Which mathematician was born first, Pyotr Novikov or Dmitri Egorov?
Pyotr Novikov Pyotr Sergeyevich Novikov (Russian: Пётр Серге́евич Но́виков ; 15 August 1901, Moscow, Russian Empire – 9 January 1975, Moscow, Soviet Union) was a Soviet mathematician.
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 .