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Gerard Debreu

 
Gerard Debreu

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Gerard Debreu



 
 
Gérard Debreu (born July 4, 1921, Calais
Calais

Calais is a town in northern France in the Departments of France of Pas-de-Calais, of which it is a sub-prefecture. Although Calais is by far the largest city in Pas-de-Calais, the department's capital is its third-largest city of Arras....
  December 31, 2004, Paris
Paris

Paris is the Capital of France and the country's largest city. It is situated on the river Seine, in northern France, at the heart of the ?le-de-France Regions of France ....
) was a French-born
France

France , officially the French Republic , is a country whose Metropolitan France is located in Western Europe and that also comprises various Overseas departments and territories of France....
 economist and mathematician. In July 1975, he became a naturalized citizen of the United States
United States

The United States of America is a Federal government constitutional republic comprising U.S. state and a federal district. The country is situated mostly in central North America, where its Contiguous United States and Washington, D.C., the Capital districts and territories, lie between the Pacific Ocean and Atlantic Oceans, Borders of the U...
. Best known as a professor of economics at the University of California, Berkeley
University of California, Berkeley

The University of California, Berkeley is a public university research university located in Berkeley, California, California, United States. The oldest of the ten major campuses affiliated with the University of California, Berkeley offers some 300 undergraduate and graduate degree programs in a wide range of disciplines....
, where he began work in 1962, he won the 1983 Nobel Memorial Prize in Economics.

His father was the business partner of his maternal grandfather in lace manufacturing, a traditional industry in Calais.

Just prior to the start of World War II
World War II

World War II, or the Second World War , was a global military conflict which involved a Participants in World War II, including all of the great powers, organised into two opposing military alliances: the Allies of World War II and the Axis powers....
 he received his baccalauréat
Baccalauréat

The baccalaur?at , often known in France colloquially as le bac or le bach?t, is an academic qualification which France and international students take at the end of the lyc?e ....
, and went to Ambert
Ambert

Ambert is a Communes of France in the Puy-de-D?me Departments of France in Auvergne in central France....
 to begin preparing for the exam for entering a grande école.






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Gérard Debreu (born July 4, 1921, Calais
Calais

Calais is a town in northern France in the Departments of France of Pas-de-Calais, of which it is a sub-prefecture. Although Calais is by far the largest city in Pas-de-Calais, the department's capital is its third-largest city of Arras....
  December 31, 2004, Paris
Paris

Paris is the Capital of France and the country's largest city. It is situated on the river Seine, in northern France, at the heart of the ?le-de-France Regions of France ....
) was a French-born
France

France , officially the French Republic , is a country whose Metropolitan France is located in Western Europe and that also comprises various Overseas departments and territories of France....
 economist and mathematician. In July 1975, he became a naturalized citizen of the United States
United States

The United States of America is a Federal government constitutional republic comprising U.S. state and a federal district. The country is situated mostly in central North America, where its Contiguous United States and Washington, D.C., the Capital districts and territories, lie between the Pacific Ocean and Atlantic Oceans, Borders of the U...
. Best known as a professor of economics at the University of California, Berkeley
University of California, Berkeley

The University of California, Berkeley is a public university research university located in Berkeley, California, California, United States. The oldest of the ten major campuses affiliated with the University of California, Berkeley offers some 300 undergraduate and graduate degree programs in a wide range of disciplines....
, where he began work in 1962, he won the 1983 Nobel Memorial Prize in Economics.

His father was the business partner of his maternal grandfather in lace manufacturing, a traditional industry in Calais.

Just prior to the start of World War II
World War II

World War II, or the Second World War , was a global military conflict which involved a Participants in World War II, including all of the great powers, organised into two opposing military alliances: the Allies of World War II and the Axis powers....
 he received his baccalauréat
Baccalauréat

The baccalaur?at , often known in France colloquially as le bac or le bach?t, is an academic qualification which France and international students take at the end of the lyc?e ....
, and went to Ambert
Ambert

Ambert is a Communes of France in the Puy-de-D?me Departments of France in Auvergne in central France....
 to begin preparing for the exam for entering a grande école. Later on he moved from Ambert
Ambert

Ambert is a Communes of France in the Puy-de-D?me Departments of France in Auvergne in central France....
 to Grenoble
Grenoble

Grenoble is a city in southeastern France situated at the foot of the Alps where the Drac River joins the Is?re River.Located in the Rh?ne-Alpes regions of France, Grenoble is the capital of the Departments of France of Is?re....
 to complete his preparation, both being in the so-called "Free Zone" during World War II
World War II

World War II, or the Second World War , was a global military conflict which involved a Participants in World War II, including all of the great powers, organised into two opposing military alliances: the Allies of World War II and the Axis powers....
.

