similar to other markets in that the forces of supply and demand jointly determine price and quantity.
However, the labour market differs from other markets in several ways. In particular, the labour market may act as a non-clearing market. While according to neoclassical theory most markets attain a point of equilibrium without excess supply or demand, this may not be true of the labour market: it may have a persistent level of unemployment. Contrasting the labour market to other markets reveals persistent compensating differentials among similar workers. Models that assume perfect competition in the labour market, as discussed below, conclude that workers earn their marginal product of labour. Households are suppliers of labour. In microeconomic theory, people are assumed to be rational and seeking to maximize their utility function. In the labour market model, their utility function expresses
Education economics or the economics of education is the study of economic issues relating to education, including the demand for education, the financing and provision of education, the comparative efficiency of various educational programs and policies. From early works on the relationship between schooling and labor market outcomes for individuals, the field of the economics of education has grown to cover all areas with linkages to education. Economics distinguishes in addition to physical capital another form of capital, no less critical as a means of production – human capital. With investments in human capital, such as education, three major economic effects can be expected: increased expenses as the accumulation of human capital requires investments just as physical capital does, increased productivity as people gain characteristics that enable them to produce more output and hence return on investment in the form of higher incomes. Investments in human capital entail an investment cost.
In European countries most education expenditure takes the form of government consumption, although some costs are borne by individuals. These investments can be rather costly. EU governments spent between 3% and 8% of GDP on education in 2005, the average being 5%. However, measuring the spending this way alone underestimates the costs because a more subtle form of costs is overlooked: the opportunity cost of forgone wages as students cannot work while they study, it has been estimated that the total costs, including opportunity costs, of education are as much as double the direct costs. Including opportunity costs investments in education can be estimated to have been around 10% of GDP in the EU countries in 2005. In comparison investments in physical capital were 20% of GDP, thus the two are of similar magnitude. Human capital in the form of education shares many characteristics with physical capital. Both require an investment to create and, once created, both have economic value. Physical capital earns a return because people are willing to pay to use a piece of physical capital in work as it allows them to produce more output.
To measure the productive value of physical capital, we can measure how much of a return it commands in the market. In the case of human capital calculating returns is more complicated – after all, we cannot separate education from the person to see how much it rents for. To get around this problem, the returns to human capital are inferred from differences in wages among people with different levels of education. Hall and Jones have calculated from international data that on average that the returns on education are 13.4% per year for first four years of schooling, 10.1% per year for the next four years and 6.8% for each year beyond eight years. Thus someone with 12 years of schooling can be expected to earn, on average, 1.1344 × 1.1014 × 1.0684 = 3.161 times as much as someone with no schooling at all. Economy-wide, the effect of human capital on incomes has been estimated to be rather significant: 65% of wages paid in developed countries is payments to human capital and only 35% to raw labor.
The higher productivity of well-educated workers is one of the factors that explain higher GDPs and, higher incomes in developed countries. A strong correlation between GDP and education is visible among the countries of the world, as is shown by the upper left figure, it is less clear, how much of a high GDP is explained by education. After all, it is possible that rich countries can afford more education. To distinguish the part of GDP explained with education from other causes, Weil has calculated how much one would expect each country’s GDP to be higher based on the data on average schooling; this was based on the above-mentioned calculations of Jones on the returns on education. GDPs predicted by Weil’s calculations can be plotted against actual GDPs, as is done in the figure on the left, demonstrating that the variation in education explains some, but not all, of the variation in GDP; the matter of externalities should be considered. When speaking of externalities one thinks of the negative effects of economic activities that are not included in market prices, such as pollution.
These are negative externalities. However, there are positive externalities – that is, positive effects of which someone can benefit without having to pay for it. Education bears with it major positive externalities: giving one person more education raises not only his or her output but the output of those around him or her. Educated workers can bring new technologies and information to the consideration of others, they can act as an example. The positive externalities of education include the effects of personal networks and the roles educated workers play in them. Positive externalities from human capital are one explanation for why governments are involved in education. If people were left on their own, they would not take into account the full social benefit of education – in other words the rise in the output and wages of others – so the amount they would choose to obtain would be lower than the social optimum. A 2013 study assesses demand- and supply-side factors that affect educational access and attainment in development countries, it shows that addressing demand-side factors, such as geographic gaps between rural and urban areas, higher levels of population growth and child labour, can have greater impact on increasing levels of education in developing countries than supply-side factors, such as constructing additional school facilities, hiring more teachers etc.
The dominant model of th
An economic system is a system of production, resource allocation and distribution of goods and services within a society or a given geographic area. It includes the combination of the various institutions, entities, decision-making processes and patterns of consumption that comprise the economic structure of a given community; as such, an economic system is a type of social system. The mode of production is a related concept. All economic systems have three basic questions to ask: what to produce, how to produce and in what quantities and who receives the output of production; the study of economic systems includes how these various agencies and institutions are linked to one another, how information flows between them and the social relations within the system. The analysis of economic systems traditionally focused on the dichotomies and comparisons between market economies and planned economies and on the distinctions between capitalism and socialism. Subsequently, the categorization of economic systems expanded to include other topics and models that do not conform to the traditional dichotomy.
