necessary to consider the second bundle. The curvature form of our connection is a tensorial
quadratic differential form in M, of type ad(G′) and with values in the Lie algebra L(G′) of G′.
Since the Lie algebra L(G) of G is a subalgebra of L(G′), there is a natural projection of
L(G′) into the quotient space L(G′)∕L(G). The image of the curvature form under this
projection will be called the torsion form or the torsion tensor. If the forms πρ in (13)
define a G-connection, the vanishing of the torsion form is expressed analytically by the
conditions
We proceed to derive the analytical formulas for the theory of a G-connection without torsion in
the tangent bundle. In general we will consider such formulas in BG. The fact that the
G-connection has no torsion simplifies (13) into the form
By taking the exterior derivative of (23) and using (18), we get
where we put
For a fixed value of k we multiply the above equation by
getting
or
Since the infinitesimal transformations Xρ are linearly independent, this implies that
It follows that Πρ is of the form
where ϕjρ are Pfaffian forms. Substituting these expressions into (24), we get
It follows that
Since G has the property (C), the above equations imply that