In 1941 he was admitted to the École Normale Supérieure
École Normale Supérieure

The ?cole normale sup?rieure is a France Grandes ?coles . The ENS was initially conceived during the French Revolution, and intended to provide the First French Republic with a new body of teacher, trained in the critical spirit and secular values of the the Enlightenment....
 in Paris
Paris

Paris is the Capital of France and the country's largest city. It is situated on the river Seine, in northern France, at the heart of the ?le-de-France Regions of France ....
, along with Marcel Boiteux. He was influenced by Henri Cartan
Henri Cartan

Henri Paul Cartan was a son of ?lie Cartan, and was, as his father was, a distinguished and influential France mathematician....
 and the Bourbaki writers. When he was about to take the final examinations in 1944, D-Day
D-Day

D-Day is a term often used in military parlance to denote the day on which a combat attack or operation is to be initiated. "D-Day" often represents a variable , designating the day upon which some significant event will occur or has occurred; see Military designation of days and hours for similar terms....
 arrived and he instead enlisted in the French army. He was transferred for training to Algeria
Algeria

Algeria , officially the People's Democratic Republic of Algeria, is a country located in North Africa. It is the largest country of the Mediterranean sea, second largest in the Arab World, and the second largest on the African continent and the eleventh-largest country in the world in terms of land area....
 and then served in French occupational forces in Germany until July 1945.

Debreu passed the Agrégation de Mathématiques exams at the end of 1945 and the beginning of 1946. By this time he had become interested in economics, particularly the general equilibrium theory of Leon Walras
Léon Walras

Marie-Esprit-L?on Walras was a French economics, considered by Joseph Schumpeter as "the greatest of all economists". He was a mathematical economics associated with the creation of the general equilibrium theory....
. From 1946 to 1948, he was an assistant in the Centre National de la Recherche Scientifique
Centre national de la recherche scientifique

The National Centre for Scientific Research is the largest governmental research organisation in France and the largest fundamental science agency in Europe....
. During these two and a half years he made the transition from mathematics to economics.

In 1948, Debreu came to the USA on a Rockefeller Fellowship which allowed him to visit several American universities, as well as those in Uppsala
Uppsala University

Uppsala University is a world-class research university in Uppsala, Sweden. Founded as early as 1477, it is the oldest such institution in the Nordic countries and is frequently ranked among the world's top 100 universities....
 and Oslo in 1949-50. Debreu began working as a Research Association and joined the Cowles Commission at the University of Chicago
University of Chicago

The University of Chicago is a private university located principally in the Hyde Park, Chicago neighborhood of Chicago. Although an older university by the same name existed prior to its founding, the modern University of Chicago credits its founding to the oil magnate John D....
 in the summer of 1950.

There he remained for five years, returning to Paris periodically. In 1954 he published a breakthrough paper titled Existence of an Equilibrium for a Competitive Economy (together with Kenneth Arrow
Kenneth Arrow

Kenneth Joseph Arrow is an United States economist and joint winner of the Nobel Memorial Prize in Economics with John Hicks in 1972. To date, he is the youngest person to receive this award, at 51....
), in which they provided a definitive mathematical proof of the existence of general equilibrium
General equilibrium

General equilibrium theory is a branch of theoretical economics. It seeks to explain the behavior of supply, demand and prices in a whole economy with several or many markets....
, using topological
Topology

Topology is a major area of mathematics that has emerged through the development of concepts from geometry and set theory, such as those of space, dimension, shape, transformation and others....
 rather than calculus
Calculus

Calculus is a branch of mathematics that includes the study of limit , derivatives, integrals, and infinite series, and constitutes a major part of modern university education....
 methods.

