The observation of the scaling properties of the structure functions w and vw of deep inelastic electron 1 2 nucleon scattering [1]+ has been taken by many people as an indication for an approximate scale invariance of the world. It was pointed out by Wilson [2], that in many field theories it is possible to assign a dimension d to every fundamental field, which proves to be a conserved quantum number as far as the most singular term of an operator product expansion at small distances ((x-y) +a) is con- JJ cerned++. Later it was shown, at the canonical level, that in many field theories the...