Anatoly Maltsev and Valentin Turchin were both from Russia, which of the two is known for his work as a mathematician?
Anatoly Maltsev:  He was a mathematician noted for his work on the decidability of various algebraic groups. Malcev algebras (generalisations of Lie algebras) are named after him. Valentin Turchin: Valentin Fyodorovich Turchin (Russian: Валенти́н Фёдорович Турчи́н , 14 February 1931 in Podolsk – 7 April 2010 in Oakland, New Jersey) was a Soviet and American cybernetician and computer scientist.
Malcev algebras (generalisations of Lie algebras) are named after him.