Under their direction he laid the basis for the important work he was later to achieve in the fields of foundations of geometry, projective geometry, topology, differential invariants and spinors.
Sa ilalim ng kanilang mga direksyon siya inihain ang batayan para sa mahalagang trabaho siya mamaya upang makamit ang mga patlang ng mga komunidad ng geometry, projective geometry, topology, kaugalian invariants at spinors.