  We develop in this article the principal constructive arguments used in
quantum field theory, limiting us to bosonic theories, for which there does not
exist any recent general presentation. The article is primarily written for
mathematicians or mathematical physicists knowing the basic arguments of
quantum field theory, and desiring to discover a general framework in which
they can be made rigorous. It also provides a glimpse of a recent series of
articles \cite{MagUnt1,MagUnt2} whose aim is to give a constructive definition
of rough paths and fractionary stochastic calculus.
