First-order tetrad gravity in Dirac's hamiltonian formalism

The Hamiltonian d3x is constructed without adding further terms. The velocities eIia and Iiab are eliminated while eI0a and I0ab remain arbitrary. The second-class constraints reduce the theory to second-order tetrad gravity. The first-class constraints differ from those in second-order formalism, but satisfy the same gauge algebra provided one uses Dirac brackets.