Weak Continuity of the Flow Map for the Benjamin-Ono Equation on the Line

In this paper we show that the floow map of the Benjamin-Ono equation on the line is weakly continuous in L2®, using “local smoothing” estimates. L2® is believed to be a borderline space for the local well-posedness theory of this equation. In the periodic case, Molinet [27] has recently proved that the flow map of the Benjamin-Ono equation is not weakly continuous in L2(T). Our results are in line with previous work on the cubic nonlinear Schrodinger equation, where Goubet and Molinet [11] showed weak continuity in L2® and Molinet [28] showed lack of weak continuity in L2(T).