His work was then directed towards the theory of manifolds, for example Generalized closed manifolds in n-space (1934), and in particular to extending the Schönflies programme to higher dimensions.
Kanyang trabaho at pagkatapos ay Directed sa teorya ng manifolds, halimbawa pangkalahatan sarado manifolds sa n-espasyo (1934), at partikular na sa pagpapalawak ng Schönflies programa sa mas mataas na sukat.