Polynomial Hamiltonian form of general relativity

The phase space of general relativity is extended to a Poisson manifold by inclusion of the determinant of the metric and conjugate momentum as additional independent variables. As a result, the action and the constraints take a polynomial form. We propose a new expression for the generating functional for the Green's functions. We show that the Dirac bracket defines a degenerate Poisson structure on a manifold and the second-class constraints are the Casimir functions with respect to this structure. As an application of the new variables, we consider the Friedmann universe.