Jean-Christophe Yoccoz (29 May 1957 – 3 September 2016) was a French mathematician. He was awarded a Fields Medal in 1994, for his work on dynamical systems.[1][2] Yoccoz died on 3 September 2016 at the age of 59.
Yoccoz attended the Lycée Louis-le-Grand,[3] during which time he was a silver medalist at the 1973 International Mathematical Olympiad and a gold medalist in 1974.[4][5] He entered the École Normale Supérieure in 1975, and completed an agrégation in mathematics in 1977.[6]
After completing military service in Brazil, he completed his PhD under Michael Herman in 1985 at Centre de mathématiques Laurent-Schwartz, which is a research unit jointly operated by the French National Center for Scientific Research (CNRS) and École Polytechnique.[6][7][8]
He took up a position at the University of Paris-Sud in 1987, and became a professor at the Collège de France in 1997, where he remained until his death.[2] He was a member of Bourbaki.[9]
Yoccoz won the Salem Prize in 1988. He was an invited speaker at the International Congress of Mathematicians in 1990 at Kyoto,[10] and was awarded the Fields Medal at the International Congress of Mathematicians in 1994 in Zürich.[11][10] He joined the French Academy of Sciences and Brazilian Academy of Sciences in 1994, became a chevalier in the French Legion of Honor in 1995, and was awarded the Grand Cross of the Brazilian National Order of Scientific Merit in 1998.[5]
Yoccoz's worked on the theory of dynamical systems. His contributions include advances to KAM theory, and the introduction of the method of Yoccoz puzzles, a combinatorial technique which proved useful to the study of Julia sets.[5]