  We show within the Wilson renormalization group framework how the flow
equation method can be used to prove the perturbative renormalizability of a
relativistic massive selfinteracting scalar field. Furthermore we prove the
regularity of the renormalized relativistic one-particle irreducible n-point
Green functions in the region predicted by axiomatic quantum field theory which
ensures that physical renormalization conditions for the two-point function can
be imposed.
