Pseudoperiodic topology

Vladimir Igorevich Arnold (or Arnol'd; Russian: Влади́мир И́горевич Арно́льд, IPA: [vlɐˈdʲimʲɪr ˈiɡərʲɪvʲɪtɕ ɐrˈnolʲt]; 12 June 1937 – 3 June 2010) was a Soviet and Russian mathematician. He is best known for the Kolmogorov–Arnold–Moser theorem regarding the stability of integrable systems, and contributed to several areas, including geometrical theory of dynamical systems, algebra, catastrophe theory, topology, real algebraic geometry, symplectic geometry, differential equations, classical mechanics, differential-geometric approach to hydrodynamics, geometric analysis and singularity theory, including posing the ADE classification problem. In his later years he shifted his research interests, investigating discrete mathematics. His first main result was the solution of Hilbert's thirteenth problem in 1957 when he was 19. He co-founded three new branches of mathematics: topological Galois theory (with his student Askold Khovanskii), KAM theory (with Andrey Kolmogorov and Jürgen Moser) and symplectic topology.