  The light-cone Hamiltonians describing both pure Yang-Mills and N=4 super
Yang-Mills may be expressed as quadratic forms. Here, we show that this feature
extends to theories of gravity. We demonstrate how the Hamiltonians of both
pure gravity and N=8 supergravity, in four dimensions, may be written as
quadratic forms. We examine the effect of residual reparametrizations on the
Hamiltonian and the resulting quadratic form.
