Flow of low energy couplings in the Wilson renormalization group
  A new form of the Wilson renormalization group equation is derived, in which the flow equations are, up to linear terms, proportional to a gradient flow. A set of co\"ordinates is found in which the flow of marginal, low-energy, couplings takes a gradient form, if relevant couplings are tuned to vanish. 
Robert C. Myers and Vipul Periwal