On the local geometry of rotating matter (Q1074889)

It is argued that spinning matter in general relativity produces translational holonomy and this in turn gives rise to torsion (proportional to the spin density) so that the Einstein-Cartan theory is not a different one from general relativity but arises from it by carrying out a smoothing process analogous to but more complicated than the derivation of equations for continuous matter from those for a set of particles. The Einstein-Cartan relationship between torsion and spin current is simply the conservation condition for angular momentum.