Well-posedness of the Fifth Order Kadomtsev-Petviashvili I Equation in   Anisotropic Sobolev Spaces with Nonnegative Indices
  In this paper we establish the local and global well-posedness of the real valued fifth order Kadomstev-Petviashvili I equation in the anisotropic Sobolev spaces with nonnegative indices. In particular, our local well-posedness improves Saut-Tzvetkov's one and our global well-posedness gives an affirmative answer to Saut-Tzvetkov's $L^2$-data conjecture. 
Junfeng Li, Jie Xiao