For the Sixth Course of the International School of Cosmology and
Gravitation of the "Ettore Maj orana" Centre for Scientific Cul- ture we
choose as the principal topics torsion and supergravity, because in our
opinion it is one of the principal tasks of today's theoretical physics
to attempt to link together the theory of ele- mentary particles and
general relativity. Our aim was to delineate the present status of the
principal efforts directed toward this end, and to explore possible
directions of work in the near future. Efforts to incorporate spin as a
dynamic variable into the foundations of the theory of gravitation were
poineered by E. Cartan, whose contributions to this problem go back half
a century. Accord- ing to A. Trautman this so-called Einstein-Cartan
theory is the sim- plest and most natural modification of Einstein's
1916 theory. F. Hehl has contributed a very detailed and comprehensive
analysis of this topic, original view of non-Riemannian space-time.
Characteristic of Einstein-Cartan theories is the enrichment of
Riemannian geometry by torsion, the non-symmetric part of the otherwise
metric-compatible affine connection. Torsion has a impact on the theory
of elementary particles. According to V. de Sabbata, weak interactions
can be based on the Einstein-Cartan geometry, in that the Lagrangian
describing weak interactions and torsion inter-- action possess
analogous structures, leading to a unification of weak and gravitational
forces.