sentences:  He arrived in mid-September 1962 at the Institut des Hautes Études Scientifiques in Bures-sur-Yvette; the IHÉS decided to support him, and he has remained associated with the institute ever since then.Poénaru defended his Thèse d'État at the University of Paris on March 23, 1963.His dissertation topic was "Sur les variétés tridimensionnelles ayant le type d'homotopie de la sphère S3", and was written under the supervision of Charles Ehresmann.