  In the early phase of general relativity Elie Cartan and Hermann Weyl thought
about the question of how the role of transformation groups could be
transferred from classical geometry (Erlangen program) to differential
geometry. They had different starting points and used different techniques, but
both generalized the concept of connection arising from Levi-Civita's
interpretation of the classical Christoffel symbols as parallel transfer in
curved spaces. Their focus differed and Cartan headed toward a much more
general framwork than Weyl (non-holonomous spaces versus scale gauge geometry).
But there also was an overlap of topics (space problem) and, at the turn to the
1930s, they arrived at an agreement on how to deal with Cartan's infinitesimal
geometric structures.
