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.
Nikolai B. Kopnin Nikolai Borisovich Kopnin (May 17, 1946 – October 20, 2013) was a Russian physicist specializing in superconductivity.