By that time he had retired from his chair, which he did in 1950, and he has ceased as joint head of the mathematics department, which happened in 1952.
Sa pamamagitan ng panahon na niya nagretiro mula sa kanyang silya, na kung saan siya ay sa 1950, at siya ay ceased bilang pinagsamang pinuno ng departamento ng matematika, na nangyari sa 1952.