  The thesis is devoted to a rigorous construction of the Wightman and Green
functions in models of the perturbative quantum field theory in the
four-dimensional Minkowski spacetime in the framework of the causal
perturbation theory developed by Epstein and Glaser. In the first part of the
thesis we give an overview of the Epstein-Glaser approach to the perturbative
quantum field theory. In the second part we construct the Wightman and Green
functions in a large class of models, generalizing the result due to Blanchard
and Seneor. To this end, we show the existence of the so-called weak adiabatic
limit. The proof of the existence of this limit is valid under the assumption
that the time-ordered products satisfy certain normalization condition. We show
that this normalization condition may be imposed in all models with interaction
vertices of the canonical dimension equal to four as well as in all models with
interaction vertices of the canonical dimension equal to three provided each of
them contains at least one massive field. Moreover, we prove that the
above-mentioned normalization condition is compatible with all the standard
normalization conditions which are usually imposed on the time-ordered
products. We consider in detail the case of the quantum electrodynamics with a
massive or massless, spinor or scalar charged field and certain model of
interacting scalar fields with the interaction vertex of dimension three which
we call the scalar model. Our result is also applicable to non-abelian
Yang-Mills theories. Using the method developed in the proof of the existence
of the weak adiabatic limit, we also show the existence of the central
splitting solution in the quantum electrodynamics with a massive spinor field.
