Whose contributions to math came later, Eugen Slutsky or Vladimir Arnold?
Eugen Slutsky Evgeny "Eugen" Evgenievich Slutsky ( ; ( Евге́ний Евге́ньевич Слу́цкий) 7 April [O.S. 19 April] 1880 – 10 March 1948) was a Russian/Soviet mathematical statistician, economist and political economist.
Nikolay Nekhoroshev Nikolai Nikolaevich Nekhoroshev (Russian: Николай Николаевич Нехорошев ; 2 October 1946 – 18 October 2008) was a prominent Soviet Russian mathematician, specializing in classical mechanics and dynamical systems. His research concerned Hamiltonian mechanics, perturbation theory, celestial mechanics, integrable systems, dynamical systems, the quasiclassical approximation, and singularity theory. He proved, in particular, a stability result in KAM-theory stating that, under certain conditions, solutions of nearly integrable systems stay close to invariant tori for exponentially long times .