In 1955 he moved to Yale University
Yale University

Yale University is a private university in New Haven, Connecticut. Founded in 1701 as the Collegiate School, Yale is the Colonial Colleges institution of higher education in the United States and is a member of the Ivy League....
. In 1959 he published his classical monograph, Theory of Value: An Axiomatic Analysis of Economic Equilibrium, (Cowles Foundation Monographs Series), which is one of the most important works in mathematical economics. He also studied several problems in the theory of cardinal utility, the additive decomposition of a utility function defined on a Cartesian product
Cartesian product

In mathematics, the Cartesian product is a direct product of sets. The Cartesian product is named after Ren? Descartes, whose formulation of analytic geometry gave rise to this concept....
 of sets.

In this monograph, Debreu sets up an axiomatic foundation for competitive markets. He establishes the existence of equilibrium using a novel approach. The main idea is to show that there exists a price system for which the aggregate excess demand correspondence vanishes. He does so by proving a type of fixed point theorem based on the Kakutani fixed point theorem
Kakutani fixed point theorem

In mathematical analysis, the Kakutani fixed point theorem is a fixed-point theorem for set-valued functions. It provides sufficient conditions for a set-valued function defined on a convex set, compact set subset of a Euclidean space to have a fixed point , i.e....
. In Chapter 7 of the book Debreu introduces uncertainty and shows how it can be incorporated into the deterministic model. Here he introduces the notion of a contingent commodity, which is a promise to deliver a good should a state of nature realize. This concept is very frequently used in financial economics
Financial economics

Financial economics is the branch of economics concerned with "the allocation and deployment of economic resources, both spatially and across time, in an uncertain environment" ....
 as a so called Arrow Debreu security.

In 1960-61, he worked at the Center for Advanced Study in the Behavioral Sciences at Stanford
Stanford University

Leland Stanford Junior University, commonly referred to as Stanford University or Stanford, is a private university research university located in Stanford, California, California, United States....
 and devoted mostly to the complex proof that appeared in 1962 of a general theorem on the existence of an economic equilibrium.

In January 1962, he started worked at the University of California, Berkeley
University of California, Berkeley

The University of California, Berkeley is a public university research university located in Berkeley, California, California, United States. The oldest of the ten major campuses affiliated with the University of California, Berkeley offers some 300 undergraduate and graduate degree programs in a wide range of disciplines....
 where he held the title University Professor and Class of 1958 Professor of Economics and Mathematics Emeritus. During his leaves in late sixties and seventies he visited universities in Leiden
Leiden University

Leiden University , located in the city of Leiden, is the List of oldest universities in continuous operation#Oldest Universities by Region university in the Netherlands....
, Cambridge, Bonn
University of Bonn

The University of Bonn is a public research university located in Bonn, Germany. Founded in 1818 the University of Bonn is today one of the leading universities in Germany....
, and Paris
University of Paris

The historic University of Paris first appeared in the 12th century. In 1970 it was reorganized as 13 autonomous university . The university is often referred to as the Sorbonne or La Sorbonne after the collegiate institution founded about 1257 by Robert de Sorbon....
.

His later studies centred mainly on the theory of differentiable economies where he showed that in general aggregate excess demand functions vanish at a finite number of points. Basically, showing that economies have a finite number of price equilibria.

In 1976 he received the French Legion of Honor. He was awarded the 1983 Bank of Sweden Prize in Economic Sciences in Memory of Alfred Nobel for having incorporated new analytical methods into economic theory and for his rigorous reformulation of general equilibrium theory. He was member of the International Academy of Science
International Academy of Science

There are at least two "International Academy of Science" organizations.One is located near Kansas City, MO, USA. It is NOT the subject of this article....
.

In 1990, he served as President of the American Economic Association
American Economic Association

The American Economic Association, or AEA, is the oldest and most important professional organization in the field of economics. It was established in 1885 by religious and social reformer Richard T....
.

Debreu married Françoise Bled in 1946 and had two daughters, Chantal and Florence, born in 1946 and 1950 respectively.

