His doctoral thesis, entitled A Proof that a Finite Group with a Fixed-Point-Free Automorphism of Prime Order is Nilpotent was supervised by Mac Lane .
Ng doktor Kanyang tisis, may karapatan Isang Katunayan na ang isang takda Group sa isang Permanenteng-Point-Libreng Automorphism ng Punong Order ay Nilpotent ay supervised by Mac Lane.