METRIC AND CENTRAL CHARGE IN THE PERTURBATIVE APPROACH TO 2-DIMENSIONAL FERMIONIC MODELS

In this work we study the most general four-fermion two dimensional model. We discuss its renormalization and compute the two loops β-functions. We analyze the structure of the abstract manifold of the coupling constants of the model using Zamolodchikov's C-theorem. We compute the four-loop contribution to the metric of this space and the corresponding five-loop central charge. We express the symmetries of the model as algebraic constraints and study their relations with the diffeomorphisms of the parameter space. © 1990.