A specialist in dynamical systems, Jean-Christophe Yoccoz (left in the photo) received the Fields Medal in 1994 for his profound results on both dynamical and structural stability. His academic record is breathtaking: the first French person to win a gold medal at the International Mathematical Olympiad (1974), he placed first in the entrance examination for the École normale supérieure (1975), became a member of the French and Brazilian academies of sciences (1994), and was appointed to the Chair of "Differential Equations and Dynamical Systems" at the Collège de France (1996). He also brought Artur Avila to France; Avila would himself go on to receive the Fields Medal (in 2014; see Tangente 161). Yoccoz’s colleagues Alain Connes, Étienne Ghys and Pierre-Louis Lions emphasize that "his proofs combine extraordinary analytical power, dazzling geometric insight and prodigious mastery of combinatorics".
In its next issue, Tangente will pay tribute to this unassuming, charming mathematician, who became an ambassador for mathematics, visiting classrooms, for example, to talk about the stability of the solar system…
