  In the Hamiltonian formulation of chiral 2k-form electrodynamics, the 2k-form
potential on the (4k+1)-space is defined up to the addition of either (i) a
closed $2k$-form or (ii) an exact 2k-form, depending on the choice of chirality
constraint. Case (i) is realized by the Floreanini-Jackiw 2D chiral boson (for
k=0) and its Henneaux-Teitelboim generalisation to k>0. For all k, but focusing
on the 6D case, we present a simple Lorentz-invariant Hamiltonian model that
realizes case (ii), and we derive it from Siegel's manifestly Lorentz invariant
Lagrangian formulation.
