The price of an exact, gauge-invariant RG-flow equation

Abstract We combine old ideas about exact renormalization-group-flow (RGF) equations with the Vilkovisky–De Witt (VDW) approach to reparametrization invariant effective actions and arrive at a new, exact, gauge-invariant RGF equation. The price to be paid for such a result is that both the action and the RGF equation depend explicitly upon the base point (in field space) needed for the VDW construction. We briefly discuss the complications originating from this fact and possible ways to overcome them.