Vladimir Igorevich Arnold was a Soviet and Russian mathematician. While he is known for the Kolmogorov–Arnold–Moser theorem regarding the stability of integrable systems, he made contributions in several areas including geometrical theory of dynamical systems theory, algebra, catastrophe theory, topology, algebraic geometry, symplectic geometry, symplectic topology, differential equations, classical mechanics, differential geometric approach to hydrodynamics, geometric analysis and singularity theory, including posing the ADE classification problem, since his first main result—the solution of Hilbert's thirteenth problem in 1957 at the age of 19. He co-founded two new branches of mathematics—KAM theory, and topological Galois theory.