Debreu died in Paris at age 83 of natural causes on New Year's Eve
New Year's Eve

New Year's Eve is on , the final day of the Gregorian calendar year, and the day before New Year's Day.New Year's Eve is a separate observance from the observance of New Year's Day....
, 2004 and was interred in the Père Lachaise Cemetery.

Major publications

  • "The Coefficient of Resource Utilization", 1951, Econometrica.
  • "A Social Equilibrium Existence Theorem", 1952, Proceedings of the National Academy of Sciences
    Proceedings of the National Academy of Sciences

    The Proceedings of the National Academy of Sciences of the United States of America, usually referred to as PNAS, is the official journal of the United States National Academy of Sciences....
    .
  • "Definite and Semi-Definite Quadratic Forms", 1952, Econometrica
  • "Nonnegative Square Matrices", with I.N. Herstein, 1953, Econometrica.
  • "Valuation Equilibrium and Pareto Optimum", 1954, Proceedings of the National Academy of Sciences
    Proceedings of the National Academy of Sciences

    The Proceedings of the National Academy of Sciences of the United States of America, usually referred to as PNAS, is the official journal of the United States National Academy of Sciences....
    .
  • "Existence of an Equilibrium for a Competitive Economy", with K.J.Arrow, 1954, Econometrica.
  • "Representation of a Preference Ordering by a Numerical Function", 1954, in Thrall et al., editors, Decision Processes.
  • "A Classical Tax-Subsidy Problem", 1954, Econometrica.
  • "Numerical Representations of Technological Change", 1954, Metroeconomica
  • "Market Equilibrium", 1956, Proceedings of the NAS.
  • "Stochastic Choice and Cardinal Utility", 1958, Econometrica
  • "Cardinal Utility for Even-Chance Mixtures of Pairs of Sure Prospects", 1959, RES
  • The Theory of Value: An axiomatic analysis of economic equilibrium, 1959
  • "Topological Methods in Cardinal Utility Theory", 1960, in Arrow, Karlin and Suppes, editors, Mathematical Methods in the Social Sciences.
  • "On 'An Identity in Arithmetic'", 1960, Proceedings of AMS
  • "Economics Under Uncertainty", 1960, Économie Appliquée.
  • "New Concepts and Techniques for Equilibrium Analysis", 1962, IER
  • "On a Theorem by Scarf", 1963, RES.
  • "A Limit Theorem on the Core of an Economy", with H.Scarf, 1964, IER.
  • "Contuinity Properties of Paretian Utility", 1964, IER
  • "Integration of Correspondences", 1967, Proceedings of Fifth Berkeley Symposium.
  • "Preference Functions of Measure Spaces of Economic Agents", 1967, Econometrica.
  • "Neighboring Economic Agents", 1969, La Décision.
  • "Economies with a Finite Set of Equilibria", 1970, Econometrica.
  • "Smooth Preferences", 1972, Econometrica.
  • "The Limit of the Core of an Economy", with H. Scarf, 1972, in McGuire and Radner, editors, Decision and Organization
  • "Excess Demand Functions", 1974, JMathE
  • "Four Aspects of the Mathematical Theory of Economic Equilibrium", 1974, Proceedings of Int'l Congress of Mathematicians.
  • "The Rate of Convergence of the Core of an Economy", 1975, JMathE.
  • "The Application to Economics of Differential Topology and Global Analysis: Regular differentiable economies", 1976, AER.
  • "Least Concave Utility Functions", 1976, JMathE.
  • "Additively Decomposed Quasiconcave Functions", with T.C.Koopmans, 1982, Mathematical Programming.
  • "Existence of Competitive Equilibrium", 1982, in Arrow and Intriligator, Handbook of Mathematical Economics
  • Mathematical Economics: Twenty papers of Gerard Debreu, 1983.
  • "Economic Theory in a Mathematical Mode: the Nobel lecture", 1984, AER.
  • "Theoretic Models: Mathematical form and economic content", 1986, Econometrica.
  • "The Mathematization of Economic Theory", 1991, AER.
  • "Innovation and Research: An Economist's Viewpoint on Uncertainty", 1994, Nobelists for the Future


External links