Remarks on exact RG equations Original Research Article

Exact RG equations are discussed with emphasis on the role of the anomalous dimension image. For the Polchinski equation, this may be introduced as a free parameter reflecting the freedom of such equations up to contributions which vanish in the functional integral. The exact value of image is only determined by the requirement that there should exist a well defined nontrivial limit at an IR fixed point. The determination of image is related to the existence of an exact marginal operator, for which an explicit form is given. The results are extended to the exact Wetterich RG equation for the one particle irreducible action image by a Legendre transformation. An alternative derivation of the derivative expansion is described. An application to image supersymmetric theories in three dimensions is described where if an IR fixed point exists then image is not small.