The IVP for the Benjamin-Ono equation in weighted Sobolev spaces II
  In this work we continue our study initiated in \cite{GFGP} on the uniqueness properties of real solutions to the IVP associated to the Benjamin-Ono (BO) equation. In particular, we shall show that the uniqueness results established in \cite{GFGP} do not extend to any pair of non-vanishing solutions of the BO equation. Also, we shall prove that the uniqueness result established in \cite{GFGP} under a hypothesis involving information of the solution at three different times can not be relaxed to two different times. 
German Fonseca, Felipe Linares, And Gustavo Ponce
math.AP