  A quantum physical projector is proposed for generally covariant theories
which are derivable from a Lagrangian. The projector is the quantum analogue of
the integral over the generators of finite one-parameter subgroups of the gauge
symmetry transformations which are connected to the identity. Gauge variables
are retained in this formalism, thus permitting the construction of spacetime
area and volume operators in a tentative spacetime loop formulation of quantum
general relativity.
