CONSTRAINT FIELD SYSTEMS IN MULTIMOMENTUM CANONICAL VARIABLES

To describe constraint field models, we apply the multimomentum Hamilt onian formalism where momenta correspond to derivatives of fields with respect to all world coordinates, not only time. If a Lagrangian dens ity is degenerate, the Euler-Lagrange equations are underdetermined an d need additional gauge-type conditions which remain elusive in genera l. One gets these conditions automatically as a part of the Hamilton e quations, but must consider a family of Hamiltonian forms associated w ith the same Lagrangian density in order to exhaust solutions of the E uler-Lagrange equations, The case of degenerate quadratic and affine L agrangian densities is elaborated. As a result, we get the universal p rocedure of describing constraint field systems. (C) 1994 American Ins titute of Physics.