The Necessary and Sufficient Conditions for Representing Lipschitz   Bivariate Functions as a Difference of Two Convex Functions(corrected)
  In the article the necessary and sufficient conditions for a representation of Lipschitz function of two variables as a difference of two convex functions are formulated. An algorithm of this representation is given. The outcome of this algorithm is a sequence of pairs of convex functions that converge uniformly to a pair of convex functions if the conditions of the formulated theorems are satisfied. A geometric interpretation is also given. 
Igor Proudnikov
math.OC math.DG