Global well-posedness for the Kawahara equation with low regularity data
  We consider the global well-posedness for the Cauchy probelem of the Kawahara equation which is one of the fifth order KdV type equations. We first establish the local well-posedness in a more suitable function space for the global well-posedness by a variant of the Fourier restriction norm method. Next, we extend local solutions globally in time by the I-method. In this paper, we apply the I-method to the modified Bourgain space. 
Takamori Kato
math.AP