Tjalling Charles Koopmans

Dutch American mathematician and economist, who won with Leonid Kantorovich the 1975 Nobel Prize in Economic Science.

He was as the youngest son of Sjoerd Koopmans (22 June 1877, Oppenhuizen, Wymbritseradeel – 19 Oct 1959 8 PM, Hilversum), a Christian head schoolmaster and Wijtske van der Zee (12 February 1878 11h30 AM, Sneek, - 22 May 1952, 12h30 PM Hilversum). His elder brothers were Jan Koopmans (Sliedrecht, 26 May 1905 - Amsterdam, 24 March 1945, Amsterdam), who became a PhD theologian and Hendrik Koopmans (13 August 1907, Sliedrecht - 12 July 1992, Zeist), who became a chemical engineer.

His brother Jan Koopmans had connections with the "Bekennende Kirche" (Confessing Church) in Germany and became a political activist during WW2. Since 1941 he worked in Amsterdam and tried to help Jewish people. At the end of the war he had to hide. On 12 March 1945, Jan was hit in his head by a lost bullet, during the execution of 24 innocent civilians, as a reprisal for the killing by resistance fighters of an SD agent in his street. Twelve days later, he died of his injuries. At that time his brother Tjalling was in the USA.

It is of interest that the Frisian name Tjalling derives from the German name Detlef, meaning "Son of the people". The name is associated with the Nordic mortal helper of Thor Thialfi. The surname "Koopmans" means (son of a) merchant. Because the English American speaking people could not pronounce the name "Tjalling" and called him "Charles", he added the name Charles when he was naturalised as an American citizen in 1946. Charles or Karl means "free man" or "to rub; to be old; grain.".

Tjalling Koopmans was a bright and musical student (composed music and played the violin), that could study Mathematics and Physics in Utrecht from age 17 until age 26 with a stipend by a private foundation — the St. Geertruidsleen stipend. He had many interests, even considered to study psychiatry, but switched in 1930 from pure mathematics to theoretical physics.