Remark on Well-posedness and Ill-posedness for the Kdv Equation
نویسنده
چکیده
We consider the Cauchy problem for the KdV equation with low regularity initial data given in the space Hs,a(R), which is defined by the norm ‖φ‖Hs,a = ‖〈ξ〉s−a|ξ|a b φ‖L2 ξ . We obtain the local well-posedness in Hs,a with s ≥ max{−3/4,−a − 3/2}, −3/2 < a ≤ 0 and (s, a) 6= (−3/4,−3/4). The proof is based on Kishimoto’s work [12] which proved the sharp well-posedness in the Sobolev space H−3/4(R). Moreover we prove ill-posedness when s < max{−3/4,−a− 3/2}, a ≤ −3/2 or a > 0.
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