Quantum field theory for non-polynomial chiral lagrangians

The author deduces Green function equations and perturbation rules for chirally-invariant quantum field theory. The ordering problem is treated by a suitable time-like averaging in the operator interaction which at the same time prevents any occurrence of delta 4(0) terms and removes ambiguities in ( delta 3(0))2 terms; these latter are known to cancel to lowest order. He also presents an equivalent lagrangian formulation which leads to the same results.