Uniqueness for SQG patch solutions
  This paper is about the evolution of a temperature front governed by the Surface quasi-geostrophic equation. The existence part of that program within the scale of Sobolev spaces was obtained by one of the authors [10]. Here we revisit that proof introducing some new tools and points of view which allow us to conclude the also needed uniqueness result. 
Antonio C\'ordoba, Diego C\'ordoba and Francisco Gancedo
math.AP