Gerard Debreu

The French-born economist and mathematician Gerard Debreu (1921–2004) won the 1983 Nobel Prize in Economics for developing a series of economic concepts, which paved the way for further researches to be carried out on those topics by future economists. In fact, he was awarded the Nobel Prize for stringent redevelopment of the general equilibrium theory and incorporating new deductive or logical methods into economic theory.

Personal life and academic career:

Born on 4th of July 1921 in France, Gerard Debreu acquired American citizenship much later, in 1975, July. However, he moved to the United States of America in 1948 on a Rockefeller Scholarship to study in several reputed American universities. He made the most out of this opportunity and studied in the Uppsala and Oslo in 1949-50, and began working as a research associate in the Cowles Commission at the University of Chicago in 1950. He moved to the Yale University in 1955. Between 1960-61, he worked at the Center for Advanced Study in the Behavioral Sciences at Stanford University. In 1962 January, he earned the titles of the University Professor and Class of 1958 Professor of Economics and Mathematics Emeritus at the University of California in Berkeley. Debreu was honored with the French Legion of Honor in 1976.

Contributions in the field of economics:

The classical monograph of Gerard Debreu, “Theory of Value: An Axiomatic Analysis of Economic Equilibrium” is considered to be one of the most significant works in the realm of mathematical economics.

Gerard Debreu also studied numerous problems related to the Theory of Cardinal Utility, where the additive decomposition of a utility function is described in terms of a Cartesian product of sets. In this monograph, Debreu offered the competitive markets, a postulational basis. He showed that the existence of equilibrium led to a refreshing pattern. His principal aim was to display the existence of a price system on the basis of which the combined excess demand balance disappears. He proved it with a type of fixed point theorem, on the basis of the Kakutani fixed point theorem.

Debreu also introduced uncertainty and displayed its application in the deterministic model. Here he innovated the concept of a contingent commodity, which today is often used by financial economists, in the form of the Arrow Debreu security.

Among Debreu's later researches, mention must be made of the theory of differentiable economies. Here, he indicated that generally, a combination of redundant demand functions disappear at a limited number of points.

Some publications:

A Classical Tax-Subsidy Problem (1954)

The Coefficient of Resource Utilization (1951)

A Social Equilibrium Existence Theorem (1952)

Nonnegative Square Matrices, co-authored by I.N. Herstein (1953)

Definite and Semi-Definite Quadratic Forms (1952)

Valuation Equilibrium and Pareto Optimum (1954)

Existence of Competitive Equilibrium (1982)

Regular Differentiable Economies (1976)