Hamiltonian electric/magnetic duality and Lorentz invariance

In noncovariant, Hamiltonian, formulation of gauge vector actions, the conditions for invariance under electric/magnetic duality transformations and their generator are transparent. Instead, satisfying Lorentz invariance — fulfilling the Dirac–Schwinger stress tensor commutators — becomes a complicated differential constraint on the Hamiltonian. The combined requirements are equivalent to the usual Lagrangian form of the duality invariance condition.