Question: Leonid Kantorovich and Vladimir Arnold both acted as what in the Soviet Union?
Sentence (from "Vladimir Arnold"): While he is best known for the Kolmogorov–Arnold–Moser theorem regarding the stability of integrable systems, he made important contributions in several areas including dynamical systems theory, catastrophe theory, topology, algebraic geometry, symplectic geometry, differential equations, classical mechanics, hydrodynamics 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.
Relevant evidence: No