Gerard Debreu

A French-born economist and mathematician (In July 1975, he became a naturalized citizen of the United States). Best known as a professor of economics at the University of California, Berkeley, where he began work in 1962, he won the 1983 Nobel Memorial Prize in Economics.
He was born in Calais. 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 he received his baccalauréat, and went to Ambert to begin preparing for the exam for entering a grande école. Later on he moved from Ambert to Grenoble to complete his preparation, both being in the so-called "Free Zone" during World War II.
In 1941 he was admitted to the École Normale Supérieure in Paris, along with Marcel Boiteux. He was influenced by Henri Cartan and the Bourbaki writers. When he was about to take the final examinations in 1944, D-Day arrived and he instead enlisted in the French army. He was transferred for training to Algeria 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. From 1946 to 1948, he was an assistant in the Centre National de la Recherche Scientifique. During these two and a half years he made the transition from mathematics to economics.…