Which Russian mathmatician contributed to number theory, Grigori Perelman or Ivan Fesenko?
Grigori Perelman Grigori Yakovlevich Perelman (Russian: Григо́рий Я́ковлевич Перельма́н ; ] ; born 13 June 1966) is a Russian mathematician. He made a contribution to Riemannian geometry and geometric topology.
Boris Feigin Boris Lvovich Feigin (Russian: Бори́с Льво́вич Фе́йгин ) (born November 20, 1953) is a Russian mathematician. His research has spanned representation theory, mathematical physics, algebraic geometry, Lie groups and Lie algebras, conformal field theory, homological and homotopical algebra.