Abstract
I present a general definition of Hamiltonian generators of asymptotic symmetries in theories of gravity in asymptotically AdS-spacetimes, within a covariant phase space formalism. It is explained how this definition is related to existing ones, including the "counterterm subtraction method", the "Weyl-tensor definition", and the spinor definition. Of particular interest are theories admitting several asymptotically AdS boundary conditions, specified by a certain function W. I show that the energy is bounded from below in such theories if W is bounded from below, and that solutions minimizing the energy have to be static. The relevance and relation of these results to the AdS-CFT correspondence is briefly explained.