  A covariant Hamiltonian description of Palatini's gravity on manifolds with
boundary is presented. Palatini's gravity appears as a gauge theory satisfying
a constraint in a certain topological limit. This approach allows the
consideration of non-trivial topological situations. The multisymplectic
framework for first-order covariant Hamiltonian field theories on manifolds
with boundary, developed in [Ib15], enables analysis of the system at the
boundary. The reduced phase space of the system is determined to be a
symplectic manifold with a distinguished isotropic submanifold corresponding to
the boundary data of the solutions of the Euler-Lagrange equations.
