Within massless phi4(4)-theory we set up the formalism which is needed
, when the coupling lambda is permitted to become an external field, i
.e. a function of space-time. In particular we have worked out the act
ion of the corresponding Callan-Symanzik operator and conformal transf
ormations on the vertex functions, and furthermore how the Weyl transf
ormations act on the theory with the energy-momentum tensor invariantl
y coupled. With the help of the Weyl consistency condition we have sho
wn that in the limit of constant coupling the Weyl breaking can entire
ly be written in terms of differential operators, but that otherwise,
for truly local coupling, new breaking terms survive.