Today the dominant form of economic organization at the world level is based on market-oriented mixed economies. Economic systems is the category in the Journal of Economic Literature classification codes that includes the study of such systems. One field that cuts across them is comparative economic systems, which include the following subcategories of different systems: Planning and reform. Productive enterprises. Public economics. National income and expenditure. International trade, finance and aid. Consumer economics. Performance and prospects. Natural resources. Political economy. There are multiple components to economic system. Decision-making structures of an economy determine the use of economic inputs, distribution of output, the level of centralization in decision-making and who makes these decisions. Decisions might be carried out by a government agency, or by private owners. An economic system is a system of production, resource allocation and distribution of goods and services in a society or a given geographic area.
In one view, every economic system represents an attempt to solve three fundamental and interdependent problems: What goods and services shall be produced and in what quantities? How shall goods and services be produced? That is, by whom and with what resources and technologies? For whom shall goods and services be produced? That is, to enjoy the benefits of the goods and services and how is the total product to be distributed among individuals and groups in the society? Every economy is thus a system that allocates resources for exchange, production and consumption; the system is stabilized through a combination of threat and trust, which are the outcome of institutional arrangements. An economic system possesses the following institutions: Methods of control over the factors or means of production: this may include ownership of, or property rights to, the means of production and therefore may give rise to claims to the proceeds from production; the means of production may be owned by the state, by those who use them, or be held in common.
A decision-making system: this determines, eligible to make decisions over economic activities. Economic agents with decision-making powers can enter into binding contracts with one another. A coordination mechanism: this determines how information is obtained and used in decision-making; the two dominant forms of coordination are planning and markets. An incentive system: this induces and motivates economic agents to engage in productive activities, it can be based on moral suasion. The incentive system may encourage the division of labor. Organizational form: there are two basic forms of organization: actors and regulators. Economic actors include households, work gangs and production teams, joint-ventures and cartels. Economically regulative organizations are represented by the market authorities. A distribution system: this allocates the proceeds from productive activity, distributed as income among the economic organizations and groups within society, such as property owners and non-workers, or the state.
A public choice mechanism for law-making, establishing rules and standards and levying taxes. This is the responsibility of the state, but other means of collective decision-making are possible, such as chambers of commerce or workers’ councils. There are several basic questions that must be answered in order for an economy to run satisfactorily; the scarcity problem, for example, requires answers to basic questions, such as what to produce, how to produce it and who gets what is produced. An economic system is a way of answering these basic questions and different economic systems answer them differently. Many different objectives may be seen as desirable for an economy, like efficiency, growth and equality. Economic systems are segmented by their property rights regime for the means of production and by their dominant resource allocation mechanism. Economies that combi
Operations research, or operational research in British usage, is a discipline that deals with the application of advanced analytical methods to help make better decisions. Further, the term operational analysis is used in the British military as an intrinsic part of capability development and assurance. In particular, operational analysis forms part of the Combined Operational Effectiveness and Investment Appraisals, which support British defense capability acquisition decision-making, it is considered to be a sub-field of applied mathematics. The terms management science and decision science are sometimes used as synonyms. Employing techniques from other mathematical sciences, such as mathematical modeling, statistical analysis, mathematical optimization, operations research arrives at optimal or near-optimal solutions to complex decision-making problems; because of its emphasis on human-technology interaction and because of its focus on practical applications, operations research has overlap with other disciplines, notably industrial engineering and operations management, draws on psychology and organization science.
Operations research is concerned with determining the extreme values of some real-world objective: the maximum or minimum. Originating in military efforts before World War II, its techniques have grown to concern problems in a variety of industries. Operational research encompasses a wide range of problem-solving techniques and methods applied in the pursuit of improved decision-making and efficiency, such as simulation, mathematical optimization, queueing theory and other stochastic-process models, Markov decision processes, econometric methods, data envelopment analysis, neural networks, expert systems, decision analysis, the analytic hierarchy process. Nearly all of these techniques involve the construction of mathematical models that attempt to describe the system; because of the computational and statistical nature of most of these fields, OR has strong ties to computer science and analytics. Operational researchers faced with a new problem must determine which of these techniques are most appropriate given the nature of the system, the goals for improvement, constraints on time and computing power.
The major sub-disciplines in modern operational research, as identified by the journal Operations Research, are: Computing and information technologies Financial engineering Manufacturing, service sciences, supply chain management Policy modeling and public sector work Revenue management Simulation Stochastic models Transportation In the decades after the two world wars, the tools of operations research were more applied to problems in business and society. Since that time, operational research has expanded into a field used in industries ranging from petrochemicals to airlines, finance and government, moving to a focus on the development of mathematical models that can be used to analyse and optimize complex systems, has become an area of active academic and industrial research. In the 17th century, mathematicians like Christiaan Huygens and Blaise Pascal tried to solve problems involving complex decisions with probability. Others in the 18th and 19th centuries solved these types of problems with combinatorics.
