Which mathematician was the father of physicist Nikolai Borisovich Delone: Jakow Trachtenberg or Boris Delaunay?
Jakow Trachtenberg Jakow Trachtenberg (17 June 1888 – 1953) was a Jewish mathematician who developed the mental calculation techniques called the Trachtenberg system.
Boris Demidovich Boris Pavlovich Demidovich (Russian: Борис Павлович Демидович ; Belarusian: Барыс Паўлавіч Дземідовіч ; Novogrudok, March 2, 1906 – Moscow, April 23, 1977) was a Soviet/Belorussian mathematician.