Integrable chiral theories in 2+1 dimensions

Following a recent proposal for integrable theories in higher dimensions ba sed on zero curvature, new Lorentz invariant submodels of the principal chi ral model in 2 + 1 dimensions are found. They have infinite local conserved currents, which are explicitly given for the su(2) case. The construction works for any Lie algebra and in any dimension, and it is given explicitly also for su(3). We comment on the application to supersymmetric chiral mode ls. (C) 1999 Elsevier Science B.V.