### Gerard Debreu was a French-born American economist who made numerous contributions to economics, the most notable of which was his introduction of mathematical precision to economic theories such as supply and demand. In 1983, he was awarded the Nobel Memorial Prize for his exceptional contributions to economics, particularly in the subject of general equilibrium. Debreu spent the majority of his career at Yale University and the University of California, Berkeley. He was honored with various honors, including being named an officer of the French Legion of Honor in 1976 and being elected to the National Academy of Sciences in 1977. He was extremely passionate about politics and human rights. He was also known for his pleasant, polite, and humble demeanor. His research in the latter portion of his life were mostly focused on the theory of differentiable economies. He battled to prove that aggregate excess demand functions vanish at a finite number of sites in general. In other words, his study establishes the existence of a finite number of pricing equilibria in economies.

## Childhood and Adolescence

On July 4, 1921, Gerard Debreu was born in Calais, France, to Camille and Fernande Debreu. His father committed himself when he was young, and his mother died of natural causes, leaving him an orphan.

He received the most of his education at his hometown and graduated from high school before the outbreak of WWII. He then traveled to Ambert to study for his university admission exams.

He was unable to complete his final exams due to the war, and instead had to enlist in the French army, after which he was deployed to Algeria for training. Then, until July 1945, he served in the occupying French army in Germany.

Debreu completed his Agrégation in Mathématiques exams after the war ended. By this time, he had developed an interest in economics, particularly in Leon Walras’ general equilibrium theory.

From 1946 to 1948, he worked as an assistant at ‘The French National Centre for Scientific Research.’ He transitioned from mathematics to economics during the course of these two and a half years.

In 1948, Debreu was awarded a Rockefeller Fellowship, which allowed him to travel to the United States. It allowed him to travel to various colleges in the United States, as well as those in Uppsala and Oslo.

## Career of Gerard Debreu

Working as a Research Associate was Gerard Debreu’s first job. In 1950, he became a member of the University of Chicago’s Cowles Commission. Despite the fact that he stayed in the city for five years, he returned to Paris on occasion.

Debreu had to devote all of his time and attention to his studies because the Cowles Commission exceeded his expectations and presented him with a stimulating intellectual environment. He progressed in his work on Pareto Optima, utility, and the existence of a general economic equilibrium thanks to debates, discussions, and study in mathematical economics.

In 1954, he and Kenneth Arrow, an economist, writer, and political theorist, released a paper titled “Existence of Equilibrium for a Competitive Economy.” They used topological rather than calculus-based methods to prove the existence of a general equilibrium in this paper.

In 1959, he released the classic monograph ‘Theory of Value: An Axiomatic Analysis of Economic Equilibrium.’ He established the mathematical underpinnings for Adam Smith’s concept of supply and demand equilibrium, which he originally articulated nearly two centuries ago, in 1776. Debreu was able to establish tools for analyzing elements that influence equilibrium.

He worked at Stanford’s Center for Advanced Study in the Behavioral Sciences from 1960 to 1961. Debreu spent the most of his time here attempting to prove a broad theorem about the existence of an economic equilibrium.

In January 1962, he began working at the University of California, Berkeley. He was a University Professor of Economics and Mathematics at the time.

He took many long leaves in the fall of 1968. He went to schools including the University of Lorain, Churchill College, Cambridge University, and others. During the 1970s, he conducted research in Berkeley. In the 1980s, he concentrated on topics such as alternative utility functions and the characterisation of an economy’s excess demand functions.

## Major Projects of Gerard Debreu

‘Existence of an Equilibrium for a Competitive Economy,’ which he co-authored with Kenneth Arrow, was his first publication. Leon Walras was the first to formulate the state of the economy at any given point in time as the solution of a system of simultaneous equations that represent consumer demand for products, producer supply of goods, and the equilibrium condition that supply equals demand on each market. Walras, on the other hand, was unable to provide conclusive evidence to support his theory, according to which each consumer acted to maximize their utility and each producer acted to maximize their profit. However, utilizing calculus-based approaches, Gerard Debreu and Kenneth Arrow were able to prove the idea in this study.

Gerard Debreu’s 1959 book, Theory of Value: An Axiomatic Analysis of Economic Equilibrium, is widely recognized as one of the most influential works in mathematical economics. The mathematical foundations for the phenomenon of equilibrium in supply and demand theory are supplied and discussed in this work. Adam Smith expressed it for the first time in 1776. Its logical correctness is demonstrated, and its efficiency qualities are examined.

Gerard Debreu’s ‘Mathematical Economics: Twenty Papers’ was released in 1986. The author chose the twenty papers in this book that are connected to mathematical economics. This book also includes a brief introduction by Werner Hildenbrand, a German economist and mathematician who examines Professor Debreu’s contribution to economic theory as well as discusses the significance of these articles in the evolution of the field.

Another of Debreu and Arrow’s most important publications, Landmark Papers in General Equilibrium Theory, Social Choice, and Welfare, was released in 2001. The publications that, in their opinion, have made the most significant contributions are collected here for the benefit of economics students and scholars.

## Achievements & Awards

In 1976, he was awarded the French Legion of Honor.

Gerard Debreu received the Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel in 1983 “for his rigorous reformulation of the theory of general equilibrium and for incorporating new analytical tools into economic theory.”

## Personal History and Legacy

Gerard Debreu married Françoise Bled in 1945. Chantal and Florence, their two daughters, were born in August 1946 and February 1950, respectively.

At the age of 83, he died in Paris, France, on December 31, 2004.

**Estimated Net Worth**

Gerard Debreu’s net worth was estimated to be between $1 and $5 million when he died, according to Wikipedia, Forbes, IMDb, and other online sources. As a professional Economist, Gerard Debreu made a lot of money. Gerard Debreu was born in France.