He returned to the country of his birth in 1955 when he was appointed professor of mathematics at the École Polytechnique Fédérale in Zurich. Happy to be back in his native land, he had to make a difficult decision when he was offered a permanent professorship at the Institute for Advanced Study at Princeton in the following year.
Siya bumalik sa bansa ng kanyang kapanganakan sa 1955 kapag siya ay hihirangin ng mga propesor sa matematika at sa École Polytechnique Fédérale sa Zurich. Masaya na bumalik sa kanyang katutubong lupa, siya had sa gumawa ng isang mahirap na desisyon kapag siya ay inaalok ng isang permanenteng pagkapropesor sa Institute for Advanced Study in Princeton at ang mga sumusunod na taon.