On Fermi systems with strong forward scattering in d spatial dimensions

We consider a specific generalisation to spatial dimensions d greater than one of a formalism based upon conservation laws and the associated Ward identities, that exactly solves the one-dimensional Luttinger model, and expose its inadequacies for d > 1. We conclude that findings arrived at through application of this generalised formalism concerning systems of fermions with strong forward scattering, in particular that d=1 would be the cross-over dimension from Luttinger- to Fermi-liquid state, are open to question.