the late sixties and early seventies who set up the framewok of the method in its more thorough and complete version. According to his own words, he did so in his search for a better understanding of what a quantum field theory is. To this end he also introduced another tool, the Operator Product Expansion (OPE) for the field operators. Both the RG method and the OPE have become two conerstones in modern Quantum Field Theory.

It has been long known that the physics of (1+ 1)-dimensional quantum many-body systems and 2D statistical field theories were very special in many aspects when compared to their higher dimensional generalizations. It was after the seminal work by Belavin, Polyakov and Zamolodchikov (BPZ) [@bpz] when the special role of conformal symmetry in two dimensions was brought about in connection to those many special properties exhibited by 2D systems such as, criticality, integrability, etc... The basic tool employed by BPZ to develop their conformal program was precisely one of the tools introduced by Wilson, the OPE, which with the help of two-dimensional conformal symmetry is powerful enough so as to classify the local fields forming the local algebra according to the irreducible representations of 