Charles Babbage's research into the cost of transportation and sorting of mail led to England's universal "Penny Post" in 1840, studies into the dynamical behaviour of railway vehicles in defence of the GWR's broad gauge. Beginning in the 20th century, study of inventory management could be considered the origin of modern operations research with economic order quantity developed by Ford W. Harris in 1913. Operational research may have originated in the efforts of military planners during World War I. Percy Bridgman brought operational research to bear on problems in physics in the 1920s and would attempt to extend these to the social sciences. Modern operational research originated at the Bawdsey Research Station in the UK in 1937 and was the result of an initiative of the station's superintendent, A. P. Rowe. Rowe conceived the idea as a means to analyse and improve the working of the UK's early warning radar system, Chain Home, he analysed the operating of the radar equipment and its communication networks, expanding to include the operating personnel's behaviour.
This allowed remedial action to be taken. Scientists in the United Kingdom including Patrick Blackett, Cecil Gordon, Solly Zuckerman, C. H. Waddington, Owen Wansbrough-Jones, Frank Yates, Jacob Bronowski and Freeman Dyson, in the United States with George Dantzig looked for ways to make better decisions in such areas as logistics and training schedules The modern field of operational research arose during World War II. In the World War II era, operational research was defined as "a scientific method of providing executive departments with a quantitative basis for decisions regarding the operations under their control". Other names for it included quantitative management. During the Second World War close to 1,000 men and women in Britain were engaged in operational research. About 200 operational research scientists worked for the British Army. Patrick Blackett worked for several different organizations during the war. Early in the war while working for the Royal Aircraft Establishment he set up a team known as the "Circus" which helped to reduce the number of anti-aircraft artillery rounds needed to shoot down an enemy aircraft from an
Financial economics is the branch of economics characterized by a "concentration on monetary activities", in which "money of one type or another is to appear on both sides of a trade". Its concern is thus the interrelation of financial variables, such as prices, interest rates and shares, as opposed to those concerning the real economy, it has two main areas of focus: corporate finance. The subject is concerned with "the allocation and deployment of economic resources, both spatially and across time, in an uncertain environment", it therefore centers on decision making under uncertainty in the context of the financial markets, the resultant economic and financial models and principles, is concerned with deriving testable or policy implications from acceptable assumptions. It is built on the foundations of microeconomics and decision theory. Financial econometrics is the branch of financial economics that uses econometric techniques to parameterise these relationships. Mathematical finance is related in that it will derive and extend the mathematical or numerical models suggested by financial economics.
Note though that the emphasis there is mathematical consistency, as opposed to compatibility with economic theory. Financial economics has a microeconomic focus, whereas monetary economics is macroeconomic in nature. Financial economics is taught at the postgraduate level. Specialist undergraduate degrees are offered in the discipline; this article provides an overview and survey of the field: for derivations and more technical discussion, see the specific articles linked. As above, the discipline explores how rational investors would apply decision theory to the problem of investment; the subject is thus built on the foundations of microeconomics and decision theory, derives several key results for the application of decision making under uncertainty to the financial markets. Underlying all of financial economics are the concepts of present value and expectation. Calculating their present value allows the decision maker to aggregate the cashflows to be produced by the asset in the future, to a single value at the date in question, to thus more compare two opportunities.
An immediate extension is to combine probabilities with present value, leading to the expected value criterion which sets asset value as a function of the sizes of the expected payouts and the probabilities of their occurrence. This decision method, fails to consider risk aversion. In other words, since individuals receive greater utility from an extra dollar when they are poor and less utility when comparatively rich, the approach is to therefore "adjust" the weight assigned to the various outcomes correspondingly.. Choice under uncertainty here may be characterized as the maximization of expected utility. More formally, the resulting expected utility hypothesis states that, if certain axioms are satisfied, the subjective value associated with a gamble by an individual is that individual's statistical expectation of the valuations of the outcomes of that gamble; the impetus for these ideas arise from various inconsistencies observed under the expected value framework, such as the St. Petersburg paradox.
The concepts of arbitrage-free, "rational", pricing and equilibrium are coupled with the above to derive "classical" financial economics. Rational pricing is the assumption that asset prices will reflect the arbitrage-free price of the asset, as any deviation from this price will be "arbitraged away"; this assumption is useful in pricing fixed income securities bonds, is fundamental to the pricing of derivative instruments. Economic equilibrium is, in general, a state in which economic forces such as supply and demand are balanced, and, in the absence of external influences these equilibrium values of economic variables will not change. General equilibrium deals with the behavior of supply and prices in a whole economy with several or many interacting markets, by seeking to prove that a set of prices exists that will result in an overall equilibrium; the two concepts are linked as follows: where market prices do not allow for profitable arbitrage, i.e. they comprise an arbitrage-free market these prices are said to constitute an "arbitrage equilibrium".
Intuitively, this may be seen by considering that where an arbitrage opportunity does exist prices can be expected to change, are therefore not in equilibrium. An arbitrage equilibrium is thus a precondition for a general economic equilibrium; the immediate, formal, extension of this idea, the fundamental theorem of asset pricing, shows that where markets are as described —and are additionally complete—one may make financial decisions by constructing a risk neutral probability measure corresponding to the market. "Complete" here means that there